保护性耕作对土壤养分分布及冬小麦吸收与分配的影响

Effect of conservation tillage on wheat and soil nutrient distribution and absorption

通过田间试验研究了华北平原山前平原区不同耕作方式下土壤氮、磷、钾等养分分布及冬小麦吸收与分配变化和对产量的影响。试验设深翻耕秸秆还田(MC)、秸秆还田旋耕(X)、秸秆粉碎免耕(NC)和整秸覆盖免耕(NW)4种冬小麦播前土壤耕作方式。试验结果表明,6年的不同耕作处理对土壤养分分布及冬小麦吸收与分配有显著影响。秸秆还田旋耕可显著提高土壤表层(0～5 cm)有机质、全氮以及碱解氮、速效磷、速效钾含量,但随土壤深度增加,提高效果呈逐渐下降趋势;20～30 cm土层土壤有机质、全氮和速效氮含量显著低于秸秆粉碎免耕处理。两种免耕模式(NC、NW)植株的全氮、全磷、全钾含量在苗期明显低于翻耕(MC)和旋耕(X)模式,在返青期差异最为显著。到拔节和扬花期,免耕(NC、NW)植株的全氮、全磷、全钾含量与翻耕(MC)和旋耕(X)之间的差异逐渐减少,并最终影响到籽粒养分的积累。

Conservation tillage technology improves soil environment,reduces wind and water erosion,and mitigates sandstorm.As a mode of agricultural technology,conservation tillage is drawing more and more global attention.Agricultural soils are increasingly managed through conservation or no-tillage.The objective of this study was to identify the effects of different conservation tillage pat-terns on N,P,K distribution in both soil and wheat,and also on their absorption of wheat in the North China Plain.The investigated till-age patterns included no-tillage with crushed straw（NC）,no-tillage with entire straw（NW）,traditional tillage with crushed straw（MC） and rotary tillage with crushed straw（X）.The 6-year experiment showed significant differences in soil nutrient distribution and absorp-tion,and also in wheat distribution among different tillage patterns.Rotary tillage significantly increased organic matter,total nitrogen and available N,P,K contents in the 0～5 cm surface soil.The contents of these nutrients gradually decreased with increasing soil depth.Soil organic matter,total and available N contents were lower under rotary tillage than NC in the 20～30 cm soil layer.The contents of total N,P and K in plants under the two modes of no-tillage（NC and NW） were significantly lower than that under traditional tillage（MC） and rotary tillage（X） at seedling stage.The differences among these modes of tillage were most significant at reviving stage.At jointing and flowering stages,the differences in total N,P,K contents of plants between the non-tillage（NC and NW） and tillage（MC and X） treatments gradually dropped;and finally significantly influenced grain nutrient content.