Effect of Pre-Rice Mungbean and Cattle Manure Application on Growth and Yield of Organic Rice

抄録

The objective of this research was to investigate the effect of different rates of organic fertilizers with or without mungbean crop residues incorporated into the soil after harvesting, on growth and yield of transplanted rice as well as economic return of mungbean as pre-rice crop. An experiment was conducted in a farmer’s field in Muang Yai Village, Khon Kaen Province, Thailand, in 2011. A split-plot arrangement of treatments in a RCBD (randomized completed block design) was used, with pre-rice mungbean or fallow with weeds incorporated into the soil in main plots, and cattle manure at four rates (0; 3,125; 6,250; 9,375 kg/ha) as subplots. Incorporation of mungbean residue into the soil provided 3.2 t of dry matter per ha containing 50.2 kg N, 9.8 kg P and 166.2 kg K per ha. Incorporation of weeds in the fallow treatment provided 1.7 t of dry matter per ha containing 11.3 kg N, 2.8 kg P and 90 kg K per ha. Mungbean residues incorporated into the soil significantly increased plant height and tiller number per hill but had no significant effect on top dry weight per hill of the succeeding rice crop at panicle initiation stage (PI). At harvest, pre-rice mungbean significantly increased top dry weight per hill of rice. Application of different rates of cattle manure significantly affected plant height at PI and harvest. Cattle manure applied at the highest rate (9,375 kg/ha) had the highest plant height. Grain yield of rice was not significantly affected by pre-rice management. However, incorporation of mungbean residues produced an increase in rice grain yield over fallow treatment of 416 kg/ha (or 17%). Incorporation of mungbean significantly increased panicle number per hill. Incorporation of mungbean residue and application of cattle manure at 6,250 kg/ha produced the maximum panicle number per hill. Cattle manure application at the rate of 9,375 kg/ha resulted in the maximum rice grain yield (2,920 kg/ha). No significant interaction between pre-rice residue management and cattle manure application was found on rice grain yield. Growing mungbean before rice provides the advantage of marketable grain of mungbean to 1.6 t/ha. The net economic return was found highest in growing mungbean alone with transplanted rice later (2,855US $/ha) or three times higher than the fallow treatment.