旱田
2.This paper analyzed the yield performance by applying different quantity DCD and nitrogen fertilizer in water field and dry field.
3.Three culm traits,basal culm thickness(BCT),culm length (CL) and culm strength (CS),of DH lines and their parents under upland and lowland ecosystems at milk stage were studied.
4.Shun-Cheng Lee, 2001, 12, Economic Liberalization and Comparative Study on the Trade Competitive Structure Adjustment Policy in Taiwan and Germany, Bonn University, Bonn, Germany, December 10-15, 2001.
5.Then it analyses the different function of irrigation projects as glebe ,paddy field, farmland in the Xia, Shang and Western Zhou Dynasties, further proves the irrigation works of southern paddy field area is earlier than north drying farming area, so the north irrigation project technology is from southern China.
6.In addition, to solve the lack of water supply at an elevation of 350 to 500 meters river terraces, a great amount of expense was spent on building Bai-Leng Irrigation Canal, which provided enough irrigating water for the agriculture on river terraces and converted the free-range use of Hsin-Hse river terraces to the intensive use.
7.Applying38.6kg /hm 2 DCD reached the highest yield. And the optimum DCD quantity was33.9kg /hm 2 with a proportion of1∶0.15～0.18and could be used as safe applying quantity for corn.
8.C pools of total organic carbon(TOC),dissolved organic carbon(DOC) and soil microbial biomass carbon(SMBC) was determined for bulk soils from the two fields respectively. Soil particle size factions(PSFs) were separated using low energy ultrasonic dispersion and the TOC of them determined using CNS analyzer. Selected samples of bulk soil and PSFs from both rice and corn fields were used for 13C natural abundance measurement with Finnigan MAT251 mass spectrometer.
9.Through analyzing the contents of metabolites of BHC and derivatives of DDT in the runoff from paddy and corn land in the Western Songnen Plain, it was found that the contents of BHC and DDT were very lower and β BHC, which accounted for 73 5%～99 5% of the contents of BHC, was the main metabolite of BHC in the runoff. Among the derivatives of DDT, only p,p DDT was detected out.
10.The urease and alkaline phosphatase appeared to have a clearly correlated tendency. The level of enzyme activity in the vegetable garden soil profile was higher than that of crop soil. The enzyme activity of vegetable garden soil showed positive correlation with soil organic matter, total nitrogen, total phosphorus and available phosphorus.
