Time filter

Source Type

Messiga A.J.,Agriculture and Agri Food Canada | Messiga A.J.,Laval University | Ziadi N.,Agriculture and Agri Food Canada | Morel C.,French National Institute for Agricultural Research | And 4 more authors.
Field Crops Research | Year: 2012

The benefits of no till (NT) management in the short to medium terms need to be examined over decades of continuous cropping. Our objectives were to (i) assess the long term effects of tillage practices (no-till (NT) and mouldboard plough [MP]) and biennial P×N fertilizer rates applied to the maize phase of a two-year maize-soybean rotation on grain yield, Mehlich-3 P (PM3), and Olsen P (POl), and (ii) determine whether NT practice affects the relationships between PM3, POl and P budgets. The study site was established in 1992 on a clay loam soil of the St-Blaise series (Dark Grey Gleysol). The experimental design is a split plot with NT and MP assigned to main plots and nine combinations of 3 P (0, 17.5, and 35kg Pha-1) and 3N (0, 80, and 160kg Nha-1) additions assigned to subplots. Maize and soybean grain yield response to P additions was obtained only twice between 1992 and 2010. On average, grain yields were reduced by 10-25% in NT compared to MP treatments in 11 years. The dynamics over years of PM3 and POl (0-15cm) in unfertilized P treatment was similar in NT and MP. In contrast, P fertilized NT maintained greater PM3 and POl than MP. This difference in soil tests P was due to greater P accumulation in the 0-5cm and 5-10cm soil layers of NT. Under MP, soil tests P and P budgets over the P treatments were linearly related and for this specific MP treatment, we calculated that a P budget of ±100kg Pha-1 would change PM3 by 12kgha-1 and POl by 7kgha-1. Under NT, a cubic model fitted closely to the experimental data due principally to a more than proportional change in soil tests P relative to P budgets in fertilized P treatments. We conclude that additions of P fertilizer in NT systems changes the dynamics of P in the rooting zone, suggesting the importance of approaches to monitor P dynamics specifically tailored for NT systems that integrates the variability caused by the absence of mixing the fertilizer, residues, and soil. © 2012 .

Xie M.,Agriculture and Agri Food Canada | Xie M.,Inner Mongolia Agricultural University | Tremblay N.,Agriculture and Agri Food Canada | Tremblay G.,Center de recherche sur les grains inc. | And 3 more authors.
Canadian Journal of Plant Science | Year: 2013

The response of corn yield to in-season nitrogen rate (ISNR) fertilizer applications in a temperate humid climate is conditioned to a great extent by prevailing weather conditions, which affect nitrogen use efficiency and raise the level of uncertainty for making management decisions. A better understanding of the effects of temperature, expressed as accumulated corn heat units (CHU), and precipitation would help to ensure that a "closer-to-optimal" nitrogen rate is supplied at side-dressing. A meta-analysis was performed using a database of nitrogen response trials conducted from 1997 to 2008 in 60 locations in the corn grain production area of Québec, in conjunction with a weather database. Meta-analysis is a statistical procedure for combining results from a series of studies that is used in many fields of research. It is used to assess treatment effect (also called effect size) in a group of studies or experiments. Corn yield response to ISNR was negatively correlated with overall CHU accumulation, but positively correlated with CHU accumulation before side-dressing. Responses also showed a stronger relationship with cumulative precipitation (PPT) before side-dressing than after side-dressing. High and evenly distributed precipitation before sidedressing tended to increase responses to ISNR. It can be concluded that low CHU, low precipitation and low precipitation evenness before side-dressing reduce the impact of ISNR on corn yield.

Tremblay G.J.,Center de recherche sur les grains inc. | Boisvert J.,McGill University | Frechette G.E.,Center de recherche sur les grains inc. | Saulnier M.,Center de recherche sur les grains inc. | And 2 more authors.
Canadian Journal of Soil Science | Year: 2011

In Quebec, the recommended fertilizer requirements have been lowered since 1994. A study was undertaken from 1998 to 2005 in a 4-yr rotation of wheat (Triticum aestivum L.), soybean [Glycine max (L.) Merr.] and grain corn (Zea mays L.) to verify the midterm mineral fertilizer requirements (N, P, K) for these field crops. Four levels of nitrogen (N) and three levels of phosphorus (P) and potassium (K) were compared on a clay soil of the Saint-Lawrence Lowlands. Nitrogen requirements based on this study corresponded to the recommended levels of each field crop tested. Recommended phosphorus rates did not maintain initial PM-III soil level (1998). However, crop yields were not affected by this decrease in soil PM-III level. To improve fertilizer recommendation tables, it should be relevant to determine with more accuracy the critical phosphorus and potassium values for field crops on other typical Quebec soils.

Loading Center de recherche sur les grains inc. collaborators
Loading Center de recherche sur les grains inc. collaborators