绿洲灌区地膜秸秆交替覆盖玉米农田土壤水分利用特征

在甘肃河西绿洲灌区,通过田间试验研究了不同耕作(免耕、传统耕作)与覆盖方式(全膜覆盖、70%地膜覆盖+30%捆状玉米秸秆覆盖、70%地膜覆盖+30%不覆盖、50%地膜覆盖+50%捆状玉米秸秆覆盖、50%地膜覆盖+50%不覆盖)对土壤耗水特性、玉米产量及水分利用效率的影响。结果表明:免耕地膜秸秆交替覆盖(NTP7S3、NTP5S5)较传统耕作全膜覆盖(CTP)降低了玉米农田棵间蒸发量,降低比例分别为20.7%与19.1%,玉米秸秆捆状覆盖显著降低了棵间蒸发量,较不覆盖降低59.0%～60.8%,而相邻地膜覆盖较秸秆覆盖提高棵间蒸发量达到29.9%～32.3%,说明NTP7S3与NTP5S5降低棵间蒸发量主要源于秸秆覆盖带较好地抑制土壤水分蒸发的作用。免耕地膜秸秆交替覆盖减小了玉米营养生长期(拔节～开花期)的耗水量,增大了生殖生长期(开花～完熟期)的耗水量,有效协调玉米各生育阶段耗水互补、竞争关系,NTP7S3与NTP5S5较对照CTP降低全生育期总耗水量3.6%与11.6%,棵间蒸发量占总耗水量之比(E/ET)降低17.7%与8.6%,以NTP7S3处理水分高效利用的调控效应较好;NTP7S3处理玉米获得较高的籽粒产量与水分利用效率,较CTP增产4.6%,水分利用效率提高8.4%。西北绿洲灌区地膜秸秆交替覆盖结合免耕替代传统耕作全膜覆盖并没有导致玉米产量和水分利用效率的降低,反而具有增产增效的作用,是玉米生产中地膜减投增效的可行措施。

Soil water use characteristics of maize field alternatively mulched with straw and plastic film in oasis irrigation area

The effects of tillage practices (no\|tillage, NT; conventional tillage, CT) and mulching patterns (whole plastic mulching, P; 70% plastic mulching and 30% straw mulching, P7S3; 70% plastic mulching and 30% no mulching, P7S0; 50% plastic mulching and 50% straw mulching, P5S5; 50% plastic mulching and 50% no mulching, P5S0) were used to test water consumption characteristics, yield performance and water use efficiency of maize in the Hexi oasis irrigation area of Gansu Province. The results showed that NTP7S3 and NTP5S5 treatments reduced soil evaporation of maize field by 20.7% and 19.1% in comparison to CTP treatment, respectively. In terms of different mulching strips, compared to no straw mulching, maize straw mulching significantly reduced soil evaporation by 59.0% to 60.8%. Adjacent plastic mulching increased soil evaporation by 29.9% to 32.3% in comparison to maize straw mulching. These results indicated that reducing soil evaporation with NTP7S3 and NTP5S5 treatments was mainly due to the better inhibition of soil evaporation by maize straw mulching. Alternate mulching of plastic and maize straw with no\|tillage decreased water consumption in the vegetative growth period (jointing\|flowering period) of maize, but water consumption was increased in the reproductive period (flowering\|full ripening period) of maize, which effectively adjusted water demand contradiction of maize growth at each growth stage. NTP7S3 and NTP5S5 treatments decreased water consumption by 3.6% and 11.6%, and reduced the proportion of evaporation to evapotranspiration (E/ET) by 17.7% and 8.6%. The NTP7S3 treatment had a better effect for enhancing the efficient utilization of soil water. Therefore, NTP7S3 treatment had greater grain yield and water use efficiency by 4.6% and 8.4% than CTP treatment. These results revealed that alternate mulching of plastic and maize straw with no\|tillage instead of whole plastic mulching with conventional tillage did not lead to a decrease in the grain yield and water use efficiency of maize, but increased grain yield and water use efficiency, thus, this practice can be a feasible measure to reduce plastic input and increase productivity in maize production in the oasis irrigation area of northwestern China.