Fertigation is a promising strategy to improve nitrogen use efficiency, yield, and quality of cabbage (Brassica oleracea var. capitata), but there is a lack of data relevant to growers in Ontario. Field trials were conducted in 2003 and 2004 to determine the optimum rate of water and nitrogen application in terms of yield and quality of `Huron' cabbage. Treatments consisted of combinations of target soil moisture levels (25% to 100% field capacity) and nitrogen fertilizer (0–400 kg·ha-1 N) as dictated by a central rotatable composite design. Nitrogen applications were split with 50% broadcast and incorporated before planting and the remaining split into weekly applications via a trickle irrigation system. Water was applied two to three times per week to bring soil moisture up to the target levels. Maximum marketable yield was reached at a combination of 400 kg·ha-1 N and a soil moisture target of 100% field capacity. Many heads were undersized or undeveloped at low rates of nitrogen. Applications of nitrogen required for high yield and quality can pose a risk of leaching; however, use of fertigation minimizes potential in-season leaching. Estimated total residual nitrogen at harvest ranged from 83–211 kg·ha-1 N, which could have a negative impact on the environment. Thus, there is a considerable challenge to reduce environmental impact without economic losses. Improved knowledge of in-season nitrogen requirements might further reduce the levels of nitrogen applied without reducing yield and quality.
(220) Determination of Water and Nitrogen Requirements of Cabbage using Fertigation
