Canola and oat forage potential may be affected by climatic conditions when sown early. The objective of this study was to evaluate the forage canola and oat potential in four early sowing dates (September 11 and 25; October 9 and 23) during the 2012-2013 and 2013-2014 cycles in Matamoros, Coahuila, Mexico. Growth cycle duration, chemical composition, dry matter (DM), crude protein (CP), and net energy for lactation (NEL) yields were determined. High temperatures and long photoperiods affected crops seeded on September 11, accelerating growth and reducing canola (26.6%-31.7%) and oat (15.8%) DM yields. As of September 25, canola cv IMC 205 reached DM yields (7746 kg ha -1 -9276 kg ha -1 ) similar to those obtained by oat (8115 kg ha -1 -9507 kg ha -1 ), while canola cv Hyola 401 obtained such yields only until October 23. Canola chemical composition was better than that found in oat, with higher CP, but lower acid detergent fiber (ADF) and neutral detergent fiber (NDF) contents. Canola equaled oat CP yields (972 kg ha -1 -1215 kg ha -1 ) in the first sowing date, while in the other three other canola sowings reached higher yields (1193 kg ha -1 -1889 kg ha -1 ). As for NEL yields, no difference was observed between both species. The best sowing date for canola is from September 25 on, with CP production advantages over oat.
Materials and Methods
Study Site, Soil Preparation, and FertilizationThis study was conducted on clay soil, at La Laguna Experimental Station in the Instituto Nacional de Investigaciones Forestales, Agricolas y Pecuarias (INIFAP) located in Matamoros, Coahuila, Mexico (25° 32' N, 103° 14' W, and 1150 m above sea level). The soil in the experimental site is deep (> 1.8 m), with 150 mm m -1 available water [17], 0.75% organic C content, [1], and a pH value of 8.14. Climatic variables data were obtained from a meteorological station located 50 m away from the experiment site. Seedbed preparation was done through disk plough at a depth of 0.30 m, followed by double disking and zero-slope levelling.Nitrogen and phosphorus fertilizer dose was calculated considering their availability in the soil and canola and oat extraction capacity, for an average DM yield of 8132 kg ha -1 , a 32.0 g kg -1 N concentration [4,5], and a 3.0 g kg -1 P content in the forage [18,19]. N and P estimated requirements were 260 kg N ha -1 and 62 kg P2O5 ha -1 , for both crops). Considering that the 0.3 m-deep soil analysis indicated an availability of 28.5 kg N ha -1 , and 24.8 kg P2O5 ha -1 , doses of 250 kg N and 60 kg P2O5 were applied per ha. Before sowing, each experimental plot was manually fertilized with 75 kg N ha -1 (ammonium sulphate) and 60 kg P2O5 ha -1 (monoammonium phosphate). Posteriorly, before the first and second irrigations, 87.5 kg N ha -1 were applied, in the form of granular ammonium sulphate. No potassium fertilizer application was made because soils in this area present high available potassium content, with average values of 3030 kg ha -1 at a depth of 0.30 m [1].
Treatments, Sowing, and Irrigation...
