Increased hill density can compensate for yield loss from reduced nitrogen input in machine-transplanted double-cropped rice

摘要

Reducing external inputs, including labor and N fertilizer, is critical to sustainable double-cropped rice production in China. Dense planting is a recommended strategy to reduce N rate in rice production, and this strategy may be more practical for machine-transplanted rice as machine transplanting can achieve high hill density with less labor. However, little work has been done to demonstrate the feasibility of such a strategy in machine transplanted double-cropped rice. This study was conducted to determine the effects of reduced N rate and increased hill density on yield attributes and grain yield in machine-transplanted double-cropped rice. Field experiments were done in two years with three treatments: (1) high N rate with low hill density (HNLD), (2) low N rate with low hill density (LNLD), and (3) low N rate with high hill density (LNHD).