覆膜和灌水量对农田水热动态和制种玉米生长的影响

Effects of Film Mulching and Irrigation Amount on Farmland Water-Heat Dynamics and Growth of Seed-maize

覆膜和节水灌溉是我国西北旱区应对水资源短缺、提高作物水分生产率的主要措施。为了探索覆膜与灌溉制度对农田水热和制种玉米生长的综合影响,揭示农田耗水及水分利用效率的变化规律,于2017年在中国农业大学石羊河流域农业与生态节水试验站进行了制种玉米田间试验,设置覆膜与水分2个控制因素,覆膜分别为完全覆膜(M1)与不覆膜(M0)2个水平,水分设置W1、W2、W3、W4和W5 5个水平,分别为当地传统灌溉定额的100%、85%、70%、55%和40%,灌水方式为滴灌,共10个处理。结果表明:相同灌水条件下覆膜相对于不覆膜处理,可减少棵间蒸发,增高生育前期土壤温度,使株高和叶面积指数的增长速率高于不覆膜,提前7~10 d达峰值,增产达6.5%~44.6%,水分利用效率提高16.9%~50.4%。但覆膜可阻滞降雨入渗,以单次典型降雨32.4 mm为例,覆膜较不覆膜降雨入渗百分比降低22.4%。相同覆膜条件下,土壤贮水消耗量随着灌水量的减少而增多,因此土壤贮水量随着灌水量的增加而增加。灌水量越多,制种玉米株高、叶面积指数和最终干物质累积量越高,而水分利用效率则越低。覆膜条件下,W1处理产量最高,W3次之,且两者之间无显著性差异,水分利用效率则为W5处理最高,W3次之。M1W3处理可以在保证较高产量的同时,水分利用效率较MIW1提高17.6%。综上,在当地制种玉米生产中,虽然覆膜可能减少地表降水入渗,但可以使生育期提前、减少棵间蒸发,对于节水增产有一定的促进作用。

Film mulching and water-saving irrigation are the main measures to cope with water resources shortage and increase crop water productivity in the arid region of Northwest China. In order to explore the comprehensive influence of film mulching and irrigation system on farmland water and heat condition and seed-maize growth and reveal the variation of farmland water consumption and water use efficiency,field experiments of seed-maize were conducted at Shiyanghe Experimental Station for Water-saving in Agriculture and Ecology of China Agricultural University in 2017. The experiments involved ten treatments,i. e.,two levels of film mulching,full-mulching（M1） and non-mulching（M0） and five irrigation amount levels of drip irrigation,i. e.,W1,W2,W3,W4 and W5,respectively 100%,85%,70%,55% and 40% of the local traditional irrigation quota. Results showed that compared with nonmulching,film mulching can reduce soil evaporation and increase soil temperature in early stage,which resulted in higher growth rate of plant height and leaf area index,and reached their maximum values by7 ~ 10 d in advance,increased the yield of seed-maize by 6. 5% ~ 44. 6% and the water use efficiency by16. 9% ~ 50. 4% under the same irrigation conditions. But film mulching can block rainfall infiltration.For example,when the rainfall was 32. 4 mm,the percentage of rainfall infiltration into the soil was22. 4% less than that of non-mulched treatment. Under the same film mulching condition, theconsumption of soil water storage was increased with the decrease of irrigation amount,thus the soil water storage was increased with the increase of irrigation amount. The higher irrigation amount was,the higher the plant height,the LAI and the total dry biomass were,while the lower the water use efficiency was.The yield of W1 was the highest and that of W3 was the second under the condition of film mulching,and there was no significant difference between them. While for the water use efficiency,W5 was the highest and W3 was the second. The M1 W3 treatment can keep higher maize yield with water use efficiency enhanced by 17. 6% compared with that of M1 W1. In conclusion,although field mulching may reduce the infiltration of rainfall,it can advance the growth period and reduce soil evaporation,which enhanced yield and saved water in the production of local seed-maize to some extent.