基质型缓释尿素对蕹菜产量、品质及氮肥利用率的影响

Effects of matrix-based slow-release urea on biomass,quality,and nitrogen use efficiency of water spinach

通过两年田间小区试验,分析基质型缓释尿素对蕹菜产量、品质性状以及氮肥利用率的影响,并结合室内氮素损失模拟试验、植株形态生理性状、田间土壤矿质氮含量等解析其影响机制。结果表明,与常规尿素相比:基质型缓释尿素可降低氮素淋溶(9.2个百分点)和氨挥发损失风险(8.7个百分点);提高田间土壤矿质氮含量(6.7%以上);提高蕹菜叶面积(8.5%以上)和叶片SPAD(18.4%以上);改善蕹菜叶片净光合速率(11.1%以上)、气孔导度(14.3%以上)、羧化效率(25.1%以上);提高蕹菜叶片硝酸还原酶活性(11.4%以上);提高根系表面积(7.7%以上),有利于植株同化积累和养分利用,进而提高蕹菜生物学产量(18.4%以上)和氮肥表观利用率(7.3个百分点以上);但对蕹菜的品质性状(如:维生素C、粗蛋白、可溶性糖和硝酸盐)无显著影响。综上,基质型缓释尿素可降低氮素损失风险、提高土壤氮素有效性、促进蕹菜生长,该型缓释肥在蕹菜等蔬菜生产中具有应用前景。

Frequent irrigation and high nitrogen application rates cause great nitrogen losses in vegetable fields,which can potentially be alleviated by using slow-release fertilizers such as matrix-based slow-release urea(MSU).However,little is known about the effects of MSU in vegetable fields.The study aimed to(i)determine the effects of MSU on nitrogen leaching and ammonia volatilization;and(ii)investigate the effects of MSU on growth and nitrogen use efficiency of water spinach(Ipomoea aquatica Forsk).A 2-year field experiment(2016~2017)was conducted to determine the effects of MSU on biomass,morphological and physiological traits,and nitrogen use efficiency of water spinach.Three treatments were control test(CK,without nitrogen application),regular urea(RU),and MSU.The nitrogen leaching and ammonia volatilization were studied with laboratory experiments.The results showed that compared with RU treatment,MSU treatment reduced nitrogen leaching(by 9.2 percentage points)and ammonia volatilization(by 8.7 percentage points);MSU treatment increased soil inorganic nitrogen concentration(by≥6.7%);MSU treatment increased leaf area(by≥8.5%)and leaf SPAD(by≥18.4%);MSU treatment improved leaf net photosynthetic rate(by≥11.1%),stomatal conductance(by≥14.3%),and carboxylation efficiency(by≥25.1%);MSU treatment improved leaf nitrate reductase activity(by≥11.4%);MSU treatment increased root area(by≥7.7%);MSU treatment increased plant biomass(by≥18.4%)and nitrogen apparent recovery efficiency(by≥7.3%);however,MSU treatment had little effects on vegetable quality(e.g.,vitamin C,crude protein,soluble sugar,and nitrate nitrogen).Overall,MSU is a promising slow-release fertilizer for production of vegetables such as water spinach,due to its effects on improving plant growth and apparent recovery efficiency and reducing the risk of nitrogen loss.