Evaluation of Culture Media Including Vermicompost, Compost and Manure under Drought Stress in Iranian Petunia (Petunia hybrida)

Organic fertilizers are derived from animal matter, human excreta or vegetable matter. (e.g. compost, manure). Organic fertilizers are carbon-based compounds that increase the productivity and growth quality of plants. Organic fertilizers preserve food cycle; reduce pollution and remediation of soil physicochemical properties and stabilization of plants in soil. Use of these organic fertilizers ensures that the food items produced are free of harmful chemicals. As a result, the end consumers who eat these organic products are less prone to diseases such as cancer. In addition to the on-farm production possibilities of organic fertilizers, organic fertilizers help in maintaining the soil structure and increasing its nutrient-holding capacity. Organic fertilizers are easily bio-degradable and do not cause environmental pollution. On the other hand, chemical fertilizers contaminate both the land and water, which is a major cause of diseases for human beings and is the force behind the extinction of a number of plant, animal, and insect species.
Material and In order to investigate the effect of organic fertilizers (vermicompost, compost and manure) on morpho physiological characteristics of Petunia hybrida an experiment based on a completely randomized design with three replications was conducted at the Ferdowsi University of Mashhad.Irrigation treatments consisted of three levels (100 % of field capacity by irrigation at a rate of 360 cc (D1), 50% of field capacity by as much as 180 cc (D2) and 25 % of field capacity by as much as 90 cc (D3 )), and four fertilizer treatments (control, compost, vermicompost and manure). Some traits such as stem fresh weight leave fresh weight, flower fresh weight, length, diameter and number of flowers, SPAD index, leaf area, relative water content and membrane stability index were measured.
The results showed that effects of the treatments on traits such as flower fresh weight, length, diameter and number of flowers, SPAD index, relative water content and membrane stability index were significant at 1% level. The interaction of two factors on traits such as stem and flower fresh weight, flower number, leaf area, leaf fluorescence, relative water content and membrane stability index was significant. Thus the weight of a single flower per plant increased with the application of vermicompost fertilizers, compost and manure, respectively, 16/26, 65/9 and 40/8% over control at 100% capacity. Irrigation with treated manure at 25% field capacity (D3) increased length of flower over 14% compared to control. In 50% of field capacity (D2) with vermicompost in the context of the membrane stability index was 62% which, compared to control treatments at the same level of irrigation, was increased by 67%. Use of manure and vermicompost seems to improve adverse effects of drought stress.
Manure and vermicompost improves soil aeration, enriches soil with micro-organisms (adding enzymes such as phosphatase and cellulase), Enhances germination, plant growth, and crop yield and also improves water holding capacity.