EVALUATION OF YIELD, YIELD COMPONENTS AND SOME PHYSIOLOGICAL AND QUALITATIVE TRAITS OF CORN AFFECTED BY CHEMICAL AND BIOLOGICAL NITROGEN FERTILIZERS

In order to evaluate the yield, yield components and some physiological and qualitative traits of corn treated with nitrogen fertilizers (biological, chemical and integrated), a field experiment was conducted at the Agricultural Research Station of Khorramabad during 2016 growing season. Treatments were arranged in a complete randomized block design with four replications. Experimental treatments consisted of 100% chemical fertilizer (urea), bio-fertilizer (nitroxin), integration of bio-fertilizer + 25% chemical fertilizer, integration of bio-fertilizer + 50% chemical fertilizer, integration of bio-fertilizer + 75% chemical fertilizer and the control. Results showed that the effect of different treatments of fertilizers on all measured traits, except for number of rows in each ear and carotenoids, was significant. The results indicated that integration of bio-fertilizer + 75% chemical fertilizer affected the highest grain yield (9.31 t ha(-1)), dry biological yield (20.96 t ha(-1)), number of kernels in each row (41.67), plant height (201.02 cm), hecto-liter weight (0.82 g cm(-3)), chlorophyll b (0.43 mg g(-1) FW), total chlorophyll (1.1 mg g(-1) FW) and leaf area index (LAI) (4) and there was no significant difference among this treatment and 100% chemical fertilizer (N) and integration of bio-fertilizer + 50% chemical fertilizer treatments in all measured traits. The greatest harvest index (45.8) and grain protein-content (9.1%) resulted from the integration of bio-fertilizer + 50% chemical fertilizer treatment. Also the highest 1000-grains weight (281.13 g) and chlorophyll a (0.66 mg g(-1) FW) were caused by 100% chemical fertilizer (urea) treatments. Results showed that integration of bio-fertilizer + chemical fertilizer could be considered as a means to reduce the consumption of chemical fertilizers for sustainable agriculture.