Evaluation of the effects of deficit irrigation on water use efficiency and some growth indices of potato (Solanum tuberosum L.), in the presence of biofertilizers

Potato (Solanum tuberosum L.), is the third most important crop in the world after rice and wheat in terms of consumption. This crop needs optimal irrigation to achieve proper growth and ultimately acceptable yield. Considering the climatic conditions of the Iran, it is necessary to study the effects of deficit irrigation on potato and to investigate the methods of increasing the drought stress resistance of this crop.

In order to investigate the tuber yield, physiological indices and water use efficiency of potato in the two cropping years 2019-2020, a factorial experiment was conducted in a randomized complete block design with three replications in the Agricultural Research and Training Center of Natural Resources of Hamadan Province. Each year, the experimental treatments included irrigation interval as the first factor at four levels (irrigation after 70, 90, 110 and 130 mm cumulative evaporation from Class A evaporation pan) and the second factor was bio-fertilizer at six levels. Bio-phosphate (B), Glomus. mossea (GM), G. fasciculotum (GF), G. mossea+ Bio-phosphate (BGM), G. fasciculotum + Bio-phosphate (BGF) and Control (C) were administered factorially.

The results showed that increasing irrigation stress reduced tuber yield but the application of Bio-fertilizers improved the adverse effects of drought stress. The results also showed that the drought stress of 130 mm evaporation compared to the treatment of 70 mm evaporation (Control), led to a decrease in tuber yield and leaf area index, by 46.79 and 46.81%, respectively. The results related to potato yield showed that the use of three bio-fertilizers G. mossea, G. fasciculotum and Bio-phosphate had the greatest effect on tuber yield and leaf area index. The improvement tuber yield under conditions of severe drought stress by using bio-fertilizer treatments compared to the control was 38.65% for G. mossea, 37.41% for G. fasciculatum, 32.63% for bio-phosphate, 20.11% for bio-phosphate + G. mossea and 12.91% for bio-phosphate + G. fasciculatum. Based on the results the application of Glomus fasciculatum and G. mossea bio-fertilizers in the treatment of severe drought stress modified the stress effects by 36.36 and 30%, respectively, compared to the non-use of bio-fertilizer. Application of biofertilizers in all irrigation treatments moderated the adverse effect of drought stress on water use efficiency index. The use of Glomus musea, G. fasciculatum and biophosphate biofertilizers led to an increase in water use efficiency index in severe drought stress treatment compared to the control treatment by 38.38, 36.6 and 30.87%, respectively.

Therefore, the use of mycorrhizae G. fasciculatum and G. mossea also bio-Phosphate is recommended separately for areas that suffer from drought stress during the potato growing season.