@article{oai:repository.naro.go.jp:00001638, author = {松山, 宏美 and MATSUYAMA, Hiromi and 渡邊, 和洋 and WATANABE, Kazuhiro and 松尾, 和之 and MATSUO, Kazuyuki}, journal = {中央農業総合研究センター研究報告, Bulletin of the National Agricultural Research Center}, month = {Mar}, note = {Because of the poor yield response of soybean to chemical fertilizer, many farmers cultivate soybean without this treatment, although there is a concern about soil degradation. Field experiment was conducted when the cropping sequence was as follows: rice, wheat and soybean, in order to examine the effects of fertilizer omission and removal of rice and wheat residues on subsequent soybean yield and the nutrient content of the soil. In addition, the nitrogen composition of soybean field soil with and without basal fertilizer was studied in the farmer's fields in staple soybean cropping area.  The omission of basal fertilizer for soybean did not cause yield reduction. The results of soil chemical analysis after soybean cropping indicated a significant difference in exchangeable potassium, but not in total nitrogen and inorganic nitrogen, between the conditions with and without basal fertilizer. A slight decline in available phosphorus levels was also observed with basal fertilizer omission. The restoration of rice and wheat straw did not influence the yield of following soybean, or the total nitrogen and inorganic nitrogen content of the soil, but it reduced available phosphorus content of the soil.  Nitrogen composition of the no-tillage soybean field soil with and without basal fertilizer was determined by the sequential extraction method. No significant difference was observed in the amount of total nitrogen and the composition of nitrogen between the conditions with and without basal fertilizer. Although a slight decline in available phosphorus levels was also observed in the fields without fertilizer, this decline could not be ascribed to fertilizer omission because of the higher crop yield and phosphorus uptake observed in these fields.  According to our results, the omission of basal fertilizer for no-tillage soybean does not have any detrimental effects on soybean yield and nitrogen status; however, it is necessary to monitor the levels of exchangeable potassium and available phosphorus by soil diagnosis.}, pages = {1--8}, title = {不耕起ダイズ作における基肥省略が土壌養分に及ぼす影響}, volume = {25}, year = {2016}, yomi = {マツヤマ, ヒロミ and ワタナベ, カズヒロ and マツオ, カズユキ} }