Kundu Manik Chandra, Mandal Biswapati
State Agricultural University, Kalyani 741 235, West Bengal, India.
Environ Sci Technol. 2009 Aug 1;43(15):5837-43. doi: 10.1021/es803590a.
Nitrate (NO(3-)N) contamination of drinking groundwater is a serious worldwide problem. We studied the mechanistic pathways of the nitrate enrichment in a drinking groundwater system of an intensively cultivated district in India and predicted the enrichment through modeling. Analysis of groundwater samples (3472) showed that the nitrate content during the postmonsoon season (0.87 mg L(-1)) was higher than the nitrate content during the premonsoon season (0.58 mg L(-1)). It decreased with increasing depth of the aquifers sampled (r = -0.38), decreasing N-fertilizer application rate (r = 0.74), increasing average root length of the cropping systems followed (r = -0.54), and their efficacy for N-utilization (r = -0.61). Soil properties (136 representative samples) like bulk density (r = -0.72), hydraulic conductivity (r = 0.56), clay (r = -0.29), organic carbon (r = 0.72), NO(3-)N (r = 0.82), and potentially plantavailable soil N (pAvN) (r = 0.82) added to the variability of its enrichment. Prediction of nitrate enrichment by multiple regression equations with selected mastervariables explained 83.6-85.8% of the variability. Results indicate that potentially plant available soil nitrogen, commonly measured for fertilizer recommendation, may help in predicting nitrate enrichment under long-term intensively cultivated alluvial agroecosystems.
饮用水源地下水中的硝酸盐（NO(3-)N）污染是一个严重的全球性问题。我们研究了印度一个集约化种植区饮用水源地下水系统中硝酸盐富集的机制途径，并通过建模预测了这种富集情况。对3472个地下水样本的分析表明，季风后季节的硝酸盐含量（0.87毫克/升）高于季风前季节的硝酸盐含量（0.58毫克/升）。它随着所采样含水层深度的增加而降低（r = -0.38），随着氮肥施用量的减少而降低（r = 0.74），随着后续种植系统平均根长的增加而降低（r = -0.54），以及随着它们对氮利用效率的提高而降低（r = -0.61）。土壤性质（136个代表性样本），如容重（r = -0.72）、水力传导率（r = 0.56）、黏土（r = -0.29）、有机碳（r = 0.72）、NO(3-)N（r = 0.82）和潜在植物可利用土壤氮（pAvN）（r = 0.82）增加了其富集的变异性。用选定主变量的多元回归方程预测硝酸盐富集，解释了83.6 - 85.8%的变异性。结果表明，通常用于推荐施肥的潜在植物可利用土壤氮，可能有助于预测长期集约化种植的冲积农业生态系统中的硝酸盐富集情况
