Authors

Abstract

The cultivation of salt-tolerant rice (sea rice) along beaches has become an effective measure for the restoration and utilization of saline-sodic land, so this paper studies the effects of irrigation and nitrogen fertilization on soil Na+ in root zone and sea rice yield, and provides a scientific basis for planting sea rice. A pot experiment (two-factor split plot) of sea rice with salt stress (10 g NaCl/kg soil) was carried out. The main plot consists of three types of irrigation methods: flooding irrigation (F), intermittent irrigation (I), and controlled irrigation (C). The subplots are three types of nitrogen fertilizers: urea (U), controlled-release urea (R), and mixed fertilizer (M) with U and R. The results showed: (1) The soil water-soluble Na+ of MI was significantly smaller than that of other treatments with NaCl, but the Ca2+/Na+ and Mg2+/Na+ were opposite. (2) The nitrogen uptake and dry weight of rice of MI were significantly larger than those of other treatments with NaCl, and were respectively 23% and 32% higher than UI, 49% and 16% higher than MF, 56% and 38% higher than UF, 75% and 61% higher than RI, 76% and 50% higher than RF. (3) The sea rice yield of MI was increased by 105%, 154%, 262%, 338%, and 428% compared with MF, RF, UF, RI, and UI, respectively. Therefore, the MI can effectively reduce the Na+ and increase the Ca2+/Na+ and Mg2+/Na+ in root layer soil, and promote the nitrogen absorption and production of sea rice. So the article recommends that M and I methods should be adapted to plant sea rice on coastal saline-sodic soil.

Abstract in Chinese

【目的】近年来，种植耐盐水稻（海水稻）已成为沿海滩涂及盐碱地修复与利用的有效措施，但针对海水稻的水肥管理配套技术研究还较少。本文开展了水氮调控对根层土壤Na+及海水稻产量影响的研究，为优化海水稻的水氮管理提供科学依据。【方法】在加氯化钠(10g/kg)高盐胁迫下，采用两因素裂区设计进行海水稻盆栽试验。主处理是施肥量相等的普通尿素（U）、控释尿素（R）、混合氮肥（M）3种氮肥；副处理为淹水灌溉（F）、间歇灌溉（I）、控制灌溉（C）3种灌水方式。另设未加NaCl的无盐对照，共10个处理。【结果】（1）MI处理的土壤水溶性Na+在水稻生育期内基本保持不变，且显著小于其它加盐处理的，而其它加盐处理的Na+均呈增加趋势；MI处理的土壤Ca2+/Na+和Mg2+/Na+随着水稻生长期的延长显著增大，且在水稻孕穗期和成熟期时，显著大于其它加盐处理的。（2）MI处理的海水稻吸氮量和干重显著大于其它加盐处理的，分别比UI高23%和32%，比MF高49%和16%，比UF高56%和38%，比RI高75%和61%，比RF高76%和50%。（3）水氮调控对海水稻的产量影响显著。MI的产量分别比MF提高105%，比RF提高154%，比UF提高262%，比RI提高338%，比UI提高428%。【结论】MI处理能有效降低耕层土壤中的水溶性Na+，而提高水溶性Ca2+/Na+和Mg2+/Na+，减轻根层土壤Na+对海水稻的危害，促进海水稻的氮素及生物量累积，增加海水稻产量。因此，本文建议在NaCl危害较重的滨海盐渍地上种植海水稻，应采用控释尿素与尿素混合施肥，并综合间歇式浇灌的水肥管理模式。