荒漠草原棕钙土地带凋落物分解速率与分解过程的研究

1985—1987年作者在内蒙古荒漠草原对两种主要植物短花针茅和蓖齿蒿的凋落物进行了分解速率与分解过程的研究,结果表明: 1.这两种植物材料的分解,大抵可分为三个阶段。1)快速失重阶段;一般一年左右时间,约有40%凋落物被分解;2)缓慢失重阶段:一般2—4年左右时间,约有40—80%凋落物被分解;3)极缓慢失重阶段:一般4→10年时间,约有80%凋落物被分解。2.在分解过程中,各种营养物质的分解表现出不同的特点。在第一阶段,脂肪分解最快,从原来的100%很快被分解,只剩下20%,其次是灰分、蛋白质可分解50%,而无氮浸出物可保留初始状态的70%左右,纤维素分解甚慢,仅分解掉20%左右。总之,在第一阶段分解过程中,各种营养物质的分解表现出脂肪>灰分、蛋白质>无氮浸出物>纤维素。3.荒漠草原区凋落物的分解较温带森林区要低。在温带森林95%的凋落物被分解约需4年,而在荒漠草原。约需8—16年。

THE STUDY ON THE LITTER DECOMPOSITION RATES AND PROCESSES IN THE BROWN SOIL STEPPE ZONE OF INNER MONGOLIA

The litter decomposition rates and the processes of stipa breviflora and artemisia pectinata under the brown soil steppe zone in Inner Mongolia in this paper have been studied during 1985--1987.The results are as follows. 1.The decomposition of the plants can be devided into three stages: a.The high losing. weight stage: about 40% of the total weight decomposed during one year; b.The slower lesing weight stage: about 40--80% of the total weight decomposed during two to four years; c.The slowest losing weight stage: about 80% of the total weight decomposed durin? four to ten years. 2. During the process of the decomposition, each nutrient shows different characteristics. The speed of decomposition of raw fat is the highest during the first stage, only 20% of the total weight remained;the de- coinposition rates of protein and ash were 50%; the no--nitrogen lea- ching remained at 70% of its total weight; the decomposition process of cellulose is the slowest: about 80% remained.In a word, the decom- position rates of these nutrients during the first stage are different: raw fat>ash and protein>no--nitrogen leach>cellulose. 3. The litter decamposition process in the desert steppe area is slower than that of in the temperate forest area. It will take about four years for the litter to be decomposed in the temperate forest region, while the similar process will take over ten years in the desert steppe area.