Effect of Different Levels of Pelleted Poultry Manure and Chemical Fertilizer on Fodder Quality and Maize (Zea mays L.) Grain Yield

Introduction Maize (Zea mays L.) ranks first in terms of forage production among forage plants by producing about 490 million tons of fresh and silage forage in the world. Chemical fertilizers are used to increase crop yields and provide human food, but reduce soil organic matter content and, in the long run, pose a serious environmental risk, resulting in contamination of arable soils and surface and groundwater. Organic manures reduce the harmful effects of chemical fertilizers by producing humus and increasing the activity of the soil microbial community. Utilization of non-chemical resources such as farmyard manure in combination with chemical fertilizers can lead to soil fertility and increase yield and crop quality because combined fertilizer systems can provide most of the plant's nutritional needs by increasing the absorption efficiency of nutrients in crops. Considering the importance of organic manures and their combination with chemical fertilizers, this experiment was conducted in order to investigate the effects of different levels of poultry manure, chemical fertilizer, and their combination on yield, yield components, and maize forage quality. Materials and Methods The research was carried out in the research farm of Kurdistan University located in Dehgolan County, Kurdistan Province, Iran in the crop year 2017-2018. The experiment was performed in the form of randomized complete blocks with three replications. Experimental treatments included different levels of pelleted poultry manure in combination with chemical fertilizers: Figure 2. T1: no fertilizer (control), T2: 1250 kg of poultry manure + zero kg of recommended chemical fertilizer, T3: 1250 kg of poultry manure + 25% of the recommended chemical fertilizer, T4: 1250 kg of poultry manure + 50% recommended chemical fertilizer, T5: 2500 kg of poultry manure + zero kg of recommended chemical fertilizer, T6: 2500 kg of poultry manure + 25% of recommended chemical fertilizer, T7: 2500 kg of poultry manure + 50% Recommended chemical fertilizer, T8: 5000 kg of poultry manure + 0 kg of recommended chemical fertilizer, T9: 5000 kg of poultry manure + 25% of recommended chemical fertilizer, T10: 5000 kg of poultry manure + 50% of chemical fertilizer Recommended, T11: 100% recommended chemical fertilizer. In this experiment, traits such as plant height, 1000-seed weight, biological and grain yield, seed nitrogen, starch, oil contents and forage quality were measured. Results and Discussion The results of the analysis of variance showed that the plant height, grain yield, biological yield, grain nitrogen, starch and oil contents, and oil yield were affected by fertilizer treatments at a probability level of 1%. The index harvest of maize was significant at the level of 5% probability. The number of plants per square meter and 1000-seed weight were not affected by fertilizer treatment. The highest plant height (241.2 cm), number of ears per plant (1.2 ears), 1000-seed weight (26.99 g.m-2), seed yield (12.76 tons per hectare) and biological yield (26.42 tons per hectare) were observed in the treatment of 5000 kg of plated chicken manure + 50% of the recommended chemical fertilizer. The highest percentage of fodder silage protein (12.58%) and silage ash (10.32%) was observed in the treatment of 2500 kg of plated chicken manure + 50% of the recommended chemical fertilizer. The highest percentage of insoluble fibers in neutral detergent was observed in the T6 and T8 treatments, and the lowest percentage of insoluble fibers in neutral detergents was observed in the T10 treatment. The highest and lowest percentages of insoluble fibers in acidic detergent were in the T2, T4, and T3 treatments, respectively. According to the results of the present experiment, the combination of chemical fertilizer with different amounts of chicken manure has reduced the consumption of chemical fertilizers, and in addition to saving on the consumption of fertilizer and the resulting costs, the harmful effects on the environment have also been reduced, and the condition of the soil in terms of fertility in the long term, the percentage of soil organic matter will improve. Conclusion  The results of the experiment showed that combined fertilizer treatments were superior compared to pure chemical fertilizer and pure poultry manure treatments, improved the yield and yield components of maize and caused a reduction in chemical fertilizers consumption. Chemical fertilizer treatment provided acceptable yield only at high levels.