Management Practices to Conserve Soil Nitrate in Maize Production Systems
1997
Zhou, Xiaomin | MacKenzie, Angus F. | Madramootoo, Chandra A. | Kaluli, J Wambua | Smith, Donald L.
Residual soil N following maize (Zea mays L.) harvest is susceptible to leaching over winter. There is no available information regarding the combination of intercropping system and water table control to conserve soil N in maize production systems. A 2-yr study was conducted to examine the effects of cropping systems (monocrop maize, and maize intercropped with annual Italian ryegrass [Lolium multiflorum Lam.]) and water table controls (free drainage, or subirrigation to establish water table depths at 70 and 80 cm below the soil surface) on conserving soil N, under climatic and soil conditions of southwestern Québec. The resulting six treatments were fertilized in the spring with 270 kg N ha⁻¹. The effects of adding fertilizer at 0, 180, and 270 kg N ha⁻¹ on monocrop maize with free drainage were also investigated. Soil cores of 1 m in depth were collected in the spring and fall of 1993 and 1994. In 1993, intercropping decreased the amount of NO⁻₃-N in the top 1 m of the soil profile by 47% (92.3 kg N ha⁻¹) relative to monocropped maize at harvest time. Water table depth had less effect on soil NO⁻₃-N content than cropping system. Both increasing water table depth and monocrop maize enhanced downward movement of NO⁻₃-N during the growing season and following spring. More NO⁻₃-N was present in freely drained subsoil under maize given 270 kg N ha⁻¹ than under maize given 180 kg N ha⁻¹.
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