山西褐土长期施钾和秸秆还田对冬小麦产量和钾素平衡的影响

在山西石灰性褐土一年一作条件下,通过16年的田间定位试验,研究了长期施钾和秸秆还田对小麦产量和土壤钾素平衡的影响。结果表明,只施用氮、磷肥,冬小麦年平均产量5.5 t/hm2,土壤钾素养分严重亏缺,年平均亏缺104.3 kg/hm2,与试验前的初始值比较,土壤速效钾和缓效钾含量分别下降23.6%和14.3%。在施用氮、磷肥的基础上每年施用钾肥(K2O 150 kg/hm2),平均增产10.2%以上;小麦秸秆还田平均增产6.6%以上,二者配合平均增产17.6%,年平均吸钾量提高32.0 kg/hm2。与试验初始值比较,土壤速效钾、缓效钾分别提高38.6%和11.0%。在施用氮、磷肥的基础上,长期施用钾肥和秸秆还田在显著增加冬小麦的经济产量、生物产量和吸钾量的同时,也减少年度间因气候因素等影响引起的产量变异,提高年度间产量和植物吸钾量的稳定性。

Effects of long-term potassium application and wheat straw return to cinnamon soil on wheat yields and soil potassium balance in Shanxi

Under the condition of wheat-fallow rotation on a calcareous cinnamon soil in Shanxi province, a long-term field experiment was conducted for 16 years to study the effects of long-term potassium(K)application and wheat straw return on wheat yields and soil K status. The results show that application of nitrogen(N)and phosphate(P)fertilizer only without K addition to the system(NP treatment)results in an average yield of 5.5 t/ha and an average annual deficit of 104.3 kg/ha, which indicates there is a serious deficit of soil potassium. Compared with their initial values, contents of soil available K and slowly available K are decreased by 23.6% and 14.3%, respectively. Compared with the NP treatment, the average wheat yield is increased by 10.2% under the application of K fertilizer(NPK treatment)at the rate of K₂O 150 kg/ha annually, and is increased by 6.6% under the straw return treatment(NP+St treatment). The combination of wheat straw return to soil and K application(NPK+St treatment)can increase wheat yield by 17.6%, and K uptake by wheat plants is increased by 32.0 kg/ha. Compared with their initial values, contents of soil available K and slowly available K are increased by 38.6% and 11.0%, respectively. On the base of N and P fertilizer application, wheat grain yield, biomass yield and K uptake by wheat plants are significantly increased under the long-term K application or wheat straw return, and the stability of yield and plant K uptake are improved and the yield variation among the 16 crop seasons is reduced as well.