Can foliar application of natural biostimulants reduce nitrate and fiber content in fresh green bean under soil nutrient deficiency?

Abstract Background There is a growing body of literature that recognizes the importance of natural biostimulants in the agricultural productivity. This potential can play an important role in addressing the issue of cultivation on sandy soil, which is well-known with soil nutrient deficiency stress. In the current study, the selected biostimulants (i.e., chitosan, amino acids, yeast extract, and humic acid) were foliar applied on green bean in the open field of alkaline sandy soils. Results The main results that obtained after harvesting the fresh green bean pods were confirmed that all studied biostimulants improved the quantity and quality of green bean production compared to the control. Chitosan was the best applied biostimulants for producing green bean in a lower fiber and nitrate content of pods, a higher crude protein content of pods, and higher NPK content in the leaves. Conclusion The role of studies biostimulants in promoting green bean productivity under nutrient deficiency stress may back to increase the uptake of nutrients (NPK), plant physiological (higher dry matter) and biochemical attributes (higher crude protein). More studies are needed using different applied doses and more different kinds of natural biostimulants.