The effect of Nano NPK and Compost Fertilization on growth, physiological performance and nutrient use efficiency in two Faba Bean (Vicia faba L.) varieties

Abstract

Improving nutrient use efficiency through integrated fertilization management represents a promising approach to enhance faba bean production under semi-arid agro-ecosystems. Therefore, a field experiment was conducted in the Wadi Atbah region of southern Libya during the 2025/2026 growing season to evaluate the efficacy of Nano NPK fertilizer and compost, applied individually or in combination, on the physiological performance and nutrient use efficiency of two faba bean (Vicia faba L.) cultivars. The experiment was laid out in a randomized complete block design (RCBD) featuring seven fertilization treatments and three replications. Leaf water content, SPAD chlorophyll values, relative growth rate (RGR), along with nitrogen (N), phosphorus (P), and potassium (K) use efficiencies, were systematically determined. The results revealed that fertilization treatments, cultivar types, and their interactions exerted highly significant effects on all measured traits (P < 0.001). Among the fertilization strategies, the combined application of Nano NPK and compost (T7) proved superior, recording the highest leaf water content, SPAD values, RGR, and nutrient use efficiencies, followed by the combination of 50% Nano NPK and 50% mineral NPK (T5) and mineral NPK combined with compost (T6), whereas the control treatment (T1) exhibited the lowest performance. Compared with the control, treatment T7 enhanced leaf water content, SPAD, RGR, NUE, PUE, and KUE by 28%, 26%, 31%, 31%, 29%, and 31%, respectively. Furthermore, the imported cultivar outperformed the local cultivar across all evaluated parameters. The enhanced physiological performance and nutrient use efficiency resulting from the combined application of Nano NPK and compost are primarily attributable to the synergistic interaction between both inputs. Specifically, Nano NPK supplied a prompt and adequate nutrient source to fulfill crop requirements, while compost improved moisture retention and provided essential elements supporting plant growth. Consequently, integrating Nano NPK with compost is established as an effective management strategy for semi-arid regions to optimize the physiological performance and nutrient use efficiency of faba bean.