Soil-Based Technique for Managing Nitrogen Fertilization in Wheat in some Desert Soils at West Nile Delta, Egypt
Ali M. Ali, Sherif M. Ibrahim1, Hassan A. Fawy
This paper proposed N fertilizer recommendation method for wheat grown in West Nile Delta, Egypt in order to obtain optimum yield at increased use efficiency of the applied fertilizer. The proposed method relies on target N uptake, indigenous soil N supply (ISN) and recovery efficiency of the applied N fertilizer (REN). The first season experiments (2015/2016) were conducted at five locations (El-Khatatba, South El-Tahrir, El-Bostan, North El-Tahrir and El-Nobaria). In these experiments, an increasing rate of N fertilizer from zero to 285 kg N ha-1 was applied in the tested plots. The maximum grain yield of wheat as computed from the generated quadratic function was 7286 kg ha-1 for maximum uptake of 268 kg N ha-1. From the data of the first season, prediction equations of the ISN and REN were developed depending on soil organic matter, clay content and soil available N. The second season experiments (2016/2017) were conducted at four different locations (El-Khatatba, South El-Tahrir, El-Bostan and North El-Tahrir) in order to validate the established prescriptive equation (PE) against the general recommendation (GR) and farmer practice (FP). The PE successfully regulated the N fertilizer requirements according to soil test and target yield. For instance, the application rate at El-Bostan location as guided by the PE was 185 kg ha-1 gave a grain yield of 4423 kg ha-1 with a REN of 46.8 %. However, with 285 kg N fertilizer ha-1 as GR, the obtained grain yield was 5100 kg ha-1 with a REN of 35.6 %. On the other hand, the application rate at North El-Tahrir location as guided by the PE was 330 kg N fertilizer ha-1 resulted in 7490 kg ha-1 grain yield and 66.4 % REN. However, the GR gave 7100 kg ha-1 grain yield and 51.1 % REN. These results proved the inadequacy of the GR in getting high grain yield along with high use efficiency, and then considerable wastage of the applied N fertilizer are predicted. Unexpectedly, farmers showed a remarkable ability to increase or decrease N fertilizer rates according to soil status and projected yield due to experience. Nonetheless, the PE that developed in this study gives a scientific and reasonable basis to adjust N fertilizer rate depending on soil properties, and hence plant response to the applied N fertilizer.
Key words: N management, prescriptive equation, soil test crop response, wheat