不同保水措施对退化干旱山地新植核桃园土壤养分和微生物的影响

目的]探索退化干旱山地不同保水措施对土壤理化特征的影响,为北方干旱退化山区土壤环境改良提供科学依据。方法]以太行山新垦片麻岩山地新植核桃园为试材,进行保水剂、玉米秸秆覆盖和地膜覆盖等保水措施的不同组合处理,研究土壤养分和微生物数量的变化。结果]秸秆覆盖能显著提高土壤养分含量和微生物数量。细菌、放线菌数量和有机质、全氮、全磷、全钾、有效磷、速效钾含量较对照分别提高了14.04%,17.42%,25.53%,60.29%,25.90%,15.31%,143.67%和51.44%。保水剂使得土壤养分含量和微生物数量略有下降。地膜覆盖降低了土壤细菌、真菌、放线菌、纤维素分解菌数量和有机质、全氮、全磷含量,较对照分别降低了27.19%,21.0%,10.11%,31.07%,1.11%,22.06%和6.06%,却提高了土壤全钾、有效磷、速效钾含量,较对照分别提高了12.6%,9.65%,8.09%。多元组合处理对土壤养分含量和微生物数量的影响相互之间差异较大;而保水剂+秸秆覆盖+地膜覆盖的组合并没有达到最佳效果;在所有处理中,保水剂+秸秆覆盖的组合对土壤的改良效果最好,与对照相比,提高土壤细菌、放线菌数量和有机质、全氮、全磷、全钾、有效磷、速效钾含量分别达16.67%,3.37%,6.64%,92.65%,12.67%,1.8%,94.25%和105.76%。结论]土壤养分、微生物数量与土壤水热气状况密切相关;保水措施在改变土壤水热气状况的同时,也改变了土壤养分和微生物数量。

Effects of Different Water Conversation Measures on Soil Nutrients and Microorganisms in Newly Planted Walnut Orchard in Degraded Drought Mountain Land

Objective] For the purpose of finding a well-behaved soil improvement method in degraded drought mountain lands, the influences of different soil and water conversation measures on soil physical and chemical properties were illustrated. Methods] Coneventional planting(contrast) and combined mulching treatments of water retention agent, maize straw and plastic film were designed in a newly planted walnut orchard in the drought gneiss area in Hebei Taihang Mountain in order to research their effects on soil nutrients and microorganisms. Results] Soil nutrient content and microorganism population increased significantly under straw mulch as compared with the contrast. Amounts of soil bacteria and actinomycetes, soil organic matter content, soil total N, total P, total K, effective P and available K increased by 14.04%,17.42%,25.53%,60.29%,25.90%,15.31%,143.67% and 51.44% respectively. Soil nutrient content and microorganism population declined slightly under water retention agent treatment. As compared with the contrast, the quantities of soil bacteria, fungi, actinomycetes, cellulose decomposing bacteria and the contents of soil organic matter, total N, total P decreased under plastic film mulching decreased by 27.19%, 21.0%, 10.11%, 31.07%, 1.11%, 22.06% and 6.06%; the contents of total K, effective P and available K, increased by 12.6%, 9.65% and 8.09%, respectively. The effects of combined treatments on soil nutrient contents and microorganism population were differently greatly. The most effective treatment on soil nutrients and soil microorganism amounts was not the combined treatment of water retention agent, straw and plastic film were as expected. The best measure was the combined mulching of water retention agent and maize straw. As compared with the contrast, the quantities of soil bacteria and actinomycetes, and the contents of soil organic matter, total N, total P, total K, effective P and available K, increased by 16.67%, 3.37%, 6.63%, 92.64%, 12.67%, 1.8%,94.25%, and 105.76%, respectively. Conclusion] Soil nutrient and microorganism population closely interacted with soil moisture, heat, air condition. Soil and water conversation measures can change moisture, heat, and air condition of soil. Through this, mulching can indirectly change soil nutrient and microorganism population.