《植物生理学报》 2021, 57(5): 1123-1134
氮肥形态与干湿交替灌溉下水稻土壤酶及养分差异
通信作者：徐国伟；E-mail: gwxu2007@163.com
摘 要：
以水稻‘徐稻3号’为材料进行土培试验, 设置浅水层灌溉(保持2~3 cm浅水层)、轻度干湿交替灌溉(-20 kPa)和重度干湿交替灌溉(-40 kPa) 3种灌溉方式与铵态氮、铵硝混合50:50、硝态氮3种氮肥形态处理,研究干湿交替灌溉与氮肥形态耦合对水稻土壤养分含量、土壤酶活性及地上部干物质质量的影响。结果表明: 在同一氮肥形态下, 与浅水对照相比较, 轻度干湿交替灌溉下水稻土壤脲酶、蔗糖酶、磷酸酶活性分别增加8.4%~64.6%、 4.1%~100%、 4.6%~42.1%; 碱解氮、速效磷、速效钾含量分别增加2.9%~51.5%、8.0%~82.0%、 2.5%~29.7%; 水稻地上部干物质质量明显提高, 比浅水对照平均提高13.6%。重度干湿交替灌溉则抑制土壤脲酶、蔗糖酶、磷酸酶活性, 降低土壤碱解氮、速效磷、速效钾含量, 地上部干物质质量显著降低(P<0.05)。在相同干湿交替灌溉下, 铵硝混合50:50处理提高了土壤脲酶、蔗糖酶及磷酸酶活性, 增加了土壤碱解氮、速效磷、速效钾含量, 提高了水稻地上部干物质质量。多元回归分析表明, 水稻地上部干物质质量与土壤蔗糖酶活性和土壤碱解氮含量呈显著或极显著的正相关关系。水稻生长期采用轻度干湿交替灌溉与施用铵硝50:50混合氮肥, 可以充分发挥水肥的耦合效应, 提高土壤酶活性, 提高土壤养分含量, 提高地上部干物质质量。
关键词：水稻; 干湿交替灌溉; 氮肥形态; 土壤酶; 土壤养分
收稿：2020-10-15 修定：2021-04-24
资助：国家自然科学基金(U1304316)、河南省国际合作项目(GH20190)24)、江苏省作物栽培生理重点实验室开放基金(027388003K11009) 和河南省自然科学基金(212300410341)
Corresponding author: XU Guowei; E-mail: gwxu2007@163.com
Abstract:
Alternate wetting and drying irrigation has been proven to be an effective water-saving technology for irrigated rice. Under alternate wetting and drying irrigation, the soil moisture status changes from flooding to controlled irrigation, the nitrogen form changes from ammonium nitrogen to the mixed state of ammonium nitrogen and nitrate nitrogen, and the rice development and growth greatly change compared with submerged irrigation. The information on the soil enzyme and nutritional trait under alternate wetting and drying irrigation conditions is limited. A soil experiment was conducted using a mid-season japonica rice cultivar of ‘Xudao 3’ with three irrigation regimes, including conventional irrigation, alternate wetting and moderate drying (-20 kPa) and alternate wetting and severe drying (-40 kPa) and nitrogen forms, namely, ammonium nitrogen, 50:50 ammonium–nitrate mixture, and nitrate nitrogen in 2018 and 2019. A similar result could be observed in two years. The results showed that alternate wetting and moderate drying irrigation increased activities of urease, sucrase and phosphatase and contents of alkali-hydrolyzable nitrogen, available phosphorus and available potassium by 8.4%–64.6%, 4.1%–100%, 4.6%–42.1%, 2.9%–51.5%, 8.0%–82.0%, 2.5%–29.7%, respectively. It also raised rice biomass signifcantly. By contrast, Alternate wetting and severe drying irrigation signifcantly reduced activities of urease, sucrase and phosphatase and contents of alkali-hydrolyzable nitrogen, available phosphorus and available potassium. It also decreased rice biomass at different stages. Under the same alternate wetting and drying irrigation, the enzyme activities of urease, sucrase and phosphatase in soils were increased, the contents of alkali-hydrolyzable nitrogen, available phosphorus and available potassium in soils were improved, and biomass of rice were increased at different stages. Multiple regression analysis showed that there was a signifcant or extremely signifcant positive correlation between rice biomass and sucrase activity and alkali-hydrolyzable nitrogen content in soils. The results indicated that enhanced activities of urease, sucrase and phosphatase and increased contents of alkali-hydrolyzable nitrogen, available phosphorus and available potassium in soils through alternate wetting and moderate drying irrigation interaction with 50:50 ammonium–nitrate mixture could highly beneft the increase in rice biomass. The results indicated that alternate wetting and moderate drying could harmonize root and shoot growth, and improve rice yield and nitrogen use efciency.
Key words: rice; alternate wetting and drying irrigation; nitrogen forms; soil enzyme; soil nutrient
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