膜下滴灌制度与生物炭用量对玉米生长及水氮利用效率的影响

Effects of Drip-irrigation Schedule Under Film-mulching and Biochar Amount on Corn Growth and Water-nitrogen Use Efficiency

为探明干旱地区盐碱地膜下滴灌不同灌水下限施用生物炭对玉米产量和水肥利用效率的响应差异及相互影响关系,提出较优的灌溉制度和生物炭用量。连续2年在河套灌区盐渍化农田玉米生长阶段进行小区控制试验,设计3个灌水下限[土壤基质势为-15(W15),-25(W25),-35(W35)kPa,灌水定额为22.5 mm]和3个生物炭用量水平[0(B0),15(B15),30(B30)t/hm^(2)],2因素完全随机试验设计,共9个处理。测定并分析玉米全生育期0—15 cm土壤理化性状、作物生长特征和水氮利用效率。结果表明:不同灌水下限施用生物炭整体提高玉米全生育期土壤含水率、有机质和碱解氮含量,同一灌溉水平下生物炭用量越高,各指标提升的幅度越大。施用生物炭提高玉米地上部干物质积累量和产量,灌溉水利用效率和氮肥偏生产力显著提高,且生物炭施用当年的效果普遍优于翌年。相较于不施用生物炭的对照,W15、W25、W35条件下,B15使玉米产量平均增加12.8%,10.3%,14.2%,灌溉水利用效率提高14.2%,10.4%,12.9%,氮肥偏生产力提升12.8%,10.4%,14.0%,其节水增产提效的作用普遍优于同一灌水处理的B30。建议河套灌区盐渍化农田玉米生育期的膜下滴灌灌水下限为-35 kPa,生物炭施用量为15 t/hm^(2)。

To determine the influence of biochar addition on maize yield and water-fertilizer use efficiency under limits of soil suction to trigger irrigation for mulched drip irrigation in saline-alkali areas,proposing the optimal irrigation schedule and biochar application rate,a field experiment from2015 to 2016 was carried out in the maize growth stage of the salinized farmland in the Hetao Irrigation District.Three limits of soil suction to trigger irrigation[-15(W15),-25(W25),-35(W35)kPa,and the irrigation quota was 22.5 mm]and three application rates of biochar[0(B0),15(B15)and 30(B30)t/hm^(2)]were designed.Biochar was just only applied in the first year.Soil physochemical properties in top 15 cm layer,crop growth characteristics,water and nitrogen use efficiency and economic benefits of maize in the whole growth period were measured and analyzed.The results showed that the application of biochar at different irrigation water limits increased the soil water content,organic matter,and available nitrogen content in the whole growth period of maize.For same irrigation level,the higher the amount of biochar,the greater the improvements of these measurements.Application of biochar significantly increased the dry matter accumulation and grain yield of maize plants;the irrigation water use efficiency and the partial fertilizer productivity of nitrogen were also significantly improved.Compared with the control without biochar,under the conditions of W15,W25 and W35,B15 increased corn yield by 12.8%,10.3%and 14.2%,irrigation water use efficiency increased by 14.2%,10.4%and 12.9%,and nitrogen fertilizer partial productivity increased of 12.8%,10.4%and 14.0%.For same irrigation treatment,the effect of B15 in saving water,enhancing yield was generally better than that of B30.It is suggested that the limit of soil suction to trigger irrigation is-35 kPa(22.5 mm for each irrigation)under mulched drip irrigation during the growth period of maize in salinized farmland,and the application rate of biochar is 15 t/hm^(2).