Effect of biological and nano fertilizers on growth characteristics and yield of cowpea (Vigna unguiculata L.)

One of the basic pillars of sustainable agriculture is the use of biological fertilizers with the aim of eliminating or reducing the use of chemical fertilizers. in recent years, nano fertilizers have been considered an effective solution to reduce nutrient losses and increase fertilizer use efficiency. In this regard, this study was conducted to investigate the effect of biological and nano fertilizers on the yield and morphological traits of cowpea in a factorial experiment based on a randomized complete block design for two consecutive years (2018-2020). The studied factors included 4 levels of biological fertilizers (control, Amino Zn-chelate, AminoAlexin, and Bio-20) and 4 levels of nano chelates (control, Nano B-chelate, Nano K-chelate, and Nano Fe-chelate). The results showed that years had no significant effect on the studied traits. However, the application of biofertilizers, especially Bio-20, followed by AminoAlexin, achieved the highest growth characteristics and yield. Also, among nano chelate fertilizers, iron and that potassium had the most positive effect. The study of interaction effects showed that the lowest growth characteristics and yield were observed at the control treatment. However, the highest plant height, number of flowers, number of pods per plant, pod length, number of seeds per pod and plant, 100-seed weight, and seed and straw yield were observed in Bio-20 application along with nano Fe-chelate and/or nano K-chelate. In general, we found that the combined application of biological fertilizers, especially Bio-20, along with nano Fe-chelate and nano K-chelate significantly improved the growth characteristics, yield, and yield components of cowpea.