To obtain the optimum N fertilizer amounts, sources and timing for potato, we conducted an experiment in split plot-factorial form based on randomized complete block designs with 3 replicates in Jiroft city, located in the south of Kerman Province, Iran. In this study, we took into account N sources for the main plots and N fertilizer amount and time for the subplots. As to the N fertilizer consumption timings and the levels, T1 stands for the total consumption of N fertilizer during cultivation, T2 for consumption of N at cultivation and the remaining simultaneous with the beginning of flowering and T3 for of N consumption at planting, of N consumption coincided with the soil hilling and at the same time as flowering; N rates were of the levels R1:150, R2:200 and R3:250 kg/ha. Sources were considered to be of two levels: S1=urea and S2-ammonium sulfate. According to our results, treatments were significantly different with regard to yields so as to obtain the highest yield from R3 treatment consumption at the rate 26.72 ton/ha, which statistically had no particular difference from R2 treatment with a rate of 23.86 ton/ha. In addition, the highest yield was obtained from the time T2 with the rate 30.83 ton/ha and from the source S1 the highest yield was 27.38 ton/ ha. Regarding such results, the highest yield belonged to the treatment R2S1T2. Manuscript profile

Salinity stress is one of the most important abiotic stresses that affects the cultivation of agricultural plants in large areas of the country every year.Twenty-six genotypes of cultivated barley collected from Iran were compared for salt tolerance. Plants were grown in 2Kg pots and subjected to three salinity(NaCl) treatmentsand (1.2 ,8.9 and 16.7ds/m) in a greenhouse at jiroft. The expriment was done in a factorial with complete randomized design and three replications.During vegetative growth shoot Na+ ,K+ contents were measured for all genotypes.Plant traits including the plant height ,length of spikes ,number of spikes per plant ,fresh weight and dry matter and grain yield per plant were also measured.There was a very wide variation in salt tolerance of the genotypes with regard to Na+ and K+ contents.In general tolerant genotypes with better agronomic performance contained lower Na and a higher amount of K to non-tolerant ones and these two parameters were significantly and negatively correlated(r=-0.71,p<0.01). Manuscript profile