The role of gamma radiation under balanced fertilization in increasing potato shelf life in Iran

At present, about 20 to 25 percent of agricultural products are removed as waste from the consumption cycle. Using gamma radiation is one of the methods to reduce waste in agricultural products, especially in potato (Solanumtuberosum L.). Under current conditions, gamma radiation is used in the farm products in which fertilization is based on farmer's conventional fertilizer use (urea and phosphate). The idea is to observe the effect of gamma radiation on decreasing the agricultural storage waste when fertilization is done according to the soil analysis results. To study the role of the balanced fertilization in increasing the effect of gamma radiation, a factorial experiment was conducted in the form of randomized complete block design with three replications in Pikasocultivar. In this experiment, the three factors used were: a) fertilizer application, i. e., farmer's conventional fertilization and balanced fertilization methods;  b) irradiation with gamma radiation, i. e., control and irradiate; and c) measuring the storage time factor, i. e., before and after 6 months of storage. The samples were irradiated with the dose of 0.15 kGy, then all samples were stored for 6 months at 15 to 20°C at the relative humidity of 40 to 60%. Percentages of dry matter and the concentrations of nitrate and cadmium were measured before and after the storage. The results revealed that, while the percentage of the dry matter in the samples of farmer's conventional fertilization method, that were not irradiated, increased from 16.86%to 21.44%, the irradiated samples increased from 17.68% to 19.41% during the storage period. These changes in the balanced fertilization samples in those which were not irradiated, increased from 20.09% to 23.18% and in the irradiated samples increased from 19.75% to 20.65%. By considering the obtained results, as the rate of weight loss in the tubers under the balanced fertilization was minimum, the effectiveness of gamma radiation in the condition of the balanced fertilization on the shelf life of potato tubers was proved. While the superiority of the balanced fertilization [fertilization on the basis of pre-plant soil analysis results over farmer's conventional fertilization method (N and P-fertilizers)] has been proven, gamma radiation in the condition of the balanced fertilization for increasing the potato tubers shelf life shows to act effectively, mainly due to high tubers dry matter percentage. Therefore, performing further experiments and analyses for other agricultural products under the crop balanced fertilization is highly recommended.