覆盖后秋浇对翌年春玉米生育期水热盐及产量的影响

为探讨寒旱盐灌区覆盖后秋浇对翌年春玉米生育期水热盐状况的影响,2013年10月—2015年10月在河套灌区盐渍土壤进行覆盖秋浇后翌年春玉米田间试验,设5个处理,秸秆覆盖量0.9 kg/m2(F0.9)、秸秆覆盖量0.6 kg/m2(F0.6)、玉米整秆覆盖(YZ)、地膜覆盖(DM)、未覆盖(CK)。试验于每月中旬进行取土测定土壤含水率、电导率,玉米收获后测定籽粒产量及生物产量与经济系数。结果表明:秋浇前地面覆盖影响翌年春玉米生育期内各处理的土壤温度,地膜覆盖处理耕层地温均值最高,秸秆覆盖处理的土壤温度低于未覆盖处理,且秸秆覆盖使得春季土温升温缓慢而不利于春播作物生长;各处理覆盖秋浇后的土壤含水率均高于未覆盖处理CK,无论是播期的土壤储水量还是生育期内的土壤储水量,秸秆覆盖处理的蓄水保墒性地膜覆盖处理及未覆盖处理;各处理0~40 cm覆盖秋浇后的土壤含盐量均值均低于CK,其中处理YZ的土壤含盐量最低;地面覆盖处理的籽粒产量和生物产量均高于未覆盖处理CK,籽粒产量最高的是处理YZ;各处理中,玉米整杆覆盖处理YZ和粉碎的玉米秸秆覆盖量为0.9 kg/m2的产量与经济系数较高。研究可为覆盖秋浇农艺节水应用提供参考。

Effect of autumn irrigation after mulching on water-heat-salt and yield of following spring maize

In order to investigate the impacts of autumn irrigation after mulching on water-heat-salt conditions during maize growth in the next spring in cold-drought-salt irrigation district,field experiments was carried out in the saline soil in Hetao irrigation district (located at 40°92′N、107°18′E) from October 2013 to October 2015.There were 5 treatments including mulching with 0.9 kg/m2 straw (F0.9),0.6 kg/m2 straw (F0.6),whole maize straw (YZ) and plastic film (DM),and no mulching (CK).The maize straw was chopped into 3-5 cm length after harvesting in the treatment of F0.6 and F0.9.The YZ treatment used the whole maize straw with amount of 6 plants per meter.The plastic film was white polythene film in width of 70 cm,thickness of 0.020 mm,and spacing among film was 40 cm.The plot for each treatment had a length of 8 m and a width of 5 m.Each treatment replicated 3 times.The soil was loam with bulk density of 1.48 g/cm3 and pH value of 8.01.The straw and plastic film was mulched on 31st,October.The irrigation carried out on 1st,November with amount of 150 mm.The maize was planted in the next April.It was harvested on 25th,September.Measured items included soil moisture,electrical conductivity,soil temperature,maize yield,biological yield,and economic coefficients.The electrical conductivity was converted into soil salinity by an empirical equation.Groundwater depth was observed during the experimental process.The results showed that the average soil temperature at 0-20 cm was 16.07 ℃ for F0.9,16.66 ℃ for F0.6,16.64 ℃ for YZ,20.08 ℃ for DM,and 18.59 ℃ for CK,respectively.The straw mulching decreased soil temperature and did not facilitate rapid growth of maize.During the non-frozen period,the groundwater depth averaged 1.57 m during the 2 years.The soil moisture at 0-20 cm averaged 26％-30％ for the mulching treatment and 22.68％ for the CK.The soil water storage was significantly higher in the straw mulching treatment than in the CK.The soil water storage of YZ was highest among the treatments.The soil salinity at 0-40 cm averaged 0.82,0.76,0.71,1.05 and 1.38 g/kg for the treatment of F0.9,F0.6,YZ,DM and CK,respectively.The treatment of YZ had the lowest soil salinity and could effectively inhibit soil salinization.Dynamics of soil salinity showed that the soil salinity at the mature stage of maize was higher than that before sowing at 0-20 cm while that at 60-120 cm was lower than that before sowing except for CK.The YZ treatment had the best salinization control effect.The grain yield of mulching was significantly higher than that of CK (P＜0.05).Compared with CK,the treatments of YZ,F0.9,F0.6 and DM increased the grain yield by 108.79％,82.75％,58.55％ and 68.05％,respectively (P＜0.05).The biological yield of YZ was higher than DM,F0.6 and F0.9 and that of CK was lowest.The economic coefficient of YZ and F0.9 was 19.91％ and 24.15％ higher than that of CK(P＜0.05),respectively.Overall,the treatment of YZ and F0.9 had the highest yield and economic coefficient.This study provides valuable information for application and development of autumn irrigation after mulching technology in Hetao irrigation district.