长期不施磷肥对旱地红壤养分比例与玉米产量的影响

Effects of long-term no phosphorus fertilization to upland red soil nutrients ratio and maize yield

在湖南祁阳国家红壤肥力与肥料效益长期监测基地,于2008年对已有18年旱地红壤肥料试验历史的不施肥、NK、NP、PK、NPK处理下玉米产量、pH以及养分状况等指标进行了研究。结果表明,长期不施磷肥、只施氮钾肥导致玉米绝产。施用磷肥有极显著的增产作用,其中NP、PK与NPK处理分别比不施肥处理玉米增产33.2%、66.39%与151.45%。施磷的增产作用主要体现在玉米穗粒数、百粒重以及公顷穗数的增加。长期施用氮肥造成了土壤酸化,尤以NK处理酸化严重（pH值降至4.1）,导致玉米产量连年下降。长期不施磷肥、只施氮钾肥,导致土壤全磷量和有效磷量降低,而全氮、全钾、碱解氮、有效钾量增加,表现为土壤氮磷钾养分比例严重失衡。NK处理的土壤氮磷钾全量比例为2.8∶1∶44.5,其它施磷处理的为1.09~1.32∶1∶17.96~19.36;NK处理的土壤氮磷钾速效量为31∶1∶57,其它施磷处理的为0.7~1.16∶1∶1.07~4.6。

A fixed-site long-term fertilization experiments were carried out in 2008 in ＂Qiyang Red Soil Fertility and Fertilizer Efficiency Long-Term Monitoring Base＂ to study the effect of CK,NK,NP,PK and NPK treatments which were founded before 18 years on upland red soil nutrients,pH and maize yield.The results showed that,long-term application of only nitrogen and potassium fertilizer but no phosphorus fertilizer treatment caused no yield on maize.Application of P fertilizer could increase maize yield significantly.Compared with CK treatment,the treatments of NP,PK and NPK could increase maize yield by 33.2%,66.39% and 151.45% respectively.The effect of applying phosphorus fertilizer on increasing yield presented as the increase of kernel numbers,100-seed weight and spike number per hectare.Long-term application of nitrogen fertilizer could cause soil acidity,which resulted in the decline of maize yield by years.Long-term application of only nitrogen and potassium fertilizer but no phosphorus fertilizer treatment could decrease content of soil total phosphorus and available phosphorus,increase content of soil total nitrogen,total potassium,available nitrogen and available potassium.The ratio of soil total nitrogen,phosphorus and potassium with the treatment of NK was 2.8∶1∶44.5,and that of applying phosphorus fertilizer treatments was 1.09~1.32∶1∶17.96~19.36.The ratio of soil available nitrogen,phosphorus and potassium with the treatment of NK was 31∶1∶57,and that of applying phosphorus fertilizer treatments was 0.7~1.16∶1∶1.07~4.6.The ratio of soil total nitrogen,phosphorus and potassium of NK was imbalanced,which caused soil acidity more serious.