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Utilisation de la crotalaire, Crotalaria juncea, comme engrais vert pour la gestion des nématodes phytoparasites de la carotte en sol organique

Les sols organiques sont une ressource importante pour les cultures maraîchères. Par contre, ces cultures sont très exigeantes en termes de contrôle phytosanitaire, de fertilisation et de travail du sol. Combinées à la problématique d’affaissement des sols organiques, les pratiques actuelles menacent la pérennité de cette ressource. Dans cette étude, nous testons le potentiel de la crotalaire (Crotalaria juncea) comme engrais vert afin de contrôler les nématodes phytoparasites et comme apport de carbone. L’enfouissement de la crotalaire a permis de réduire de dix fois les populations du nématode cécidogène du Nord (Meloidogyne hapla) et d’augmenter significativement les rendements de carottes l’année subséquente. Aucun effet significatif n’a cependant été observé sur le nématode des lésions, Pratylenchus penetrans.Organic soils are an important resource for vegetable crops. However, these crops are very demanding in terms of pest control, fertilization and tillage. Combined with organic soil subsidence, current practices threaten the sustainability of this resource. In this study, we test the potential of Sunn hemp (Crotalaria juncea) as a green manure to control populations of plant-parasitic nematodes and as a carbon input to the soil. Incorporating Sunn hemp resulted in a ten-fold reduction in populations of the northern root-knot nematode (Meloidogyne hapla) and a significant increase in carrot yields the following year. However, no significant effect was observed on the root-lesion nematode, Pratylenchus penetrans

Corn response to nitrogen is influenced by soil texture and weather

Citation: Tremblay, Nicolas, Yacine M. Bouroubi, Carl Bélec, Robert William Mullen, Newell R. Kitchen, Wade E. Thomason, Steve Ebelhar, et al. “Corn Response to Nitrogen Is Influenced by Soil Texture and Weather.” Agronomy Journal 104, no. 6 (2012): 1658–71. https://doi.org/10.2134/agronj2012.0184.Soil properties and weather conditions are known to affect soil nitrogen (N) availability and plant N uptake. However, studies examining N response as affected by soil and weather sometimes give conflicting results. Meta-analysis is a statistical method for estimating treatment effects in a series of experiments to explain the sources of heterogeneity. In this study, the technique was used to examine the influence of soil and weather parameters on N responses of corn (Zea mays L.) across 51 studies involving the same N rate treatments which were carried out in a diversity of North American locations between 2006 and 2009. Results showed that corn response to added N was significantly greater in fine-textured soils than in medium-textured soils. Abundant and well-distributed rainfall and, to a lesser extent, accumulated corn heat units enhanced N response. Corn yields increased by a factor of 1.6 (over the unfertilized control) in medium-textured soils and 2.7 in fine-textured soils at high N rates. Subgroup analyses were performed on the fine-textured soil class based on weather parameters. Rainfall patterns had an important effect on N response in this soil texture class, with yields being increased 4.5-fold by in-season N fertilization under conditions of “abundant and well-distributed rainfall.” These findings could be useful for developing N fertilization algorithms that would allow for N application at optimal rates taking into account rainfall pattern and soil texture, which would lead to improved crop profitability and reduced environmental impacts