Research On Properties Of Organic Substrate In Soilless Culture Based On Biogas Residue

Because of so many advantages, such as overcoming continuous cropping obstacles, saving water, saving fertilizer, saving labor, fine quality and high yield etc, soilless culture was widely researched in agriculture sector in the world. Many approaches can be realized for soilless culture. In the course of crops' soilless culture, generally speaking, nutrition is delivered to crops through special nutrient solution. This brings it high cost and complex techniques, and also makes it difficult for common peasants to accept and master. As the result, soilless culture is sharply limited in extension and application. Therefore, it is of great important significance for the development of soilless culture to make full use of avail agricultural organic wastes in our country.The biogas residue is the solid residue, which is produced in the process of the biogas making from organic matter fermentation in the biogas pond. Besides a large quantity of nutrient such as nitrogen, phosphor, kalium etc, there are still a plentiful organism and humic acid inside biogas residue. It is a kind of harmless fertilizer that has the late effect and soon effect to the plants simultaneously. It is also a kind of substrate in soilless culture. This paper take biogas residue for raw material, was mixed with two other kinds of materials(vermiculite, perlite) in various proportions in order to regulate physic-chemical properties of biogas residue. Then, we get 34 treatments. Analysis and study of the test results of physic-chemical characteristics of these sbustrates, of which physical property including particulate diameter, bulk density, porosity, saturation capacity and chemical properties inculding electrical conductivity(EC), pH, total nitrogen, phosphorus kalium, nutrition elements contents, and heavy metal elements. The results show that the basic physic-chemical characteristics of most treatments meet the demands,but there are only twenty-two treatments meet the demands of AP/WHP; biogas residue have plenty of total nitrogen and phosphor, although vermiculite and pearlite total nitrogen and phosphorus content is not high, but with biogas residue after the certain proportion mixed, the totla nitrogen and phosphorus content extremely was still rich. Each treatment richly contains the calcium, but element of Mg,Fe,Mn lacks relatively. The heavy metal measurement result showed that Cu andCd content of biogas residue was high, Cr content of vermiculite is high, other treatments' heavy metal content are lower than below the permission standard value.On the base of analysis result of physic-chemical properties testing, 6 treatments were selected out to do cultivating test contrasted with soil. Tomato and capsicum were taken as test subjects in cultivating test. Their heights and leaf numbers were measured in different periods of time, and then analysis of variance was made with the data acquired in the test. The analysis result showed that treatment 2, namely the treatment which components propotion of biogas residue: vermiculite: perlite is 2: 3: 1, is the best one to boost growth of crops' height and leaf. Therefore, this treatment was taken for the optimized scheme.