The Nutrient Content And Releasing Rate In The Decomposability Process Of Fine Roots Of Sabina Vulgaris And Artemisia Ordosica In Mu Us Sandland

The nutrient which is released by the fine roots of plants in the process of decomposability has an important meaning to the material circulation in ecosystem. The fine roots of sand fixing plants have effect on the sandy land ecosystem in the semi-arid regions. In order to discuss this effect, the buried-bag method was taken in this paper to determine the nutrient, ash and energy changing in the decomposability process of the fine roots of natural Sabina vulgaris and Artemisia ordosica, the experimental area lies in the north of the exploitation and management research center of Mu Us Sandland. The result indicates:1. The original content summation of total C, N, P, K, Ca and Mg in the fine roots of Sabina vulgaris and Artemisia ordosica were 570.700g.kg^-1 and 589.100g.kg^-1, respectively. The content of Ca in the fine roots of Sabina vulgaris was higher than the content of Artemisia ordosica by 1.86 times, the content of C in the fine roots of Artemisia ordosica was higher than the content of Sabina vulgaris by18.400g.kg^-1; The content of P and K in the fine roots of Artemisia ordosica was higher than the content of Sabina vulgaris by 2.6 times and 5.7 times, respectively. The content of N and Mg in the fine roots of Artemisia ordosica was also higher than Sabina vulgaris.2. In the process of decomposability, the release rate of total C, N, P, K, Ca and Mg were different. During the two-year period of the process of decomposability, the cumulative decomposability rate of Ca behaved as enrichment and other elements behaved as release. In the process of decomposability, the release rate of Sabina vulgaris was lower than Artemisia ordosica. During the two-year period, the cumulative release rate of total C, N, P, K and Mg in the fine roots of Artemisia ordosica were 34.79%,0.21%,0.14%,1.86% and 0.10%,respectively.The enrichment rate of Ca was (0.24%);the cumulative release rate of total C, N, P, K and Mg in the fine roots of Sabina vulgaris were 19.47%,0.07%,0.04% ,0.28% and 0.04%, respectively. The enrichment rate of Ca was (0.21%).3. The original content summation of ash in the fine roots of Sabina vulgaris and Artemisia ordosica were 58.700 g.kg^-1 and 58.200 g.kg^-1, respectively. The total dry weight heat values were 19.695mJ.kg^-1 and 19.323 mJ.kg^-1, respectively. Two years later, the content of ash had increased to 81.833 g.kg^-1 and 92.100 g.kg^-1, respectively. But the total dry weight heat values bad decreased to 19.049 mJ.kg^-1 and 18.446 mJ.kg^-1, respectively.