Response of Soft Wheat (Triticum aestivum L.) to Slow-Release Nitrogen Fertilizers in a Semi-Arid Rainfed Mediterranean Climate Area of Morocco

Reasoned fertilization is an essential element of the agroecological approach, which aims first and foremost to improve soil and plant growth. The objective was to examine how slow-release nitrogen fertilizer will perform on the wheat productivity compared to conventional quick-release nitrogen fertilizers. A slow-release nitrogen cover fertilizer Duramon (24% N) was applied to soft wheat and compared to conventional nitrogen fertilizers as well as the local farmer practices. A randomized complete blocks design was adopted with four replications and four sites and repeated during three cropping seasons. Stand density, plant canopy height, tillers/plant, spikes/plant, biological yield, grain yield and harvest index were evaluated. Compared with conventional quick-release nitrogen fertilizers, the slow-release nitrogen significantly (P≤0.05) improved tillering, spikes/plant, canopy height, biological yield, grain yield and harvest index. It achieved an average total biomass and grain yields of 3220 kg DM/ha and 978 kg/ha, respectively. The average gains for total biomass and grain yields were 14% and 21%, respectively. However, when compared with the local farmers’ practices, the gains obtained were significantly higher, with 123% and 175% for the slow-release N fertilizer and 95% and 128% for the conventional quick-release N fertilizer, respectively. The harvest index was improved by N application, rising from 25% in local controls up to 30% for slow-release N fertilizers. In conclusion, compared with conventional quick-release nitrogen fertilizers and local practices, the use of slow-release fertilizers with less units of nitrogen applied significantly improved spikes number, biological and grain yields and harvest index, even in dry years.