عنوان مقاله [English]
Chemical fertilizers have a significant effect on food production in the world and are one of the essential components in today's agriculture. It has been reported that the doubling of agricultural food production up to the 1990s, partly attributed to the increasing the use of nitrogen and phosphorous fertilizers by 6.9 and 3.5-fold, respectively. Increasing the use of chemical fertilizer in crop production systems, resulting in many environmental problems such as water, soil and air pollutions and also increasing the vulnerability of the agricultural ecosystems through the declining biodiversity. Therefore, conventional agriculture approaches in today's world are not acceptable because of relting onapplication of too much on artificial inputs and auxiliary energy infusions such as chemical fertilizers and pesticides creates an unstable farming system.. Organic fertilizers, such as animal manures, are able to increase soil water holding capacity, reduction drought stress, increase soil microbial diversity, improve the physical structure of the soil and prevent soil erosion. Various reports suggest that the combination of chemical and manure fertilizers to improve the quantity and quality of crop production is more effective than the separate application. Oikeh (1998) found that in five varieties of corn that are affected by nitrogen fertilizer, grain yield and 1000 seed weight for all varieties increased. Therefore, the present study was designed and carried out in order to determine the effect of chemical and manure fertilizers and combination of them on grain yield and yield components of corn and to obtain the optimal composition of these fertilizers.
Material and Methods
In order to investigate the effect of different amounts of chemical and animal manure fertilizers and the combination of them on grain yield and yield components of corn (single cross 704), a field study was conducted in 2004-2005 growing season in agriculture experiment station of Zabol University Iran. The experiment was conducted as a randomized complete block design with four replications. The experimental treatments were T0 (no fertilizer), T1 (90 t.ha-1 cow manure), T2 (200 and 150kg.ha-1, nitrogen [N] and phosphorus [P], respectively), T3 (45t.ha-1 cow manure+100kg.ha-1 N and 75kg.ha-1 P), T4 (30t.ha-1 cow manure+133.32kg.ha-1 N and 100kg.ha-1 P), T5 (60t.ha-1 cow manure +66.66kg.ha-1 N and 50kg.ha-1 P). Sowing was carried out in the first half of March. Filed irrigation during the growing season was carried out every 7-10 days.
Results and Discussion
Results showed that yield dry matter, plant height, number of grains per ear, number of grain per row, economic yield, biological yield, and harvesting index were affected by different fertilizer treatments. The highest grain yield (4825kg.ha-1), biological yield (7850kg.ha-1), length of ear (23.9cm), number of kernel per ear (36), 1000 seed weight (176.1g) and plant height (198.3cm) were obtained at T5 (60t.ha-1 cow manure +66.66kg.ha-1 N and 50kg.ha-1 P) treatment. There was a significant difference between T5 with other treatments. The results showed that there was a significant positive correlation between grain yield and ear length (r=0.86**), seed weight (0.61**), biological yield (0.67**), number of the kernel per row (0.97**) and plant height (0.86**). In addition, combined chemical and animal fertilizer treatments compare with single chemical and animal fertilizer treatments had more effect on yield components. There were no significant differences between T1 (chemical fertilizer) and T2 (animal manure) in terms of grain yield.
Based on our results, It can be concluded that the combination of 60t.ha-1 cow manure + 66.66kg.ha-1 N with 50kg.ha-1 P was the best treatment to produce corn in the studied region.