RESUMEN
Despite the critical role of balanced nutrition in crop productivity, the use of potash (K) and zinc (Zn) is not much practiced by Pakistani farmers. The reduced nutrient uptake and crop productivity together increase the costs associated with fertilization and revisit farmers' confidence in the efficacy and profitability of fertilizers. To address this problem, a field study was conducted in the research area of the MNS-University of Agriculture, Multan, in collaboration with Engro Fertilizers Limited. The research plan consisted of five treatments, including T1 = control (without N, P, K, and Zn fertilizers), T2 = NP in practice (NP at 32-23-0 kg acre-1), T3 = recommended NP (NP at 48-34.5 kg acre-1), T4 = balanced NPK (NP+K at 48-34.5-30 kg acre-1), and T5 = balanced NPK + Zn (NPK+Zn at 48-34.5-30 + 7.5 kg acre-1). Wheat was used as a test crop, and its growth, yield, and physiological and nutritional parameters were studied. The results indicated that NPK+Zn balanced nutrition increased plant height, spike length, photosynthetic rate, water use efficiency, transpiration rate, stomatal conductance, and grain yield by 13%, 15%, 44%, 60%, 63%, 39%, and 78%, respectively, compared with the control. It was found that the combined application of NP, K, and Zn improved the recovery efficiency of applied nutrients, i.e., nitrogen recovery efficiency (NRE) by 230%, phosphorus recovery efficiency (PRE) by 136%, potassium recovery efficiency (KRE) by 135%, and zinc recovery efficiency (ZnRE) by 136% compared to NP-alone application. Agronomic use efficiency of applied fertilizers, such as potassium agronomic use efficiency (KAUE) by 71%, phosphorus agronomic use efficiency (PAUE) by 72%, nitrogen agronomic use efficiency (NAUE) by 70%, and zinc agronomic use efficiency (ZnAUE) by 72%, was observed compared to NP-alone application. The results showed that NPUE, PPUE, NPUE, and ZnPUE were reduced by 5%, 3%, 3%, and 5%, respectively, compared to NP-alone application. Our findings suggest that K and Zn should be made an essential part of wheat nutrition management for higher yield and better quality of produce.
RESUMEN
BACKGROUND: Zinc (Zn) deficiency and source-dependent Zn fertilization to achieve optimum Zn levels in rice and wheat grains remain global concern for human nutrition, especially in developing countries. To-date, little is known about the effectiveness of bioactive Zn-coated urea (BAZU) to enhance the concentration, uptake, and recovery of Zn in relation to agronomic efficiency in paddy and wheat grains. RESULTS: Field experiments were carried out during 2020-21 on the rice-wheat system at Lahore, Faisalabad, Sahiwal, and Multan, Punjab, Pakistan using four treatments viz.T1 (Urea 46% N @ 185 kg ha-1 + zero Zn), T2 (Urea 46% N @ 185 kg ha-1 + ZnSO4 33% Zn @ 15 kg ha-1), T3 (BAZU 42% N @ 103 kg ha-1 + Urea 46% N @ 62 kg ha-1 + 1% bioactive Zn @ 1.03 kg ha-1) and T4 (BAZU 42% N @ 125 kg ha-1 + Urea 46% N @ 62 kg ha-1 + 1% bioactive Zn @ 1.25 kg ha-1) in quadruplicate under Randomized Complete Block Design. Paddy yield was increased by 13, 11, 12, and 11% whereas wheat grain yield was enhanced by 12, 11, 11, and 10% under T4 at Multan, Faisalabad, Sahiwal, and Lahore, respectively, compared to T1. Similarly, paddy Zn concentration was increased by 58, 67, 65 and 77% (32.4, 30.7, 31.1, and 34.1 mg kg-1) in rice whereas grain Zn concentration was increased by 90, 87, 96 and 97% (46.2, 43.9, 46.7 and 44.9 mg kg-1) in wheat by the application of BAZU (T4) at Multan, Faisalabad, Sahiwal, and Lahore, respectively, in comparison to T1. Zinc recovery was about 9-fold and 11-fold higher in paddy and wheat grains, respectively, under BAZU (T4) treatment relative to T2 while, the agronomic efficiency was enhanced up to 130% and 141% in rice and wheat respectively as compared to T2. CONCLUSION: Thus, T4 application at the rate of 125 kg ha-1 could prove effective in enhancing the rice paddy and wheat grain yield along with their Zn biofortification (â¼34 mg kg-1 and â¼47 mg kg-1, respectively) through increased agronomic and Zn recovery efficiencies, the underlying physiological and molecular mechanisms of which can be further explored in future.