河西绿洲灌漠土长期施肥效应及土壤生产力演变

张掖绿洲灌漠土连续21 a长期肥料试验结果表明:与无肥处理产量下降相对照,施肥的增产效果逐年提高,平衡施肥增产幅度显著大于单施氮肥。单施氮肥处理土壤生产力水平由第1轮作周期的89.8%降为第7轮作周期的28.5%;在不施用有机肥条件下,种植到第3轮作周期时作物开始对施钾有反应,施钾增产率为5.5%~22.7%;氮磷钾化肥长期配合施用,作物产量水平持续不减,土壤生产力平均达93.5%,表明氮磷钾化肥配合施用并不破坏土壤生产力。有机肥与氮肥配合施用,其交互作用为正效应;有机肥与磷、钾化肥配合施用交互作用为负效应。不施任何肥料时,绿洲灌漠土土壤生产力平均下降59.6%(第1~4轮作周期);到第5~7轮作周期时,土壤生产力下降幅度保持在16.7%~22.7%相对较低且稳定的水平;化肥对作物产量的贡献份额平均为50.5%;有机肥贡献份额为21.6%;土壤自然肥力贡献份额平均为19.0%。

Effect of long-term fertilization and evolvement of soil productivity on irrigated desert soil of oasis area

The 21-year long-term fertilization experiment was carried out on irrigated desert soil in the oasis area of Zhangye.The results showed that,as the yield of no-fertilizer treatment decreased gradually,the yield-increase effect of fertilization was increased year after year,and the increase rate of balance fertilization was remarkably higher than N fertilizer.The soil productivity of N fertilizer treatment was reduced from 89.8% in the 1st rotation period to 28.5% in the 7th period.Under the condition of no organic manure,the K fertilizer became effective to the crops from the 3rd rotation period,and the yield increase rate was 5.5%~22.7%.Under the condition of long-term compounding application of N,P and K fertilizers,the crop yield kept steady,and the average soil productivity was 93.5%,showing that the compounding application of fertilizers didn't destroy the soil productivity.The interaction effect of organic manure and N fertilizer was positive,whereas that of organic manure and P or K fertilizer was negative.Without any fertilizer,the average decrease rate of soil productivity was 59.6% during the 1st to the 4th rotation period,and the decrease rate kept 16.7%~22.7% during the 5th to the 7th period.The contribution quotient of chemical fertilizer,organic manure and soil natural fertility to crop yield was 50.5%,21.6% and 19.0% respectively.