Research On Dissolved Organic Carbon And Leadching Characteristics Of The Main Soils Of Ji Lin Province

Dissolved organic carbon(Dissolved organic carbon, DOC) is one of the most active soil organic matter component, take the organic form exist in soil solution, high mobility in the soil, it’s high ues activity for plants and microorganisms a part of soil organic carbon, but also the main form of the soil nutrient transfer and loss, is a important factor in ecosystem carbon cycle. Many scholars at home and abroad take the forest soil DOC as research direction, largely ignored the role of DOC content distribution and leaching in farmland ecosystem.Therefore, this experiment taking Jilin three main soil(albic soil, chernozem, black soil) as test objectives, determined three types of soil DOC vertical distribution of content, compared DOC distribution between the various size fractions of soil aggregates, and by indoor culture experiments comparing the effects of different leaching solution treatments on DOC leaching characteristics, got the following main conclusions:1. The content of dissolved organic carbon performanced of high-yield greater than the control field, in the vertical direction of the albic soil and black soil dissolved organic carbon content showed a trend is decreasing with increasing ofsoil depth, namely existence of "up-high and down-low" trend. High-yield film mulching soil present the same trend except for the DOC content at the 20 cm soil layer.2. Albic soil high-yield and control soil are 3-1 mm and 1-0.5 mm fraction size of aggregates predominated; with increasing soil depth 0.5-0.25 mm and <0.25 mm fraction size of aggregates content gradually decreased;and large size aggregates of >5 mm is the opposite. High yield and control chernozem soil, 5-3 mm and 3-1 mm aggregate content in the soil layers changed little; 0.5-0.25 mm and <0.25 mm fraction size of the aggregates in high yield chernozem, which content with increasing soil depth increased, while the control field chernozem contrary; chernozem in the high-yield, >5 mm large size aggregates content with increasing soil depth decreases in the control field chernozem of >5 mm size aggregates present "∧" distribution. Black soil are >5 mm and 3-1 mm fraction size of the aggregates dominate, >5 mm large size aggregates content with increasing soil depth decreases, <0.25 mm fraction size of the aggregates increased with the soil depth increases.3. In different soil depths, the average content of each size of soil aggregates DOC showed high-yield higher than the average content of its control field, and 0.5-0.25 mm aggregates had the highest average content of DOC, 3-1 mm and <0.25 mm fraction size followed by and large size aggregates of >5 mm had the lowest average content of DOC. 4. The leaching solution treatment processing the largest influence on the 0-5 cm soil layer, four kinds of leaching solution treatment differences maximum. 5-10 cm soil layer take the second place, The impact minimum and the leaching solution of the difference among treatments with minimal on 10-20 cm soil layer. Organic fertilizer and mixedfertilizer treatment greatly increased the test soil organic matter, available phosphorus, potassium content, and fertilizer and mixedfertilizer treatment significantly increased the tested soil nitrogen content. Albic soil pH values with increasing soil depth increases in four leaching solution, and chernozem and black soil pH value decreased with the increase of the soil depth. Changes of four kinds of leaching solution of DOC leaching loss range respectively, water between 0.13~2.97 mg/kg, fertilizer between 0.11~2.82 mg/kg, organic fertilizer between 0.36~17.80 mg/kg, mixedfertilizer between 0.21~3.66 mg/kg.Organic fertilizer and mixedfertilizer treatment DOC leaching loss amount higher than water and fertilizer treatment, and no significant differences between water and fertilizers. At the same time comparison test for high yield and control field DOC leaching loss, high yield fields compared with the control showed stronger soil nutrient retention capacity. Organic fertilizer and mixedfertilizer treatment DOC leaching loss amount apparent peak after the fifth time leaching, and then gradually decreased. Meanwhile organic fertilizer and mixedfertilizer treatment significantly increased the content of each soil layer DOC, and 0-5 cm and 5-10 cm soil layer in a relatively large increase. Therefore, we must strengthen the focus on organic fertilizer soluble nutrients, especially DOC in the soil Leaching.