Abstract

Wheat cultivation in arid desert soils, such as the nutrient-poor Arenosols of southern Libya, faces major constraints due to low fertility, limited organic matter, and extreme climatic conditions. This study evaluated the effects of fertilizer type and timing on the growth and yield of two durum wheat cultivars, Karim and Dhahbi, grown in virgin sandy soil filled in pots. The experimental design included three factors: (1) fertilizer type (raw and anaerobically digested manure from poultry and sheep, NPK fertilizer, and an unfertilized control), (2) sowing date (2, 10, 20 or 30 days after fertilization) and (3) cultivar (Karim and Dhahbi). All fertilizers were applied at a rate equivalent to 300 kg N ha-1. The study aimed to assess how these factors and their interactions affected wheat growth and yield. Measured parameters included germination traits (germination speed, germination percentage, and time to final germination), growth characteristics (leaf area, plant height and number of tillers), and yield components (number of spikes, grains per spike, grain weight and biomass yield). Organic fertilization, especially with raw manure, delayed germination when sowing occurred immediately after application. However, sowing 20–30 days post-application reduced phytotoxic effects and improved germination. Sowing 2 or 10 days after fertilization, particularly with raw poultry manure or NPK, significantly enhanced plant height, tillering, biomass accumulation and grain weight, especially in Karim. Raw poultry manure consistently outperformed other manure treatments, achieving higher grain yields (12.4 g pot-1). In contrast, sowing 20 or 30 days after fertilization significantly (P < 0.05) reduced the number of spikes, grains per spike, and grain weight. Overall, Karim demonstrated better adaptability under fertilized conditions, particularly when sowing 2 or 20 days after fertilization. These findings highlight the importance of optimizing fertilization timing and cultivar choice to enhance wheat productivity in arid, sandy environments. Sowing 2 or 20 days after fertilization with raw poultry manure appears to be a promising strategy for sustainable wheat production in desert farming systems.