Effect of Vermicompost Application on Mineral Nutrient Composition of Grains of Buckwheat (Fagopyrum esculentum M.)

Abstract

Poor soil organic content is a major cause of declining crop productivity in developing countries. Less precipitation and high temperatures oxidize organic matter in the soils of semi-arid regions. Such a deficiency in the organic matter of the soils decreases the bioavailability of many nutrients. Organic amendments like vermicompost (VM) have the potential to overcome this problem, while decreasing the dependency on inorganic fertilizers. Thus, the aim of our study was to explore the best application rate of VM for the improvement of nutrient contents in buckwheat. We used two buckwheat cultivars i.e., Aktaş and Güneş were sown under variable rates of soil-applied VM (0, 0.75, 1.50, 2.25 and 3.00 t ha−1) in semi-arid highland conditions. The results demonstrated that the nutritional quality parameters were improved when VM was applied at the rate of 2.25 t ha−1. In addition, VM at 2.25 t ha−1 resulted in an improvement of the N and P contents of the grains. The P contents in the grains of the Güneş variety was higher (0.26%) than the Aktaş variety (0.24%). A significant improvement in Fe (%), Cu (%), Zn (%) and Mn contents (%) in the grains of buckwheat validated the efficacious functioning of 2.25 t ha−1 of VM. The Zn content of the grains was higher in the Güneş variety (34.06%) than the Aktaş variety (31.96%). However, no significant change in K, Ca and Mg was noted at any level of VM in both Aktaş and Güneş. It is concluded that a 2.25 t ha−1 VM application in the buckwheat crop under zero conventional fertilizer was the best level to boost the nutritional quality of the grains.