Study on the Effectiveness of Natural Organic Fertilizers on Cassava (Manihot esculenta Crantz.) Cultivation

Aims: In this study, the field experiment was performed to study the soil properties changes, tuber yield and nutritional quality of Cassava (Manihot esculenta Crantz.) using organic fertilizers.

Study Design: Two organic fertilizers treatments; Natural (wood ash 740 kg/ha + bat guano 740 kg/ha + defatted sesame meal 1880 kg/ha) and Vedagro (1480 kg/ha) along with Control (no fertilizer) were applied. The length of the experimental farm is 14 m, and the width is 7 m long. Totally seven rows of cassava cultivation were carried out in this 98 m2 experimental farm. Fourteen ridges were prepared in each row. In the farm, one row of cassava cultivation (14 m long) including 14 ridges was treated with no fertilizer and assigned as "Control". Next three rows were treated with natural fertilizer (defatted sesame meal, bat guano, and wood ash) and denoted as ‘Natural'. The other three rows were treated with commercial organic fertilizer Vedagro and it was assigned as ‘Vedagro'.

Place and Duration of Study: The study area is located in Seik Kyi Village, Kyon Pyaw Township, Ayeyarwady Region (latitude 15º40ʹN and longitude 94º15ʹE), Myanmar. It was conducted during the 2013 March and 2014 January cropping season.

Methodology: The soil samples were collected in randomized block design replicated three times. The characteristics and physicochemical properties of before fertilized and post harvest soil samples were studied by AOAC methods.

Results: Initial soils were acidic, very low in organic matter (OM), moderately low in N and P. The organic fertilizers used had relatively high N and P and good percentages of K, Ca and Mg. At the post harvest time, Natural and Vedagro increased soil OM, N, P, K and Mg significantly. Natural fertilizer did not much change soil pH, while Vedagro increased it. Proximate composition of Cassava on different treatments has been found as 57.02, 57.67 and 67.22% of moisture, 0.10, 0.08 and 0.09% of crude fat, 1.32, 0.56 and 0.76% of protein, 1.24, 1.01 and 1.12% of dietary fiber, 39.49, 39.77 and 38.56% of carbohydrate, 0.83, 0.91 and 0.85% ash, 161, 165 and 158 kcal /100 g based on fresh sample for Natural, Vedagro and Control, respectively.

Conclusion: Relative to Control, both Natural and Vedagro fertilizer increased tuber yield about 79%. The study revealed that both organic fertilizer treatments had high tuber yield, the high nutrient value in tuber and the least post harvest soil nutrients depleting.