Development and Dissemination of 4R Nutrient Stewardship Knowledge to Support Crop Production Intensification

The objective of the project is to develop a Nutrient Expert^® (NE) tool for Moroccan farmers and extension specialists to implement appropriate nutrient management practices for wheat production. In order to initiate this type of experiment at a farm scale, on-farm experiments were established in 2013 within the semi-arid rainfed wheat production systems of the Chaouia region. Six experimental treatments were established at five locations - three sites in Settat Province and two sites in Berrechid Province. Each on-farm experimental plot was planted with bread wheat and with durum wheat under five nutrient treatments including an optimum treatment (OPT) (150 kg N + 75 kg P₂O₅ + 100 kg K₂O kg/ha), OPT-N, OPT-P, OPT-K, a control (without fertilizers), and farmer fertilization practice (FFP). Phosphorus and K were applied at planting time, and N was applied in planting and as a topdress. The cropping season 2013-14 was dry and the cumulated rainfall was 231 and 247 mm in Settat and Berrechid, respectively, which is less than the average rainfall in the region. Due to the possibility of irrigation, 60 mm of irrigated water was applied at one site at stem elongation stage. Hence, results were analyzed separately to account for the irrigated site and rainfed sites.

In rainfed sites, results showed no significant differences in grain yield between durum and bread wheat. In rainfed areas, the OPT significantly increased grain yield compared to the omission and FFP treatments. Without application of NPK, grain yield was reduced by 0.7 t/ha (-50%) compared to the OPT and by 0.30 t/ha (21%), 0.32 t/ha (23%), 0.41 t/ha (29%), and 0.44 t/ha (31%) under the OPT-K, OPT-P, FFP, and OPT-N, respectively. Nitrogen is the most limiting nutrient for wheat production compared to P and K. The same finding was observed at the irrigated site where grain yield was reduced by 0.53 t/ha (-19%) compared to the OPT.

In both rainfed and irrigated areas, the limiting nutrient factor for wheat production followed the order N > P > K. The project is planned to continue for three years by increasing the number of on-farm experiments to 40 in four regions and with the introduction of a site-specific nutrient management (SSNM) treatment.