Abstract

Nowadays, Mycorrhizal fungi are widely used due to their symbiosis relation with roots of so many plants. These fungi, by supplying some of plant nutritional and water requirements, have a key role in all ecosystems. In this research the effects of mycorrhizal fungi and different levels of phosphorous chemical fertilizers on yield and nutrient uptake under three levels of irrigation were studied. This experiment was performed in fully randomized blocks and as a split factorial design with four replications in which different irrigation levels (A1, A2, A3) (60.120.180 mm) were placed in the main plots while different phosphor levels including P1=0 kg/ha, P2=60 kg/ha and P3=120 kg/ha of pure phosphorus were placed in the subplots. Half of these subplots inoculated by mycorrhizal fungi and the others regarded as uninoculated ones in inoculated sub plots, at seed sowing, 6 g of Mycorrhizal inoculums were placed 3 cm under the each seed. The results indicated that the effects of Mycorrhizal inoculation were statistically significant and positive on measured characteristics. Among triple interactions irrigation/chemical phosphorus/mycorrhizal inoculation had significant effects (P<0.05, 5045 kg/ha) on grain yield and (P<0.01) on Phosphorus concentration. Highest grain yield and other yield component were in A1P2G2 treatment. Results showed that in moderate water stress, by using proper amount of chemical phosphorus and mycorrhizal inoculation can compensate decrease in grain yield. Other treatments had significant difference with A2P2G2 which means by increasing water stress, increasing or decreasing amount of chemical phosphorus and without mycorrhizal inoculation grain yield of corn will decrease significantly. However, such mycorrhizal ability can help us to decrease amount of phosphorus chemical fertilizes in corn growth. Moreover, under water stress, mycorrhizal inoculation improved most of measured indexes. Therefore this kind of biofertilizer can have an important key role in agriculture of arid and semiarid climates.

Key words: Mycorrhizal symbiosis, phosphorus, water stress, corn.