No‐tillage and fertilization management on crop yields and nitrate leaching in North China Plain

A field experiment was performed from 2003 to 2008 to evaluate the effects of tillage system and nitrogen management regimes on crop yields and nitrate leaching from the fluvo‐aquic soil with a winter wheat ( Triticum aestivum L.)– maize ( Zea mays L.) double‐cropping system. The tillage systems consisted of conventional tillage ( CT ) and no‐tillage ( NT ). Three nitrogen management regimes were included: 270 kg N ha −1 of urea for wheat and 225 kg N ha −1 of urea for maize (U), 180 kg N ha −1 of urea and 90 kg N ha −1 of straw for wheat and 180 kg N of urea and 45 kg N ha −1 of straw for maize (S), 180 kg N ha −1 of urea and 90 kg N ha −1 of manure for wheat and 180 kg N ha −1 of urea and 45 kg N ha −1 of manure for maize (M). An array of tension‐free pan lysimeters (50 cm × 75 cm) were installed (1.2 m deep) to measure water flow and NO 3 − ‐N movement. No significant effect of the N management regime on yields of winter wheat and maize grain was found in the 5‐year rotation. Tillage systems had significant influences on NO 3 − ‐N leaching from the second year and thereafter interacted with N management regimes on NO 3 − ‐N loads during all maize seasons. The average yield‐scaled NO 3 − ‐N leaching losses were in order of CTS < NTS < CTU < NTU < CTM < NTM , ranging from 0.88 ( CTS ) to 6.07 ( NTM ) kg N Mg −1 for winter wheat system and from 0.99 ( CTS ) to 6.27 ( NTM ) kg N Mg −1 for summer maize system for 5 rotation years. The results showed that CTS decreased the yield‐scaled NO 3 − ‐N leaching losses while sustaining crop grain yields. Considering the lower costs, NTS could be a potential alternative to decrease yield‐scaled NO 3 − ‐N leaching losses and improve soil fertility while maintaining crop yield for the winter wheat–maize double‐cropping systems in the North China Plain.