Abstract

In Tuva, during the fallow succession on ordinary chernozem (Voronic Chernozem Pachic, WRB 2006) and chestnut soil (Haplic Kastanozem Chromic, WRB 2006), changes in the species composition of phytocenoses, total stock and structure of the phytomass, and net primary production were determined. It was found that the species composition of the zonal phytocenosis and humus stock characteristic of the virgin soils are restored first of all. The structure of belowground plant matter is restored most slowly. The first stage of the succession is characterized by the high stock of aboveground phytomass and low stock of belowground phytomass. During succession, the amount of aboveground phytomass decreases, while the amount of belowground phytomass increases. In 4–17 years, the total stock of plant matter in the ordinary chernozem and chestnut soil increases twofold and threefold, respectively, but does not reach the values typical of the reference zonal soils. In the same period, the net primary production increases by 1.5 times on the ordinary chernozem and 2.5 times on the chestnut soil. The net primary production is almost two times higher in the zonal steppes. The total net primary production (expressed in carbon) was calculated for 17 years of succession; it amounted to 67 and 49 t C/ha in the meadow steppe (chernozem) and dry steppe (chestnut soil), respectively. The total production is distributed as follows: its share spent for the accumulation of aboveground and belowground phytomass is equal in both ecosystems, whereas its share converted into humus is twice higher in the dry steppe with chestnut soil. The CO₂ emission reaches 70–75% of the total production in both cases.

中文翻译：

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休耕土壤中净初级生产和碳储量回收的变化

摘要

在图瓦，在普通黑钙土 (Voronic Chernozem Pachic, WRB 2006) 和板栗土 (Haplic Kastanozem Chromic, WRB 2006) 的休耕演替期间，植物群落的物种组成、植物群的总库和结构以及净初级生产发生了变化被确定。发现处女土带状植物群落的物种组成和腐殖质库特征首先得到恢复。地下植物物质的结构恢复最慢。演替的第一阶段的特点是地上植物群存量高，地下植物群存量低。在演替过程中，地上植物量减少，而地下植物量增加。在 4-17 年内，普通黑钙土和板栗土壤中的植物物质总储量分别增加了两倍和三倍，但没有达到参考地带性土壤的典型值。同期，普通黑钙土的净初级产量增加了1.5倍，板栗土增加了2.5倍。带状草原的净初级产量几乎高出两倍。计算了连续 17 年的总净初级生产（以碳表示）；草甸草原（黑钙土）和干草原（板栗土）的碳排放量分别为 67 和 49 t C/ha。总产量分布如下：在两个生态系统中，其用于积累地上和地下植物体的份额相等，而在板栗土壤的干燥草原中，其转化为腐殖质的份额则高出两倍。_{在这两种情况下， 2}排放量均达到总产量的 70-75%。