杂草对全膜双垄沟播田集水保墒效果影响

Effect of Weed on Water Conservation of Whole Plastic-film Mulching on Double Ridges in the Corn Field

在陇东旱塬区测定了杂草对全膜双垄沟播田地膜完好性及集水保墒效果的影响。结果表明,全膜双垄沟播玉米田杂草于播前20d开始发生,以拔节至大喇叭口期受害最大,膜面被重度撑起和撑破,集水沟消失,田间集水保墒性处于最差状态;出苗期至幼苗期受害较重,地膜被中度撑起但未被撑破,集水沟明显变浅,田间集水性处于欠佳状态,保墒性尚好;孕穗期以后,杂草逐渐腐烂死亡,之前被撑起的膜面逐渐回落,其危害逐渐减小甚至消失。玉米生育时期越晚、土层越浅,杂草引起全膜双垄沟播田土壤水分下降的幅度越大,玉米大喇叭口期至成熟期下降6.6~27.5g/kg,0~100cm土层下降22.6~6.0g/kg。杂草对全膜双垄沟播玉米主要农艺性状均产生不良影响,其中穗粒数显著减少是引起玉米减产的主要原因,草害区玉米减产20.76%。

Membrane integrity and water conservation in the corn field of whole plastic-film mulching on double ridges were tested. The results showed that weed occurred before sowing 20 d. Weeds caused the largest damage from elongate to big trumpet period. During this period, the membrane face was held up and burst, and water conservation was in the worst state. During seeding period, the membrane face was held up, but not burst, and water conservation was in poor state. After booting stage, weeds gradually decayed to die, and the membrane surface held up gradually declined and harm gradually reduced or even disappeared. Soil moisture decreased dramatically when corn growth in late period and soil layer shallow. Soil moisture decreased by 6.6 ~ 27.5 g/kg when corn in big trumpet period and maturation phase. In 0~100 cm soil layer, soil moisture decreased by 22.6~6.0 g/kg. Weed had a negative impact on corn main agronomic traits, among which the marked decline of seed number was the main cause of corn yield decreasing. Corn yield in weed area decreased by 20.76 %.