不同覆盖物对山地板栗园土壤性状及幼苗生长的影响

摘要

试验研究了不同覆盖物对瘠薄山地板栗园土壤环境因子及板栗幼苗生长的影响,为合理选择幼树抚育阶段的覆盖方式提供科学参考.选取黑地膜、黑地布、毛毡、白地膜作为覆盖材料,以清耕为对照,对不同覆盖处理下的土壤温度、水分、容重、土壤酶活性、微生物数量及板栗幼苗的生长特征进行了分析.结果表明:4种覆盖处理均可大幅提高地表温度,白地膜对提高10～30 cm土层温度最明显,而毛毡处理的10～30 cm土层温度最低,且温度变化最小,最适合根系生长.所有覆盖均能增强土壤保水能力,其中黑地膜与白地膜覆盖对提高0～ 20 cm土层含水量效果最明显,毛毡处理则对提高20 ～ 30 cm土层含水量效果最好,而白地膜处理可引发土壤水分向表层聚集现象.4种覆盖方式均可降低0 ～ 30 cm土层容重,有助于保持土壤疏松状态;但均不能提高土壤蔗糖转化酶与酸性磷酸酶活性,因此不利于土壤有机碳转化与有机磷矿化.黑地膜、毛毡和白地膜可提高蛋白酶活性,仅有白地膜可提高脲酶活性.黑地布、毛毡、白地膜覆盖均可增加微生物总数,而黑地膜则降低了微生物总数.毛毡对增加细菌和放线菌数量效果最显著,较清耕分别提高了2.2倍和37.0％.仅白地膜可增加真菌数量,但并不显著.4种覆盖处理均能增加侧根长和出苗率,但不能诱导更多侧根的发生.毛毡覆盖可显著促进主根的伸长生长、地上部生长和幼苗生物量,并对提高出苗率具有显著效果,因此最有利于板栗幼苗的生长.%This study researched the effects of different mulches on soil environment of barren hilly orchard and chestnut seedling growth to offer a scientific reference for choosing suitable mulching modes during the young seedling growth.The main soil ecological factors,such as temperature,water content,soil bulk density,soil enzyme activity,soil microorganisms,and characteristics of chestnut seedling growth were analyzed fully in different mulching treatments of black film,black plastic cloth,felt,white film,and clean tillage (as control).The results showed that all of the four mulches could increase the temperature of 0 cm soil layer in great degree,and white film mulching was the most obvious in raising 10 ～30 cm soil layer temperature.The temperature of 10 ～ 30 cm soil layer was the lowest in felt mulching with the minimum variation,so it was the most suitable for the chestnut root growth.All the mulches were beneficial to enhance the soil water content.Black film and white film were remarkable in increasing water content of 0 ～ 20 cm soil layer,and felt mulching was the most favorable in increasing 20 ～30 cm soil layer water content.Meanwhile,white film could led water transportation from the deep layer to the shallow layer.All the mulches could keep soil loose by reducing 0 ～ 30 cm soil bulk density.All the mulches were unhelpful to the turnover of soil organic carbon and mineralization of soil organic phosphorus because of the lack of increasing sucrose invertase activity and acid phosphatase activity.Black film,felt and white film could promote the protease activity,and only white film could promote the urease activity.The number of soil microorganisms rose in the treatments of black plastic cloth,felt and white film,while decreased in black film treatment.The number of bacteria and actinomycete increased more sensibly in felt treatment by 2.2 times and 37.0％ respectively compared with clean tillage.Only white film could add the number of fungi without significant level.All the four mulches were helpful in improving the lateral root length and seedling rate,while not beneficial to induce more lateral root number.Felt mulching could promote the root elongation and aboveground growth sharply,increase the seedling biomass,and boost the seedling rate significantly as well,so it would be the most appropriate method for the chestnut seedling growth.