干旱区灌溉过程中碳淋溶试验研究

Experimental Study on Carbon Leaching during Irrigation in Arid Areas

水循环过程中的碳传输是当前应对气候变化的热点问题之一。为探讨干旱区土地开发利用农田灌溉过程中可溶性碳传输的特征,通过土柱淋溶法定位模拟绿洲农田灌溉灰漠土（已开发23 a）和毗邻自然状态下未被开发的原生灰漠土,分别种植春小麦（旱田）和水稻（水田）,研究了土壤碳淋溶特征。结果表明：灌溉灰漠土和灰漠土春小麦总淋溶碳量分别为5.71 g·m-2·a-1、14.1 g·m-2·a-1,水稻分别为121.3 g·m-2·a-1、63.9 g·m-2·a-1;原生灰漠土有机碳淋溶量占总淋溶碳的54%-63.1%,而灌溉灰漠土却相反,有机碳淋溶量仅占16.3%-31.4%;随着季节的变化及农作物生长,有机碳和无机碳淋溶量逐渐减少,春小麦种植有机碳和无机碳淋溶量小于对照,水稻种植与对照无明显差异。土地开发和作物种植方式对灌溉淋溶有机碳和无机碳数量有显著影响。

The transfer of carbon in the hydrologic cycle is one of the hot-point issues to address climate change,and an important component of global carbon budgets,understanding the significance of soil carbon processes can enhance development of strategies to mitigate atmospheric carbon concentrations. In order to quantify the contribution of field irrigation to dissolved carbon transfer in arid areas,a leaching experiment on soil column to simulate irrigation was carried out. This study measured organic and inorganic carbon leaching loses from different soil（ gray desert soil and oasis farmland soil） with different crops（ spring wheat and rice） to explore the organic and inorganic carbon transport mechanism under different irrigation manners. Each soil type had 10 experiments with spring wheat and rice,respectively. Moreover,there were 3 soil columns without any crops. In the first period,the amount of organic and inorganic carbon was highest. As the change of seasons and the growth of crops,the water consumption increasing gradually reduced the amount of organic and inorganic carbon leaching; in the salt desert,organic carbon leaching account for percent 54 to 63. 1 of the total carbon leaching,higher than inorganic carbon. However in the farmland,inorganic carbon leaching accounted for percent 68. 6 to 83. 7 of the total carbon leaching,much larger than organic carbon; Rice cultivation has higher amount of irrigation,so organic and inorganic carbon leaching is higher than spring wheat; Spring wheat cultivation patterns,organic and inorganic carbon leaching from the soil of salt desert were higher than farmland soil; Rice cultivation patterns,organic carbon leaching from salt desert was also higher than farmland soil,but the amount of inorganic carbon leaching was higher in farmland soil than salt desert soil; Organic and inorganic carbon leaching of cultivation spring wheat soil was higher than contrast（ P 0. 05）,however,growing rice have no significant difference with contrast（ P 0. 05）. The results showed that soil type,crop type and amount of irrigation has a significant effect on soil organic carbon and inorganic carbon leaching.