土壤改良对土壤水水化学及碳酸盐岩溶蚀的CO2净消耗量的影响

为研究利用滤泥与不同有机肥搭配对岩溶土壤进行改良增加无机碳汇的最佳实施方案，在果化示范区开展了滤泥、滤泥+秸秆+沼液和滤泥+秸秆+牛粪等三种土壤改良方案试验，在各个改良地和对照地埋放标准溶蚀试片和土壤水收集器，测试一年试片溶蚀速率和不同月份土壤水主要阴阳离子浓度。结果表明:滤泥中含有大量钙盐和硫酸盐，导致土壤水类型为Ca-SO4。各个改良地和对照地土壤水中参与岩溶作用的Ca2+ +Mg2+ ]/HCO3-（当量浓度）均大于1，表明外源酸参与了土壤中碳酸盐岩溶蚀。施肥高峰期，试验区本底土壤CO2净消耗量出现负值，原因是硝化作用产生的H+与土壤水中HCO3-发生脱气作用，导致CO2从水中逸出。单施滤泥改良后，滤泥有机酸显著提高了试片溶蚀速率，但土壤水pH值降低，H+的大量存在导致脱气作用加剧，年均碳酸贡献率为-0.32，年均减少CO2净消耗量0.66 mmol·L-1。滤泥配施秸秆和牛粪引起8月脱气作用加剧，其他月份同样削弱了脱气作用，最终导致CO2年均净消耗量几乎不变。滤泥配施秸秆和沼液大大削弱了单施滤泥引起的脱气作用，同时减小了土壤中碳酸盐岩溶蚀速率的增强程度，最终导致CO2年均净消耗量增加了0.065 mmol·L-1，该方案为最佳增加无机碳汇的实施方案。 

Effects of filter sludge and organic manure soil improvement on soil hydrochemistry and net CO2 consumption of dissolution of carbonate rocks

In order to find the optimal soil improvement scheme that can increase inorganic carbon sink using filter sludge and different organic fertilizer, three soil improvement schemes were designed in demonstration area,namely,Filter Sludge(LN),Filter Sludge+Straw+Biogas Slurry (LNJZ)and Filter Sludge+Straw+Cow Manure(LNJN). Standard corrosion test tablets and soil water traps were buried in each modified and controlled soil to test the one-year dissolution rates and concentrations of main anions and cations in soil water in different months.The results showed that there were a large amount of calcium salt and sulfate in the filter sludge, which had resulted in the type of soil water being Ca-SO4. The values of Ca2+ +Mg2+]/HCO3- involved in karst process of all the modified and controlled soil water were more than 1, which indicated that exogenous acid involved in the dissolution of carbonate rocks in the soils. At the peak of fertilization, the net consumptions of CO2 in control soils were negative. The reason was that the H+ produced by nitrification and HCO3- in the water had degrassing effect,which led to the escape of CO2 from the water. Under LN scheme, organic acid in the filter sludge significantly increased the dissolution rate of the test tablets, but the pH value of soil water decreased and the massive presence of H+ led to the aggravation of degassing of HCO3- and H+ .And the average annual contribution rate of carbonate was -0.32, with an annual reduction of CO2 consumption of 0.66 mmol·L-1. Application of straw and cow manure caused serious degassing in August, and weakened the degassing effect in other months,resulting in almost unchanged annual net consumption of CO2.Applications of straw and biogas slurry greatly weakened the degassing effect caused by filter sludge, and reduced the enhancement degree of carbonate rocks dissolution rates, resulting in an increase of 0.065 mmol·L-1 of average annual net CO2 consumption.LNJZ was an optional scheme to increase inorganic carbon sink.