Water and nitrate dynamics under irrigated onion in a semi‐arid area

Abstract

An experiment is being undertaken on the site of Kamboinsé (Burkina Faso) to study the dynamics of irrigation water and nitrates in and under the root zone of an irrigated onion crop. The goals of the research are to follow nitrate and water transfer, to study the influence of the irrigation amount on the losses of water and nitrates and to evaluate the contribution of simulation models for improving decision support and management of water and nitrogen fertilizers in semi-arid climatic conditions.The crop under consideration is onion subjected to three different treatments: (i) application of optimal amounts of irrigation and fertilizers, (ii) application of the amounts used traditionally by local farmers and (iii) control treatments so as to evaluate natural nitrate supply and transformations. The final goal is to define appropriate amounts of irrigation and nitrogen supply in order to prevent leaching.The first results show that optimal irrigation and fertilizer supply leads to considerably fewer losses than in the case of traditional supply; nitrate leaching is double and water losses are up to three times higher in the latter case. The amount of nitrogen measured in the soil after harvest is very small.

Two-dimensional modeling of nitrogen and water dynamics for various N-managed water-saving irrigation strategies using HYDRUS

“…A low recovery of N fertilizers by crops may be more hazardous in humid regions where the N residual in the soil could be freely leached to the groundwater due to off-season precipitations. In irrigated agriculture, water draining below the root-zone due to excessive irrigation is the dominant factor controlling NO 3 − -N leaching (Tamini and Mermoud, 2002). Organic N, ammonia (NH 4 ) and nitrate (NO 3 ) are the common forms of N in soils.…”

A low environmental impact system for fertirrigation of maize with cattle slurry

“…Nitrogen losses may result dangerous for water bodies eutrophication and human health [43]. The quantity of nitrogen lost by leaching meanly depends on soil nitrate concentration and water drainage in the soil layers [37]. Evidence shows that seasonal management, soil tillage, fertilization, soils characteristics, crop potential absorption, irrigations and rain are likely to affect these losses [4,6,7,10,15,20,22,33,34].…”

Field-scale analysis of water and nutrient use efficiency for vegetable production in a West African urban agricultural system

“…So far, studies that have dealt with water and nutrient management and use efficiencies in West African vegetable production systems are still very limited, and most of them have been either qualitative or based on on-station trials (Tamini and Mermoud 2002;Eaton and Hilhorst 2003;Mermoud et al 2005;Akponikpè et al 2011) which may not be representative of UPA vegetable gardens. Most investigations were also restricted to only part of the year, even though vegetable cropping is a yearround activity and climatic variables that govern crop growth, evapotranspiration and leaching present a seasonality.…”

“…Predotova et al 2011). For instance, as part of an evaluation of gardeners' irrigation and fertilizer management practices for an onion crop in an on-station trial, Tamini and Mermoud (2002) measured leaching of 17.6 ± 7.5 kg NO 3 -N ha -1 through a loamy soil over a 3.5-month period in Ouagadougou (Burkina Faso) following the application of 35 t ha -1 of bovine manure and 83 kg ha -1 of mineral N, with an average irrigation rate of 8 mm day -1 .…”