Abstract

• In the present investigation, the effects of composted organic fertilizers (COF) on the growth and yield of corn and soil fertility were studied. Therefore, a field experiment was carried out to evaluate the effects of the composted organic fertilizers in a silty clay loam soil and laid out in Randomized Complete Block (RCB) design with six treatments and four replications, grown with corn (Zea mays L.) in Einkyitaw village, Mahlaing Township, Mandalay Region. In this research work, the composted organic fertilizers were prepared by five different weight ratios (30 kg: 20 kg : 10 kg: 5L) (cow dung: corn stalk: kokko leaves: EM) for COF-1, ( 30 kg : 30 kg : 5 L) (cow dung : corn stalk : EM) for COF-2, (60 kg : 5L) ( cow dung : EM) for COF-3, (30 kg : 10 kg : 20 kg : 5 L) (cow dung : corn stalk : kokko leaves : EM) for COF-4, (20 kg : 20 kg : 20 kg : 5L) (cow dung : corn stalk : kokko leaves : EM) for COF-5, respectively. The treatments were: six kinds-T1 (control without fertilizer), T2 (COF 1, 14 t/ha), T3 (COF 2, 14 t/ha), T4 (COF 3, 14 t/ha), T5 (COF 4,14t/ha) and T6 (COF 5, 14t/ha). In all treatments, these fertilizers with same amount were used in growing corn (Z.mays). After that, during cultivation, determination of plant height and after harvesting, the yield components such as number of ear per plot, number of kernels per ear, and weight of thousand grains were measured and grain yield were estimated. Field studies showed that the yield of corn, T1 (749.30 kg/ha), T2 (950.84 kg/ha), T3 (1030.46 kg/ha), T4 (1181.93 kg/ha), T5 (1227.80 kg/ha) and T6 (1146.44 kg/ha) were obtained from treated soils and control without fertilizer. Among these treatments, T5 (COF 4, 14 t/ha) was able to produce the highest percentage yield of corn 1227.80 kg/ha compared with control without fertilizer, the lowest percentage yield of corn 749.30 kg/ha. The nutritional values of corn grains such as moisture, ash, protein contents and elemental contents such as phosphorus, potassium, calcium were also determined. These nutritional values of corn grains were not significantly different in each treatment. Then, comparison for all fertilizers treatment before growing corn and after harvesting corn were made with respect to physicochemical compositions of the treated soil samples. Physicochemical properties of soil (texture,moisture, pH, EC, organic carbon, humus, total N, available P, available K2O, exchangeable cations (Ca2+, Mg2+) and CEC) were determined. This application of composted organic fertilizers not only produced the highest and sustainable crop yield but also improved the soil fertility and productivity of land.