灌水量对全膜垄作沟灌玉米产量及水分利用效率的影响

针对河西灌区水资源紧缺的问题,探索玉米合理的灌溉量,以期指导区域玉米合理灌溉。通过在石羊河流域设置不同的灌水量梯度,研究不同灌水量对全膜垄作沟灌玉米产量及水分利用效率,以及土壤含水率、产量要素的影响。结果表明:全膜垄作沟灌玉米灌水量从4 500 m~3·hm~(-2)增加到4 725 m~3·hm~(-2)、4 950 m~3·hm~(-2)时,产量并没有随着灌水量的增加而增加,灌水量增加到5 175 m~3·hm~(-2)时,在水分利用效率没有降低的情况下,产量相对于4 500、4 725 m~3·hm~(-2)和4 950 m~3·hm~(-2)处理明显增加11.46%、8.39%和8.54%,其中果穗长度、穗粒数和百粒重平均增加4.88%、3.27%和4.31%是其产量增加的主要原因。对于土壤含水率,玉米需水盛期的7月16日至8月3日,5 175 m~3·hm~(-2)处理显著高于其他三个处理,而灌浆期各处理间则差异不显著。与播前期相比,收获期土壤含水率降低层主要集中在20~80 cm土层,土层贮水量平均降低6.72 mm,且各处理0~110 cm土层贮水量差异并不明显。因此,本研究表明5 175 m~3·hm~(-2)为石羊河流域全膜垄作沟灌条件下的适宜灌溉量,但灌浆中后期的最后一次灌水应考虑适当降低灌水量。

Effects of irrigation amount on maize yield and water use efficiency under full mulching with ridge seeding and furrow irrigating

Field experiments were employed to find the effects of different irrigation amount on maize yield and water use efficiency under full mulching with ridge seeding and furrow irrigating in Shiyang river basins.It turned out the yield did not increase with the increase of irrigation amount from 4 500 m3· hm-2 to 4 725 m3· hm-2 and 4 950 m3· hm-2.However,without decrease in water use efficiency,when the irrigation amount increased to 5 175 m3· hm-2,the yield increased by 11.46％,8.39％ and 8.54％ in the treatments of I180,I195 and I210 respectively.The increase was mainly attributed to the average increase in spike length by 4.88％,grain number by 3.27％ and l00-grain mass by 4.31％.The soil water content was significantly higher in I225 treatment in the other three treatments at water demand peak by corn (from 16 July to 3 August),while there was no significant difference in the treatments at filling stage.Compared with the seeding stage,the decreased layers of soil water content were mainly located at 20 ～ 80 cm soil layers at harvest,and soil water storage decreased by an average of 6.72 mm.There was no significant differences of the soil water storage among treatments at 0 ～ 110 cm soil layers.It was concluded that 5 175 m3· hm-2 was the appropriate irrigation amount for maize under full mulching with ridge seeding and furrow irrigating in Shiyang river basins,but at the late filling stage it was desirable to reduce the irrigation amount appropriately.