桑粮间作田条桑根系分布格局及其对土壤水分、养分的影响

条桑在河北省东部平原沙地和丘陵梯田广泛种植,与农作物间作是其主要栽培模式。2006年在河北省迁安市进行了桑粮间作田条桑根系断面积、根量、根系直径分布特征及其对土壤水分、养分影响的研究。结果表明:根系分布主要集中在20~40 cm土层内,此范围内的根系重量占总根量的60%~80%。根系以直径小于3 mm的细根居多,占总根量的30%~40%,大于7 mm的粗根数量很少,占总根数的5%~15%。平原沙地条桑根系主要分布在距桑丛中心100 cm范围内,桑丛外缘100 cm处的根量仅为总根量的6.52%,水平延伸幅度较窄,根系垂直分布明显;丘陵梯田条桑根系水平延伸可达桑丛外250 cm处,只有少量根系垂直深入岩石中,水平分布趋势明显。条桑根量、根系直径、根系断面积分布依立地条件及土层深度的不同而异。桑丛中心外1 m处深层土壤含水量增加,桑丛附近2.5 m内没有存在严重的土壤水分亏缺。平原沙地和丘陵梯田桑丛附近条桑富集土壤养分作用明显。

Root Distribution Pattern of Mulberry Shoots Intercropped with Peanut and Its Influence on Soil Moisture and Nutrient in Qian'an

Mulberry shoots were planted in the plain sandland and hill terrace in the eastern of Hebei province,and they were mainly intercropped by peanut and maize.Root distribution of mulberry shoots and its influence on soil moisture and nutrient in Qian'an were studied.The results showed that: the weight of the roots in the 20~ 40 cm soil layer were 60%~ 80% of the total amounts,and distributed decreasingly with the depth increasing.The hairy roots(diameter<3 mm)were 30%~40% of the total amounts,concentrating in the 20~ 40 cm soil layer.The roots(diameter>7 mm) were the least and only 15% of the total amounts.The horizontal distribution mainly concentrated in the cluster of 0~ 100 cm from the center of mulberry shoots cluster in the plain sandland.The weight of roots in the 100 cm soil layer from the cluster was 6.25% of the total amounts.The root vertical distribution could reach up to 3.28 m in depth,and some roots embed the deep soil layer where the horizontal distribution range was little,but the horizontal distribution was obvious in the hill terrace.The roots horizontal distribution could reach to 250 cm in width with few roots embed the rock.The roots weight,diameter and section area distribute characteristics of mulberry shoots were different according to site condition and the depth of the soil.The deepsoil moisture could be increased.There were not obvious moisture deficits in the horizontal range near the cluster.The soil nutrient near the cluster could be improved by the mulberry shoot