The role of organic compounds in modifying functional relationships and morphophysiological traits of wheat under water stress: a correlation network analysis

Wheat (Triticum aestivum L.), playing a significant role in providing food security and agricultural economy, is one of the most important cereals in the world. The present experiment aimed to determine the optimal levels of organic compounds (fulvic acid, humic acid, and amino acids) to promote sustainable wheat (cv. Taktaz) cultivation in dry and semi-dry regions while reducing dependency on irrigation water. The experiment was conducted as a split-factorial based on a randomized complete block design (RCBD) with three replications during two cropping years, 2023–2025. Results indicated that three-way interactions were statistically significant at the 0.01 level for all traits except number of fertile spikes and number of grains per spike. According to the polygon view of the traits, applying high amounts of fulvic acid as well as average amounts of the amino acid can have positive effects on controlling stress. In addition, increasing the concentration of humic acid can compensate for low concentrations of compounds like fulvic acid and amino acids. According to the treatment stability diagram, treatments 3 (humic acid 12 L h^− 1) and 6 (amino acid 1.5 L h^− 1, humic acid 12 L h^− 1) under normal irrigation conditions, and 27 (fulvic acid 6 L h^− 1, amino acid 3 L h^− 1, humic acid 12 L/ha) under drought stress conditions, were selected as desirable treatments. The fact that increasing organic matter, like fulvic acid and amino acids, is helpful in plant metabolism regulation and resistance enhancement against drought stress reveals the effects of compounds included in these treatments on the plant’s resistance to the stress. The treatment with the highest amount of organic compounds (6 L ha^− 1 fulvic acid, 3 L ha^− 1 amino acid, 12 L ha^− 1 humic acid) was identified as the treatment with positive coefficients in relation to the first two components in both years. Under drought stress conditions in both years, grain yield had positive coefficients for the first two principal components. Likewise, flag leaf width had positive effects on the fourth component in both ^years. Treatments with high fulvic acid and medium humic acid (3 L ha^− 1 fulvic acid, 1.5 L ha^− 1 amino acid, 12 L ha^− 1 humic acid; 6 L ha^− 1 fulvic acid; and 6 L ha^− 1 fulvic acid, 8 L ha^− 1 humic acid) consistently appeared with strong relationships in the correlation network in both years. In general, treatments with moderate fulvic acid and high humic acid can be selected as desirable treatments under both normal and stress conditions. Selecting these treatments indicated that using fulvic acid and humic acid, along with an amino acid that plays a significant role, had the highest positive effects on yield improvement under both normal and irrigation stress conditions.