灌浆期叶面喷施不同硒源对水稻主要性状、硒含量和根际土壤理化性质的影响

Effects of foliar spraying different selenium sources at filling stage on main traits, selenium content and rhizosphere soil physicochemical properties of rice

  • 摘要: 【目的】探索灌浆期叶面喷施不同硒源对水稻生长、品质、硒含量和根际土壤理化性质的影响,为外源硒肥的选择及富硒水稻安全生产提供参考依据。【方法】以水稻品种鄂中5号为试验材料,设5个硒含量梯度(15.0、22.5、30.0、37.5和45.0 g/ha,以硒计),水稻灌浆期叶面喷施对应的生物纳米硒[3.0 L/ha (N1)、4.5 L/ha (N2)、6.0 L/ha (N3)、7.5 L/ha (N4)和9.0 L/ha (N5)]和亚硒酸钠[32.61 g/ha (Y1)、48.91 g/ha (Y2)、65.22 g/ha (Y3)、81.52 g/ha (Y4)和97.83g/ha (Y5)],以喷施等量清水为对照(CK)。成熟后分别调查各处理水稻的农艺性状、经济性状、品质性状、精米硒含量及根际土壤理化性质。【结果】与CK相比,生物纳米硒处理的每穗总粒数、每穗实粒数、结实率和千粒重有不同程度提高,亚硒酸钠处理则出现一定程度降低。外观品质方面,2种硒源对稻米的粒长、粒宽、粒型和透明度影响不显著(P>0.05,下同),但显著降低垩白度和垩白粒率(P<0.05,下同),最大降幅分别为23.13%(N2处理)和39.60%(N5处理); N2处理显著提高稻米的碾磨品质,精米率和整精米率分别提高3.07%和5.89%。在蒸煮品质方面,除Y2处理外其余处理均降低稻米直链淀粉含量,且Y5处理降幅最大(12.56%),施硒对胶稠度和碱消值影响不显著。施硒能提高稻米的蛋白质含量(4.76%~30.98%),且在Y3处理时增幅最大。硒对根际土壤有机质含量影响不显著,但一定程度提高碱解氮、有效磷和速效钾含量,最大增幅分别为3.86%(N1处理)、18.86%(Y5处理)和5.57%(N4处理),且喷施亚硒酸钠后均显著降低根际土壤pH。施硒能提高稻米硒含量,生物纳米硒处理的稻米机硒占比均大于95.00%,而亚硒酸钠处理的大米有机硒占比均在85.00%以下。【结论】叶面喷施不同用量的生物纳米硒和亚硒酸钠均会影响水稻的千粒重、整精米率、垩白粒率、垩白度、直链淀粉含量、蛋白质含量和硒含量。综合分析,水稻灌浆初期叶面喷施22.5或30.0 g/ha的生物纳米硒可生产出同时符合国家标准和湖北省食品安全地方标准的富有机硒大米。

     

    Abstract: 【Objective】To explore the effects of foliar spraying different selenium sources during filling period on rice growth, quality, selenium content and physicochemical properties of rhizosphere soil, so as to provide reference for the selection of exogenous selenium fertilizer and the safe production of selenium-rich rice.【Method】The rice variety Ezhong 5 was as the material, five selenium content gradients(15.0, 22.5, 30.0, 37.5 and 45.0 g/ha, calculated by selenium) were set, the corresponding biological nano selenium[3.0 L/ha(N1), 4.5 L/ha(N2), 6.0 L/ha(N3), 7.5 L/ha(N4)and 9.0 L/ha(N5)]and sodium selenite[32.61 g/ha(Y1), 48.91 g/ha(Y2), 65.22 g/ha(Y3), 81.52 g/ha(Y4)and 97.83 g/ha (Y5)]were sprayed on the leaf surface of rice during filling stage, and equal amount of water spraying as control(CK). In this research, the agronomic traits, economic traits, quality traits, selenium content of rice and physicochemical properties of rhizosphere soil were investigated respectively.【Result】The results showed that the biological nano selenium spraying improved the grains per panicle, filled grains per panicle, seed setting rate and the 1000-grain weight compared with CK, while these indexes decreased in sodium selenite spraying treatment. In terms of appearance quality, grain length, grain width, grain shape and transparency were not significantly(P>0.05, the same below)different from CK by two different selenium sources, but they significantly(P<0.05, the same below)reduced the chalkiness and chalky grain rate, with the maximum decline of 23.13%(N2 treatment)and 39.6%(N5 treatment)respectively. N2 treatment significantly improved the milling quality of the rice, increasing the milled rice rate and head rice rate by 3.07% and 5.89% respectively. In terms of cooking quality, all treatments except Y2 treatment reduced the content of rice amylose content, with the largest decrease in Y5 treatment(12.56%), at the same time, selenium application had no significant effect on the glue consistency and alkali elimination value. Selenium application increased the protein content of rice(4.76%-30.98%), and the largest increase was observed in Y3 treatment. The organic matter content of rhizosphere soil was no significantly affected by the application of selenium, but the contents of alkali-hydrolyzed nitrogen, available phosphorus and available potassium were increased by 3.86%(N1 treatment), 18.86%(Y5 treatment)and 5.57%(N4 treatment)respectively. Meanwhile, the pH of rhizosphere soil was significantly decreased after spraying with sodium selenite. Selenium application could improve the selenium content of rice, but the organic selenium content of rice after biological nano selenium spraying was more than 95.00%, while organic selenium contents of rice in all treatments of sodium selenite were less than 85.00%. 【Conclusion】Different amounts of biological nano selenium and sodium selenite affect the 1000-grain weight,head rice rate,chalky grain rate,chalkiness,amylose content,protein content and selenium content of rice. According to comprehensive analysis, the application of 22.5 or 30.0 g/ha biological nano selenium in the stage of rice grain filling is suitable for the production of organic selenium-rich rice that meets the national standard and local food safety standard of Hubei Province.

     

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