甘肃省陇东旱塬区全膜双垄沟播玉米田杂草消长动态

Weed Shift Dynamics in a Whole- Film Double- Furrow Sown Corn Field from Longdong Plateau

在陇东旱塬区研究了全膜双垄沟播和露地玉米田杂草的消长动态,结果表明,全膜双垄沟播田杂草发生期(4月上中旬)较露地约提前1个月。全膜双垄沟播田杂草群落的物种丰富度及其密度分别呈"N"字形和"∧"形,均与露地相似,但其波动幅度明显大于露地,高峰期均明显早于露地。全膜双垄沟播和露地种植模式下,阔叶杂草物种丰富度和密度的波动幅度均远大于禾本科杂草。全膜双垄沟播玉米田阔叶杂草群落鲜质量及其单株鲜质量均呈"∧"形,而露地呈持续递增形,高峰期均明显早于露地,峰值均明显小于露地;全膜双垄沟播玉米田禾本科杂草群落鲜质量及其单株鲜质量波动幅度均远大于阔叶杂草,均与露地情形相反。杂草发生对全膜双垄沟播田集水、保墒及玉米生长发育均造成持续性危害,以玉米播后出苗期和玉米拔节至大喇叭口期危害最重,分别称之为第一、第二危害盛期。

Weed shift dynamics in a whole -film double -furrow sown corn field and an open field from Longdong plateau were investigated.The weed occurrence period in whole -film double -furrow sown corn field was one month earlier than at the open field(in early and mid april).Both fields had the same species abundance and weed density,which were shaped like an “N”and a “∧”,but the fluctuation and peak in the whole -film double -furrow sown corn field was ob-viously greater and earlier than that in open field.Under both planting systems,the fluctuation of species abundance and density of broadleaf weed were larger than those of grass weeds.Both broadleaf weed community fresh weight and per plant fresh weight showed a “∧”shape,and a continuous increase in peak shape was obviously earlier that in the open field but the peak was significantly less than that in open field.Community gramineous weed fresh weight and plant fresh weight fluctuations were larger than broadleaf weeds,being contrary to the situation in open field.Catchment,soil moisture and growth and devel-opment of corn were caused by persistent weed damage in the whole film double furrow sown corn field.The seeding stage and jointing stage to booting stage were <br> the most damaged,which were called the first and the second harmful periods.