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Influence of lime and farm yard manure( Télécharger le fichier original )par Dieudonne MUGOBOKA ISAE Busogo - Bachelor's Degree 2008 |
Source: Havlin (2005)
As has already been pointed out, soil organic matter has its origin for most part in the plants. Its accumulation in any soil at any particular time represents the difference between the quantities of plant residues and decay activities of microorganisms. This organic material, regardless of its origin, is found in soil in all stage of decomposition. It may vary from the fresh material to that which has undergone extensive chemical changes. It may occur as leaf or vegetable mold, peat, muck, or humus depending on the nature and extent of changes it has undergone. The decomposition of organic matter is a biochemical process and is brought about primary by microorganisms, the most important of which in most soils are bacteria, fungi, and actinomycetes. The decomposition of organic matter is extremely variable and complex which also vary constantly. Table : Composition (%) of humus from different source of organic matter.
Source: Pieters (2004) Since the decomposition of organic matter in the soil is a biochemical process, any factor that affects the activities of the soil organisms will necessarily affect the rate of organic matter decay. Several influential factors which have a bearing on the rate of organic matter decomposition may be placed in the three following groups: factors concerned with the nature of plant material (including such points as the kind of plant, age of plant and chemical composition), soil factors (including aeration, temperature and fertility) and climatic factors (the effect of moisture and temperature are particularly influential). Humus denotes the soil organic matter which has undergone extensive decomposition. It is a homogeneous compounds, it has no definite chemical composition. It is a dark colored, homogeneous mass, consisting of plant and animal materials together, with the synthesized cell substances of soil organisms. Humus is not sticky, dynamic in soils; it is a continually undergoing change. It has been pointed out that, during the decomposition of plant and animal residues, in soils, some organic constituents are more readily attacked than others and some are extremely resistant to decomposition. The starches, sugars, proteins, and amino-acids are rapidly attacked by a great variety of organism and associated with these changes, is a considerable synthesis of microbial cell substance. The cellulose and especially hemi cellulose are decomposed rapidly by a rather large variety of micro-organisms (Millar, 2004). Figure : Processes involved in fresh organic matter decomposition into humus. Fresh organic matter Erreur ! Source du renvoi introuvable. Decomposition
Fine organic matter Erreur ! Source du renvoi introuvable. Humification
Erreur ! Source du renvoi introuvable. Erreur ! Source du renvoi introuvable. Humus Mineralization Mineral elements Source: FAO (1982)
Considering their organic matter content, the nature of the organic matter and the applied doses, some farm yard manure are considered as organic amendments. The farm yard manure improves, with the character of organic amendment, improves physical properties of soil when it is incorporated in soil). The farm yard manure contains some acid compounds, susceptible of liberating H+ ions (H2CO3,NH4,H2SO4,etc...) and basic compounds, susceptible of retaining H+ ions(HCO3,CO3,NH3,SO2- ,Ca(OH)2,Mg(OH).The use of farm yard manures was thought to increase the soil acidity; In contrast, this was true only the use of farm yard manure containing much ammonia. In this case, the experiment conducted by ITCF (1982-1990) has shown that the use 330kg /year of lime has not been sufficient to maintain a p H on initial level in the treatments that has received ammonitrate 33.5 %.Thus, the total or partial replacement on ammonitrate by farm yard manure has contributed to the increase of initial p H. The effect of farm yard manure on soil p H depends on its chemical composition and transformations that happens after its incorporation in soil; In some cases, there is an increase of soil p H or alkalinization, i.e. fixation of H+ by anions such as OH- .In other cases, there is a decrease of soil p H or acidification i.e. liberation of H+ in the soil. The mineralization of organic P is a particular case; it rends to increase p H in acidic soils by formation of complexes compounds with aluminum, and decrease soil p H in alkaline soils by formation of apatite (Bodet, 2001). In the arable land, the p H can be maintained by compensate the annual bases losses (OH-,HCO3-,SO4- ,NH3, etc.. ) which neutralize the acids (H2SO4,Hcl,,HNO3, Fe3+,Al3+ etc.).These losses comprise the exportation and leaching. This concerns soils susceptible of acidification (which does not contain CaCO3) (Bodet, 2001,). The wealth of farm yard manure in mineral elements is reflected by the plant wealth in mineral. The analysis shows that in the same leaps, the composition of farm yard manure is not homogeneous; the nitrogen and phosphoric acid content are generally more from the bottom to the top consequently. According to FAO (1977), the experiments done in the station has shown that 2.17% of N, 1.3%of P2O5 of dry matter in the bottom layer of the heap, while the top layer contained 1.82%of N and 0.8% of P2O5 of dry matter. Major characteristics of FYM Ø Residual effects are only fairly strong; Ø Relative high moisture; Ø Imbalanced nutrients but high in organic matter; and Ø Low in mineral nutrients but high in organic matter. Compost is the result of aerobic decomposition of biodegradable organic matter, producing compost. Composting is the decaying of food, mostly vegetables or manure. The decomposition is performed primarily by facultative and obligate aerobic bacteria, yeasts and fungi, helped in the cooler initial and ending phases by a number of larger organisms, such as springtails, ants, nematodes and oligochaete worms. Composting can be divided into home composting and industrial composting. Essentially the same biological processes are involved in both scales of composting; however techniques and different factors must be taken into account. Green manuring is the practice of turning into the soil undecomposed green plant tissue. The function of a green manure crop is to add organic matter to the soil. As a result of the addition, the nitrogen supply of the soil may be increased and certain nutrients made more readily available, thereby increasing the productivity of the soil. According to Warman (2001) green manure offers the following benefits:
Agronomists have argued that green manuring will increase either the humus content or the supply of available nitrogen in the soil, but rarely both at the same time. The humus content is only increased appreciably if material fairly resistant to decomposition is added to the soil (high Carbon: Nitrogen ratio), and this type of plant material is typically low in nitrogen (less than 1.5 per cent on a dry-weight basis). The available nitrogen supply is only increased if readily decomposable material high in nitrogen, such as immature green plants, is incorporated into the soil. The amount of organic matter that may accumulate will vary with the soil, climatic conditions, and the age and type of crop. 2.3.2.2 Mineral soil amendments: LimeAccording to Tandon (2002), agriculture lime is a material containing oxides, hydroxides and /or carbonate of Ca and /or Mg used for neutralizing soil acidity. 2.3.2.3. Functions of LimeLime is primarily a soil amendment or conditioner and not a fertilizer, as is commonly thought. Lime performs several important functions: 1. Corrects soil acidity; 2. Furnishes important plant nutrients: Calcium and Magnesium; 3. Reduces the solubility and toxicity of certain elements in the soil such as aluminum, manganese, and iron. This toxicity could reduce plant growth under acid conditions; 4. It promotes availability of major plant nutrients. Calcium acts as a regulator and aids in bringing about the desirable range of availability of many plant nutrients. Some elements which lime aids in regulating are zinc, copper, and especially phosphorus; 5. It increases bacterial activity and hence induces favorable soil structure and relationships. Soil structure is also improved by the addition of decayed organic matter or compost. The soil becomes more porous, increasing air circulation and the ability of the soil to absorb and hold moisture (Clifford, 2003). Proper applications of lime made to extremely acid soils will increase the production of most vegetables. The main functions of lime are to reduce soil acidity, to supply nutrients, mainly calcium, to the soil, and to bring micronutrients into usable form. A well-limed soil helps to avoid such problems as blossom-end rot of tomatoes which is related to an inadequate calcium supply (Stephens, 2004). 2.3.2.4. Liming materials and their reaction in soilsLiming reaction in soil begin with the neutralization of H+ in the soil solution by adding a base (usually OH- or CO3- ) originating from the lime material.
Calcium carbonate The CaCO3 behaves as follows: CaCO3+2H+ =Ca2+ +CO2+H2O .The first reaction neutralize the H+ in soil solution. Exchangeable H+ desorbs from the CEC to buffer the decreasing H+ in solution. Two H+ on CEC are replaced by one Ca 2+.Inthis way, both soil p H and percentage B.S increase since the majority of exchangeable acidity occurs as exchangeable Al3+.
Calcium hydroxide Calcium Hydroxide Ca (OH), or slaked lime, hydrated lime or builders lime, is a white powder and difficult to handle. Neutralization of acids occurs rapidly .Slaked lime is prepared by hydrating CaO (CaO+H2O=Ca (OH) 2 and has a CCE of 136 %( Havlin et al, 2005). Calcium Oxide The Calcium Oxide (CaO) is the only material to which the term `'Lime `'may be correctly applied. Also known as unslaked lime, burned lime or quick lime, CaO is white powder, shipped in paper bags because of its caustic properties. It is manufactured by roasting CaCO3 in a furnace, driving of CO2. CaO is the most effective of all liming materials with the C.C.E 179%, compared with pure CaCO3.When unusually rapid results are required, either CaO or Ca (OH) should be used(Havlin et al,2005). When added to a moist acid soil, the Ca cations in calcium oxide displaces the exchangeable hydrogen and aluminum cations from the surface of soil colloids. The displaced H+ and Al 3+ react with sol water to yield insoluble hydroxyls. Thus, the quantity of exchangeable H+ and Al 3+ cations decreases and hence, the soil p H Values increases (Rayar, 2000). Calcium or Magnesium carbonate Calcium Carbonate (CaCO3) or Calcite, and Calcium -Magnesium Carbonate [CaMg (CO3)], or dolomite, are common liming materials. Lime stone is most often mined by opening -pit methods. The Quality of crystalline lime stones depends on clay content and other impurities. The CCE varies from 65to105.The CCE of pure CaCO3 is theoretically established at 100% while CCE of pure dolomite is 109%.The CCE of most agricultural lime is 80to 95%.Although dolomite has a slightly high CCE than calcite, dolomite has lower solubility and thus will dissolve more slowly. For dolomite to be as effective as calcite at the same application rate, dolomite should be ground twice as fine or react twice as long (Havlin et al, 2005). When applied to a moisture soil, the Calcium and Magnesium carbonate displace the exchangeable hydrogen and aluminum from exchangeable site of soil colloids. The displaced hydrogen and aluminum reacts with soil water to form insoluble aluminum hydroxyls and carbon dioxide. Thus, the quantity of exchangeable hydrogen and aluminum decreases, and consequently, the soil p H increases. In addition, the percentage base (Ca and Mg) saturation of soil colloid increases. Slag Slag behaves in soil as Calcium Silicate. Thus, when added to a moist acid soil, the calcium silicate displaces the exchangeable Hydrogen and Aluminum. The displaced hydrogen and Aluminum react with water to form insoluble Al (OH) 3.The Calcium meta-silicate fro natural deposit in North America has CCE of86%.CaSiO3 also occurs in slag by products of Iron manufacturing. In the blast furnace reduction of Fe ores, CaCO3 looses CO2 and forms CaO, which combines with molten Si to produce a slag that is either air or water cooled. The CCE of slag ranges from 60 to 90%, and usually contain appreciable amount of Mg and P, depending on the source of Iron ore and manufacturing process (Havlin, 2005)
Marl Marl are soft, unconsolidated deposits of CaCO3, frequently mixed with earthen impurities and usually quite most. Marl deposits are generally thin, recovered by drag line or power shovel after the overburden has been removed. The fresh material is stockpiled and allowed to dry before being applied in the land. Marl is almost always low in Mg, and its CCE ranges from70 to90%, depending on clay content (Havlin, 2005). Other liming materials Other materials used as liming agencies in the areas close to their sources include fly ash from coal-burning power generating plants, sludge from water treatment plants, lime or flue dust from lime, acetylene lime, picking house lime, and so on .These by products contain varying amount of Ca and Mg. 2.3.2.5. Reaction of liming material with organic and inorganic acids.The liming materials directly react with organic acids formed in soils to neutralize them. Some reactions are as follows: 2RCOOH+CaCO3= (R.COO) 2Ca+H2O+CO2 HNO3+CaCO3=Ca (NO3)2+H2O+CO2 H2SO4+CaCO3=CaSO4+H2O+CO2 RCOOH is produced by decomposition of organic matter in soils. Nitric and Sulphuric acids are produced by mineralization of organic nitrogen and sulphur compounds. They are produced from fertilizers also. 2.3.2.6 Rate of reaction of liming materialThe time period needed for completion of reaction of the liming materials is as follows: Table : Rate of reaction of liming materials
Source Rayar, 2000 2.3.2.7 Rate of applicationThe amount of lime required will vary with the degree of acidity, the soil type and the kind of lime material. Light, sandy soils require less lime than soils high in silt and clay. It is always a good practice to have the soil tested to determine the amount and kind of lime required. Soil test mailers and sampling instructions are available from County Extension Offices. Liming the lawn is an important part of good maintenance and should be included in the schedule. However, many enthusiastic gardeners are apt to over-lime. Generally, applications of lime should only be made every three to five years. Soil tests will aid the homeowner in determining the exact applications to be made. Single applications of over 150 pounds of lime per 1,000 square feet (three tons per acre) are not recommended. If over 150 pounds per 1,000 square feet are needed, apply half one year and the remaining half two to three years later, after rechecking the soil pH. It should be remembered that too much lime can be as damaging to lawn grasses as the lack of lime. Also, lime is not a cure-all to all lawn maladies but an ingredient which can correct soil acidity, thus creating favorable conditions for other factors to occur which develop favorable conditions in soil for lawn grasses. It is important that homeowners know that lime is necessary and how much is needed so that they can make the proper application for the first step toward a healthy lawn (Clifford, 2003). 2.3.2.8. Time of ApplicationTo obtain maximum efficiency and faster action, the best time to apply lime to the lawn is when the soil is being prepared for planting. This applies to the sub-soil as well as the topsoil because lime moves very slowly through the soil. Research has shown that it takes up to two years for lime to move two inches through the soil. Applications of lime on established lawns may be made at any time of the year, the most favorable time of the year being fall, winter, or early spring, in that order. If applied when the soil is too wet, it is difficult to obtain an even distribution. If heavy equipment is needed to spread the lime, make the application on level areas when the ground is frozen. Less damage is made to the soil and grass under these conditions. Alternate freezing and thawing and early spring showers hasten its penetration into the soil (Clifford, .2003). Lime must be spread evenly over the entire area because it does not move horizontally. The use of a spreader insures a better distribution and permits the lime to be placed next to flower beds or in close proximity to acid-loving plants. Pelleted lime is now available at most garden centers. Pelleted lime costs a little more but has several advantages in that it goes through a spreader more easily; may be spread by hand without being covered by dust; dust does not drift or blow into areas where lime is not wanted; eliminates such problems as tracking lime onto patios, etc. or into the house; and is easier to clean up if the bag is broken. 2.4. Generality on Carrots2.4.1. Botanical descriptionThe carrot belongs to the botanical family of Apiacea. The scientific name is Docus carrota .It is an annual or biennial erect herb up to 50 cm tall at the mature vegetative stage and up to 150 cm tall when flowering .It has taproot fleshy ,straight ,conical to cylindrical,5-50 cm long and 2-5cm in diameter at top, orange (most common), reddish violet, yellow or white. Leaves in a rosette at base of plant ,but alternating on flowering stems,2-3 pinnates ; stipules absent ,petiole long, sheathed at base, petiole and rachis pilose, segments divided into oblong to lanceolate or linear unequal rays ,strongly contacted in fruit, involucral bracts, pinnatipartite or pinnatisect, with linear lobes. Flowers mainly bisexual, but male flowers present in addition to bisexual flowers, often few dark purple sterile flowers present in the centre of umbel, 2mm in diameter,5-merous;pedicel 0.5-1-5 cm long; calyx with small teeth or absent ;petals fee, white or pinkish ,often enlarged in exterior flowers of umbel, stamens free, Ovary inferior, bristly ,2-celled,styles 2 (Grubben, et al 2004). 2.4.2. EcologyAccording to Grubben, et al. (23004), supposedly wild (or neutralized), Daucus carrota plants occur in Eritrea and Ethiopia at 1800-2100 m altitude. In their adaptation to the northern latitudes of Europe, carrots became biennial. Long days during the vegetative phase before vernalization do not cause bolting. They require vernalization at low temperature to reduce flowering .Carrots adapted to tropical and sub tropical latitudes respond to long days by bolting even before the roots have properly thickened .Carrots are mostly cultivated as cool season crop. High soil temperature, in excess of 25 0C, induces slow growth rates, fibrous roots and low carotene content. For economic yields, carrots should be grown in tropical regions at altitudes above 1200m or during the cool winter months in sub tropics. Early-maturing carrot cultivars may grow in the lowlands but yields will be low and roots will have a poor colour. Optimum air temperature is 16-24OC.Soil should be well drained, fertile and of sandy texture. Heavy clay soils may induce malformed and twisted roots and harvesting will be difficult. Optimum pH is 6.0-6.5 (Grubben, et al 2004). 2.4.3. Fertilization.For the yield of 20 tones of tap roots, the exportation is 85 kg of N, 20 kg of P, 60 kg of Ca and 15 kg of Mg. The optimum dose of fertilizers to be used depends on the reserve of soil nutrients in the soil and the required yield. The carrots require the fertilizer that has high K content. The dose of N-150 kg /ha, P-100kg /ha and K-200 kg/ha is appropriate. The carrot is sensitive to high concentration of Cl, and is also sensitive to low pH (Grubben et al, 2004). According to Grubben and Denton (2004), the liming or the use of fertilizers containing Ca, is recommended when the pH is below 5.5, the organic matter well decomposed is profitable at a moderate dose (10-20tone). The soil concentration in Mg must be moderate. The deficiency in Mg causes the leaves chlorosis, especially on old leaves, which can dry. The high concentration of Mg is harmful (Evers, 1998).According to Villeneuve and Leteinturier (1992), the Sodium improves the quality of tap root, increases the resistance to low temperature and increases the yield. The carrot is sensitive to Zinc and Bore deficiency. 2.3.4 .The yieldThe world average yield in 2002 was 21t/ha of carrot roots. In tropical Africa yield vary from 8-12t/ha; higher yields are obtained in East Africa above 1500m altitude. In Europe and the United the States to 30-12t/ha can be harvested, depending on the type of cultivar and management .Marketable yield is also much influenced by plant density and time of harvest. Root weight and uniformity are closed related to seed size and quantity seed yield are 800-200 kg /ha for open -pollinated and 7000-12000 kg /ha for F1-hybrid cultivars (Grubben, 2004). CHAPTER 3. MATERIAL AND METHODS
3.1. Experimental siteThe experiment was conducted in ISAE farm in Busogo sector of MUSANZE District in Northern Province of Rwanda. ISAE is situated in volcanic region, on altitude of 2200m above sea level. The climatic conditions (Rainfall and temperature) during experimentation are shown in the table below: Table : Rainfall and temperature during experimentation
Source: Meteorological station of ISAE (2008). 3.2. Materials3.2.1. Test plantThe test plant is Carrot (Nantes cultivar). It is a popular crop that is grown in the sector and the variety is characteristically 10-20 cm long and has cylindrical to conical tuber with fine to medium foliage (Grabben et al, 2004). 3.2.2. Farm yard manure and LimeThe farm yard manure used for soil amendment was obtained from ISAE farm. It is a mixture of animal solid wastes of different species reared at ISAE. Table : Chemical composition of farm yard manure used
The lime used is a slacked lime Ca (OH)2 obtained by burning Calcium to obtain CaO; which is slacked using water to obtain the calcium hydroxide. 3.3. Experimental designThe design of experiment was Randomized Block Design (RBD).It is composed of seven treatments each at four replicates .The size of the treatment is 2.1m X 1.2m and the treatment includes: To= Control T1=10t/ha of farm yard manure T2=15t/ha of farm yard manure T3=20t/ha of farm yard manure T4=2t/ha of Lime T5=2.5t/ha of Lime T6=3t/ha of Lime The layout of the plots on the field is shown below: Erreur ! Source du renvoi introuvable. Figure : Layout of plots on the field 3.4. Setting up of the experiment3.4.1 Tillage and application of manure and lime.The cultural tillage practice was carried out one month before sowing so that the soil is rendered loose. Thereafter the plots were demarcated and lime was immediately incorporated into the plots to be treated with lime according to the randomization of the experiment. Manure was added to the required plots two weeks before sowing. 3.4.2 SowingSowing was done by spreading seeds in the furrow at 30cm spacing between rows. Each plot comprises 7 rows of sown seeds and the sowing rate was 7.56g/plot. Immediately after sowing, the plots were mulched. The mulch material remained on the plots for one week and was thereafter removed immediately after seed germination. 3.5. Maintenance of the experimentWeeding was done twice during the growing season. The first weeding was done one month after sowing while the second was carried out 46 days after sowing. The weeding was done simultaneously with earthing up of the soil and thinning that resulted to approximately 5 cm between the plants in a row. 3.6.4 HarvestingHarvesting has been done in 90 days after sowing, i.e. after plants have shown the sings of maturity (when the foliage has started to dry). 3.7. Data Collection3.7.1 .Soil samplingSoil samples were collected in each plot after demarcation and bulked to obtain the composite sample for each treatment plot. In each plot the auger samples were taken from each of the four corners and centre of the plot and these were bulked to form a composite sample. The soil sampling was repeated after crop harvesting. 3.7.2. Crop growth characteristics.For crop growth measurement, three crop stands were selected per treatment plot and their height determined in cm at after 30 days; 60 days; and 90 days of crop sowing. For the cop yield evaluation, three rows of crops were systematically selected and harvested per treatment plot. The length and middle diameter of the carrot tubers from each harvested plots were measured and the weight of tuber per plot taken using weighing balance. 3.7.3. Yield measurementsFrom the weight of the sampled plants per plot, the weight of crop yield per plot was determined using simple arithmetic proportion. Thereafter, the yield of crop was expressed in tons/hectare. 3.7.4. Laboratory analysisThe soils samples at before sowing and after crop harvesting were separately analyzed for PH; total exchangeable acidity; extractible phosphorus; organic carbon; total nitrogen; calcium and magnesium contents. Both water and KCl PH were determined by potentiometer method using a solution of water or KCl mixed with a soil at a proportion of 1/2.5. The measurement of p H was done using an electrode made for this purpose (I.I.TA, 1981). Total exchangeable acidity was determined by titratimetric dosing of H+ and Al3+ percolated at a normal solution of potassium chloride. The two ions were titrated together using Sodium Hydroxyl 0.01N (I.I.T.A, 1981). Extractible phosphorus was determined by photo calorimetric method of BRAY II. The development of blue color was done ammonium fluoride 0.03N and Hydrogen Chloride 0.01N while percentage of transmittance was measured using spectrophotometer at wavelength of 712nm (I.I.TA,1981). Organic carbon was determined by WAKLEY and BLACK method or oxidation method by moist way(Pansu et al,2003) .This method is based on oxidation of carbon by potassium dichromate(K2Cr 2O7) in the presence o sulfuric acid. After decantation, the carbon in solution is measured by photometric method at 600nm. The organic matter is estimated by multiplying the organic carbon obtained by VAN BEMMELEN factor of 1.724 (I.I.TA, 1981). Total nitrogen was determined by Khijeldhal method. This method consists of mineralizing nitrogen contained in soil sample by concentrated sulfuric acid with green catalyst specifically ammonium sulfate formed by distillation. It is transformed to ammonia by action of a base (NaOH) by vaporizing boric acid 2%.The quantity of nitrogen was obtained by titrating the solution with sulfuric acid (H2SO4/70). Calcium and Magnesium were extracted using a normal solution of Ammonium Acetate and EDTA, at a p H of 7. The quantity of elements present (Ca and Mg) were obtained using a standard formula. The quantity of biomass from each plot was weighed and a sample from each plot was taken. After drying on air, the samples were analyzed for phosphorus content in the plant biomass. 3.8. Statistical analysis of data.The data collected in respect of the experiment were analyzed for the analysis of variance using AGRES statistical package. Where significance difference occurs, L.S.D (Least Significance Difference) was used to separate the means. CHAPTER 4. Results and Discussion4.1. Soil chemical properties4.1.1 The soil reactionThe p H before experiment varies from 5.6 to 5.9 and 4.5 to 4.7; respectively for p H water and pH KCl (1N) .These data show that, according to norms of interpretation established by RUTUNGA (1980) found on appendix1, the soil is classified into «very acidic» to «moderately acidic» soils. The pH water and KCl (1N) after experiment varies respectively from 5.7 to 6.5 and 4.6 to 5.6. The mean values of p H water are shown on the figure below: Erreur ! Source du renvoi introuvable. Figure : pH water before and after experiment according to treatments From the figure 2, it is remarked that the pH has remained constant for T0 (which has not received the amendments) and increased for other treatments that have received different doses of amendments. The ANOVA table below shows whether the difference observed between treatments is significant. Table : ANOVA for the pH water after experiment
CV % = 6.4 The ANOVA above shows that the difference between treatments is significant at 1 % threshold as the value of observed F is greater than the value of F table at 1% threshold. The difference observed between blocks is not significant as the F ratio is lower than the value of F .table at the same threshold. Table : Mean separation for pH water after experiment
The mean separation above shows that the treatments are classified into four homogeneous groups (A, AB, B, and C). The treatments that received organic amendments (T1, T2, T3) show the slight increase in pH; and that is due, according to NKUSI(1984) and KHASAWNEH (1986), deactivation of acidic cations (Al, Fe ,H) by organic compounds produced during humus formation. The high increase in pH has been observed in treatments that have received mineral amendments. This phenomenon is a result of higher capacity of lime to lower soil acidity. The figure below shows the variation of pH KCl according to treatments. Erreur ! Source du renvoi introuvable. Figure : p H KCl before and after experiment The figure above shows the almost no variation for T0 (Control) and the increase in pH KCl for treatments that have received the amendments. The ANOVA table below shows whether the difference observed between treatments is significant. Table : ANOVA for pH KCl after experiment
CV %= 4.8 The ANOVA table above shows that there is a significant difference between treatments as the value of observed F is greater than the value of F table at 1 % threshold. The mean separation below classifies treatments in homogeneous groups according to their performance. The difference observed between blocks is not significant as the F ratio is lower than the value of F .table at the same threshold Table : Mean separation for pH water after experiment
The mean separation above shows that the treatments are classified into four groups (A, AB, B, and C). As stated for pH water, the increase in pH KCl (1N) for the treatments received amendments is due to neutralization of active acidic cations by organic compound and the power of lime to reduce the active soil acidity (NKUSI, 1984). 4.1.2 Organic matterThe organic matter content on experimental site varies from 5.585% to 5.672%, and 5.46% to 6.9%, respectively before and after experiment. According to MUTWEWINGABO and RUTUNGA (1987), the soil is classified into «humic soils». The figure below shows the variation of organic matter according to treatments: Erreur ! Source du renvoi introuvable. Figure : Organic matter content before and after experiment. From the figure above, it is observed that the organic matter content has depleted in treatments T0, T4, T5 and T6 while it has increased for T1, T2 and T3. The ANOVA table below shows whether the difference observed between treatments is significant. Table : ANOVA table for soil organic matter after experiment
CV %= 6.88 The ANOVA table below shows that the difference between treatments is significant at 1% threshold as the value of calculated F is greater than the value of table at 1% threshold. The difference observed between blocks is not significant as the F ratio is lower than the value of F .table at the same threshold. Table : Mean separation for soil organic matter observed after experiment
Referring to the above mean separation table, all treatments are classified into two groups where T3, T2 and T1 are into group A while T4, T5, T6 and T0 are classified into group B. From these, it is clear that treatments within which organic matter (FYM) has been applied result in improvement of soil organic matter and this varies according to the amount applied. The depletion of organic matter in T0 is due to the loss by mineralization(little a bite) and leaching by rainfall while in T4,T5 and T6,in addition to leaching due to rainfall, the increase in pH (figure 4 and 5) has influenced the microbial activity in terms of organic matter decomposition and mineralization(RAYAR,2000). The increase in organic matter content for T1, T2 and T3 is caused by the addition of FYM and it increases as the added manure increases. 4.1.3 Total NitrogenThe total Nitrogen content varies from 0.270%to 0.2836% and 0.269% to 0.339%, respectively before and after experiment. This classifies the soil N content in «very low» range» to «low «range (ANONYME, 1991). The figure below indicates the variation of Nitrogen according to treatments: Erreur ! Source du renvoi introuvable. Figure : Variation of Nitrogen content according to treatments before and after experiment From the figure above, there has been Nitrogen depletion for T0, T4, T5 and T6 while an increase in nitrogen content is observed in T1, T2, and T3. The ANOVA table below shows whether the observed difference is significant. Table : ANOVA table for total nitrogen
CV %= 3.22 From the ANOVA table above, it is observed that there is a significant difference between treatments at 1% threshold as the value of calculated F is greater than the value of F table at 1%threshold. The difference observed between blocks is not significant as the F ratio is lower than the value of F .table at the same threshold. Table : Mean separation for Total soil Nitrogen observed after experiment
From mean separation table, the total soil nitrogen observed after harvesting are classified into 5 homogenous groups and treatments which have received organic matter prove to results in better improvement of soil into total nitrogen compare to T4, T5, T6 and T0 where no organic material had been applied (Rayar,2000). The decrease of nitrogen in those treatments is due to plant up take, leaching by rainfall water and depletion of depletion of organic matter by the causes mentioned early. The increase in Nitrogen for the remaining treatments is due to the addition of FYM, which contains a certain quantity of Nitrogen (Raymond, 1990). 4.1.5. Total exchangeable acidityThe total exchangeable acidity varies from 1.88 to 1.92 and 1.80 to 1.92, respectively before and after experiment. The figure below shows the variation of total exchangeable acidity according to treatments: Erreur ! Source du renvoi introuvable. Figure : Total exchangeable acidity before and after experiment The figure above shows that the total exchangeable acidity has increased for T0, and decreased for other treatments. It has slightly decreased for treatments that have received organic amendments and a wide variation (decrease) is observed on treatments that have received mineral amendment (lime).The ANOVA table shows whether the observed difference is significant. Table : ANOVA table for soil exchangeable acidity
CV %= 2.63 The above ANOVA table shows that there is high significant difference between treatments at threshold of 1 %as the F table is greater than Calculated F at 1 % threshold. The difference observed between blocks is not significant as the F ratio is lower than the value of F .table at the same threshold Table : Mean separation for total exchangeable acidity after experiment
From the mean separation of total exchangeable acidity, it sin observed that the treatments are classified into five homogeneous groups (A, AB, B, C, D). The increase in total exchangeable acidity for T0 is due to slight decrease in organic matter and basic cations due to leaching by rainfall. The decrease of total exchangeable acidity is due to the property of organic matter compounds that neutralize the active acidic cations and the acidity neutralizing power of lime (Nyle, 2003). 4.1.6. Exchangeable Calcium and MagnesiumThe quantity of Ca and Mg present in soil before experiment varies respectively from 0.62 to 0.64 meq/100gr of soil and 0.26 to 0.28meq/100gr of spoil. According to Pietrowich (1985), the soil Ca content classifies the soil in «excessively poor «range while the Mg content classifies the soil in «very poor « range. The figure below shows the Ca variation according to treatments before and after experiment: Erreur ! Source du renvoi introuvable. Figure : Variation in Ca content according to treatments before and after experiment From the figure 8, there has been Ca depletion for T0, no variation in Ca content for T2 and T3, slight increase in Ca content for T4, T5 and T6, which are treatments that have received the mineral amendments (lime). The ANOVA table below shows whether the difference observed between treatments is significant Table : ANOVA for exchangeable Ca content after experiment
From the ANOVA above, it is observed that there is a significant difference between treatments at 1 % threshold as the value of F observed is greater than the value of F table at the same threshold. The difference observed between blocks is not significant as the F ratio is lower than the value of F .table at the same threshold. Table : Mean separation for exchangeable Ca content after experiment
From the above mean separation, it is observed that the treatments are classified into four groups (A, B, BC, and C). The low level of Ca in T0 is attributed to Ca uptake by crops, and leaching due to rainwater percolation. For T1,T2 and T3, there has been no increase and slight increase in Ca content, which is due to, according to GAUCHER, coted by NKUSI(1984), chelating power of organic ions compounds to Ca2+,Al3+, and Fe3+, though it supplies a certain quantity of Ca during decomposition and mineralization. The remarkable increase in Ca content for T4, T5 and T6 is due to high supply in Ca from applied lime to respective treatments. The figure below shows the variation of Mg before and after experiment according to treatment Erreur ! Source du renvoi introuvable. Figure : Variation of Mg content according to treatments From the figure above, it seems that the Mg content has been decrease for T0, slightly decreased in T1, constant for T2, T3 ad T4, slightly increased for T5 and T6. The ANOVA table below shows whether the difference observed between treatments is significant. Table : ANOVA for exchangeable Mg after experiment
From the above table, there is no significant difference between treatments as the value of observed F is lower than the value of F table at 5 % threshold. The difference observed between blocks is not significant as the F ratio is lower than the value of F .table at the same threshold The decrease in T0 is due to Crop uptake and loss due to leaching by rainfall water. The no variation for T2, T3 and T4 is due to supply of small quantity of Mg by the amendments applied and reduction leaching due to improved water holding capacity by organic amendment. 4.1.4. Available phosphorusThe available phosphorus in soil varies from 60ppm to 60.5ppm and 59.8ppm to 75.815ppm, respectively before and after experiment. This range classifies the soil into «high content» range (MUTWEWINGABO et RUTUNGA, 1987), (Van Der Zaag, 1981). The variation of available phosphorus before and after experiment according to treatments is shown on the figure below: Erreur ! Source du renvoi introuvable. Figure : Available phosphorus before and after experiment. It is observed from the figure above that there is a decrease in available phosphorus content for T0 .This may be caused by crop uptake, leaching by rainfall water and phosphorus retention by acidic cations as both p H and Total exchangeable acidity has increased. For other treatments, there has been an increase in available phosphorus content. The ANOVA table below shows whether the difference observed among treatments is significant. Table : ANOVA table for available phosphorus after experiment.
CV %= 15.1 From the above table, it is clear that a high significant difference at threshold of 1% occurs between treatments as F. observed is greater than F. table at 1% threshold. The difference observed between blocks is not significant as the F ratio is lower than the value of F .table at the same threshold. Tableau : Mean separation for available phosphorus observed after trial
Considering the mean separation of available phosphorus, it is remarkable that all treatments are classified into five groups (A, B, C, CD, and D). In the treatments that have received FYM, increase in available phosphorus is due to liberation of phosphorus in the decomposition phase of organic matter (Russell, 1980).In this phase, the organic acids formed also dissolve the unavailable phosphorus and become available phosphorus (Rayar, 2000). For the treatments that have received lime, the increase in available phosphorus is due to neutralization of power of active acidic cations by lime as it has been discussed in chapter 2. 4.2 PLANT GROWTH4.2.1 Height of plants at 30 daysThe results obtained on plant heights after 30 days in different plots as per 7 treatments are presented on appendix 2 while the mean heights are presented on the following figure: Erreur ! Source du renvoi introuvable. Figure : Heights of plants after 30 days in the study zone It was observed that the mean heights vary from 8.3cm to 18cm with the general mean of 11.8cm.The T2 and T3 showed the highest values while T0 shows the lowest value. Though the difference between treatments has been revealed, ANOVA test is to be conducted to know whether the difference observed between treatments is significant. Table : ANOVA Test for heights of plants at 30 days
C.V %=8.04 From the table above, there is a significant difference between treatments at 1%threshold as the value of F Ratio is greater than the value of F on the table at the mentioned threshold. The difference observed between blocks is not significant as the F ratio is lower than the value of F .table at the same threshold. Table : Mean separation of plant s heights after 30 days of sowing
The table mentioned above shows that the treatments are classified into 6 groups (A, B, C, CD, and DE, E).The group A shows the best results T3.The group B represents the mean heights of T2, while the group C shows the mean heights of shows the mean heights of T6.The treatments T5, T1, T4, and T0 are almost the same. The best results for T3, followed by T2 are due, according to Miller and Donahue (1990), the supply of the plant nutrients, especially Nitrogen which is the limiting factor for plant growth. 4.2.2Heights of plants at 60 days after sowingThe results obtained on plant heights after 60 days in different plots as per 7 treatments are presented on appendix 3 while the mean heights are presented on the following figure: Erreur ! Source du renvoi introuvable. Figure : Heights of plants after 60 days in the study zone From the figure 11, it is observed that the mean heights vary from 20cm to 31.5cm with the general mean of 25.8cm.T3 shows the highest value while T2, T5, and T6 Are almost on the same level.T1 and T4 show the lower values while the lowest value is observed on T0. The ANOVA test below shows if the difference observed between treatments is significant or not. Table : ANOVA test for plant heights at 60days
C.V%=5.89 The ANOVA, test above showed the significant difference between treatments at 1% threshold because the value of Ratio is greater than the value of F table at the mentioned threshold. The difference observed between blocks is not significant as the F ratio is lower than the value of F .table at the same threshold. Table : Mean separation of plant heights after 60 days of sowing
The mean separation table above indicates that the treatments are classified into 3 groups (A, B, C).The group A is for treatment T3 (20t of FYM\ha) with the best result. The group B is for T2 (15t of FYM\ha), T5 (2.5t of lime/ha) and T6 (3t of lime /ha). The group C is composed by T0 (control), T1 (10t of FYM/ha) and T4 (2t of lime/ha). The highest result s from T3 is due to the supply of plant nutrients by manure, especially Nitrogen, which is a limiting factor for plant growth. For other groups, it is observed that ,as the dose increases, the height of plant also increases (the increase in dose for each amendment results in increase for plant heights) and this shows the effectiveness of both organic and mineral amendments in creating the favorable conditions for plant growth (Laura,1998). 4.2.3 Plant heights at 90 days after sowingThe results obtained on plant heights after 90 days in different plots as per 7 treatments are presented on appendix 4 while the mean heights are presented on the figure below: Erreur ! Source du renvoi introuvable. Figure : Heights of plants after 90 days in the study zone It was observed that the mean heights vary from 41.8cm to 50.2 cm with the general mean of 45.2cm. T3 and T2 show the highest values while T1, T5, and T6 Are almost on the same level with the middle values, followed by T0 and T4 with the lowest values. The ANOVA test below show whether the difference observed between treatments is significant. Table : ANOVA test for plant heights at 90 days
C.V %=3.95 From the table above, the ANOVA test shows that there is a significant difference between treatments at 1% threshold as the value of F Ratio is greater than the value of F table at 1% threshold. The difference observed between blocks is not significant as the F ratio is lower than the value of F .table at the same threshold. Table 26: Mean separation of plant heights after 90 days of sowing
The mean separation table above classifies the treatments into 4 homogeneous groups(A,B,BC,C).The group A represents T2 and T3 with the best results (15t/ha and 20t/ha of FYM). The group B is for T5 and T6, which have received respectively 2.5t/ha and 2t/ha of lime. The third group (BC) is for T1 (with 10/ha of FYM) and the last group is for T4 and T0, which have received respectively 2t /ha of lime and control. The best results from group A depends on the supply of plant nutrient from FYM, especially nitrogen, which is the limiting factor for plant growth. For group B, BC, and C, the treatments seem to have almost the same performance. 4.3 Yield evaluation4.3.1 Length of tap-root at harvesting time (cm)The results obtained on tap-roots length at harvesting time in different plots as per 7 treatments are presented on the appendix 5 while the mean lengths are presented on the following figure: Erreur ! Source du renvoi introuvable. Figure : Length of tap-roots at harvesting time in the study zone It was observed that the mean length vary from 11.5cm to 17.1cm with the general mean of 15 cm .The T3 shows the highest value while T6,T5,and T1 represents the middle values. The lowest values were observed from T4 and T0.The analysis of variance below indicates whether this difference observed between treatments is significant. Tableau : Analysis of variance for tap-root length at harvesting time
C.V%=4.06 From the table above, there is a significant different between treatments at 1% threshold as the value of F ration is greater than the value of F Table at 1 % threshold. The difference observed between blocks is not significant as the F ratio is lower than the value of F .table at the same threshold. Table : Mean separation of tap-root length at harvesting time
The table above shows that the treatments are classified into 4 groups(A,B,C,D).the group A(T2, T3and T6) shows the best results .The group B represents T5 while group C is for T1 and T4.The lowest value is observed on T0. The highest values for group A and B (T2,T3,T6 and T5) is due to the supply of Nitrogen and Phosphorus from application of FYM and the liberation of phosphorus by application of lime (Russel,1980). 4.3.2. Tap-root diameter (cm) at harvesting timeThe results obtained on taproot diameter at harvesting time as per 7 treatments are presented on appendix 6 while the mean tap root diameters are presented in the following figure: Erreur ! Source du renvoi introuvable. Figure : Tap root diameter at harvesting time in the study zone From the figure above, it is observed that the mean diameter vary from 2.7cm to 4.4cm with general mean of 3.5 cm.T3,T2 and T6 show the highest values ,followed by T5,T4,T1 and lastly T0.The ANOVA test below shows whether the difference between treatments is significant. Table : ANOVA test for tap-root diameter
CV: 3.88 The above table shows that the difference between treatments is significant at 1 % threshold as the F ratio is greater than F Table at 1 % threshold. The difference observed between blocks is not significant as the F ratio is lower than the value of F .table at the same threshold. Table : Mean separation of tap-root diameter at harvesting time
The mean separation table above classifies the treatments into 5 homogeneous groups.T3 and T2 are classified into group A, T6 into group B,T5 into group C,T1into group D, T4 and T0 into group E. The T3 and T2 show the best results, followed by T5 and T6.This is justified by the supply of Phosphorus from FYM and the liberation of Phosphorus by application of lime, which is essential nutrients for root development (Russel, 1980). 4.3.3 Yield of Carrot taproot at harvesting timeThe results obtained on carrots tap root yield in different plots as per 7treatments are presented on appendix 7 while the mean yields are presented on the following figure: Erreur ! Source du renvoi introuvable. Figure : Yield of taproot at harvesting time in the study zone It was observed that the mean yields vary from 121t/ha to 26.5t/ha with the general mean of 19.4t/ha.According to Grabben (2004), the yields obtained from plots are around the average yield obtained all over the world, which is 21t/ha. The ANOVA test below indicates whether the difference between treatments is significance. Table : ANOVA test for yield of taproots at harvesting time
C.V=4.45 From the table above, the ANOVA test shows that there is a significant difference between treatments at 1% threshold as the value of F Ratio is greater than the value of F Table at 1 % threshold. The difference observed between blocks is not significant as the F ratio is lower than the value of F .table at the same threshold Tableau : Mean separation of yields at harvesting time
The table above shows that the treatments are classified into 5 groups ((A, B, C, D and E).The group A is for T2, and T3.The group B is for T6, group C is for T5 while T1 and T4 are in group D. The last group is for T0 (control).It is observed that T2 and T3 are the best treatments, followed by the treatments T5 and T6. This testifies the role of both organic and mineral amendments in improving plant growth conditions (Russel, 1980).For treatments T1 and T4, there is no significant difference and the lowest value is for the treatment that has not received any amendment (T0). CHAPTER 5. CONCLUSION AND RECOMANDATIONS5.1 ConclusionThe study entitled « Influence of FYM and lime on availability of Phosphorus ,growth and yield of carrot in volcanic soil of Busogo» had the aim of comparing the effect of FYM and Lime on availability of phosphorus and other related parameters such as Organic matter content ,pH (both water and KCl),Total Nitrogen, Exchangeable Magnesium and Calcium, and total exchangeable acidity ,and consequently on growth and yield of carrots in the mentioned area. The obtained results have shown that both water and KCl pH have increased where both lime an FYM have been applied while they have slightly decreased in T0 (control) .Before experiment, both pH water and KCl varied from5.6 to 5.9 and 4.5 to 4.7 respectively. After experimentation, they respectively varied from 5.7 to 6.5 and 4.6 to 5.6. The organic mater content was 5.603 % in control and slightly decreased up to5.52 % due to leaching by high rainfall that took place during the experimentation. In the treatments that received lime, there also was a decrease in organic matter content. Before experiment, the organic matter content was 5.654 %, 5.585 % and 5.62 %, and it became 5.52 %, 5.5 % and 5.46 %, respectively for T4, T5 and T6 after experiment .In treatments where the FYM was applied, there was an increase in organic matter content, which was 5.62 %, 5.672 % and 5.63, and became 6.2 %, 6.64 % and 6.9, respectively for T1, T2 and T3 after experiment. The total nitrogen decreased in control and treatments that received lime and increased where the FYM was applied. Before experiment, the total nitrogen was 0.276 %, 0.270 %, 0.269 % and 0.270 % for respectively Control, T4, T5 and T6. At the end of experiment, the total nitrogen content was respectively 0.276 %, 0.270 %, 0.269 % and 0.270 %. For the treatment that received organic matter, there was an increase in total nitrogen; the total nitrogen content was 0.279 %, 0.2836 % and 0.280 and it became 0.29 %, 0.320 % and 0.339 % after experiment, respectively for T1, T2 T3. The Ca content in soil slightly decreased in control and increased in other treatments. Before experiment, it varied from 0.62 meq/100g to 64 meq/100. After experiment, it varied from 0.6 meq/ 100g to 0.75 meq/ 100g. The Mg showed the little change in all treatments. It decreased in Control and increased in all other treatments. It varied from 0.26 meq/100g to 0.28 meq/100g and 0.24 meq/100g to 0.296 meq/100g, respectively before and after experiment. The phosphorus increased in all treatments except Control where there was a decrease. It varied from 60 ppm to 60.5 ppm and 59.5 ppm to 70 ppm, respectively before and after experiment. According to obtained results, both lime and manure improved soil properties. For the height of plant, it varies from 8.3 cm to 11.2 cm, 20 cm to 29 cm and 41.8 cm to 45 cm respectively at 30 days, 60 days and 90 days. The length of tap root at harvesting time varied from 11.5 cm and 17.1 cm and the diameter varied from 2.7 cm to 3.9 cm. The yield of tap root varied from 12.1t/ha and 22.5 t/ha. For all agronomic parameters, the FYM showed the best performance, followed by lime and the Control showed the last performance. 5.2. RecommendationsFrom the results obtained above, the following recommendations are formulated: Ø The use of organic matter is of paramount important in volcanic soil of Busogo as it plays a major role in improving soil properties and supplying nutrients to grown crops. Chemical fertilizers must be used in combination with organic matter to supply others plants nutrients because even if Phosphorus may be sufficient, in the absence of others elements, their effect is not remarkable for increasing the yield. Ø As the volcanic area is subjected to high rainfall all over the year, the soil is susceptible to become more acidic by leaching of basic cations (Rayar, 2000). The liming is necessary after soil pH analysis because the soil pH below 5.5 is not suitable to many crops as it causes the Aluminum toxicity to crops (Arthaud, 1982). Ø In case of liming, both calcite and dolomite limes are recommended as the level of both Magnesium and Calcium is very low. Ø The study should be repeated in different seasons and at different sites in volcanic soils, using different sources of both organic and mineral amendments, to verify the obtained results. The study of effect of the combination of different sources of both organic and mineral amendments should be carried out to compare their influence on the phosphorus availability. REFERENCE1. ANONYME, 1991, Mémento de l'Agronome, techniques rural Afrique, 4 ème édition, Paris, p 1635 2. ARTHAUD, M, 1981, Guide sur la fertilisation phosphatée, Belgique, pp2- 20 3. BODET, J.M, RAYMOND, L. DONAHUE and MILLER, R.W, 2001, Fertiliser avec les engrais de la ferme, Paris, France, pp15-20 4. BERTRAND, P, 2000, Fertiliser avec les engrais de la ferme, Paris, France, pp15-20 5. CLEMENT, J .M, 1981, Larousse agricole, 1ere Edition ,Washington, USA 6. DONAHUE, R, 1990, Soil, 7 Prentice -Hall, New Jersey, England.pp 122-254 7. DAHLGREN, R.A., SAIGUSA, M. and UGOLINI, F.C., 2004. The Nature and Properties of volcanic ash soil. Newdheli ,India. 8. F.A.O, 1982, Recyclage des résidus agricoles organique en Afrique, Rome, Italie, p 82 9. GRABBET,G,J and DANTO,O.A, 2004, Vegetables, PROTA Foundation /Backhuys public ICTA, Wageningen, Netherland ,p 48ation, 10. GRUBBEN.G.J.H., DENTO, O.A, 2004, Ressources végétales de l'Afrique tropicale, 2eme édition, Wangeningen, Pays bas. 736p 11. GUPTA, I.C, 1995, Alkali Westland environment and reclamation, Jodhpur, India, p 102 12. HAVLIN ,J,L et all, 2005,Soil fertility and fertilizers, an introduction to nutrient management,7 th edition, New jersey ,England, p 58 13. IITA, 1981, Analyse des prélèvements pédagogiques et végétaux, Manuel no 11, Ibadan, Nigeria, pp 10-12 14. JUO, ASR, (1978). Selected methods for soil land plant analysis.2eme edition .Ibadan, p52. 15. KHASAWNEH F.E, SAMPLE, E.C, and KAMPRATH, E.J (1986). The role of phosphorus in agriculture,p910 16. LAURA, V.S, 1998, Soil fertility management, Wageningen, Netherlands, pp 123-142 17. . MATHIEU, C et PIELATAIN, F, (2003). Analyse chimique des sols. Méthodes choisis. Edition Tec et Doc, Paris, Lavoisier, Nouvelle edition, P, 387. 18. MILLAR, C.E, 2004, Soil fertility, New Delhi, India, pp 125 -245 19. MINAGRI, 1985, National seminar on fertilization of Rwanda soil, Kigali, Rwanda, 15-18 20. MOHSIN and CÓRDOVA and VALVERDE, , 1995, Acidic soils management, New Delhi, India, pp 185-204 21. MOUGHALIB, 2005, Notes de Cours, Institut Agronomique et Veternaire, Hassan II. Rabat. 22. MUTWAWINGABO .B et RUTUNGA.V, 1987, Etude des sols de l'essai d'intensification de l'agriculture de Gikongoro, Rwanda, p 87 23. NKUSI, A, 1984, Contribution à l'étude du phosphore dans le sol, évaluation de cinq méthodes de détermination du phosphore assimilable dans le sol par essai en vase de végétation, Mémoire, Faculté d'Agronomie, Butare, p 123 24. NTAHOMPAGAZE, 2000, Agriculture au Rwanda. Kigali. 25. NYLE and BRADY, 2002, The nature and property of soil,30 th edition, New York 959 26. PANSU, T.L, PRASAD, R. and J. F. POWER, 2003, Analyse du sol, des minéralogiques, organiques et minéral, IRAD, Springer verlan, France,p 993 27. PIELTAIN, F, 2003, Analyse chimique des sols, Paris, France, p1-30 28. PIETERS, A.J, 2004, Methods of soil fertilization, Newdheli, India, 158-200 29. PIETROWICH, 1985, Calibration of soil test RUBONA. 30. QUANTIN, P, 1992, Les sols d'Archipel volcanique des nouvelles hybrides, ORSTOM, Paris, France, p 12-15 31. RAYAR A.J, 2000, Sustainable agriculture in sub-Saharan Africa, the role of soil productivity, 1 st edition, Chennai, India. P 35. 32. RAYMOND, W, 1990, Soils, an introduction to soil and plant growth, sixth edition, prince hall, England, p 46 33. RAYMOND, L. DONAHUE and MILLER, R.W. (1990). An introduction to soils and plant growth. Prentice Hall of India, New Delhi. 34. RUSCH, H.P, 1982, La fécondité du sol, Paris, France, pp 123-140 35. RUSSEL, J.E, 1980, Soil conditions and plant growth, London, England, 36. RUTUNGA, V, 1981, Les sols du Rwanda pour un non pédologue, Bulletin agricole, p 17 37. SYERS J, K, RUSSEL J.E, 1994, Soil science and sustainable land management in tropics, Wallingford, p 24 38. TANDON, H.L.S (2002), Dictionary of soil fertility, fertilizers and integrated nutrient management, fertilization development and consultation organisation, Newdheli, India, pp 45 39. VAN DER ZAGG, 1981, La fertilité des sols du RWANDA, Notes techniques de l'ISAR no 9, BUTARE, p 42 40. WILD, A, 1993, Soil and environment, an introduction, Cambridge University, Cambridge, pp 166-178 41. WILLEN, F and LETEINTURIER, J, 1992, La carotte, Tome II, Paris, France Pp 225-227
Appendix : Results of soil analysis Before experiment
Appendix : Height of plants at 30days (cm)
Appendix : Height of plants at 60 days (cm)
Appendix : Height of plants at 90 days (cm)
Appendix : Root length at harvesting time (cm)
Appendix : Taproot diameter at harvesting time (cm)
Appendix : Yield of Tap root carrots at harvesting time (t/ha)
Appendix : Norms of interpretation of results of p H analysis
Source: Mutwewingabo and Rutunga (1987) Appendix : Norms of interpretation for analysis O M, available P, exchangeable and C/N Ratio
Source: Mutwewingabo and Rutunga (1987) Appendix : Norms of interpretation for analysis CEC and exchangeable cations.
Source: Pietrowich, 1985 Appendix : Empirical scale of fertility in function of N content and p H N% 0.2 0.3 0.45
Source: Anonym: 1991
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"Nous devons apprendre à vivre ensemble comme des frères sinon nous allons mourir tous ensemble comme des idiots" | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||