Water and Nitrogen Management at the Booting Stage Affects Yield, Grain Quality, Nutrient Uptake, and Use Efficiency of Fragrant Rice Under the Agro-Climatic Conditions of South China

Abstract

The present study was conducted to assess the effects of water and nitrogen applications at the booting stage on yield, grain quality, and nutrient use efficiencies in fragrant rice in the early (March–July) and late (July–November) seasons of 2013. The experiment was comprised of two fragrant rice cultivars, i.e., Nongxiang 18 and Basmati; three nitrogen levels, i.e., 0 kg N ha−1 (N0), 30 kg N ha−1 (N1), and 60 kg N ha−1 (N2); and three water levels, i.e., 2–4 cm water layer well-watered (W0), water with a soil water potential of −15 ± 5 kPa (W1), and water with a soil water potential of −25 ± 5 kPa (W2), which were randomized in a split-split plot design. Results showed that Basmati produced a higher grain yield than Nongxiang 18 (16.20 and 9.61% in the early and late season, respectively), whereas the W1 exhibited the maximum grain yield and harvest index. The moderate application of nitrogen (N1) at the booting stage resulted in higher grain yield, nevertheless, cultivar, water, and nitrogen revealed different trends for some of the grain quality attributes, i.e., brown rice rate, milled rice rate, head milled rice rate, protein content, and amylose content as well as nutrient uptake and use efficiencies in the double rice production system. Basmati had a higher nitrogen harvest index (NHI; 18.28–20.23%) and P harvest index (PHI; 3.95–12.42%) but lower physiological P use efficiency for biomass (PPUEB; 7.66–23.66%) and physiological K use efficiency for biomass (PKUEB; 2.53–7.10%) than Nongxiang 18 in both seasons. Furthermore, the grain number per panicle, biomass yield, grain P uptake, and the whole plant P uptake were significantly related to the grain yield of fragrant rice. In both seasons, the interaction of water and nitrogen (W × N) had a significant effect on panicle number, grain quality attributes, and N, P uptake of straw, as well as the physiological N, P use efficiency for grain and the physiological N, K use efficiency for biomass. Overall, results suggest that moderate nitrogen and irrigation input at the booting stage could be feasible to improve the productivity and quality of the double rice production system with improved nutrient use efficiency under the agro-climatic conditions of South China.

Comparative analysis of sorghum (C4) and rice (C3) plant headspace volatiles induced by artificial herbivory

“… 36 , 37 In contrast, a representative of C3 plants, rice, is highly dependent on water and nutrient supply to achieve the expected yield. 38 With respect to quantitative VOC differences between rice and sorghum, it is possible to infer from a large volume of indirect evidence that C3 and C4 metabolic networks might be actually involved in the empirically observed differential emission of VOCs in our experiments. Previously, Niinemets and Reichstein 39 , 40 concluded that the amounts of VOCs released by plants are affected by stomatal conductance, which, reportedly, tends to be lower in C4 compared to C3 plants, especially under high light conditions.…”

Biosynthesis of 2-Acetyl-1-pyrroline in Fragrant Rice: Recent Insights into Agro-management, Environmental Factors, and Functional Genomics

“…Low water levels generally led to an increase in grain 2-AP contents, possibly due to enhanced endogenous proline contents that later converts into 2-AP. , Moderate drought (soil water potential −25 kPa) at the booting and grain filling stage enhanced the grain 2-AP contents. , Thus, a proper irrigation schedule together with N application may have a significant impact on aroma biosynthesis in fragrant rice. Water–nitrogen interaction (e.g., application of 30 kg ha –1 N fertilizer and −20 kPa irrigation water at the tillering stage) significantly increases grain 2-AP contents in rice as well as increases the yield. ,− The aromatic quality of rice is also affected by factors such as the time of field draining and harvesting in relation to physiological maturity, moisture content, and weather conditions . Low planting density and early harvesting can boost aroma content, and the best aroma (aroma score 3) can be found 20 days after 50% flowering .…”

Optimization of liquid fertilizer management improves grain yield, biomass accumulation, and nutrient uptake of late‐season indica fragrant rice

“…10 On the other hand, growing late-season rice is conducive to high yield with better grain quality owing to suitable temperature and light intensity in south China. 11 Deng et al 12 reported that the yield of late season rice and fertilizer use efficiency were improved by N fertilizer management. Previous studies reported that nitrogen application had a significant effect on leaf area index and leaf photosynthesis rate.…”