黄土高原坡耕地植物篱—作物间作系统水分利用特征研究

利用陇中黄土高原典型雨养农业区坡耕地布设田间试验,设置5个处理:裸坡休闲(F)、小麦单作(W)、小麦/甘草(W/L)、小麦/菘蓝(W/I)和小麦/苜蓿(W/A)。通过探讨植物篱-作物间作系统的小麦产量表现及其土壤水分利用特性,明确不同植物篱-作物复合系统土壤耗水特征及影响机制,以期为黄土高原坡耕地适宜植物篱的筛选提供理论依据。结果表明:小麦生育期和休闲期0~200 cm土壤剖面含水量较低,基本接近作物有效水分下限(crop lower limit,CLL)。植物篱-作物间作能够起到积蓄降水的作用,但主要体现在耕层0~30 cm土壤,且以小麦/苜蓿处理效果最佳。不同处理棵间蒸发量和蒸发占总耗水量的比重有一定的差异,其中小麦/甘草处理耗水量最高(250.98 mm),裸坡休闲总蒸发量较大(197.30 mm)。裸坡处理棵间蒸发占耗水量的比例高达80%以上,主要表现为土壤蒸发,而小麦/甘草主要表现为作物蒸腾,说明植物篱-作物复合系统可一定程度有效降低棵间蒸发量和蒸发占总耗水量的比重,增加作物蒸腾量。不同间作系统小麦耗水量与单作耗水量并无差异,但其产量提高了60.00%~83.55%,进而明显提高了小麦水分利用效率。

Soil water utilization characteristics of slope land in hedgerow and grain crop intercropping systems on the Loess Plateau

This study investigated soil water utilization characteristics in hedgerow intercropping systems by analyzing the grain yield and water consumption characteristic in hedgerow and grain crop intercropping systems on the Loess Plateau of central Gansu. Five treatments were compared: fallow (F), wheat monoculture (W), wheat and Licorice inter-cropping (W/L), wheat and Radix isatidis intercropping (W/I) and wheat and alfalfa intercropping (W/A). The results showed that the soil moisture along 0-200 cm soil profile of croplands with different treatments was obviously lower, being equal to crop lower limit. Soil water content at 0-30 cm was greatly improved under hedgerows and grain crop intercropping systems with highest soil water content in the W/A treatment. The highest water consumption (251.0 mm) occurred in the W/L treatment, while the lowest (197.3 mm) occurred in the W treatment. The ratio of soil evaporation and water consumption was higher than 80% in the F treatment, indicating that water loss was mainly through evaporation in the F treatment but mainly through transpiration in hedgerows-crop intercropping systems. Hedgerows and grain crop intercropping systems were able to decrease E/ET to some extent and increase crop transpiration. There were treatment differences for water consumption, but grain yields in intercrop systems were 60.0% to 83.6% higher than wheat monoculture. As a result, water use efficiency improved from 49.7% to 76.1% under hedgerows and grain crop intercropping systems compared to wheat monoculture.