Effect of organic fertilizers and split application of nitrogen on yield and yield components of rice

Due to market price, rice production in Isfahan province has expanded to many locations, where there is enough fresh water for a cropping season, with no considerations on negative aspects of this practice. Organic fertilizers have been recommended as an amendment to reduce the negative impact of puddling on soil physical and chemical properties. This experiment was conducted to study the effects of cow manure on sustainability of rice yield under soil submergence and puddling practice. According to a randomized complete block design with three replications, rice were planted under six fertilizer treatments for three years. Treatments included three methods of urea applications, two levels of cow manure and a no fertilizer application as a check. Analysis of variance revealed a significant yield difference among fertilizer treatments for the first year of the experiment. Mean yield comparisons showed that highest yield was obtained when 104 kg/ha nitrogen was applied at different rice growth stages. In the second year, except for 1000-grain weight, other measured traits were significantly different among fertilizer treatments. In this year, significantly higher yield were obtained from the plots that received the highest organic manure each year (32 ton/ha). Lowest yield belonged to the check treatment. Analysis of variance for the third year^,s data also indicated a significant difference among fertilizer treatments for plant dry weight, number of plants per hill, plant height and seed yield. Similar to the second year, highest value on these traits belonged to treatment with highest organic fertilizer, and the lowest to the check treatment. It may be concluded that organic manure application in rice culture could sustain a higher yield compared to chemical fertilizers, which is a common practice in Isfahan province.