Role of Nutrient Management in Yield, Quality and Nutrient Content of Egyptian Clover (Trifolium alexandrinum L.) Under Calcareous Soil Conditions

Abstract

Nutrient management is vital for maximizing forage crop yield and economic viability; however, improper application can result in decreased yield and quality. Therefore, two seasonal experiments were conducted during the winter seasons of 2022-2023 and 2023-2024 to examine the impact of varying nitrogen, phosphorus and potassium (NPK) levels, along with the foliar application of zinc, on the forage yield and nutrient content of Egyptian clover or berseem (Trifolium alexandrinum L.) grown in calcareous soil conditions (>36% CaCO3). The experiment consisted of eight treatments, including two NPK levels (50% and 100% of the recommended dose) and two forms of Zn (Zn NPs and Zn Edta at 0.2 and 0.5% as foliar sprays), compared with the control (without treatment). Results showed that NPK full dose (100%) or in combination with Zn NPs significantly improved fresh and dry weight by an average of 67%, and 80%, respectively, across all cuts. Whereas, the highest protein percentage in berseem forage occurred with 50% NPK and foliar Zn NPs. Protein yield per unit area was highest with 100% NPK and foliar Zn NPs in the second and third cuts. Furthermore, Zn NPs boosted manganese (Mn) levels in the 2nd cut but decreased them in the 3rd cut. Iron (Fe) and Mn were mostly in normal ranges, but zinc was often below normal levels. Overall, Zn NPs increased forage yields. The results of translocation factor (TF) for micronutrients from the soil to berseem plants showed that TF values were > 1 for all micronutrients except for Cu in several instances in the 2nd cut in such calcareous soil. Furthermore, micronutrient translocations were arranged in the following order Cu < Zn <Mn  <Fe in the 2nd and 3rd cuts. Our study suggested that there is a beneficial role of correcting Zn deficiency under calcareous soil conditions which is reflected on berseem yield and quality and nutrient status. Thus, using ZnO NPs along with the full recommended dose of NPK is a suitable approach to enhance berseem crop yield and quality in calcareous soil.