Evaluation of Physiological Characteristics in Peanut (Arachis hypogaea L.) in Response to Plant Cutting and Application Methods of Zn and Ca nano-Chelates

Peanut (Arachis hypogaea L.) is one of the most important legume crops and it is rich in oil (47-53 %) and protein (25-36 %). Peanut has very high nutrient requirement. On the contrary severe mineral nutrient deficiency due to inadequate and imbalanced use of nutrients is one of the major factors responsible for low yield in peanut (Kabir et al., 2013). Zinc (Zn) plays an important role in the production of biomass. Furthermore, Zn may be required for chlorophyll production, pollen function and fertilization (Kaya and Higgs, 2002; Pandey et al., 2006). Among the nutrients, Zn deficiency causes yield loss to the maximum of 40% in peanut (Arunachalam et al., 2013). Plant response to Zn deficiency occurs in terms of decrease in membrane integrity, susceptibility to heat stress, decreased synthesis of carbohydrates, cytochromes nucleotide, auxin and chlorophyll (Singh, 2007). Calcium (Ca) is required by peanut plants from the initial stage of pegs appearance until pods maturity. Ca deficiency aborts or shrivels fruit and leads to high percentage of empty pods. The comparison of the various methods of peanut plants fertilization is more important. Peanuts need full sun and topping of main stem in peanut plants could improve solar radiance penetration in to the canopy. Thus, the objective of this experiment was to evaluate the effects of plant topping, Zn and Ca nano-fertilizers and their application on peanut yield. This experiment was carried out in 2016 cropping season as split split plot arrangement based on a randomized complete block design with three replications. Nano-chelates including nano-chelated Zn, nano-chelated Ca and simultaneous usage of nano-chelated Zn and nano-chelated Ca fertilizers and check as the main plots, the application of methods such as the soil utilization of nano-chelates, foliar application and integrated method of the soil utilization and foliar application of fertilizers as sub plots, and topping of the main stem at 10 and 20 centimeters above the floor and no topping as control comprised the experimental treatments. In this experiment, the highest seed yield, biological yield, fruit (pod) yield and peanut hull production were observed as affected by simultaneous usage of Zn and Ca nano- chelates, integrated method of the soil utilization and foliar application of Zn and Ca nano- chelates and topping of the main stem at 20 centimeters above the floor. The greatest fresh forage and hay yield was shown under simultaneous usage of Zn and Ca nono- chelates integrated method of the soil application and foliar spraying of Zn and Ca nano-chelates and topping of the main stem at 10 centimeters above the floor. But the highest percentage of hollow pods per plant and fruit harvest index were achieved under no topping of the peanut stem. It seems that dividing Ca nano-chelate application could improve peanut reproductive growth. But Zn deficiency during the reproductive growth enhanced hollow pod numbers due to probable photosynthetic capability increment of peanut plant.In general, simultaneous application of Zn and Ca nano-chelates and integrated methods of their usage and topping of the main stem at 20 centimeters above the floor increased fruit and grain yield of peanut under Guilan climatic condition.