【作者】 王艳士；

【导师】 罗菊春； 王庆锁；

【作者基本信息】 北京林业大学 ， 生态学， 2005， 硕士

【摘要】 目前,我国土壤风蚀严重,沙尘暴困扰京津,而且日趋恶化。在治理过程中,人们认识到在植树造林、草原建设的同时还应该注意农田保护。如何既能防止起沙,又不影响农民的收入,还能提高经济效益呢?实行保护性农业是其有效途径之一。 我们在2004年在山西大同市浑源县对试验区不同类型土地土壤风蚀进行野外观察与室内分析,并且通过测定土壤水分,作物和气象资料,运用水分平衡原理研究了林、草和农田等三种土地利用方式的耗水规律,比较了它们的水分利用效率、经济效益和生态效益,得出以下初步结论: 在防止风蚀作用方面,果树林地>苜蓿地>免耕>翻耕。试验结果表明:采用保护性耕作具有良好生态效应,可以有效地控制农田风蚀沙化,减轻风蚀危害。 在生理方面,玉米在固定光强下进行测试后发现,在低光强下,免耕的光合速率比翻耕高35%左右,覆盖与翻耕相当,少耕比翻耕高约8%,随着光强的增高,覆盖的光合速率迅速提高,覆盖一直保持在最高水平,光合和蒸腾都比较强烈。 土壤的表层温度翻耕比免耕高0.3℃,5cm和10cm处免耕比翻耕高0.4℃;15cm和20cm处5月7月两者相当,6月,免耕比翻耕高0.6℃。 干旱期在1m以上,各处理储水量比较接近,而在1m以下,覆盖、免耕的土壤储水量增加量分别比翻耕高31.6%、28.6%;雨季2m土层中,覆盖、免耕的土壤储水量减少量分别是翻耕的54.2%、58.6%;稳定期覆盖土壤储水量增加5.4mm,而免耕减少了1.2mm,翻耕则减少了4.2mm。 从最终结果看,免耕的产量比翻耕高19.3%,总耗水量覆盖和免耕比翻耕分别少耗水33.6 mm和26.2mm,覆盖和免耕的水分利用效率比翻耕分别提高2.8%和15%。 保护性耕作2米内土壤水分比苜蓿、林地的水分高60～110%,种植苜蓿和林地的土壤水分接近植物利用下限,由于黄土高原降雨变率大,因此预测土壤含水量动态有助于确定农林复合生态系统中的作物序列,对降低农业生产风险,维护生态安全有重要的意义。更多还原

【Abstract】 At present, as the problem of soil wind erosion and cropland desertification becomes very serious in China, the strong sandy storm occurred ,once again arouse people’s concern about the issue of controlling sandy storm. People understand that afforestation, planting grasses and developing conservation tillage were the effective measures on reducing winderosion. How to reducing winderosion and improve farmers’ income at the same time? The role of conservation tillage should be special pay attention.In the paper, research on occurrence mechanism and control technology of wind erosion in agricultural lands is reviewed. Base on the observed soil moisture ,crop and meteorological data in hunyuan, shanxi province in 2004, the principle of water banlance was used to study water depletion of natural forest, artificial grassland and farmland, water use efficiency, economic benefits and ecological benefits were compared under different land use types. The primary results showed that:In reducing winderosion, fruit trees > Alfalfa land > no-tillage land > tillage land. Results show: conservation tillage, which features more residue cover and less soil disturbance, could remarkably reduce soil loss; residue cover was found to be more efficient for soil conservation.The results show: under low light regimes, No-tillage’photosynthesis increase 35% than Tillage’, Sub-tillage’ is the same as tillage’, Reduce-tillage’ increase 8% than Tillage’; While light regimes add, Sub-tillage’photosynthesis increase soon. Under high light regimes, Sub-tillage’photosynthesis and transpiration durnalvaviation is the most.In soil’s surface, Tillage’s temperature is higher 0.3 ℃ than No-tillage’s; But Tillage’s temperature is lower 0.4°C than No-tillage’s in 5,10cm depth; Tillage’s temperature is the same as No-tillage’s in May and July, Tillage’s temperature is lower 0.6 ℃ than No-tillage’s in June in 15,20cm depth.During arid period, soil water storage of different treatments is the same above 1m depth while soil water storage of Sub-tillage and No-tillage increase 31.6% and 28.6% than Tillage’soil water storage; Soil water storage variation of Sub-tillage and No-tillage decrease 54.2%, 58.6% than Tillage’ in 2m depth during rainy season; Soil water storage ofSub-tillage increase 5.4mm , No-tillage and Tillage decrease 1.2mm and 4.2mm during stable period.No-tillage’yield is much more 19.3% than Tillage; Water consumption of Sub-tillage and No-tillage is less 33.6 mm, 26.2mm than Tillage; Water use efficiency of Sub-tillage and No-tillage increase 2.8%, 15% than Tillage.Conservation tillage’water content has obviously higher about 60~110% than Alfalfa and woodland, which may lead to desiccation. As the Loess Plateau is subject to high rainfall variability, the prediction of soil water change is more important to make decision on crop sequence in complex agriculture-ecosysterm to minimize production risk and safeguard ecosysterm.更多还原