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集约化生产下农田土壤碳、氮含量变化是衡量土壤肥力持久性的重要指标.对常规水稻-蚕豆轮作地、露地蔬菜地、3年塑料大棚地和10年以上塑料大棚地的土壤pH、电导率(EC)、土壤有机碳(SOC)和总氮(TN)含量及δ13C和δ15N同位素丰度进行测定,研究了集约化生产程度对土壤特性的影响.结果表明:与水稻-蚕豆轮作地相比,露地蔬菜地、3年塑料大棚地和10年以上塑料大棚地0～20 cm耕层土壤pH分别降低1.1、0.8和0.7,而土壤EC分别是水稻-蚕豆轮作地的4.2、4.9和5.2倍;土壤碳、氮含量随塑料大棚地生产年限的增加总体上呈先增大后减小的趋势.与水稻-蚕豆轮作地相比,10年以上塑料大棚地0～20、20～40、40～60、60～80、80～100 cm土层的土壤SOC含量分别下降了54%、46%、60%、63%和59%,土壤TN含量分别下降了53%、53%、71%、82%和85%.农田集约化生产程度显著影响土壤SOC、TN含量和δ13C、δ15N丰度,土壤δ13C丰度与SOC含量呈显著负相关.土壤δ13C丰度可作为评价农田土壤碳循环受人为干扰强度的指标.
The changes of carbon and nitrogen contents in farmland under intensified production are important indexes to measure the persistence of soil fertility.The soil pH, conductance of conventional paddy field with broad bean sprouts, open vegetable land, plastic shed of 3 years and plastic shed of more than 10 years (EC), soil organic carbon (SOC) and total nitrogen (TN) content and δ13C and δ15N isotopic abundance were measured to study the effects of intensified production on soil characteristics. The results showed that: The soil pH decreased by 1.1, 0.8 and 0.7, respectively, while the soil ECs were 4.2, 4.9 and 5.2, respectively, in paddy field and broad bean fields The soil carbon and nitrogen content increased first and then decreased with the increase of the production period of plastic greenhouse.Compared with the field of rice and broad bean rotations, the plastic greenhouse with the length of 10 years or more was 0-20, 20-40, The soil SOC content decreased by 54%, 46%, 60%, 63% and 59% in 40 ~ 60, 60 ~ 80 and 80 ~ 100 cm soil layers, and decreased by 53%, 53% and 71% , 82% and 85%, respectively.The intensive production of farmland significantly affected soil SOC and TN contents and δ13C and δ15N Degree, the soil was δ13C abundance SOC significant negative correlation. Δ13C abundance can be used as soil Soil carbon cycle evaluation by human interference strength indicator.