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| DOI：10.13522/j.cnki.ggps.2025283 |
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| Effects of flooding and drainage on rice yield and nutrient losses in paddy fields |
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CHENG Jie, WANG Bingrui, SHI Hong, SHI Yuanzhi, ZHAO Shujun, WAN Shaoyuan, CAI Shuo
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1. Jiangxi Central Station of Irrigation Experiment, Nanchang 330201, China;
2. School of Water Resources and Environmental Engineering, East China University of Technology,
Nanchang 330013, China; 3. Nanjing Hydraulic Research Institute, Nanjing 210029, China;
4. College of Hydraulic & Environmental Engineering, China Three Gorges University, Yichang 443002, China
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| Abstract: |
| 【Objective】Flooding and drainage in paddy fields strongly influence rice growth, yield formation, and nutrient losses. However, their mechanistic effects on crop productivity and nutrient leaching remain poorly understood. This paper aims to elucidate these mechanisms. 【Method】Experiments were conducted in pots. Sediment contents of 0 kg/m3 (S0), 0.10 kg/m3 (S1) and 0.25 kg/m3 (S2), inundation duration with continuous flooding of 3 days (F1) and 6 days (F2), and water recession for 3 days (D1) and 6 days (D2) were applied during the tasseling and yellow ripening stages of early-season rice and the tillering and jointing stages of mid-season rice. The control (CK) was conventional management used by local farmers. In total, there were 13 treatments. In each treatment, we measured changes in sediment content, total nitrogen (TN), ammonium nitrogen (NH4+-N), nitrate nitrogen (NO3--N) and total phosphorus (TP) concentrations in the effluents, as well as rice yield and yield components.【Result】①Flooding resulted in yield reductions ranging from 11.07% to 69.96%; on average, the F1D1 and F1D2 treatments showed the least yield loss for both early- and mid-season rice. ②Sediment concentration decreased significantly over time during the drainage process and was reduced by more than 50% six days after the onset of drainage. ③TN, NH4?-N, NO3--N and TP concentrations increased during both flooding and drainage processes, with early-season rice exhibiting the highest concentrations at the tasseling stage and mid-season rice at the tillering stage. ④TN, NH4?-N and TP concentrations in the effluent were negatively correlated with early-season rice yield, while their correlations with mid-season rice yield were not statistically significant.【Conclusion】Flooding and drainage critically influence rice yield and nutrient losses in paddy fields. Our experiment showed that flooding for 3 days followed by a 3-6 day drainage minimized yield loss to 18.67%-50.33% for early-season rice and 32.38%-38.35% for mid-season rice, with TN and TP concentrations in the effluent remaining below 25.82 mg/L and 1.41 mg/L, respectively. These strategies can be used in irrigation and drainage system design. |
| Key words: rice; total growth period; flooding and receding; pollutants; yield; nonpoint source pollution |
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