Effect of Organic Fertilizers on Yield and Yield Components of Safflower (Carthamus tinctorious L.)

Introduction Soil organic matters impose direct and indirect effect on crop production through providing of nutrients and also improvement of soil physical condition and stimulation of plant growth. It also seems that plant production based on application of organic fertilizers is more stable than application of chemical fertilizers. So, there has been lots of attention from agronomists, ecologists and consumers toward organic fertilizers. In organic farming, agricultural ecosystem is considered as a living thing and integrated totality, so in this system, soil, crop, microorganisms and micro-climate affect on each other and also are under the effect of each other. For better performance of this system, each component should be in its appropriate condition. Periodical reverse of organic matter to soil and crop rotation will improve biological and physical characteristics of soil. However, balance of nutrients in organic matter which is available for plant is important because causes less dependence to chemical fertilizers. Indeed, nutrients balance is more important than application of chemical fertilizers that can lead to water pollution and decreasing quality of food products. Application of chemical fertilizers caused considerable increasing of farmer's income in last decade. These fertilizers also imposed ecological and environmental problems. In Iran like most of the countries, overusing of chemical inputs like fertilizers has caused destruction of water and soil resources. In addition, leaching of soluble chemical fertilizers specially nitrogen fertilizers has caused pollution of drinking water and overfilling of the water of lakes and ponds in some regions. So researchers have done a lot of effort to replace organic and biological fertilizers with chemical one. The aim of this experiment was to study the effect of organic fertilizers on safflower production. Materials and Methods In order to evaluate the effect of organic fertilizers and two different application dates of them on safflower an experiment was conducted at Islamic Azad University of Shirvan, Iran, in growing season of 2012-2013 and 2013-2014. Date of first application was two month prior of planting and date of second application was simultaneous with planting. Amounts of vermicompost included 4, 7 and 10 ton ha-1, municipal solid waste compost included 5, 10 and 15 ton ha-1, cow manure included 20, 33 and 50 ton ha-1, nitrogen chemical fertilizer included 100 kg ha-1 and control. Experiment was conducted as split plot based on randomized complete block design with three replications. Application time of organic fertilizers located in main plots and each one of organic fertilizers levels with nitrogen fertilizer and control as a independent treatment located in subplots. Required rates of different fertilizers were scattered by hand into the plots on 20th Feb then no operation was done until April 21th. On April 21th, main plots which should have been applied fertilization simultaneous with planting were received fertilizers. At this time, all of the plot which have been received fertilizers on Feb 20th plus plots which received fertilizers recently were planted simultaneously. Data were combined analyzed by MSTAT-C software and means were compared with Duncan’s test at the 5% level of probability. Results and Discussion The results showed that in first growing season, fertilizer application before planting caused 12% yield increment of safflower compared with fertilizer application at planting time but in second growing season, fertilizer application at the time of planting caused 12.8% yield increment of safflower compared with fertilizer application before planting. Enough time for manure decomposition can be the reason for this difference. In first year in fertilizer application before planting, all treatments except 10 ton h-1 municipal solid waste compost produced more seed yield than control and chemical fertilizer treatments. In fertilizer application at planting time, chemical fertilizer treatment produced the highest seed yield compared with other treatments. The faster availability of nitrogen chemical fertilizer is the reason for more seed yield in this treatment compared with organic fertilizers. In second year in fertilizer application before planting all treatments except 4 ton h-1 vermicompost and 15 ton h-1 municipal solid waste compost produced more seed yield compared with control and chemical fertilizer treatments but in fertilizer application at planting time chemical fertilizer, 4 and 7 ton h-1 vermicompost showed higher seed yield. Conclusions According to the results of this experiment, using 5 ton h-1 municipal solid waste compost before planting is the best treatment to use in safflower production in northern Khorasan