Growth and productivity response of local pepper plants to compost fertilization, mineral fertilizers and foliar spraying with micronutrients under sandy soil conditions in the Waddan region, Libya

Abstract

This study was conducted in the Waddan region (Al-Jufra) to evaluate the response of a local pepper cultivar to seven fertilization treatments, which included a balanced mineral fertilizer NPK (20-20-20), an organic fertilizer, and micronutrient foliar application. The results demonstrated statistically significant differences (P \le 0.05) among all studied treatments, where the integrated nutrient management treatment (T7: 100% NPK + Organic Fertilizer + Micronutrients) exhibited a distinct superiority across all growth and yield parameters. Treatment T7 recorded the maximum values for plant height (76.0 cm), stem diameter (18.8 mm), and total chlorophyll content (59.2 mg/g FW). This physiological enhancement reflected positively on the yield components, as the same treatment achieved the highest weight for a 20-fruit sample (435.0 g) and the maximum total crop yield per experimental plot (1235.0 g). Conversely, the control treatment (T1) consistently recorded the lowest values.

 The study underscores the critical importance of integrating organic fertilizer with mineral and foliar applications, a combination that provided a natural chemical shield that effectively minimized nutrient leaching within the porous sandy soil profile. Consequently, treatment T7 retained the highest concentrations of available soil macronutrients, recording 53.10 mg/kg for N, 23.30 mg/kg for P, and 350. mg/kg for K, as well as available micronutrients with values of 3.77 mg/kg for Mn, 3.65 mg/kg for Fe, and 1.38 mg/kg for Zn. Furthermore, available soil boron exhibited a precise and progressive response, reaching 0.82 mg/kg which physiologically optimized fruit-set success, reduced flower drop, and ensured uniformity in fruit size