有机混合物的制备及其在退化沙地恢复方面的应用

针对科尔沁沙地沙漠化和农牧业生产中的重大生态和经济问题，利用微生物定向培育技术，选择土壤和牛粪混合的菌源母质筛选出具有较强分解能力的纤维素分解菌群（NMCel）；将玉米秸秆和牲畜粪便按照5∶3（干重比）的比例混合，加入稀释后的NMCel菌液进行有氧发酵，发酵60d后制备成具有一定保水性、透气性和粘性的有机混合物。这种有机混合物对裸沙的修复能力较好，可以显著提高裸沙地表土壤碳氮含量和促进裸沙地表生物结皮的形成。有机混合物的最佳播撒方式是：在裸沙表面播施差不嘎蒿（Artemisia halodendron）、胡枝子（Lespedeza davurica）、狗尾草（Setaria viridis）等固沙植物种子后播撒1kg·5m^-2有机混合物，然后覆盖遮阴网。有机混合物的播撒使沙丘裸露创面的植被盖度从6%增加到26%，保水性提高24%~47%，抗风蚀能力提高了5.4~8.6倍。

Organic Compound and Its Utilization in Sandy Land Restoration

Our study focused on the ecological and economical issue that caused by desertification and farming production in Horqin Sandy Land. We use microbial cultivation technique to screen efficient cellulose decomposing microbial flora (NMCel) from the matrix of sand soils and cattle dung. Maize straw and cattle dung (the dry weight ratio is 5∶3) were used to produce organic compound, adding diluted NMCel to accelerate the compound decomposition rate. The organic compound had a good potency of water holding capacity, air permeability, and viscosity after 60 days fermentation. The organic compound was very efficient to rehabilitate bare sand dunes, and it can increase surface soil organic carbon and total nitrogen, and accelerate biological soil crust formation. Take cost and ecological effects in consideration, we optimized the dune restoration method: put the organic compound (1 kg·5m^-2) on the bare sand dunes after sowing the seeds of Artemisia halodendron, Lespedeza davurica,Setaria viridis and so like sand-fixing plants, and then cover the organic compound by shadow nets. The field experiment showed that the optimized method increased vegetation coverage from 6% to 26%, improved soil water hold capacity by 24%-47%, and enhanced wind erosion resistance ability by 5.4-8.6 times compared with natural restoration.