Influence of lime and farm yard manure
par Dieudonne MUGOBOKA
ISAE Busogo - Bachelor's Degree 2008
Harvesting 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).
Soil 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.
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.
From 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.
The 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.