苏北滩涂区施肥对菊芋生长和土壤氮素累积的影响

通过在苏北滩涂区开展的田间试验,分析了不同施肥量对菊芋地下、地上干物质累积,及对土壤铵态氮、硝态氮的累积及其动态变化过程的影响。结果表明,氮素是苏北沿海滩涂菊芋生长的关键限制因子,增施氮肥可以显著提高菊芋地下和地上干物质的积累。在氮肥供应充足情况下,适当增施磷肥（75kg·hm^-2）可以增加菊芋地下和地上干物质的积累。施氮量小于150kg·hm^-2时,土壤中氮素处于净消耗状态,施氮量225kg·hm^-2时,不仅可以获得菊芋地下和地上干物质的最大产量,且有助于土壤氮素的累积。硝态氮是苏北沿海滩土壤氮素淋失的主要形态,且降水是导致硝态氮淋失的重要原因。随施氮量增加,土壤氮素淋失的风险加大。

Effects of Fertilization on the Growth of Jerusalem artichoke and Soil Nitrogen Accumulation in the Coastal Area of North Jiangsu Province

Based on the field experiment conducted in the coastal area of North Jiangsu Province, the effects of different fertilizer levels on the dry matter accumulations of Jerusalem artichoke under-and above-ground, and on the accumulations and dynamics of ammonium nitrogen and nitrate nitrogen were analyzed. Results showed that nitrogen was the key limiting factor for the growth of Jerusalem artichoke in the study area, and increasing use of nitrogen fertilization could significantly improve the dry matter accumulation on under-and above-ground. Appropriate phosphorus fertilize（r75 kg·hm^-2）could increase the dry matter accumulations of Jerusalem artichoke on under-and above-ground, under an adequate supply in nitrogen. Soil nitrogen was in a net consumption as nitrogen was less than the rate of 150 kg·hm^-2. Not only maximal dry matter accumulations of Jerusalem artichoke on under-and above-ground were obtained, but also nitrogen was accumulated in the soil at the nitrogen rate more than 150 kg·hm^-2. Nitrate nitrogen was the main leaching form of nitrogen in the study area. Nitrate nitrogen leaching was affected by rainfall, the threat showed to increase with the increase of nitrogen application rate.