斜发沸石对干湿交替稻田土壤速效钾和产量的影响

为了进一步探究斜发沸石在干湿交替稻田中的应用潜力,设置不同灌溉模式(淹灌和干湿交替灌溉)和不同斜发沸石用量(0、5、10t/hm2)的大田裂区试验,对2017-2018年稻田土壤速效钾动态变化和产量进行了研究。结果表明:稻田增施斜发沸石显著提高了水稻产量,在10t/hm2水平下产量最高,增产率达8.7%～22.3%。斜发沸石对稻田表层土壤速效钾含量和植株地上部钾素积累的提高有显著正效应,干湿交替灌溉显著提高了各生育期植株地上部钾素积累量,提高幅度分别为11.81%～21.42%(2017年)、9.69%～23.79%(2018年)。通径分析表明,斜发沸石增产是因为其显著增加了分蘖肥期和穂肥期土壤速效钾含量,提高了抽穗开花期和黄熟期地上部钾素积累。研究可为揭示干湿交替灌溉下提高钾肥利用效率的应用潜力,并一定程度上缓解稻田缺钾的局面提供依据。

Impact of zeolite on dynamic of soil available potassium and grain yield in alternate wetting and drying rice system

The impact of zeolite (Z) on the dynamic of soil available potassium in the rice production system remains unknown, especially in the alternate wetting and drying (AWD) irrigation rice production system. To explore the application potential of zeolite in alternate wetting and drying rice system, a 2-year experiment was conducted to determine the effects of Z on grain yield and soil available potassium under different Z application rates and irrigation methods using the split plot design. A Japonica rice (cv. Shen Dao 529) was cultivated in brown loam soil. Treatments included 2 irrigations methods (CF: continuously flooded irrigation, AWD: alternate wetting and drying irrigation) as main plots and 3 zeolite application rates (0, 5, and 10 t/hm2) as sub-plots within each of main plots. The experiment was repeated in 2018 but Z was not applied, and the plots in 2018 experiment were same as 2017 experiment. The results showed that Z application at the rate of 10 t/hm2 significantly increased grain yield as compared with no zeolites, in particular Z application at the rate of 10 t/hm2 in the AWD rice production system, of which the yield was 8.7%-22.3% higher than the zeolite-free treatment in the CF rice production system. Zeolite had a significant positive effect on the surface soil available potassium content, and above-ground dry matter accumulation as well as the K accumulation of rice plants in the rice field. Z application at the rate of 5-10 t/hm2 increased the surface soil available potassium content in the basel fertilizer stage, tiller fertilizer stage and panicle fertilizer stages, above-ground dry matter accumulation in later tillering stage, jointing-booting stage, heading-flowering stage, milky ripening stage, and yellow ripening stage and improved the aboveground K accumulation of rice plant in the later tillering stage, jointing-booting stage, heading-flowering stage, milky ripening stage, yellow ripening stage. The positive effects of Z observed were even more obvious when applied into the AWD rice production systems relative to the CF one. Compared with the most commonly used treatment (CF and Z-free treatment), the AWD irrigation in combination with 10 t/hm2 Z application average increased the surface soil available potassium content in the basal fertilizer stage, tiller fertilizer stage and panicle fertilizer stages, above-ground dry matter accumulation in Jointing-booting stage, heading-flowering stage, milky ripening stage, Yellow ripening stage (except later tillering stage) and improved the aboveground K accumulation of rice plant in the later tillering stage, jointing-booting stage, heading-flowering stage, milky ripening stage, yellow ripening stage by 11.81%-21.42% in 2017 and 9.69%-23.79% in 2018. The rice yield component results revealed the increased yield in Z treatment was mainly caused by increased effective tiller number at harvest, while path analysis of dynamics in average soil available potassium at different fertilization stages and above-ground K accumulation of rice plants at different growth stages further suggested that the increased grain yield in zeolite treatment was mainly due to increase of soil available potassium content in tiller-panicle fertilizer stage and panicle fertilizer-harvest stage caused by increased zeolite, and increased aboveground K accumulation of rice plant in the heading-flowering stage and yellow ripening stage. In addition, these positive residual activities could maintain for at least 2 years after initial application in both the CF and AWD rice production systems.