干旱区土地利用和土壤改良及植被恢复方式对沙地养分的恢复效应

为研究干旱区土地利用、土壤改良和植被恢复方式对沙地养分的恢复效果，在乌兰布和沙漠东北缘开展试验研究。研究表明，土地利用方式和人为合理的经营活动对沙漠化土地肥力的恢复和提高有较大影响，在农业耕作制度中，其改土培肥效应以草田轮作最高，农作物套种次之，农作物单种最低；在荒漠沙地上种植农作物较果树更有利于保护土壤生态环境；在荒漠沙地上造林，应以防护林为主，不宜营造大规模杨树速生丰产林；在沙地上营造灌木薪炭林，可起到改良贫瘠沙地的功效；在沙地上种植沙打旺、草木樨和苜蓿均可有效的提高沙化土地肥力，以沙打旺效果最好，草木樨次之，苜蓿最差；在围栏封沙育草中，不同植物群落类型对沙地土壤改良效果有所不同，多植物群落优于单一植物群落。土壤氮磷比由高到低依次排序为白刺＋沙蒿＞沙蒿＋沙竹＞沙蒿＞沙竹＞小花棘豆＋沙蒿＞白刺＞小花棘豆，土壤氮磷比的高低主要取决于氮素水平。

Effect of Arid Region Land Use and Soil Modified and Vegetation Restoration on Sandy Nutrient Recovery

To study the arid land use,soil modified and vegetation restoration on sandy nutrient effect,the research is carried out in the Ulan Buh Desert northeastern margin.The results showed that land use and human activities on desertification and rational management to restore and improve land fertility,have greater influence in the agricultural farming systems,its improving soil fertility and crop rotation of grass as the highest,followed by crop intercropping,crop monoculture minimum.In the desert sand,crops have more ability than fruit to protect soil ecological environment; afforestation in the desert sand,protection forest should be mainly,not to create large-scale poplar forest; in the sand to create a fuelwood,can play an improved effectiveness of barren sand; planted in the Astragalus adsurgens Pall.,Melilotus suaveolrns Ledeb.and Medicago sativa L.can effectively improve the sandy soil fertility,Astragalus adsurgens Pall.was the best,Melilotus suaveolrns Ledeb.,Medicago sativa L.was the worst; grass in the fenced sand sports,different plant communities on sandy soil improvement effect of different,plant communities better than the single.Order of nitrogen and phosphorus ratio were Nitraria tangutorum Bobr.+ Artemisia ordosica Krasch.>Artemisia ordosica Krasch.+Psammochloa villosa>Artemisia ordosica Krasch>Psammochloa villosa>Oxytropis glabr+Artemisia ordosica Krasch.>Nitraria tangutorum Bobr.>Oxytropis glabr,the level of soil nitrogen and phosphorus ratio main depends on the nitrogen level.