1、 PDF外文：http:/ 中文2700字毕业 论文 外文资料翻译 题 目 耕作方式与氮肥用量对土壤中 有机物和氮的百分含量的影响 学 院 &n
2、bsp;资源与环境 专 业 环境工程 班 级 0701
3、 学 生 张学雷 学 号 2007
4、0203070 指导教师 王惠 二一 一 年 三 月 二 十 日 济南大学毕业 论文外文资料翻译 - 1 - 【原文】 Pakistan Journal of B
5、iological Sciences 6 (24): 2017-2019, 2003 ISSN 1028-8880 1M.S. Akter, 2M.F. Hossain, 3U.K. Majumder 4M.S.I. Sikder and 5M.M.A.A. Chowdhury 1Soil Analysis Division, Bangladesh Rural Advancement Committee (BRAC), Bangladesh 2 & 4Department of Agronomy and 3Department of Statistics, Hajee Mohammad
6、 Danesh Science and Technology University, Dinajpur-5200, Bangladesh 5Soil Resources Development Institute (SRDI), Dinajpur, Bangladesh Effect of Tillage Practices and Nitrogen Rates on the Organic Matter (%) and N (%) Content in Soil INTRODUCTION Tillage is the oldest and most fundamental activity
7、of human being for crop production. Different tillage operations may influence organic matter, nitrogen content and other physical properties of soil (Singh et al., 1996).The organic matter content of the soil improves the main biological and chemical capacities of the soil. Growth promoting substan
8、ces and enzymes induce crop growth and yield and improve the quantity of the produce. The organic combination of nitrogen with organic matter in the soil constitutes the major store-house from which nitrogen is slowly made available to the crop. Tillage treatment significantly influenced the organic
9、 matte content of the soil upto a depth of 0-30 cm (Rahman,1977). Different application rates of nitrogen influenced on the total %N content in soil. Nitrogen plays the key rolein plant nutrient and its management practices is an extremely important aspect for crop production. Out of all nutrients t
10、he requirement of N for plant is far more than other elements (Gill et al., 1978). The soils of tropical and sub tropical zones including all agro-ecological regions of Bangladesh are seriously deficient in nitrogen. This may be due to low level of organic matter and continuous cropping with little
11、or no nitrogen fertilizer application.Therefore organic matter and nitrogen in soil could be increased by proper tillage operation along with optimum N application. MATERIALS AND METHODS The experiment was conducted at the Bangladesh Agricultural University Farm, Mymensingh during aman season, 1998.
12、 The soil was sandy loam having pH 6.9. The experiment was laid out in split-plot design with three replications. Three tillage treatments 济南大学毕业 论文外文资料翻译 - 2 - arranged to the mainplot and four nitrogen rates to the sub-plots. Three tillage practices, four nitrogen levels were used in t
13、his study (Table 1). The unit plot size was 4 .0x2.5m. The experimental aman rice CV. Binashail plots were fertilized P2O5 40 kg ha1 K2O 33 kg ha1 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
14、were taken from three different depth and spots at the area 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 chemical analysis. The soil s
15、ample 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 determined by modified Kjeldahl method after digestion with cone. H2SO4 , catalyst mixture (K2SO4+ CuSO4 , 5
16、H2O + Sc powder, 100:10:1) and H2O2 and then distillation with 10 N NaOH solution. The ammonia distilled over was absorved 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 percen
17、tage of organic carbon as described by Black (1965) and the organic matter content was calculated by multiplying the %organic carbon with Van Bemmelen factor 1.73 (Piper, 1950). RESULTS AND DISCUSSION Organic matter content: Organic matter content in soil was statistically significant du
18、e 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） at 0-10 cm soil depth. Minimum organic matter content (0.24%) was found by 20 cm deep tillage (T2) treat
19、ment at 20-30 cm depth. Deep tillage favoured for rapid decomposition of organic matter than no tillage. Decomposition 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 Boy
20、le et al. (1989). Also reported that no 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 content of the soil upto a depth of 0-30 cm an
21、d 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 (Table 2). The highest organic matter content (0.71%) was measured in no tillage with higher rates of nitrogen (105 kg N ha1) and the lowest (0.22%) in deep tillage with no nitrogen application
