Effect of Salicylic acid, Biofertilization and Sowing Dates on Peanut (Arachis hypogaea L.) Yield under Semi-arid Conditions

TWO FIELD experiments were carried out in El-Kharga Experimental Farm of Desert Research Center, Al- Wadi Al- Gadeed Governorate in a sandy clay loam soil, during two summer seasons of 2010 and 2011 to study the effect of salicylic acid application, biofetilization and sowing dates on yield and its components, and the chemical composition of peanut (Giza, 6 cultivar).
The study included four levels of salicylic acid, i.e., zero salicylic acid, 100, 150 and 200 ppm salicylic acid(SA), four different biofertilization treatments, i.e., without biofertilization (Br), Bacillus megatherium (PDB),Pseudomonas fluorescence (PS) and mixed biofertilization treatment (PDB+PS), Rhizobia was applied as base treatment and three sowing dates: April 20^th, May 15^th and June 10^th . The studied factors were arranged in a split- split design with four replications, where sowing date constituted the main plots, salicylic acid was arranged in the sub plots and biofertilizations were occupied sub-sub plots.
Based on yield and yield components data, it was concluded that the early sowing (April 20^th) produced the highest significant parameters of peanut plants; plant height, weight of pods per plant, number of pods per plant, 100-seeds weight, pod and seed yields and protein and oil yields. On the reverse,the lowest values were obtained at late sown (June, 10^th) throughout the studied two seasons (2010 and 2011). Early sown gave the chance of growing plant to complete all of its physiological processes (vegetative and reproductive processes) at proper time than that of late sown. Delaying of peanut sowing till (June, 10^th) caused a decline in all of the studied parameters throughout the studied seasons. Increasing SA levels from 100 to 200 ppm increased significantly all the studied parameters as compared with control in the studied two seasons. Mixed biofertilization treatment had a significant effect on yield and its components as compared with the single biofertilization treatments. Also, biofertilization treatment resulted in higher values of soil microbiological properties, i.e. total microbial counts, counts of phosphate dissolving bacterial (PDB), Pseudomonas count and nodule characteristics.