The Development Of Earthworm Feed With Cow Dung As Substrate

Three experiments were conducted to study the appropriate pretreatment methods of the cow dung as the main raw material for vermicomposting and the suitable feed for earthworm and to investigate the appropriate levels of potassium chloride, superphosphate and urea in the earthworm feed in order to provide a theoretical basis for preparation of the earthworm's complete nutritious feeds.1) Preparing the feed for the earthwormCattle dung and corn straws were used for the prepatation of four kinds of feed for earthworm, that were unfermented cow dung (CD0), fermented cow dung for 10 days (CD10), fermented cow dung for 20 days (CD20) and fermented cow dung for 30 days (CD30 ). Unfermented cow dung was made as follow, fresh cattle dung were dried at 110℃and then ground. CD10, CD20 and CD30 were made as follow, according to the carbon and nitrogen content of fresh cattle dung and corn straw, the ratio used for the composting experiment was 25:1 at the beginning of experiment. The weight ratio of cattle dung and corn straw was 5.6:1 and water content was adjusted to 65%. And then the raw material were mixed thoroughly. After that they were feed into three composting boxes and fermented for 10, 20 and 30 days respectively. At the end of composting, the composted materials was mixed completely and dried and ground. The results showed that there were significant difference between the experiments indexes, including pH value, EC value, carbon and nitrogen ratio, nutritional status, N-NH4 content and N-NO3 content among the CD10, CD20 and CD30, but these indexes values were fallen into the suitable ranges for the growth and fertility of earthworm.2)Selection of earthworm feedExperiment was conducted to study the effect of four kinds of feed on the growth and reproduction performance of earthworms which belonged to Eisenia foetida.The feed were unfermented cow dung (CD0), fermented cow dung for 10 days (CD10), fermented cow dung for 20 days (CD20) and fermented cow dung for 30 days (CD30 ). The four kind of feed were feed into a total of 20 plastic basin with 5 repeat respectively; each plastic basin were placed 10 juvenile earthworms(about 1week old) for vermicomposting. During the process of the experiments, the individual weight, growth rate, cocoon productions, cocoon hatching rate were measured for 13 weeks, and at the end, the physical and chemical properties of vermicomposted were measured. The results indicated that the earthworm could growth and reproduce in the four feed normally and the worm's individual weight, growth rate, cocoon productions and cocoon hatching rate for CD0 and CD30 were higher than CD10 and CD20, but there were not significant difference between CD0 and CD30 for these indexes. From the viewpoint of process and costing, the CD0 was more simple and more economic. At the same time, we could find that both pH value and carbon to nitrogen ratio of feed were decreased, but the total nitrogen, the total phosphorus and the total potassium increased after vermcomposting for 13 weeks, thus the fertilizer efficiency of vermicomposting was higher than the composting.3)Effect of additive on the growth and reproduction performance of earthwormThere were three independent trails to determine the effect of potassium chloride, superpho- sphate and urea additive level on the growth and reproduction performance of earthworm. The level of Potassium chloride included 0, 0.2, 0.4, 0.6, 0.8 and 1.0g/kg respectively; The level of superphosphate included 0, 0.25, 0.5, 0.75, 1.0 and 1.25g/kg respectively; The level of urea additive included 0,2.0,2.25,2.5,2.75 and 3.0g/kg respectively. There were four repeats for each additive level, therefor a total of 72 plastic basins were needed for three kind of additive. Ten juvenile earthworms, which were similar in body weight, about 170mg, were caculated in each basin. The individual weight, growth rate, cocoon productions, cocoon hatching rate and other indicators were measured for a period of 13 weeks of earthworm vermicomposting.The results indicated that the individual weight, cocoon productions, cocoon hatching rate increased gradually along with the increase of potassium chloride add level, and maximizing at the level of 0.6g/kg for potassium chlorid, and then decreased gradually. So, we suggested the optimum level was 0.6g/kg for potassium chloride when the unfermented cow dung (CD0) was used for the earthworm culturing. The results indicated also that the individual weight, cocoon productions, cocoon hatching rate increased gradually along with the increase of superphosphate add level, and maximizing at the level of 0.6g/kg for superphosphate, and then decreased gradually. So, we suggested the optimum level was 0.6g/kg for superphosphate when the unfermented cow dung (CD0) was used for the earthworm culturing. As well as, the results indicated that the individual weight, cocoon productions, cocoon hatching rate increased gradually along with the increase of urea add level, and maximizing at the level of 0.6g/kg for urea, and then decreased gradually. So, we suggested the optimum level was 0.6g/kg for urea when the unfermented cow dung (CD0) was used for the earthworm culturing.