Matter Production Characteristics and Nitrogen Use Efficiency under Different Nitrogen Application Patterns in Chinese Double-Cropping Rice Systems

Abstract

Panicle-stage nitrogen fertilizer is popular in parts of China due to its higher nitrogen recovery efficiency compared to basal and tiller nitrogen. However, the effect of conversion from basal to panicle-stage nitrogen on matter production, grain yield, and nitrogen use efficiencies (NUE) in Chinese double-cropping rice systems remains largely unknown. Here, we elucidate the effect by using two types of one-time basal nitrogen patterns (A and B), three panicle-N allocation patterns (C, D, and E), and the local conventional patterns (CK). The two-year experiment demonstrates that E (basal/tiller/spikelet-promoting /spikelet-developing nitrogen = 0:4:3:3) produced the greatest annual grain yield, nitrogen agronomic efficiency, and nitrogen partial productivity. The annual dry matter weight and nitrogen increment of panicle, nitrogen transportation of stems contributes the most to annual yield and NUE. Furthermore, the yield increase could be attributed to the higher effective panicles, plant dry matter weight at tillering, and net photosynthesis rate at heading. Moreover, years and varieties affect the yield in different N treatments. The improvement in the net photosynthesis rate at the milk stage also significantly increases nitrogen recovery efficiency. These findings suggest that it is worth paying attention to the rational ratio of tillering to panicle fertilizer without applying a base fertilizer, to synchronously increase the grain yield, NUE in Chinese double-cropping rice systems.

The effect of nitrogen and water management on the yield and endogenous hormone levels of drip‐irrigated rice

“…At 20 days after heading, increasing the proportion of fertilizers applied at the panicle and grain‐filling stages (N 2 ) increased the grain dry matter accumulation of the two cultivars under W 1 (Figure 3). The results indicate that the increase in the proportion of fertilizers applied at the panicle and grain‐filling stages promoted biomass allocation to the aboveground parts of rice plants under W 1 after heading, particularly biomass allocation to grains, which was significantly increased (W. T. Zhou et al., 2022). Therefore, a suitable increase in the proportion of fertilizers applied at the panicle and grain‐filling stages (N 2 ) effectively promoted the transport of nutrients to grains at 20 days after heading and allocated more energy to seed setting.…”

Increasing Planting Density and Reducing N Application Improves Yield and Grain Filling at Two Sowing Dates in Double-Cropping Rice Systems

“…Interestingly, under the same dense planting condition (D2, D3), the decrease of nitrogen fertilizer would reduce panicles per m 2 , but under the same nitrogen fertilizer condition, the increase in planting density would increase panicles per m 2 ( Table 3 ). It has also been suggested that increasing the number of rice plants appropriately without excess nitrogen application can achieve an increase in yield, which means that increasing density can increase yield [ 26 ]. Thus, the loss of panicles per m 2 caused by reduction can be compensated for by dense planting [ 39 ].…”

“…The cultivation environment, including sowing date adjustment, nitrogen fertilization, and planting density management has already been adjusted to alleviate rice yield loss [ 25 , 26 , 27 ]. Enhancing rice yield components and promoting grain filling is the basis of high yields.…”