Effect of topdressing on individual leaf photosynthesis at different position in direct-sown rice with non-woven fabric mulch system

Summary

Direct sowing with non-woven fabric mulch is the new organic rice cultivation system. We studied the effect of topdressing on individual leaf photosynthesis at different position and grain yield in rice plants cultivated by this system. Leaf photosynthetic rate at the different leaf position per plant (P N-LP) of the third and fourth to lower leaves was higher when the topdressing amount was increased. Without topdressing or in no-fertilizers plots, the P N-LP values of lower leaves were very low. The leaf photosynthetic rate per unit leaf area (P N-LA) decreased gradually as the leaf position became lower. Again, the P N-LA values of the top-dressed plots at the lower leaves were higher than that of plots without topdressing or without fertilizers. The lower leaves maintained a higher P N because of a higher rate of nitrogen accumulation due to topdressing. The higher rate of photosynthesis in these leaves resulted in better root activity, which contributed to a better ripening percentage and ultimately higher rice grain yield.