Heterogeneity in Rice Tillers Yield Associated with Tillers Formation and Nitrogen Fertilizer

Abstract

Rice (Oryza sativa L.) farmers generally overcome low seeding rates with additional nitrogen (N) fertilization to develop more productive tillers. However, not every tiller provides high productivity; instead, a sufficient N source leads to the production of tillers with low yield potential. The objectives of this study were (i) to quantify the heterogeneity within tillers regarding yield formation at different N levels and (ii) to examine the differences in tiller growth period, grain yield, and carbon (C) and N concentrations at different N levels. In 2013 to 2014, field experiments consisted of a randomized complete block design with three N fertilizer rates. Gini coefficient was adopted to analyze the heterogeneities of various tillers regarding grain yield. Results showed that tiller heterogeneity was enhanced with increasing N levels. Under the same N rate condition, the grain yield of productive tillers decreased with the later‐emerging tillers. The early‐emerging tillers possessed the characteristics of long growth period, strong intercepted photosynthetic active radiation, and high C/N ratio in straw. The N‐induced enhancement in rice population mainly occurred due to the increase in grain yield of early‐emerging tillers. However, this upward trend would emerge peak value after sufficient N supply. Therefore, analyzing the limiting factors for low production of late‐emerging tillers may provide a novel perspective on further improving the rice population yield.Core Ideas Heterogeneity in rice tillers yield is increased with increasing N rates. Short growth period is not the key limiting factor to late‐emerging tillers. Early‐emerging tillers pre‐empt the uppermost light source and shade the late‐emerging tillers. Early‐emerging tillers possess higher C/N ratio in straw than late‐emerging tillers. Late‐emerging tillers have higher yield potential under sufficient N supply.