Sustainable Soil Management: Evaluating the Effect of Organic Phosphorus in Sheep Manure and Zeolite Application on Yield and Yield Components, Gas Exchange and Chlorophyll Fluorescence Dryland Barley (Hordeum vulgare L.)

Nowadays, conventional farming has resulted in many negative foot prints such as groundwater Pollution, soil erosion, and decreasing food quality, therefor using alternative management methods, such as organic farming are necessary for crops sustainable production. Application of organic phosphorus (sheep manure) and zeolite could improve crop yield by supplying nutrients and modifying soil physical, chemical, and biological properties. Due to the importance of barley (Hordeum vulgare L.), this research was aimed to evaluate the effect of organic phosphorus in sheep manure and the use of zeolite on yield and yield components, gas exchange and chlorophyll fluorescence of dryland barley in a factorial format in the form of a basic design of randomized complete blocks in 3 replications in the years 2021 and 2022 in the farm of the Faculty of Agriculture of the University Azad, located in Kamalvand section of Khorramabad city. The studied factors include four levels of sheep manure (0, 3, 6 and 9ton h−1) as a source of organic phosphorus and four levels of zeolite (0, 4, 8 and 12ton h−1). The results showed that the use of sheep manure (3ton h−1) and zeolite (4-6ton h−1) increased the weight of 1000 seeds, seed yield, biological yield, harvest index and Fv at the end of two years of experiment. The average comparison of interaction effects zeolite × sheep manure showed that the highest number of seeds per spike (21), Fm and Fv/F0 (28,637.8 and 5.28) from the treatment of 4 ton h−1 zeolite and 3 ton h−1 sheep manure, number Spikes per plant (1064 and 1069) and photosynthesis rate (11.42 and 11.93 umol m−1 s−1) from treatments of 4 and 12 ton h−1 of zeolite with 3 ton h−1 sheep manure, transpiration rate (3.67, 3.62 and 3.80 mmol m−1 s−1) from the treatments of 9 ton h−1 zeolite and the treatment of no application of sheep manure, the treatment of 4 ton h−1 zeolite with the consumption of 6 ton h−1 sheep manure and the treatment of 12 ton h−1 zeolite with Consumption of 3 ton h−1 sheep manure, stomatal conductance (0.56 and 0.59 mol m−2 s−1) from treatments of 4 and 8 ton h−1 zeolite with consumption of 6 ton h−1 of sheep manure and F0 and F0/Fm (17. 6819 and 0.28) were obtained from the treatment without using zeolite and sheep fertilizers. Based on the comparison of the average interaction year × zeolite × sheep manure, the highest amount of carbon dioxide under the stomata with an average of 249.33 mmol m−2 s−1 was observed in the treatment of 4ton h−1 of Zeolite and 3ton h−1 of sheep manure in the first year, which compared to the control treatment in the first and second year increased the amount of carbon dioxide under the stomata by 24 and 19%, respectively. In general, it can be said that the use of Zeolite fertilizers (soil improver) along with sheep manure in the study farm can improve the yield, photosynthesis and chlorophyll fluorescence characteristics of barley, and the results of this experiment can be used in organic and sustainable agricultural systems.