不同覆盖措施对枸杞根系生长和土壤环境的影响

Effects of mulching patterns on root growth and soil environment of Lycium barbarum

耐旱枸杞是西北干旱地区重要的经济作物,为了进一步了解不同覆盖时间和覆盖材料对枸杞土壤环境和水分利用的影响,为枸杞抗旱节水栽培与水分高效利用研究提供理论依据,以3年生‘宁杞1号’为试验材料,研究了秸秆和地膜在春季和秋季进行覆盖后,枸杞根系生理特性和分布、土壤储水量和温度等根系和土壤环境的变化规律。结果表明:地膜和秸秆覆盖都可以提高土壤储水量,秋季覆盖更有利于冬季水分储存,使土壤储水量在早春分别增大到裸地对照的117.1%和114.4%;地膜和秸秆秋季覆盖使土壤平均温度比裸地对照高18.0%和7.1%,春季覆盖使平均温度比裸地对照分别高6.4%和2.3%;不同覆盖处理均可以增大根系比导率年平均值,秋季覆膜比导率变化最显著,达裸地对照的109.95%,春季覆秸秆比导率变化最小,仅为裸地对照的100.3%;覆盖处理在低温季节可以使根系活力升高,而在高温季节可以使根系活力降低;根冠比在秋季和春季覆膜后变化最显著,分别为裸地对照的87.42%和90.35%;表层0～20cm和水平距离40～60cm处,细根分布比例最大的均为秋季覆膜,分别达裸地对照的133.5%和116.7%,细根分布比例最小的均为春季秸秆覆盖。综合分析表明,覆盖模式与植株根系的生长、分布和土壤水分状况密切相关,使土壤环境和根系分布发生变化,更有利于利用土壤浅层和横向较远处的水分和营养物质。

Lycium barbarum is the main commercial crop across arid lands in northwestern China.In order to further understand the effects of different mulching patterns on root growth and soil environment,a mulching experiment was conducted at the Agricultural Demonstration Site in Gulang,Gansu Province(37.30°N,103.29°E).The experiment consisted of four treatments-plastic film mulching from spring of the second year(PMs),plastic film mulching from autumn of the first year(PMa),stalk mulching from spring of the second year(SMs)and stalk mulching from autumn of the first year(SMa).Root physiological characteristics and distribution,soil water storage and temperature of three-year-old plants of‘Ningqi 1’L.barbarum were studied.The results showed that both plastic film mulching and straw mulching improved soil water storage,and autumn mulching was better for winter soil water storage,which increased to 117.1%and 114.4%of that of CK(no mulching),respectively,in the next early spring.PMa and SMa respectively increased average temperature of soil by 18.0%and 7.1%,while PMs and SMs increased average temperature of soil by 6.4%and 2.3%,compared with CK.Both plastic film mulching and straw mulching improved annual specific conductivity of root,and the change in specific conductivity was most significant under PMa,reaching 109.95%of CK.Also change in specific conductivity was smallest in FMs,100.3%of CK.While mulching treatment increased root activity in low temperature seasons,it decreased root activity in high temperature seasons.Change in root/shoot ratio was most significantly under plastic film mulching,with PMa and PMs values of 87.42%and 90.35%of that of CK,respectively.Within 0?20 cm soil layer and 40?60 cm horizontally around the plants,the largest proportion of fine roots was under PMa(reaching respectively 133.5%and 116.7%of CK)and the smallest proportion was under FMs.It suggested that mulching pattern was closely related with root growth and distribution.Also soil moisture changed soil environment and root distribution.Mulching was good for water and nutrient utilization in shallow soils and in horizontal far from Lycium barbarum.