The role of cover crops in irrigated systems: Water balance, nitrate leaching and soil mineral nitrogen accumulation

• Published in: Agriculture, ecosystems & environment Vol. 155; pp. 50 - 61
• Main Authors: Gabriel, J.L., Muñoz-Carpena, R., Quemada, M.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier B.V 15-07-2012; Elsevier
• Subjects: Agricultural and forest climatology and meteorology. Irrigation. Drainage; Agricultural and forest meteorology; Agronomy. Soil science and plant productions; barley; Biological and medical sciences; canopy; capacitance; Catch crops; corn; cover crops; Cropping systems. Cultivation. Soil tillage; developmental stages; Diffuse pollution; digital images; Drainage; fallow; Fundamental and applied biological sciences. Psychology; General agroecology; General agroecology. Agricultural and farming systems. Agricultural development. Rural area planning. Landscaping; General agronomy. Plant production; Generalities. Agricultural and farming systems. Agricultural development; Generalities. Cropping systems and patterns; Hordeum vulgare; image analysis; Irrigation. Drainage; leaching; mathematical models; mineral soils; nitrates; nitrogen; Numerical models; nutrients; roots; semiarid zones; soil solution; soil water balance; soil water content; topsoil; Vicia villosa; Water balance and requirements. Evapotranspiration; Water percolation; water use efficiency; winter; Zea mays; Drainage; Diffuse pollution; Water percolation; Numerical models; Catch crops; Water; Irrigation; Underground leaching; Cover crop; Ecology; Nitrates; Water balance; Modeling; Soils; Inorganic nitrogen; Catch crop; Nonpoint pollution; Percolation; Numerical simulation
• ISSN: 0167-8809; 1873-2305
• DOI: 10.1016/j.agee.2012.03.021

► Cover crops reduced nitrate leaching in irrigated systems. ► More than 77% of nitrate leaching occurred during the intercrop period. ► Vetch, less efficient than barley at controlling leaching, enhanced soil N retention. ► Cover crops recycled N inside the cropping system. ► Coupling field data and model efforts allowed quantification of water and N balance components.
Using cover crops (CC) in semiarid irrigated areas is often limited by low nutrient and water-use efficiency. This work was conducted over 3.5 years to determine the effect on NO3− leaching, water balance and soil mineral N accumulation of replacing fallow with CC in irrigated systems. Treatments studied during the maize (Zea mays L.) intercrop period were: barley (Hordeum vulgare L.), vetch (Vicia villosa L.) and fallow. Soil water content was monitored daily to a depth of 1.3m and used with the numerical model WAVE to describe the water balance. Determination of crop canopy parameters was based on digital image analysis, and root depth in capacitance sensor readings. Nitrate leaching was calculated multiplying drainage by the soil solution nitrate concentration. Soil mineral N was determined before sowing CC and maize. Over the study, cumulative nitrate leaching in the fallow, vetch, and barley was 346, 245, and 129kg N-NO3−ha−1, respectively; occurring more than 77% during the intercrop period. In dry winters, NO3− accumulated in the topsoil, and CC controlled the NO3− leaching during the initial maize growth stages. Vetch was less efficient than barley at controlling leaching, but enhanced soil N retention. The CC controlled NO3− leaching and recycled N inside the cropping system.