摘要
室内模拟研究3个pH梯度降雨和3水平的施氮量对水耕铁渗人为土土壤酸化的影响。结果表明,不同pH降雨及施氮处理土壤的酸度累积量为4.73～15.57 mmol H+每柱,分别以pH 6.5降雨和不施氮处理、pH 2.5添加高氮量(N2)处理酸化速率为最低和最高,相同pH降雨处理下,致酸量随施氮量增加而上升;相同施氮下,不施氮处理土壤酸度累积随降雨pH降低而增加,但中施氮量(150 mg kg-1土)和高施氮量(300 mg kg-1土)下,pH 4.5处理土壤酸度累积量则小于pH 6.5处理;不同降雨及施氮处理NO3-淋溶致酸量为4.32～12.88 mmol每柱,NH+4淋溶消耗H+量为0.01～0.29 mmol每柱;正常酸沉降(pH 6.5)下,中施氮量和高施氮量处理致酸量都大于各梯度pH降雨的致酸量。以上结果表明,单施氮处理的致酸量大于单纯的酸沉降处理,而无论是降雨还是施氮,NO-3淋溶在加速土壤酸化进程中占主导作用。
Samples of Fe-leachi-Stagnic Anthrosols were collected and incubated with different rates of CaCO3 and H2SO4 amended through titration, for indoor simulation of variation of the pH buffering capacity of the soil as affected by rainfall, different in pH （2.5, 4.5 and 6.5） and nitrogen application, different in rate （0, 150 mg kg-1 and 300 mg kg-1 ） , and further for exploration of effects of rainfall and N application on soil total acid induced and on leaching of min- eral N. Results show that soil acidification rate ranged from 4.73 mmol H ＋ to 15.57 mmol H ＋ per column, being the lowest in the treatment with rainfall 6.5 in pH and N application zero and the highest in the treatment with rainfall 2.5 in pH and N application rate N2. Soil acidification rate increased with N application rate, regardless of pH of rainfall. In the treatment with zero N application rate, soil acid accumulated with decreasing pH in rainfall. In the treatments with N application rate being, soil acid accumulation was the highest when the rainfall was 2.5 in pH, and the lowest when the rainfall was 4. 5 in pH. Leaching of nitrate induced soil acidification and the amount of acid induced by leaching of nitrate ranged from 4.24 to 13.18 mmol per column in the experiment, while leaching of NH4 consumed H ＋ at a rate of 0.01 to 0.29mmol per column. In the treatment with rainfall normal in pH, 6.5, N application at 15 mg kg-1 and 30 mg kg-1 increased soil acid by 11.34 mmol and 12.96 mmol per column, respectively, which was more than it did in the treatment with rain- fall 2.5 in pH （9.49 mmol per column） , and in the treatment with rainfall 4. 5 pH （6.87 mmol per column） and more than the amount of H ＋ rainfall 4. 5 in pH brought in （0.16 mmol per＂ column）. The above findings show that application of nitrogen alone may induce more acid than acid depostion with rainfall could bring in. However, no matter whether rainfall or N application, leaching of NO3- plays a leading role in accelerating soil acidification.
出处
《土壤学报》
CAS
CSCD
北大核心
2012年第2期303-310,共8页
Acta Pedologica Sinica
基金
江苏省农业科技自主创新资金项目(cx(09)625,cx(10)431)
现代农业产业体系建设专项(CARS-11-B-15)
国际合作项目IPNI(Jiangsu-10)资助
关键词
降雨
施氮量
水耕铁渗人为土
酸碱缓冲容量
酸化
Rainfall
Nitrogen application rate
Fe-leachi-Stagnic Anthrosols
Soil pH buffering capacity
Acidification
