Effects of Biofertilizer and Chemical Fertilizer on Maize Yield and leaf Characters in Different Irrigation Conditions

In 2015 with about five million tons of corn, Iran was world’s fifth largest corn importer. Maize is one of the main crops for poultry and livestock feed in Iran. The average of area in Kermanshah province in recent years has been more than 45,000 hectares. But in 2015 this amount has decreased by 30 thousand hectares, 15580 hectares, which is the main reason for water scarcity in the region. On the other hand application of chemical fertilizers in conventional agriculture severe environmental problems, increased production costs and negative effects on biological cycles causes. The objective of this study was to determine the effect of biofertilizers and chemical fertilizers on yield and yield components of Maize under normal and deficit irrigation condition in western Iran region and looking for the best biological treatments could be applied to the maize to get a high yield in addition to keep our environment clean and safe.
Field experiments were conducted for two years (2014 – 2015) at the agricultural research farm, Agricultural and Natural Resources Research Centre in Kermanshah, Iran. In this research, effects of vermicompost and Azotobacter as a boifertilizers and chemical fertilizers on yield and yield components of Maize under normal and deficit irrigation was investigated in two sites. Sites included normal irrigation and deficient irrigation (65% optimum water requirement) and each site was conducted as the factorial split plot in a randomized complete block design with three replications and three factors. Treatments included Azotobacter in the main plots (non-inoculation and inoculation), vermicompost (consuming 0, 2, 4 and 6 ton/ha) and chemical fertilizers included N,P,K (100%, 50% and 0% recommendation based on soil test) in the sub plots. Irrigation treatments (deficit and adequate irrigation) in the middle phase of growth stage (approximately V6) began. Statistical analysis included analysis of variance to compare mean by least significant difference (LSD) by SAS statistical software and graphs were performed by EXCEL.
Results showed that, the grain yield of maize, LAI, leaf chlorophyll contents and NDVI were significantly influenced by irrigation levels, but Azotobacter no significant effect on this traits. Grain yield, LAI, leaf chlorophyll contents and NDVI were decreased by deficient irrigation. Vermicompost and chemical fertilizer increased these traits in normal and deficit irrigation. Vermicompost at 2, 4 and 6 ton/ha consistently and significantly increased grain yield in both irrigation condition. There was no significant difference on grain yield between 6 ton/ha application of vermicompost in linked together 50% of advised chemical fertilizers, and 100% of recommended fertilizer, hence it is possible to reduce chemical fertilizers application up to 50%. Similarly Laekemariam and Gidago (2012) recommended applying integrated of compost at 5 ton ha-1 along with chemical fertilizer to obtain better yield of maize. Kemal and Abera (2015) reported Application of recommended dose of inorganic fertilizer along with vermicompost at 6 ton/ha to maize not only enhanced productivity of maize but also improved soil fertility in terms of higher available N, P, K and organic carbon content over the control and recommended N, P and K.
Although the vermicompost and Azotobacter were not able to provide all the nutritional requirements for Maize but the results indicated that the use of 6 ton/ha vermicompost and Azotobacter in soil, 50% of the maize fertilizer supplied and that means a 50% reduction in the consumption of chemical fertilizers and less pollution of the soil and the environment. On the other hand, the results showed that under deficient irrigation vermicompost and Azotobacter increased grain yield. As a general conclusion these results suggested that integrating bio fertilizer with 50 percent of recommended NPK fertilizers are appropriate for sustainable maize production in normal and deficient irrigation.