Dry Matter Yield Response to Seeding Rate and Row Spacing in Direct-seeded and Double-harvested Forage Rice

Nakano, Hiroshi; Hattori, Ikuo; Morita, Satoshi

doi:10.6090/jarq.53.255

Cited by 4 publications

(5 citation statements)

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“…In this study, we identified growth‐related indicators that affected white‐back grain percentage and grain protein content. Growth‐related traits are influenced by the growing season, planting density, and cultivar (Nakano & Morita, 2009; Nakano & Tsuchiya, 2012; Nakano et al., 2008, 2012, 2014, 2019). Therefore, it is imperative to examine the relationships among grain appearance, protein content, and growing conditions to achieve an optimal methodology for N application.…”

Section: Discussionmentioning

confidence: 99%

Identification of growth‐related indicators affecting the appearance and protein content of rice grains

et al. 2022

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To facilitate the stable production of rice (Oryza sativa L.) in a changing climate, it is imperative to establish optimal N application rate via growth diagnosis. In this study, field experiments were conducted to identify useful indicators of white‐back grains and protein content of rice. During the reproductive stages in 2018 and 2019, we applied N at different rates and recorded the soil and plant analyzer development (SPAD) readings and normalized difference vegetation index (NDVI) measurements. The white‐back grain percentage and grain protein content were more strongly correlated with SPAD readings and NDVI during the reproductive stage when the 2018 and 2019 data were combined than with the separate data for each year. In the combined 2018 and 2019 data, SPAD readings were the most dominant factor affecting white‐back grain percentage at 4–2 wk before heading, whereas NDVI was the most dominant factor at 1 wk before heading. Similarly, in the combined 2018 and 2019 data, SPAD readings were the most dominant factors for grain protein content on all measurement days, and NDVI was one of the dominant factors at 1 wk before heading. These results suggest that SPAD readings at 4–2 wk before heading and SPAD readings and NDVI at 1 wk before heading are useful indicators for determining the optimal N application rates during the reproductive stage to reduce the occurrence of white‐back grains and to regulate the grain protein content.

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Section: Discussionmentioning

confidence: 99%

Identification of growth‐related indicators affecting the appearance and protein content of rice grains

et al. 2022

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“…In this study, we discovered that TIL PI was determined predominantly by planting density and N til , which could be expressed as either seeding rate or ASD (Table 3). Previous studies also demonstrated the significant influence of seeding rate on rice tiller numbers under direct‐seeded conditions 26 . Although both models, using either seeding rate or ASD as input, performed similarly well in the early season, the model with ASD as input outperformed the model with seeding rate as input in the late season, as indicated by the F value and R 2 values for the equations.…”

Section: Discussionmentioning

confidence: 74%

“…Previous studies also demonstrated the significant influence of seeding rate on rice tiller numbers under direct-seeded conditions. 26 Although both models, using either seeding rate or ASD as input, performed similarly well in the early season, the model with ASD as input outperformed the model with seeding rate as input in the late season, as indicated by the F value and R 2 values for the equations. Furthermore, when pooled data from the early and late seasons were analyzed, the R 2 of the model using seeding rate as input were 0.351 in 2017 and 0.741 in 2020, which was significantly lower than that with ASD as input in both years (0.856 in 2017 and 0.892 in 2020).…”

Section: Discussionmentioning

confidence: 89%

Determining nitrogen topdressing rates in accordance with actual seedling density and crop nitrogen status in direct‐seeded rice

Peng,

Wang,

et al. 2023

J Sci Food Agric

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BACKGROUNDAdjusting nitrogen (N) input based on actual seedling density (ASD) and plant N status is a practical approach for improving the yield stability of direct‐seeded rice. However, the adjustment of topdressing N rates has been empirical in the past. This study aimed to establish a quantitative approach for determining N topdressing rates during tillering (Ntil) and panicle development (NPI) based on ASD and crop N status in direct‐seeded rice. Field experiments were conducted involving twelve treatments, consisting of four Ntil and three seeding rates in 2017, and eight treatments combining seeding rate, Ntil, and NPI in 2020.RESULTSLinear regression analysis revealed that the tiller number at panicle initiation (TILPI) was predominantly influenced by ASD and Ntil. The determination coefficients (R2) of the regression models ranged from 0.887 to 0.936 across the four‐season experiments. The results indicated that Ntil could be accurately determined using ASD and the target maximum tiller number. Similarly, grain yield was significantly influenced by the N uptake at panicle initiation (NUPPI) and NPI, with R2 of 0.814 and 0.783 for early and late season of 2020, respectively. This suggested that NPI could be calculated based on NUPPI and the target grain yield.CONCLUSIONOur findings offer a quantitative method for establishing N topdressing rates for tillering and panicle development, relying on the monitoring of actual seedling density and plant N status in direct‐seeded rice production.This article is protected by copyright. All rights reserved.

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“…In this study, we proposed a novel topdressing method after analysis of the relationships between grain yield and growth‐related factors. Both grain yield and biomass are influenced by growing season, planting density, and cultivars in southwestern Japan (Nakano & Morita, 2009; Nakano & Tsuchiya, 2012; Nakano, Morita, Hattori, & Sato, 2008, Nakano et al., 2012, Nakano, Hattori, & Morita, 2014, 2019). Thus, examining the relationships between grain yield and growth‐related traits of rice plants grown under various cultivation methods is very important for further adjustment of this method.…”

Section: Discussionmentioning

confidence: 99%

A weather‐adaptive topdressing method to enhance rice yield in southwestern Japan

et al. 2020

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Rice (Oryza sativa L.) plants grown in southwestern Japan are subjected to large variations in air temperature and solar radiation during the rainy season which can affect their growth. Therefore, in this study, a novel nitrogen (N) application method for topdressing was proposed to increase grain yield under different weather conditions. Field experiments were conducted to determine the grain yield response to the soil and plant analyzer development (SPAD) readings and normalized difference vegetation index (NDVI) during the early reproductive stage in 2018 and 2019. As the rainy season ended in early July in 2018 but continued until late July in 2019, the daily mean solar radiation during the vegetative and early reproductive stages was 26% lower in 2019 than in 2018. Grain yield was 10% lower in 2019 than in 2018, mainly due to the lower number of spikelets. During the early reproductive stage, the SPAD readings and NDVI were higher in 2019 than in 2018, suggesting that the biomass and N concentration in 2019 were lower and higher than those in 2018, respectively. Statistical modeling examination of grain yield response to growth-related factors revealed that the N application rate during the reproductive stage and SPAD readings were significant predictors in 2018, whereas the N application rate and NDVI were significant predictors in 2019. Our findings suggest that SPAD readings and NDVI are key factors for determining N application rate during the reproductive stage under higher and lower solar radiation conditions during the vegetative and reproductive stages, respectively. Abbreviations: NDVI, normalized difference vegetative index; SPAD, soil and plant analyzer development. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

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Dry Matter Yield Response to Seeding Rate and Row Spacing in Direct-seeded and Double-harvested Forage Rice

Cited by 4 publications

References 12 publications

Identification of growth‐related indicators affecting the appearance and protein content of rice grains

Identification of growth‐related indicators affecting the appearance and protein content of rice grains

Determining nitrogen topdressing rates in accordance with actual seedling density and crop nitrogen status in direct‐seeded rice

A weather‐adaptive topdressing method to enhance rice yield in southwestern Japan

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