河西边缘绿洲荒漠沙地开垦后土壤性状演变及土壤碳积累研究
发布时间：2019-04-28 19:41
【摘要】：【目的】土壤养分变化及碳积累过程是评价绿洲农田生态系统结构、功能和生产力演化的重要指标。本研究的目的是通过了解西北干旱区自然荒漠开垦为灌溉农田后该指标的变化,揭示干旱区新垦农田土壤发育及演变规律,为新垦沙地持续利用提供指导。【方法】选择河西走廊中段临泽边缘绿洲0—46年开垦时间序列的沙地农田,取样分析0—60 cm土壤剖面的物理、化学性状变化及碳积累特征,通过比较2008年与2014年的耕层土壤(0—20 cm)测定结果,分析近几年土壤性状的变化。【结果】耕层土壤砂粒含量随开垦利用年限的增加而逐渐降低,但显著的变化发生在开垦16年后的农田,且最近10年土壤粒级组成变化不明显;在沙地开垦后的最初20年,耕层土壤有机碳(SOC)及全氮含量呈线性增加,20年后增加趋势减缓。开垦46年后,SOC、全氮、碱解氮、速效磷含量分别增加了9.0倍、6.3倍、6.3倍和13.5倍,耕层土壤无机碳(SIC)含量增加了77.1%;速效钾随开垦年限的增加呈先降低而后增加的趋势。20—40 cm和40—60 cm土层SOC及氮、磷、钾养分含量随开垦年限延长而逐渐增加,但变化幅度小于耕层土壤。2008—2014年的6年间,不同开垦年限的同一地块耕层土壤粒级组成未发生变化,但SOC及氮、磷、钾养分有明显的积累。沙地开垦46年后0—60 cm土层SOC、SIC和全碳的年平均固存量分别为0.75、0.79和1.47 kg·hm-2·a-1;SOC的积累主要发生在0—20 cm耕作层,而SIC的积累在40—60 cm土层。荒漠沙地转变为灌溉农田后有巨大的碳固存潜力;土壤黏粉粒增加对SOC及养分的积累和保持起重要作用。【结论】沙地开垦为灌溉农田后,随利用年限的增加,土壤肥力显著改善,但开垦46年后土壤肥力仍处于较低水平。对新垦沙地农田,要实现土地可持续利用和生产力持续提高,须采取提升土壤肥力水平的农田管理措施。
[Abstract]:[objective] the change of soil nutrient and the process of carbon accumulation are important indexes for evaluating the structure, function and productivity evolution of oasis farmland ecosystem. The purpose of this study is to reveal the development and evolution of newly reclaimed farmland in arid areas by understanding the changes of this index after the reclamation of natural deserts into irrigated farmland in the arid areas of northwest China. [methods] the cultivated land of Linze marginal oasis in the middle part of Hexi Corridor was selected and the change of physical and chemical properties and the characteristics of carbon accumulation in 0 ~ 60 cm soil profile were analyzed by sampling and analyzing the time series of reclamation time series in the middle part of Hexi Corridor. The changes of soil properties in recent years were analyzed by comparing the results of soil cultivation in 2008 and 2014 (0? 20 cm). [results] the content of sand grains decreased gradually with the increase of reclamation and utilization years. However, the significant change occurred in the farmland after 16 years of reclamation, and the change of soil particle size composition was not obvious in the last 10 years. In the first 20 years after land reclamation, the organic carbon (SOC) and total nitrogen (TN) content in cultivated soil increased linearly, but the increasing trend slowed down after 20 years. After 46 years of reclamation, the contents of total nitrogen, alkali-hydrolyzed nitrogen and available phosphorus of SOC, increased by 9.0 times, 6.3 times and 13.5 times, respectively, and the (SIC) content of inorganic carbon in cultivated soil increased by 77.1%. The available potassium decreased at first and then increased with the increase of reclamation time. The contents of SOC, nitrogen, phosphorus and potassium in 20 ~ 40 cm and 40 ~ 60 cm soil layers gradually increased with the increase of reclamation time. In the six years from 2008 to 2014, there was no change in the grain size composition of the same soil in the same plot with different reclamation years, but SOC and nitrogen, phosphorus and potassium nutrients had obvious accumulation. The average annual sequestration of SOC,SIC and total carbon in 0 / 60 cm soil layer was 0.75, 0.79 and 1.47 kg 路hm-2 路a-1 respectively after 46 years of reclamation. The accumulation of SOC mainly occurred in 0-20 cm tillage layer, while the accumulation of SIC in 40-60 cm soil layer. There is great carbon sequestration potential after the desert sandy land is transformed into irrigated farmland. [conclusion] the increase of soil clay grain plays an important role in the accumulation and maintenance of SOC and nutrients in sandy land. [conclusion] after reclamation into irrigated farmland, the soil fertility improved significantly with the increase of utilization years, but the soil fertility was still at a relatively low level after 46 years of reclamation. In order to realize the sustainable use of land and the continuous improvement of productivity, farmland management measures should be taken to improve the level of soil fertility in newly cultivated sandy land.
【作者单位】： 中国科学院西北生态环境资源研究院临泽内陆河流域研究站/中国科学院内陆河流域生态水文重点实验室;
【基金】：国家自然科学基金(91425302,41401337)
【分类号】：S151.9
，
本文编号：2467909
[Abstract]:[objective] the change of soil nutrient and the process of carbon accumulation are important indexes for evaluating the structure, function and productivity evolution of oasis farmland ecosystem. The purpose of this study is to reveal the development and evolution of newly reclaimed farmland in arid areas by understanding the changes of this index after the reclamation of natural deserts into irrigated farmland in the arid areas of northwest China. [methods] the cultivated land of Linze marginal oasis in the middle part of Hexi Corridor was selected and the change of physical and chemical properties and the characteristics of carbon accumulation in 0 ~ 60 cm soil profile were analyzed by sampling and analyzing the time series of reclamation time series in the middle part of Hexi Corridor. The changes of soil properties in recent years were analyzed by comparing the results of soil cultivation in 2008 and 2014 (0? 20 cm). [results] the content of sand grains decreased gradually with the increase of reclamation and utilization years. However, the significant change occurred in the farmland after 16 years of reclamation, and the change of soil particle size composition was not obvious in the last 10 years. In the first 20 years after land reclamation, the organic carbon (SOC) and total nitrogen (TN) content in cultivated soil increased linearly, but the increasing trend slowed down after 20 years. After 46 years of reclamation, the contents of total nitrogen, alkali-hydrolyzed nitrogen and available phosphorus of SOC, increased by 9.0 times, 6.3 times and 13.5 times, respectively, and the (SIC) content of inorganic carbon in cultivated soil increased by 77.1%. The available potassium decreased at first and then increased with the increase of reclamation time. The contents of SOC, nitrogen, phosphorus and potassium in 20 ~ 40 cm and 40 ~ 60 cm soil layers gradually increased with the increase of reclamation time. In the six years from 2008 to 2014, there was no change in the grain size composition of the same soil in the same plot with different reclamation years, but SOC and nitrogen, phosphorus and potassium nutrients had obvious accumulation. The average annual sequestration of SOC,SIC and total carbon in 0 / 60 cm soil layer was 0.75, 0.79 and 1.47 kg 路hm-2 路a-1 respectively after 46 years of reclamation. The accumulation of SOC mainly occurred in 0-20 cm tillage layer, while the accumulation of SIC in 40-60 cm soil layer. There is great carbon sequestration potential after the desert sandy land is transformed into irrigated farmland. [conclusion] the increase of soil clay grain plays an important role in the accumulation and maintenance of SOC and nutrients in sandy land. [conclusion] after reclamation into irrigated farmland, the soil fertility improved significantly with the increase of utilization years, but the soil fertility was still at a relatively low level after 46 years of reclamation. In order to realize the sustainable use of land and the continuous improvement of productivity, farmland management measures should be taken to improve the level of soil fertility in newly cultivated sandy land.
【作者单位】： 中国科学院西北生态环境资源研究院临泽内陆河流域研究站/中国科学院内陆河流域生态水文重点实验室;
【基金】：国家自然科学基金(91425302,41401337)
【分类号】：S151.9
，
本文编号：2467909
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