Investigation of mineral and biological contaminants transport caused by organic fertilizers through different soils texture via irrigation

By increasing the world population and more need to supply food, farmers attend to use of pesticides, chemical fertilizers and organic manures, excessively. Organic manures in compare with chemical fertilizers, in addition to supply nutrients, can improve soil characteristics such as structure and increasing permeability. Thus uses of manures are increasing nowadays. Surplus and incorrect use of organic fertilizers cause some pollutants enterance to agricultural drainage water and irrigation runoffs and also contamination of groundwater and other environmental problems. Manure pollutants can be divided to chemicals (nitrate, phosphorous, heavy metals and so on) and biological (fecal coliform, virus and parasites). So, attention to pollutant resources of environment. Thus, in order to determine the rate of microbial and nitrate contaminants transport in soil profile and under the root development region, a set-up of lysimeters were used in laboratory condition. To determine pollutants rate, the manure poultry, cow and sewage sludge used on top soils of lysimeters by 35 tone/ha. The fermentation 15-tubes standard method test then, carried out for measuring microbial pollution and spectrophotometer method for nitrate in drainage water samples. The lysimeters filled by two different soil textures of loam and silt loam up to 60 cm height. For microbial tests, six lysimeters and for study of nitrate transport, 24 lysimeters were used. In nitrate transport, a factorial experiment in a completely randomized design with three replications was used. The results showed that the nitrate concentration and coliforms transport in soil profile of loam texture was more than silt loam soil, which can refer to disturbed and texture of soil. Also sludge treatment was caused the most nitrate concentration (88.15 mg/lit), and the lowest was monitored in control treatment (42.10 mg/lit). Also cow and poultry manure nitrate concentration in drainage water samples of lysimeters were about 84.28 mg/lit and 76.86 mg/lit, respectively. For microbial contaminations (total coliform), poultry manure had maximum rate (mean 1000 MPN /100ml), sewage sludge