An investigation into the effects of sowing time, N and P fertilizers on seed yield, oil and protein production in Canola

Abstract

Canola (Brassica napus L.) has been grown in Kerman province, Iran, for many years. However, little information is available on its response to sowing date, nitrogen (N) and phosphorous (P) fertilizers. Therefore, a field study was conducted in a research station located 17 km southwest of Kerman, investigating the effects of early and late October sowing, N and P fertilization in 2005 and 2006. The design used with split plot arrangement was randomized complete block design. Canola was sown after barley and alfalfa in the first and second year, respectively. At early October sowing 2005, 3.4 t seed ha−1 were obtained with fertilization of 300 kg N ha−1 and 50 kg P ha−1. In 2006, alfalfa had enriched soil with N. Consequently, at early October sowing 2006, 200 kg N ha−1 and 50 kg P ha−1 produced 3.9 t seed ha−1. N and P fertilizers had increased total dry matter accumulation and seed yield, while oil and protein production were increased as a result of seed yield increase. Delayed sowing reduced growth; therefore, seed, oil and protein production were decreased. It is concluded that sowing time and fertilizing according to soil test results cause optimum canola yields.