封育对荒漠草原枯落物蓄积量的影响

Effects of Closing Grazing on the Litter Amount in Desert Steppe

为了深入研究围栏封育和围栏放牧两种利用方式对荒漠草原植物向土壤养分归还的影响,以宁夏盐池县3个成对封育围栏和放牧围栏(放牧率分别为0.58、0.65、0.80只羊·hm^-2)为研究对象,利用样线调查法、方差分析法对两种利用方式在灰钙土和风沙土土壤基质下枯落物的蓄积量、不同生活型植物的枯落物含量及影响因子的研究,探讨了枯落物蓄积量对草原利用方式与土壤基质的响应。结果表明:①围封对枯落物蓄积量具显著影响。荒漠草原封育围栏枯落物蓄积量在53.2~141.9 g·m^-2,是其放牧围栏的2.82倍。②灰钙土上封育围栏枯落物蓄积量是放牧围栏的3.86倍,但两种围栏在风沙土上的枯落物蓄积量却没有显著差别。③与地上生物量相比,草本植物在枯落物蓄积量结构中的下降以及灌木在蓄积量中的增加,可能是分解转化难易程度导致的。

In this study,the line intercept method and variance analysis were used to analyze the effects of closing grazing and fenced grazing on the soil nutrient content in desert steppe.The litter amount over two soil matrixes(aeolian sand soil and sierozem)in three-paired enclosure plots and fenced grazing plots fenced for different years in Yanchi County,Ningxia Hui Autonomous Region were studied,where the grazing rates were 0.58,0.65 and 0.80 sheep·hm^-2.respectively.The response of litter accumulation to grassland utilization and soil matrix was discussed.The results showed that:①There was a significant effect of enclosure on the litter amount in the community.The litter amount in the enclosure plots in desert steppe varied in a range of 53.2-141.9 g·m^-2,and it was 2.82 times of that in the fenced grazing plots;②There was no significant difference in litter amount between the two kinds of plots on the aeolian sandy soil;on sierozem,however,the litter amount in the enclosure plot was 3.86 times of that in the fenced grazing plot;③Compared with the above-ground biomass,the reduction of litter amount of herbaceous plants and the increase of litter amount of shrub plants may be caused by the difference of decomposition and transformation.