Agronomic Growth Performance of Super Rice under Water-Saving Irrigation Methods with Different Water-Controlled Thresholds in Different Growth Stages

Abstract

Many water-saving techniques have been developed for rice production in response to irrigation water scarcity. The selection of the water-saving methods and the optimum thresholds for obtaining maximum benefits of these regimes are largely site-specific depending mainly on soil type, soil texture, and the environment. A two-year (2017 and 2018) experiment was conducted to evaluate the response of the agronomic growth performance, yield, and water use of super rice varieties under different irrigation regimes in Jiangsu Province, China. The irrigation regimes were comprised of different water-controlled thresholds, in different growth stages. Treatments included traditional flooding irrigation (FI, as the control) and the following four water-saving irrigation (WSI) regimes: shallow adjusting irrigation (WSI1), rainwater-catching and controlled irrigation (WSI2), controlled irrigation (WSI3), and drought planting with straw mulching (WSI4). The results showed that WSI treatments significantly increased the irrigation water use efficiency by 20.60% to 56.92% as compared with FI. The WSI treatments significantly decreased the crop evapotranspiration during the rice growth period. The grain yields of WSI1, WSI2, and WSI3 were significantly increased (6.62%~7.20% for WSI1, 8.21%~12.39% for WSI2, and 8.30%~12.91% for WSI3) as compared with that of the control, whereas WSI4 decreased the rice yield by 11.69%~18.10%. This research implies that WSI2 and WSI3 have the greatest potential for promotion in the lower reaches of the Yangtze River. An optimization of the irrigation threshold of WSI1 and WSI4 should be considered to guarantee the overall benefit.

Evaluation of Growth, Yield, and Water Productivity of Paddy Rice with Water-Saving Irrigation and Optimization of Nitrogen Fertilization

“…Other studies have postulated that more yield under AWD might be attributed to better grain-filling and increased root proliferation to take up more water and nutrients [74,77]. This is in agreement with [65], who reported up to 13% yield increase under watersaving irrigation treatments compared to flooding irrigation. Ref.…”

“…These results are in agreement with [63,64], who reported an increase of plant height under AWD water management and 90 kg N ha −1 nitrogen level. However, Zheng et al [65] reported contradicting results from China, showing that the final plant height was significantly higher under flooding irrigation than of that under water-saving irrigation treatments during both years of experiments.…”

“…Zheng et al [65] reported an increase of up to 5.3% dry matter yield under AWD compared to traditional flooding irrigation. Another study [76] reported that nitrogen fertilizer enhances more leaf area, which leads to higher photo assimilates and thereby results in more dry matter accumulation.…”

Aerobic Rice with or without Strategic Irrigation in the Subtropics

“…The number of spikelets per panicle and the number of panicles per plant are determined well before flowering, but the fertility of spikelets, in particular functional pollen, is determined during the 10 days before and around flowering. Strategic irrigation did improve the number of spikelets per panicle (Table 5), in accordance with the data of [63], and averaged over both years increased spikelet fertility of all varieties, on average by 36%.…”

Improving the Climate Resilience of Rice Farming in Flood-Prone Areas through Azolla Biofertilizer and Saline-Tolerant Varieties

“…Both of these parameters, the number of productive tillers and the 100 grain weight, affect the grain weight per plant. With more productive tillers and larger grains, the grain weight per plant increases [23]. As stated earlier, panicle formation is strongly influenced by nutrient availability, of which nitrogen is crucial [24].…”