Early growth stage water management effects on the fate of inorganic N, growth and yield in rice

Abstract

Water and nitrogen (N) play vital roles in rice (Oryza sativa L.) production. Water-saving management decisions can influence soil conditions (oxidation and reduction), and these soil conditions affect the fate of N in paddy soil. We designed three irrigation regimes, namely, conventional irrigation (Flooding), shallow water depth (SWD), and a Non-flooding treatment, for our study. For the Flooding treatment, a ponding water depth of 0.05-0.06 m was maintained for 99 days after transplanting (DAT), and the water was drained 20 d before harvesting. For the SWD treatment, a ponding water depth of 0.01-0.02 m was maintained from 20 DAT to 99 DAT, and water was drained 20 d before harvesting. For the Non-flooding treatment, the plots were saturated (not flooded) from 20 to 57 DAT. After 57 DAT, a ponded water depth of 0.01-0.02 m was maintained until 99 DAT, and the water was drained 20 d before harvesting. The N fate and rice growth did not differ between the treatments during the early growth stages in response to the differences in water management. Rice root activity during the middle growth stage was higher for SWD, which was possibly because of the above-ground biomass and other factors during the middle growth stage of the rice. We found that the recovery efficiencies for N fertilizer, N uptake and above-ground biomass at the heading stage were higher for SWD than for the other two treatments. Although the soil status (reduction or aerobic conditions) was the same for the different water treatments up to the maximum tiller number stage, either the SWD or Non-flooding option could be used to conserve water. In addition, the fate of the N fertilizer, the N use efficiency, the rice growth and the rice yield were the same or higher with these two treatments than with the Flooding water management treatment.

Etude comparative de l’efficacité de deux types de composts organiques sur la performance agroéconomique de l’amarante (Amaranthus cruentus L) dans les jardins familiaux au Bénin

“…Cela pourrait expliquer la grande taille et le nombre élevé de feuilles enregistrés avec la fiente de volaille compostée comparativement à la bouse de vache compostée. De pareilles améliorations à travers l'action de l'azote ont été observées par Hu et al (2014) et Rahman et al (2013) sur l'augmentation en taille et en nombre de talles du riz.…”

Non-thermal plasma enhances rice seed germination, seedling development, and root growth under low-temperature stress

“…The consequences of cold stress manifest in yield losses resulting from poor germination and seed establishment, stunted growth patterns, plant failure, sterile spikelets, delayed flowering, and reduced seed filling [5]. Root distribution and development play vital roles in facilitating water and nutrient access and absorption in rice [6]. The rice root system synthesizes trans-zeatin, a phytohormone and potent cytokinin, which enhances leaf photosynthesis and seed-filling capacity [7].…”

Effects of Water Management Practices on Methane Emissions and Rice Yields in East Asian Paddy Fields: A Regional-Scale Meta-Analysis

“…논에서 물 관리를 통해 CH 4 배출량을 감축하는 방법은 현재까지 가장 경제적이며, CH 4 배출 억제에 가장 효과적인 방법으로 알려져 있다 (Yagi et al, 2020;Qian et al, 2022). 논물 관리는 혐기 조건을 호기 조건으로 변경하는 활동으 로 호기성 환경에서 합성된 CH 4 영양균 (methanotrophic bacteria)이 CH 4 생성 고세균 (methanogenic archaea)의 활 동을 제한하고, 토양 산화 환원 전위 (Eh)를 증가시켜 CH 4 배출량을 감소시키는 방식이다 (Rahman et al, 2013;Sha et al, 2022). 논물 관리 방식에는 중간낙수 (Wu et al, 2019b;He et al, 2022), 간헐적 관개 (Nishimura et al, 2020;Qian et al, 2022), 습윤 관개 (Wei et al, 2019;Zhang et al, 2019), 천수답 (Wu et al, 2019b;Zhang et al, 2021) 등 다양한 방법이 제시되고 있다.…”