不同肥料种类对稻田红壤碳氮淋失的影响

土壤中碳、氮淋失降低土壤肥力,污染水体环境.为探究不同施肥种类对稻田红壤碳氮淋失影响,本试验依托中国科学院千烟洲生态站(114°53’E,26°48’N)1998年建立的红壤稻田长期定位控制试验,选用负压法采集土壤溶液,研究秸秆还田(ST)、有机肥(OM)、化肥(NPK)对土壤碳、氮淋失状况及时间动态的影响.结果表明:1稻田土壤中氮素淋失以铵态氮(NH+4-N)为主,施用NPK使土壤中NH+4-N(1.2 mg·L-1±0.1 mg·L-1)淋失最严重,施用OM使土壤中可溶解性有机碳(DOC)(27.3 mg·L-1±1.6 mg·L-1)淋失最严重,且土壤中DOC和NH+4-N均在水稻营养生长期淋失最严重(P<0.05);2施用OM与NPK可以增加稻田红壤中NH+4-N、DOC、总有机碳(SOC)和总氮(TN)含量,且施用NPK增加TN效果最显著,施用OM增加SOC最显著;3土壤渗漏液中DOC含量与稻田红壤中SOC含量呈显著正相关(P<0.01),土壤渗漏液中NH+4-N含量与稻田红壤中TN含量呈显著正相关(P<0.01).

Effects of Different Fertilizer Species on Carbon and Nitrogen Leaching in a Reddish Paddy Soil

Enhanced fertilization could decrease nitrogen utilization rate and increase carbon and nitrogen leaching, leading to water pollution in agricultural ecosystem. A long-term field experiment had been established on a reddish paddy soil of Qianyanzhou Ecological Experimental Station (114°53'E, 26°48'N) in Jiangxi Province in 1998. Soil solution samples were collected by clay tube and vacuum pump. Four fertilizer species treatments were selected: control with no fertilizer (CK), straw return (ST), nitrogen, phosphorus and potassium mineral fertilizers (NPK) and pig manure (OM), aiming to evaluate the effects of different species of fertilizer on carbon and nitrogen leaching in a double rice cropping system. The results showed that: 1 ammonium nitrogen (NH₄⁺-N) was the major type of N in soil leachate in reddish paddy soil. The application of NPK could significantly increase the ammonium nitrogen concentration (1.2 mg·L^-1±0.1 mg·L^-1) compared with the CK, ST and OM treatments, and the application of OM could significantly increase the dissolved organic carbon (DOC) concentration (27.3 mg·L^-1±1.6 mg·L^-1) in soil leachate. The carbon and nitrogen leaching were more notable in the vegetative growth stage than the reproductive growth stage of rice (P<0.05); 2 the long-term application of NPK and OM increased the NH₄⁺-N, DOC, soil organic carbon (SOC) and total nitrogen (TN) contents. The NPK was best beneficial to improve TN contents and OM to improve SOC contents. 3 The DOC contents in soil leachate and SOC in paddy soil had a positive correlation (P<0.01), while NH₄⁺-N contents in soil leachate and TN contents in paddy soil had a positive correlation (P<0.01).