Effect of Zeolite application on the yield and quality of soybean under water and non-water stress

Background and objectives: Soybean (Glycine max L.) is the most important oil crop having the largest area under cultivation in the world. Every year, water stress causes great damages on crops in the world, particularly in Iran with arid and semi-arid climate so application of materials such as Zeolite in soil can reduce the adverse effects of water stress. However, the effect of Zeolite in increasing soil water storage capacity is different and it depends on several factors such as soil physical properties (for examples: texture and porosity) and amount, size and type of applied Zeolite. This research was conducted to investigate the effect of Zeolite on soybean quantitative and qualitative yield under conditions of water stress and non-water stress in two types of soil with different textures.
 Materials and methods: In order to investigate the effect of Zeolite on soybean quantitative and qualitative yield under water stress and non-water stress conditions in two types of soil with different textures, an experiment was conducted as split, split plot arrangements based on randomized complete block design with four replications and 12 treatments in 48 plots at the green house of Sari Agricultural Sciences and Natural Resources University. The main factor was different levels of irrigation (irrigation based on discharge of 25 percent of available water and irrigation based on discharge of 50 percent of available water) and sub factors included soil texture (silty clay and sandy loam) and levels of Zeolite application (0, 4, 8 gram per kilogram soil). At physiological maturity stage, crop was harvested and soybean yield and yield component were measured.
 Results: The result showed that water stress caused a decrease in the number of pods, seeds, 1000 seed weight, oil percentage and seed yield, but protein percentage increased. The application of Zeolite in soil caused an increase in the number of pod, number of seed, 1000 seed weight, protein percentage and seed yield but oil percentage was not affected by Zeolite application. Interaction between different levels of irrigation and soil texture showed that interaction between two factors had influenced and also showed that undesirable effects of water stress on yield and component yield in sandy soil was more than those in silty clay soil. Interaction between different levels of irrigation and application of Zeolite showed that with increasing 8 gram per kilogram soil in normal irrigation condition, the amount of seed yield increased about 6 percent and with increasing 8 gram per kilogram soil in water deficit condition, the amount of seed yield increased about 13 percent.
 Conclusion: Application of Zeolite in different levels of moisture caused a significant increase in seed yield and component yield of soybean. Using 8 grams of zeolite in one kilogram of soil, in addition to higher performance of production, in soils with light texture, can maintain soil moisture and prevent yield losses.