Effects of barley straw application and tillage method on soil physical property and soybean yield in paddy field.

摘要

This study was conducted to determine the effect of tillage methods such as ploughing and rotary tillage (PRT), rotary tillage (RTG), no-tillage after barley straw application (NTB), and barley straw mulching after ploughing and rotary tillage (BPR) on the growth and the yield of soyabean when cultivated after the cultivation of barley. The methods were compared with the control method in which ploughing and rotary tillage after barley straw incineration was applied. Barley straw application resulted in increase in organic matter, total nitrogen, phosphate, and exchangeable cation regardless of tillage methods. Porosity and moisture level in paddy soil was ranked as follows: PRT > RTG > BPR > control > NTB. Decomposition rate of barley straw dramatically increased to 41.7% toward 30 days after soyabean sowing, higher in NTB, DRB, and RTG than in BPR. Weed occurrence was decreased by 36% in NTB and 40% in BPR. Root activity, nodulation and the dry weight per plant of soyabean at flowering stage were highest in NTB and lowest in PRT. Soyabean yield in NTB was 3070 kg/ha increasing by 19%, whereas that in PRT was not increased. Therefore, in case of a frequent rain during the cultivation of soyabean in paddy field PRT could result in excess moisture level in soil, the cultivation without tillage is desirable..