水稻-榨菜轮作体系中施肥研究

Study on Fertilization Status of Rice-Tumorous Stem Mustard Rotation System

采用调查研究方法对重庆市涪陵区水稻-榨菜轮作体系中的养分管理现状进行了研究，结果表明，在水稻-榨菜轮作体系中，榨菜季氮肥施用量普遍偏高，各农户之间施用量差异较大，施肥不足与过量并存．每公顷氮肥施用量最低为207．0kg，最高为564．0kg，平均施氮量为349．5kg／hm^2，其中60％的农户施氮量大于330．0kg／hm^2．氮肥在整个生育期的分配出现前轻后重；氮磷钾养分施用不平衡，偏施氮肥，钾肥用量不足，施用的氮磷钾（含有机肥投入）平均为N：384．0kg／hm^2，P205：127．5kg／hm^2，K2O：144．0kg／hm^2，氮磷钾养分的施用比例为1：0．332：0．375；在投入的养分中化肥氮磷钾分别占总施肥量的91．0％，65．9％和15．6％，即氮主要由化肥提供，钾主要由有机肥提供；有50％多的农户未施用化学钾肥，榨菜收获后，普遍采用榨菜叶直接还田，80％以上的农户在水稻季不施用任何肥料，20％的农户根据水稻长势在分蘖末期施用少量（0-69kg／hm^2）氮肥．

The present status of nutrient resource management in rice-tumorous stem mustard rotation system were studied by investigation. The result showed that the nitrogen fertilizer was used a little more in tumorous stem mustard in Chongqing and the utilization differences among farmers were so obvious that probably led to the fertilizer lack or excessiveness. The average amount of nitrogen application was 349.5 kg N/hm^2 with the maximum 564.0 kg N/hm^2 arid the minimum^207.0 kg N/hm^2 , 60% farmers used the nitrogen fertilizer more than 330.0 kg N/hm^2 and the nitrogen fertilizer was used more in the beginning of growth stage than later which didn＇t accord with the nutrient absorption rule of the tumorous stem mustard. The nutrient equilibrium was lost with nitrogen excessively and potassium scarcely. The average amount of nutrient （contained organic manner） used in tumorous stem mustard was 384.0 kg/hm^2N, 127.5kg/hm^2 P2O5 and 144. 0 kg/hm^2 K2O,the ratio of N,P2O5 and K2O inF, ut was 1：0. 332：0. 375. Among the total nutrient input, the fertilizer of N, P and K accounted for 91.0%, 65.9% and 15.6% respectively, which showed that the nitrogen was mainly provided by fertilizer and the potassium was provided mostly by organic manner. The potassium fertilizer wasn＇t used by 50% peasant households. After tumorous stem mustard being harvested, its leaves were turned over to field immediately. No fertilizer was used in rice by 80% of peasant households. If being used, the nitrogen fertilizer application was below 69 kg N/hm^2.