The Effects of Different Nitrogen Sources on Yield and Yield Components of Sweet Corn (Zea mays L. saccharata)

IntroductionSweet corn (Zea mays L. saccharata) is one of the tropical cereals of graminae which is cultivated in order to use for ear. Nitrogen is one of the most important nutrients and key factors to achieve desirable yield. Fertilizers play a major role in crop productivity. However, nowadays, excessive use of fertilizers have been found to have a negative impact on yield and environment. Introducing new management methods based on nitrogen and water use efficiency showed some improvements in the quality and quantity of crop production in association with the health of the community. In fact, soil organic matter content should be maintained in the appropriate level to improve fertility. Using municipal solid waste compost and poultry manure are appropriate solutions. They can increase soil organic matter, modify physicochemical properties and improve crop production. Moreover, they are able to solve problems caused by the accumulation of municipal solid waste compost and poultry manure.
Material and MethodsIn order to investigate the impact of different sources of nitrogen on yield and yield components of sweet corn, a field experiment was conducted as a randomized complete block design with three replications in Marvdasht in 2013. Treatments included different resources of fertilizer: 200 kg.ha-1 net nitrogen (T1), 300 kg.ha-1 net nitrogen (T2), 8 ton.ha-1 poultry manure (T3), 24 ton.ha-1 municipal solid waste compost (T4), 150 kg net nitrogen 2 ton municipal solid waste compost (T5), 100 kg net nitrogen 4 ton poultry manure (T6), 150 kg net nitrogen 6 ton municipal solid waste compost (T7), 100 kg.ha-1 net nitrogen 12 ton municipal solid waste compost (T8) and fertilizer free (control) (T9). At the time of crop maturity, two square meters from middle of each plot were harvested to measure yield and yield components. Statistical analysis was performed using the SAS statistical software. Least significant difference (LSD) test at the five percent level calculated for mean comparison.
Results and DiscussionResults indicated that the different sources of nitrogen had significant effect on the number of grains per row and the number of grains per ear as well as ear and canned yield except for the number of ears per m2 and number of row per ear. Mean comparison indicated that the highest ear yield (2178 g.m-2) was obtained in the treatments of 100 kg N 4 tons of poultry manure (T6) and the lowest yield (1188 g.m-2) in control (T9). Using of organic sources of nitrogen with chemical fertilizer led to increase ear yield. In other words, integrated treatments had better effect on yield than chemical and organic treatments. In addition, the highest canned harvest index (42.8 ton.ha-1) and ear harvest index (48.7 ton.ha-1) was related to 100 kg net nitrogen 12 ton municipal solid waste compost (T8) treatments. Municipal solid waste compost and poultry manure in the 100 and 150 kg nitrogen levels caused to increase of canned harvest index and ear harvest index. This matter is indicative more effect of municipal solid waste compost than poultry manure on two indices.Generally, the combined use of organic manures and chemical fertilizers could be an appropriate method to increase sweet corn yield and soil fertility. According to the obtained results, T6 treatment can be recommended.
ConclusionBased on the obtained results, it seems that single application of organic fertilizers cannot lead to maximum yield, therefore, to obtain the optimal yield integrated application of organic and chemical fertilizers (T6) can be recommended for farmers in the region.