Effect of Organic Amendments and Synthetic Substances on Copper Availability, Absorption, and Wheat Productivity

Copper (Cu) plays a crucial role in various physiological processes in wheat plants and its presence is significant for the formation and structure of gluten in wheat grain. The effect of organic and synthetic substances on copper availability, absorption, and wheat productivity can vary depending on the specific substance and its interaction with the soil, plants, and environmental conditions. So, a research trial was conducted during seasons of 2021/2022 and 2022/2023 to assess the impacts of various soil conditioners (T1: Control; T2: Compost; T3: Zeolite; T4: Compost + Zeolite) as main plot treatments, as well as the addition of copper sulphate (Cu1: Control; Cu2: 3.0 kg fed-1; Cu3: 6.0 kg fed-1) as sub-main plot treatments. The study aimed to evaluate the effects of these treatments on plant performance and the availability of soil nutrients, with a particular focus on copper. The superior treatment for obtaining the highest values of N, P, K % of straw after 65 days from sowing was the combined treatment of zeolite and compost (T4), while the check treatment (T1) yielded the minimum values. Also, both studied rates of copper sulphate (3 and 6 kg fed-1) significantly increased the values of straw N, P, K % compared to check treatment (Cu1). The superior treatment for obtaining the highest values of grain and straw yield (Mg ha-1) as well as grain chemical constituents [(N, P, K (%), Fe, Mn, Zn, Cu ( mgkg-1)] and grain content of carbohydrate and protein was the combined treatment of zeolite and compost (T4), followed by T2 treatment (compost alone then T3 treatment (zeolite alone) and lately the check treatment (T1). In terms of grain and straw yield (Mg ha-1) and the chemical constituents of the grain (Fe, Mn, Zn, and Cu in mgkg-1), the second rate of copper sulphate (3 kg fed-1) outperformed the third rate (6 kg fed-1) and the control treatment (without CuSO4). This difference in performance can be attributed to the emergence of copper sulphate toxicity at the higher rate of 6 kg fed-1. However, when considering the chemical constituents of the grain (N, P, K in %) as well as the carbohydrate and protein content of the grain (%), the third rate (6 kg fed-1) showed superiority compared to the second rate (3 kg fed-1) and the control treatment (without CuSO4). Generally, the best performance in terms of yield and the most studied traits were achieved under the combined treatment of T4 and Cu2 (3 kg fed-1).on the other hand, the addition of compost and zeolite (either alone or in combination) increased the availability of soil Cu. Simultaneously, the addition of copper sulphate contributed to raising nutrient availability as well. Finally, these improvements can positively impact the economic value of wheat crops, promote food security, and contribute to overall agricultural productivity.