Effects of organic, biological and chemical fertilizers on yield and chemical compounds of barberry during on-year

Seedless barberry (Berberis vulgaris L.) is one of the most valuable products of Iran's exports and is one of the most promising products of Southern Khorasan Province, the only seedless barberry production center in the world. The area under cultivation of this product in South Khorasan as the first producer (with 98% of Iran's barberry production) is 14656.5 hectares, indicating the important position of this product in the region's economy and creating productive employment in the province (Kamyab et al, 2016). This shrub is one of the plants that all its parts (leaf, root, stem and fruit) are used in medicine and food industry (Martynove et al., 1984). The fruits of the barberry have a cool and dry nature, and in the traditional medicine, the liver and heart are supplemented, the gastric hemorrhage and the blood supply and hemorrhoids. Also, the leaf is an appropriate drug for ulcers and diarrhea (Mirhaidar, 1993). The integrated application of organic and chemical fertilizers sustains the intense production system, which can be attributed to the improvement of soil quality characteristics and release of nitrogen (Salehi et al., 2014). Organic fertilizers with the production of humus reduce the adverse effects of chemical fertilizers and increase the efficiency of fertilizer application (Yang et al., 2005). The aim of this research was to investigate the effect of the integrated nutritional composition of organic, biological and chemical fertilizers on the yield as well as physiological and biochemical characteristics of barberry. Since barberry has fruiting period, in this research the effect of fertilizer treatments on high yielding years has been investigated.

This experiment was conducted as split plot randomized complete block design with three replications in commercial garden in Qaen during 2016. Main treatments comprised four application type of fertilizer (1-no fertilizer application, and application of 2-Chemical fertilizer, 3-organic fertilizer and 4-50 percent of chemical along with 50 percent of organic fertilizer). Sub treatments were no fertilizer, application of Phosphate Barvar-2, humic acid, and Phosphate Barvar-2 + humic acid. The measured characteristics included the fresh weight of fertile branch, fresh and dried weight of berries, ash percentage, dry matter percentage, nitrogen, phosphorous, potassium, anthocyanin, flavonoids, vitamin C and total phenol in the berries. Statistical analysis of the data was performed using SAS software version 9.1 and comparison of means by Tukey method at 5% probability level.

Considering that the main- and sub-fertilizer treatments have a significant effect on the most of the measured traits at 1% probability level, the effectiveness of the main and secondary fertilizer treatments in barberry can be obtained. The results of this study showed that the combination of organic and chemical fertilizers + Phosphate Barvar-2 + humic acid with positive effect on the traits related to the yield was the best treatment. The treatment also had the highest percentage of ash, anthocyanins and vitamin C in the berries. This treatment and other integrated treatments were better in comparison with the application of separate organic and chemical fertilizers in most of the traits. Accordingly, the integrated application of animal and chemical fertilizers with equal amounts can be recommended instead of separate application in order to achieve greater yield and quality in barberry.

These results suggested that the greatest yield and quality of berries was obtained at integrated application of chemical and organic fertilizer along with fertigation of humic acid and Phosphate Barvar-2, indicating positive effect of the combined application of organic and chemical fertilizer over the separate application of the fertilizer on the yield and yield components of barberry. The application of humic acid with other fertilizer sources can reduce the excessive use of fertilizers and their leaching and help maintain soil and water resources. Biofertilizer 2 also improves the amount of phosphorus in soil and improves the absorption of phosphorus of barberry plant, by improving the amount of phosphorus available in soil as well as decreasing phosphorus fertilizer consumption. Therefore, it is very important to plan large-scale fertilizer management in the field of this strategic product of Iran. In order to be surer of the results, it is also necessary to carry out research in off-year of barberry