Soil pH Dynamics and Nitrogen Transformations Under Long-Term Chemical Fertilization in Four Typical Chinese Croplands

• Published in: Journal of Integrative Agriculture Vol. 12; no. 11; pp. 2092 - 2102
• Main Authors: MENG, Hong-qi, XU, Ming-gang, LÜ, Jia-long, HE, Xin-hua, LI, Jian-wei, SHI, Xiao-jun, PENG, Chang, WANG, Bo-ren, ZHANG, Hui-min
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2013; Science Press; College of Natural Resources and Environment, Northwest A&F University, Yangling 712100, P.R.China%Key Laboratory of Crop Nutrition and Fertilization, Ministry of Agriculture/Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, P.R.China; Elsevier
• Subjects: available nutrients; available nutrients ecosystem long-term fertilization N distribution soil pH; ecosystem; long-term fertilization; N distribution; soil pH; 中国; 农业生态系统; 土壤pH值; 土壤速效养分; 氮素; 钾化肥; 长期施用; 长期施肥试验; available nutrients; N distribution; ecosystem; long-term fertilization; soil pH
• ISSN: 2095-3119; 2352-3425
• DOI: 10.1016/S2095-3119(13)60398-6

Long-term fertilization experiment provides the platform for understanding the proton budgets in nitrogen transformations of agricultural ecosystems. We analyzed the historical （1990-2005） observations on four agricultural long-term experiments in China （Changping, Chongqing, Gongzhuling and Qiyang） under four different fertilizations, i.e., no-fertilizer （control）, sole chemical nitrogen fertilizer （FN）, sole chemical phosphorous and potassium fertilizers （FPK） and chemical nitrogen, phosphorous and potassium fertilizers （FNPK）. The significant decline in topsoil pH was caused not only by chemical N fertilization （0.29 and 0.89？pH at Gongzhuling and Qiyang, respectively） but also by chemical PK fertilization （0.59？pH at Gongzhuling）. The enhancement of available nutrients in the topsoil due to long-term direct nutrients supply with chemical fertilizers was in the descending order of available P （168-599%）〉available K （16-189%）〉available N （9-33%）. The relative rate of soil pH decline was lower under long-term judicious chemical fertilization （-0.036-0.034 ？pH yr-1） than that under long-term sole N or PK fertilization （0.016-0.086 ？pH yr-1）. Long-term judicious chemical fertilization with N, P and K elements decreases the nutritional limitation to normal crop growth, under which more N output was distributed in biomass removal rather than the loss via nitrate leaching. We concluded that the N distribution percentage of nitrate leaching to biomass removal might be a suitable indicator to the sensitivity of agricultural ecosystems to acid inputs.