Li Yun, Zhou Jian-Bin, Dong Yan-Jie, Xia Zhi-Min, Chen Zhu-Juin
College of Resources and Environment, Northwest A & F University, Yangling 712100, Shaanxi, China.
Ying Yong Sheng Tai Xue Bao. 2012 Dec;23(12):3309-16.
Taking the litters of species Hippophae rhamnoides, Medicago sativa, Populus simonii, Robinia pseudoacaci, Salix psammophila, and Stipa bungeana in the Loess Plateau of Northeast China as test objects, and by using mesh bags, this paper studied the dynamic changes of the litters mass, carbon, and nitrogen during decomposition after buried in the field in semiarid region. The litters buried were from one, two, or three of the plant species, and mixed thoroughly with equal proportion of masses. During decomposition, the mass loss rate, total carbon and nitrogen release rates, and total soluble carbon and nitrogen contents of different litters were higher at the early than at the later decomposition stage. After 412 d decomposition, the average mass loss rate of the litters was in the order of mixed litters of three plant species > mixed litters of two plant species > one plant species litter. By the end of this experiment, the average release rates of the litter total carbon and nitrogen ranked as one plant species litter > mixed litters of two plant species > mixed litters of three plant species, the litter soluble organic carbon content was mixed litters of two plant species > mixed litters of three plant species > one plant species litter, while the litter soluble total nitrogen content was mixed litters of three plant species > mixed litters of two plant species > one plant species litter. Correlation analysis showed that the litter mass loss rate had definite correlation with the litter soluble organic matter, especially soluble organic carbon. From the viewpoint of mass loss rate, the mixture of the litters of P. simonii, H. rhamnoide, and M. sativa was the optimum. It was suggested that in the process of returning farmland into forestland and grassland in the gully and valley region of Loess Plateau, it would be required to rationally increase plant species diversity to improve soil fertility.
以中国东北黄土高原地区的沙棘、紫花苜蓿、小叶杨、刺槐、沙柳和本氏针茅的凋落物为试验对象，采用网袋法，研究了半干旱地区野外掩埋后凋落物质量、碳和氮在分解过程中的动态变化。掩埋的凋落物来自1种、2种或3种植物，并按质量等比例充分混合。在分解过程中，不同凋落物的质量损失率、总碳和氮释放率以及总可溶性碳和氮含量在分解前期均高于后期。分解412 d后，凋落物平均质量损失率顺序为3种植物混合凋落物＞2种植物混合凋落物＞1种植物凋落物。至试验结束时，凋落物总碳和氮的平均释放率顺序为1种植物凋落物＞2种植物混合凋落物＞3种植物混合凋落物，凋落物可溶性有机碳含量为2种植物混合凋落物＞3种植物混合凋落物＞1种植物凋落物，而凋落物可溶性总氮含量为3种植物混合凋落物＞2种植物混合凋落物＞1种植物凋落物。相关性分析表明，凋落物质量损失率与凋落物可溶性有机物尤其是可溶性有机碳有一定相关性。从质量损失率来看，小叶杨、沙棘和紫花苜蓿凋落物的混合效果最佳。建议在黄土高原沟壑区退耕还林还草过程中，应合理增加植物物种多样性以提高土壤肥力。
