環(huán)境工程外文資料翻譯--耕作方式與氮肥用量對土壤中有機(jī)物和氮的百分含量的影響

1、畢業(yè)論文外文資料翻譯 畢業(yè)論文外文資料翻譯題 目 耕作方式與氮肥用量對土壤中 有機(jī)物和氮的百分含量的影響 學(xué) 院 資源與環(huán)境 專 業(yè) 環(huán)境工程 班 級 0701 學(xué)

2、 生 張學(xué)雷 學(xué) 號 20070203070 指導(dǎo)教師 指導(dǎo)教師 王惠 二〇一一年三月二十日濟(jì)南大學(xué)畢業(yè)論文外文資料翻譯- 2 -arranged to the mainplot and four nitrogen rates to

3、 the sub-plots. Three tillage practices, four nitrogen levels were used in this study (Table 1). The unit plot size was 4 .0x2.5m. The experimental aman rice CV. Binashail plots were fertilized P2O5 @ 40 kg ha?1 K2O @ 33

4、 kg ha?1 with TSP and MP during final land preparation. Urea was top dressed in three installments after 10, 25 and 40 days after transplanting. The soil samples were taken from three different depth and spots at the are

5、a to make a composit soil sample before transplanting and after harvest. The samples were air dried and ground to pass through a 2 mm (10 mseh) sieve. The ground sample were stored in clean plastic containers for chemica

6、l analysis. The soil sample were analysed for the determination of nitrogen content in the laboratory of Soil Science Depaartment, Bangladesh Agricultural University, Mymensingh. Nitrogen contents of the soil were determ

7、ined by modified Kjeldahl method after digestion with cone. H2SO4 , catalyst mixture (K2SO4+ CuSO4 , 5H2O + Sc powder, 100:10:1) and H2O2 and then distillation with 10 N NaOH solution. The ammonia distilled over was abso

8、rved in H3BO3 indicator solution and titrated with 0.01 N H2SO4 (Jackson, 1973). The results were expressed in percentage. Wet oxidation method was followed to determine percentage of organic carbon as described by Bla

9、ck (1965) and the organic matter content was calculated by multiplying the %organic carbon with Van Bemmelen factor 1.73 (Piper, 1950).RESULTS AND DISCUSSIONOrganic matter content: Organic matter content in soil was st

10、atistically significant due to different tillage practices (Table 1). Tillage operations changed organic matter content in soil at different depth. Maximum organic matter content (0.69%) was measured under no tillage (T0

11、）at 0-10 cm soil depth. Minimum organic matter content (0.24%) was found by 20 cm deep tillage (T2) treatment at 20-30 cm depth. Deep tillage favoured for rapid decomposition of organic matter than no tillage. Decomposit

12、ion rate of organic matter was reduced by no tillage as a result organic matter content becomes high under no tillage. The result was supported by Agenbag and Maree (1989) and Boyle et al. (1989). Also reported that no

13、 tillage and to a lesser extent shallow tine tillage tended to increase organic carbon contents in the 0-10 cm soil profile. Rahman (1997) reported that tillage operation significantly influenced the organic matter conte

14、nt of the soil upto a depth of 0-30 cm and highest organic matter content was measured by no tillage operation. The interaction effect of tillage and nitrogen on organic matter content was not statistically significant (