马铃薯连作栽培的土壤水分效应研究

以宁南山区连作1年、3年、6年、10年的马铃薯地块为研究对象,利用定位观测数据,对不同连作年限下马铃薯生长特性及土壤水分变化规律进行研究。结果表明:马铃薯植株高度、叶面积和日净光合速率随连作年限的增加而降低;开花前后是马铃薯需水的高峰期,各连作年限马铃薯地块土壤水分的季节变化趋势一致,但连作6年、10年土壤含水量明显低于连作1年、3年;开花期不同连作年限土壤水分均在40～60cm层出现水分含量较低的干土层,干化程度随连作年限的增加而加重;连作6年的马铃薯地块在40～60cm处土壤水分含量降至11.63%,开始出现轻度干层迹象,连作10年40～60cm处土壤含水量为10.54%,逐步向中度干层过渡;且连作年限超过3年土壤水分利用效率明显降低。由于宁南山区土层深厚,土壤表层水分可通过降雨得到恢复,而连作超过3年深层土壤水分难以恢复,并对土壤水分环境产生深刻的负面影响。

Ecological effects of continuous potato cropping on soil water

This paper presents a field experiment of continuous potato cropping for 1 year, 3 years, 6 years and 10 years with the aim of investigating biological characteristics of potato and dynamic variations in soil water. The experimental results indicate that with increasing year of continuous cropping, potato height, leaf area and net photosynthetic rate decrease. Pre- and post flowering is the water requirement peak of potato. Seasonal variation trends of soil water at different soil layers under different cropping durations are similar, but significantly differ among different cropping year treatments. For different cropping year treatments soils are dry in 40~60 cm soil layer during potato flowering stage, and with increasing year of continuous cropping, soil desiccation is aggravated. Under 6 and 10 years of continuous cropping, soil water content is 11.63% and 10.54% in 50 cm soil layer, gradually developing from light to medium desiccation. For 3 or more years of continuous potato cultivation, WUE decreases drastically. Rainfall in the hilly regions of South Ningxia, where soil layer is usually deep, complements soil water in the upper soil layers. However, deep soil water compensation is hardly realized under potato continuous cropping for more than 3 years. For more 3 years continuous potato cropping, negative ecological and environmental consequences of soil water shortage occur in study area.