Interactions of maize and Italian ryegrass in a living mulch system: (2)Nitrogen and water dynamics
Liedgens, Markus ; Frossard, Emmanuel ; Richner, Walter
In: Plant and Soil, 2004, vol. 259, no. 1-2, p. 243-258
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- Water and nitrogen availability may limit the growth of the main crop competing with a cover crop in a living mulch system. Some aspects of the dynamics of water (soil water content and deep percolation) and nitrogen (concentration in soil solution and leachate) were studied in maize (Zea mays L.) sown into a bare soil (BS, conventional cropping) or into a living Italian ryegrass (Lolium multiflorum Lam.) mulch (LM) during three years. Eight lysimeters (1.0 by 1.0m square surface area and 1.1m deep) with ceramic suction cups, TDR probes and a drainage pipe were used each. In LM a 0.3m wide strip was kept free of grass around the maize row. The living mulch reduced the soil water content between 0.3 and 0.9m soil depth, which remained lower even after intense rainfall. Deep percolation over the entire maize crop season was at least 40% lower in the LM compared to the BS treatment. In LM the nitrate concentrations in the soil solution and in the leachate (usually <10mgL−1) were very low. In BS the nitrate concentration in the leachate reached as much as 70mgL−1. Losses of N in LM did not reach 1% of the values observed in BS. Reduced water and N availability in LM contribute to explain the decrease in growth and yield of the maize plants, and are in good agreement with the dense root system developed in this cropping system as compared to BS. The challenge for the development of living mulch systems is to improve the uptake of water and nitrogen by the roots of the main crop in a competitive environment without affecting the capacity of the cover crop to prevent N losses by leaching