紫色丘陵区桑树林地土壤理化性质及其抗蚀性研究

Soil Physicochemical Properties and its Anti-erosion of Mulberry Forest Land in Purple Hilly Area

[目的]为对桑树水土保持效益的客观评价提供科学依据。[方法]通过室内理化性质分析法,研究桑树林地土壤理化性质及其抗蚀性能。[结果]桑树林地可显著改善土壤理化性质,提高土壤抗蚀性能,增加土壤有机质含量,其中剑持的土壤改良效果最好,有机质含量最高（30.67 g/kg）,是湖桑32号的1.82倍。各样地土壤团聚体分布均不均匀,风干土团聚体主要分布在＞5 mm范围;3种桑树林地＞0.25 mm风干土团聚体（94.50%～97.00%）和水稳性团聚体（50.16%～61.66%）含量均较高,并以嘉陵20号水稳性团聚体含量最大（61.66%）,表明该桑树对改善土壤结构和增强其土壤稳定性效果最好。嘉陵20号水稳性指数为0.52,其结构体破坏率最小（36.43%）,水稳性团聚体的GMD和MWD分别为1.06和1.33 mm,表明抵抗降雨侵蚀和径流冲刷能力最强。嘉陵20号的内摩擦角为13.712°,为剑持的1.40倍,湖桑32号的黏聚力最大,说明这2种桑树均对土壤有较高的改良作用。[结论]剑持对土壤理化性质的改良最优,嘉陵20号在改善土壤团聚体稳定性方面具有较高优势,湖桑32号可以提高土壤黏聚力以增强土壤的抗侵蚀力,三者在对土壤的水土保持效应方面各有优势。其中,嘉陵20号在各方面的表现较优,对土壤的改良效果最显著。

[Objective]The research aimed to provide scientific basis for evaluating soil and water conservation benefits of mulberry objectively. [Method] Soil physicochemical properties and soil anti-erodibility of mulberry forest lands were studied using the mean of soil physicochemical properties analysis. [Result]Mulberry improved soil physicochemical properties,soil anti-erodibility and soil organic content significantly,in which Jianchi forest land had the best effect on improving the condition of soil and the soil organic content was the highest（ 30. 67 g / kg）,1. 82 times higher than that of Husang-32. The size distribution of soil aggregate was uneven for all experimental plots,and dried aggregate mainly distributed in 〉 5mm. The content of 〉 0. 25 mm dried aggregate（ 94. 50-97. 00%） and water stable aggregate（ 50. 16-61. 66%） from three different varieties of mulberry forest lands were greater,in which the content of water stable aggregate of Jialing-20 forest land was the highest（ 61. 66%）,which indicated that Jialing-20 had the best effect on improving soil structure and soil stability. Water stable index of Jialing-20 forest land was 0. 52,and its structural damage rate was the minimum（ 36. 43%）. GMD and MWD of water stable aggregate were 1. 06 and 1. 33 mm respectively,which indicated that its capability of resisting rainfall erosion and runoff scouring were the strongest. The angle of internal friction of Jialing-20 was 13. 712 °,1. 40 times higher than Jianchi. The cohesion of Husang 32 was the highest. It showed that all of these two could make effective influence for the soil. [Conclusion]Jianchi had the best effect on soil physicochemical properties and Jialing-20 had more advantage in improving the stability of soil aggregates,in the orther side Husang 32 could improve the soil cohesion in order to enhance the anti-erosion ability of the soil. All these three kinds of mulberry played an important role in soil and water conservation. Compared with the other two factors,Jialing-20,which was the best in all directions,had the best effects on the soil.