The Evolution Of Humus And Organic Nitrogen Forms And Its Relation Of N Supply Capacity In Sheltered Soil

This experiment take the Shandong Province sheltered cultivation soil as the research object, including Shouguang, Jiyang, Feicheng, the system has studied the humus and organic nitrogen forms and its relation of nitrogen supply capacity in sheltered cultivation soil. The main results as follows:1.The contents of soil organic matter, total N and available N in sheltered cultivation were higher than them in the open cultivation and were increasing with the cultivation year increasing, and the contents in 0~20cm were higher than them in 20~40cm soil layer obviously.2.The contents of humus,HA and FA in sheltered ground were higher than them in the open field and were increasing with the cultivation year increasing, and the contents in 0~20cm were higher than them in 20~40cm soil layer obviously. HA/FA and HA(%) also had the increase compared to the open cultivation.3. The contents of humus combined, loose humus, stable humus and tight humus in sheltered ground were higher than them in the open field and were increasing with the cultivation year increasing. L/T also had the increase compared to the open cultivation. With the cultivation year increasing, the content changes of them had the trend which assumes first increases then reduced.4. Loose humus and stable humus were the primary form of humus combined, and the transformation rate of loose humus had reduced, its of stable humus had increased.Soil humus activity had increased; the nutrition contition had improved.5.The contents of Amino acid N in 0~20cm were higher than them in 20~40cm soil layer obviously, and the percentage of Hydrolysable unidentified N,...