The Effect of Cow Manure, Nitrogen, Phosphorus and Corm Weight on the Yield Characters of Colchicum (Colchicum kotschyi Boiss.)

Meadow saffron (Colchicum) is a non-domesticated medicinal plant, rich in isoquinoline alkaloids. These alkaloids are used in medicines mainly for their anti-gout and myorelaxant properties. Meadow saffron has an unusual biology that does not favor cultivation. Flowers of Meadow saffron appear in September and fruits mature in June. The corms enter dormancy phase in winter (January to March) and after fruiting in summer (June to September). Each year, a mother corm produces one daughter corm, or sometimes two daughter corms. The uptake of mineral element in plant is a complex process that governed by numerous factors influencing each other. nitrogen, phosphorus, and potassium application can significantly increase the yield and improve the quality of plants. Meadow saffron need more consider in fertilization managements in comparison with other crops because it has shallow roots than other crops and exposes to more problems in uptake of immobile nutrients in the soil. The object of this study was to determine the effect of different fertilizers and mother corm weight on yield characters of Colchicum kotschyi Boiss.

This experiment was conducted as factorial layout based on a randomized complete block design with three replications at Research Station, Ferdowsi University of Mashhad, Iran, in two years, 2012- 2013 and 2013-2014. The Corms of Colchicum kotschyi Boiss. were harvested from natural site of Binalood Mountains during their summer dormancy. The mother corm weight was considered as a factor in the experiment, because of the variation between the collected corms. In order to evaluate fertilizers effect, soil analysis was conducted. So, the experimental factors were: mother corm weight (less than 40 g and more than 40 g), cow manure (0 and 50 t.ha-1), urea (0 and 50 kg.ha-1) and superphosphate (0 and 25 kg.ha-1). Before planting, cow manure and superphosphate were well mixed with soil and urea was added to soil during emergence of leaves. Planting date was 28th August 2012. Planting depth was 12-15 cm and the space between plants was 25 cm. During flowering, flower number was recorded. Plants were harvested when the color of leaves and capsules were changed from yellow to brown, and characteristics such as corm yield, seed yield, biological yield, 1000-seed weight, capsule number, capsule dry weight, seed number, seed dry weight, corm and seed HI were measured. Data analysis was done by SAS Ver. 9. Mean comparisons were done by LSD test at 5% probability.

At the first year of experiment, most of transplanted corms did not flower due to transplanting. Therefore, just the results of the second year were presented here. The results showed that mother corm weight had significant effect on the yield (p≤0.05). The weight of daughter corms was increased by increasing mother corm weight, because of more supply of nutrients. The weight of the corm is basically determined by the amount of total food stored in the corm by the plant through the process of photosynthesis. The initial plant growth and its vigor are determined by the amount of food supplied to the growing plant by the corm. The results showed that seed yield characters were affected by the cultivated corm weight. The most flowers per area unit, capsule number per plant, seed number and dry weight per plant were belonged to heavier cultivated corms. The effect of corm weight on corm HI was not significant (p≤0.05), but smaller corms had more seed HI than bigger corms (p≤0.05). The effect of cow manure on most characters was significant (p≤0.05). Corm yield and corm HI increased in cow manure treatment in comparison with control. Organic fertilizers cause improvement of soil structure, better development of roots, regulation of soil temperature and useful microorganisms, supply of nutrients for plant and supports plant in nutrient absorption. Capsule number, capsule dry weight and seed number per plant were not influenced by cow manure. The number of capsules per plant and the number of seeds per capsule were determined during fertilization. The only parameter that can vary during capsule development was the thousand-seed weight. The results showed that seed dry weight per plant, 1000-seed weight, seed yield and seed HI were decreased in cow manure treatment in comparison with control. It seems that cow manure has more effect on vegetative growth and decrease proportion of seed compared to corm in whole plant weight. Meanwhile, the competition between corm and seed for photosynthetic materials may decrease seed dry weight. The effect of superphosphate was significant on some studied characters. Superphosphate utilization was increased corm yield and biological yield compared to control. Many researchers reported that phosphorus that was effective in leaf photosynthesis and carbon metabolism in plants. Phosphorus increased seed dry weight per plant, seed yield and 1000-seed weight. Phosphorus is a very important nutrient in plant nutrition and is more effective in the formation of flower, fruit and seed. Many researches have shown that phosphorus promote reproductive growth.

The results showed that colchicum could have a good response to treatments especially cow manure and superphosphate. It seems that more levels of fertilizers especially urea could improve quantitative and qualitative yield of plant.