西南碳酸盐岩石质山地土壤-植被系统中矿质养分不足问题的思考

本文提出了矿质养分不足可能是西南石漠化喀斯特山地植被生产力低和植被修复困难重要原因的观点。桂西北环江喀斯特农业生态站和黔中清镇王家寨小流域碳酸盐岩石灰土坡地的平均土壤质量厚度(<2mm),分别为21.95kg/m2和16.04kg/m2。以地上部分生产力4.8t/ha.a,灰分含量9.5%计,植被每年要从土壤中吸取45.6g/m2.a的矿质养分,相当于两地土壤总量的约千分之二。土壤总量少导致的西南碳酸盐岩石质山地土壤矿质养分不足,可能是植被生产力低下的重要原因。纯碳酸盐岩硅酸盐矿物含量低,成土速率低。长期不断的收获植物,不可避免地要带走矿物质,导致喀斯特山地土壤矿质养分的减少,进而抑制植物生长.施用矿质肥料可能是促进喀斯特石质山地植被修复的重要措施。

Ponderation on the Shortage of Mineral Nutrients in the Soil-Vegetation Ecosystem in Carbonate Rock-distributed Mountain Regions in Southwest China

A piece of opinion is pointed out in this paper that the shortage of mineral nutrients is one of the key factors leading to low vegetation productivities and difficulties of vegetation remediation in the rocky-desertification karat regions in Southwest of China.The mean soil mass depths(<2mm)on the slopes are 21.95 kg/m~2 in the Huanjiang Experimental Station of Karst Ecosystem,CAS,Northwest Guangxi and 16.04 kg/m~2 in the catchment of Wangjiazai Gully central part of Guizhou,respectively.Taking that the overground vegetation productivity is 4.8 t/ha.a,and the mineral ash content of plants is 9.5~A,vegetation will adsorb 45.6 g/m~2 of mineral nutrients of vegetation per year,which account for about 2%of the total soil mass in the two places.The shortage of mineral nutrients,resulting from the limited amount of total soil mass,may be the key factor leading to low vegetation productivities in the carbonate rock-distributed mountain regions.Pure carbonate rocks have low silicate mineral contents and low soil formation rates,too.Continuous harvesting of plants in the long period should take out mineral matter and result in reduction of mineral nutrients in the soils,consequently,restraining vegetation growth.Application of mineral fertilizers may be a significant measure for vegetation emaciation in the rocky desertification karst mountain regions in Southwest China.