Diversifying cropping sequence reduces nitrogen leaching risks

Beillouin Damien, Pelzer Elise, Baranger Edouard, Carrouée Benoit, Gernay Charles, de Chezelles Emmanuel, Schneider Anne, Jeuffroy Marie-Hélène. 2021. Diversifying cropping sequence reduces nitrogen leaching risks. Field Crops Research, 272:108268, 8 p.

Quartile : Outlier, Sujet : AGRONOMY

Résumé : Overuse of chemical fertiliser in cereal cropping systems has resulted in severe degradation of air and water quality. Diversifying cropping sequence with legumes provides a natural source of nitrogen (N), but also increases N leaching risks after their growing period. Here, we hypothesize that legumes and other break crops, i.e., crops grown to diversify the cropping sequence, reduce N leaching at the rotation scale due to their contribution to increasing nutrient use efficiency and crop N recovery of the following cereal crops. In two 4-year experiments conducted in northern France, we monitored agronomic performance and the changes in the soil mineral N content at field scale in six preceding crop-current crop combinations including winter wheat (Triticum aestivum), pea (Pisum sativum L.) and oilseed rape (Brassica napus L.). We quantified N leaching after each crop as a function of the preceding crop with a water-fluxes model based on soil mineral N content, climate data and soil characteristics. We then simulated N leaching at the rotation scale, for 20 years of climate conditions and various cropping management systems. We show that growing pea or oilseed rape reduced soil mineral N content at harvest of the following cereals (up to mean values of −28 and −19 kg N ha−1 respectively), and N leaching risks during winter of the following cereals compared to the wheat-wheat cropping sequence. Although N leaching was higher during the winter after pea was cultivated, the cumulative losses over four experimental years of the pea cropping sequences were not significantly higher than the no-break cropping sequences. Over the 20 climate years, sequences including pea, oilseed rape, volunteers or catch crops reduced simulated N leaching by up to 40 % compared to wheat monoculture. Our study confirms that N leaching not only depends on the current crop but is also affected by the preceding crop. A large potential reduction in nitrogen leaching could be achieved in many intensive cereal-growing regions with very limited cropping sequence diversity.

Mots-clés Agrovoc : rotation culturale, diversification, azote, Fixation de l'azote, lessivage du sol, légumineuse, Triticum aestivum, Pisum sativum, Brassica napus, teneur en azote

Mots-clés géographiques Agrovoc : France

Mots-clés libres : Nitrogen, Leaching, Crop rotation, Expérimentation

Classification Agris : F08 - Systèmes et modes de culture
P35 - Fertilité du sol
P33 - Chimie et physique du sol

Champ stratégique Cirad : CTS 2 (2019-) - Transitions agroécologiques

Auteurs et affiliations

• Beillouin Damien, CIRAD-PERSYST-UPR HortSys (FRA) ORCID: 0000-0003-2014-3482 - auteur correspondant
• Pelzer Elise, Université Paris-Saclay (FRA)
• Baranger Edouard, Université Paris-Saclay (FRA)
• Carrouée Benoit, Terres Inovia (FRA)
• Gernay Charles, Université Paris-Saclay (FRA)
• de Chezelles Emmanuel, Université Paris-Saclay (FRA)
• Schneider Anne, Terres Inovia (FRA)
• Jeuffroy Marie-Hélène, AgroParisTech (FRA)

Source : Cirad-Agritrop (https://agritrop.cirad.fr/599025/)

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