首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 31 毫秒
1.
A new site-specific nutrient management approach was developed to break the apparent attainable yield barrier of 6 t·ha−1 in the double rice cropping system of Zhejiang. On-farm experiments involving 21 rice-growing farmer families and NPK long-term experiments commenced in 1997 in the central part of Zhejiang Province to assess the status of soil fertility and productivity under intensive rice-rice cropping. A new site-specific nutrient management (SSNM) approach has been developed for this studied area. Field-specific fertilizer recommendations are calculated considering indigenous nutrient supply, reasonable grain yield targets and corresponding nutrient demand, nutrient balance and nutrient use efficiency, as well as socio-economic factors. The agronomic performance of SSNM was tested against the farmer's fertilizer practice (FFP) in four 1998–1999 cropping seasons. Across seasons and years, SSNM consistently increased plant nutrient uptake, grain yield and profit by about 10%–15% compared to the FFP. Yield levels of 7.5 t·ha−1 or more seem achievable and sustainable through introduction of SSNM and improved extension services in Zhejiang Province. Project supported by the International Fertilizer Industry Association(IFA), the Potash and Phosphate Institute, Canada (PPIC), and International Potash Institute(IPI).  相似文献   

2.
Potential growth of two widely-grown hybrid rice varieties in the Jinhua district of Zhejiang Province, Shanyou63 for mid-rice and Xieyou46 for late rice, was simulated using a crop growth model of WOFOST. Parameters of the rice growth in WOFOST were calibrated through field experiments from 1999 to 2002 in Jinhua. The potential yield simulated with WOFOST was about 12 t/ha for Shanyou63 and 10 t/ha for Xieyou46, which are in good agreement with the highest recorded yield obtained in this area. Under farmers practice, current yield is about 7.5 t/ha for Shanyou63 and 6.5 t/ha for Xieyou46. There is a gap between the actual rice yield and the potential yield for these two hybrid rice varieties grown in this area. The attainable target yields were set to 70% to 75% of their potential yields for the two varieties. A recently developed software ＂Nutrient Decision Support System （NuDSS）＂ for irrigated rice was used to optimize nutrient management for these two rice varieties. According to NuDSS, the optimal fertilizer N requirement for the target yields was about 150 kg/ha for Shanyou63 and about 120 kg/ha for Xieyou46, which were only about 70% of the fertilizer N application under current farmers＇ practice. Comparing with farmers＇ practice, there is great potential to increase actual rice yields and to reduce fertilizer N use rates by improving rice crop management practice in Jinhua.  相似文献   

3.
ＩＮＴＲＯＤＵＣＴＩＯＮＺｈｅｊｉａｎｇＰｒｏｖｉｎｃｅｌｏｃａｔｅｄｉｎｓｏｕｔｈｅａｓｔｅｒｎＣｈｉｎａｂｅｌｏｎｇｓｔｏｔｈｅｓｕｂｔｒｏｐｉｃａｌｃｌｉｍａｔｉｃｚｏｎｅｗｉｔｈｗａｒｍｔｅｍｐｅｒａｔｕｒｅ (ｍｅａｎｔｅｍｐｅｒａｔｕｒｅ 1 5-1 8℃ )ａｎｄａｄｅｑｕａｔｅｒａｉｎｆａｌｌ (ａｎｎｕａｌｐｒｅｃｉｐｉｔａ ｔｉｏｎ 1 1 0 0 -1 90 0ｍｍ) .Ｏｆｔｈｅｔｏｔａｌｏｆ1 .62ｍｉｌ ｌｉｏｎｈａｃｕｌｔｉｖａｔｅｄｌａｎｄｉｎｔｈｉｓｐｒｏｖｉｎｃｅ ,1 .2 7ｍｉｌｌｉｏｎｈａａｒｅｒ…  相似文献   

4.
在品种和施氮量相同的条件下,施氮方法对植株吸氮有很大影响.前期控氮,中期补施穗肥的方法可延长植株吸氮高峰持续时间,增加植株氮素总积累量,对防止植株早衰,增加稻谷产量,提高氮肥利用率,都有良好的作用.  相似文献   

5.
Soil test crop response （STCR） correlation studies were carried out in Vindhyan alluvial plain during 2001 to 2004 taking IR-36 as test crop to quantify rice production in the context of the variability of soil properties and use of balanced fertilizers based on targeted yield concept. The soils were developed on gently sloping alluvial plain with different physiographic settings and notable variation in drainage condition. Soil properties show moderate variation in texture （loamy to clay）, organic carbon content （4.4 to 9.8 g/kg）, cation exchange capacity （10,2 to 22.4 cmol （p＋）/kg） and pH （5.3 to 6,4）, Soil fertility status for N is low to medium （224 to 348 kg/ha）, P is medium to high （87 to 320 kg/ha） and K ranges from medium to high （158 to 678 kg/ha）. Database regarding nutrient requirement in kg/t of grain produce （NR）, the percent contribution from the soil available nutrients [CS （%）] and the percent contribution from the applied fertilizer nutrients [CF （%）] were computed for calibrating and fbrmulating fertilizer recommendations. Validity of the yield target for 7 and 8 t/ha was tested in farmers＇ fields and yields targets varied at less than 10%. The percent achievement of targets aimed at different level was more than 90%, indicating soil test based fertilizer recommendation approach was economically viable within the agro-ecological zone with relatively uniform cropping practices and socio-economic conditions.  相似文献   

6.
The main objective of this work was to compare the applicability of the single leaf (the uppermost leaf L1 and the third uppermost leaf L3) modified simple ratio (mSR705 index) and the leaf positional difference in the vegetation index between L1 and L3 (mSR705L1-mSR705L3) in detecting nitrogen (N)-overfertilized rice plants. A field experiment consisting of three rice genotypes and five N fertilization levels (0, 75, 180, 285, and 390 kg N/ha) was conducted at Xiaoshan, Hangzhou, Zhejiang Province, China in 2008. The hyperspectral reflectance (350–2500 nm) and the chlorophyll concentration (ChlC) of L1 and L3 were measured at different stages. The mSR705L1 and mSR705L3 indices appeared not to be highly sensitive to the N rates, especially when the N rate was high (above 180 kg N/ha). The mean mSR705L1-mSR705L3 across the genotypes increased significantly (P<0.05) or considerably from 180 to 285 kg N/ha treatment and from 285 to 390 kg N/ha treatment at all the stages. Also, use of the difference (mSR705L1-mSR705L3) greatly reduced the influence of the stages and genotypes in assessing the N status with reflectance data. The results of this study show that the N-overfertilized rice plants can be effectively detected with the leaf positional difference in the mSR705 index.  相似文献   

7.
Field experiments were conducted at Cereal Crops Research Institute, Pirsabak, Nowshera, Pakistan, during winter 2003~2004 and 2004~2005 to evaluate the effect of nitrogen and sulfur levels and methods of nitrogen application on canola (Brassica napus L. cv. Bulbul-98) under rainfed conditions. Four levels of S (0, 10, 20, and 30 kg/ha) and three levels of N (40, 60, and 80 kg/ha) and a control treatment with both nutrients at zero level were included in the experiments. Sulfur levels were applied at sowing while N levels were applied by three methods (100% soil application, 90% soil 10% foliar application, and 80% soil 20% foliar application). The experiments were laid out in randomized complete block (RCB) design having four replications. Oil content increased significantly up to 20 kg S/ha but further increase in S level did not enhance oil content. Glucosinolate content increased from 13.6 to 24.6 μmol/g as S rate was increased from 0 to 30 kg/ha. Protein content increased from 22.4% to 23.2% as S rate was increased from 0 to 20 kg/ha. Oil content responded negatively to the increasing N levels. The highest N level resulted in the highest values for protein (23.5%) and glucosinolate (19.9 μmol/g) contents. Methods of N application had no significant impact on any parameters under study.  相似文献   

8.
The ecosystem characteristics of soil microorganism and the nutrient uptake of irrigated rice were investigated in a split-block experiment with different fertilization treatments, including control (no fertilizer application), PK, NK, NP, NPK fertilization, in the main block, and conventional rice and hybrid rice comparison, in the sub block. Average data of five treatments in five years indicated that the indigenous N supply (INS) capacity  相似文献   

9.
宏观经济学是经济管理类专业的基础理论课程,其全英课的实施有助于培养学生具有国际化视野和在英语环境中从事经济管理工作的能力。论文简述了高校开设宏观经济学全英课的重要意义,介绍了宏观经济学全英课教学模式,然后论文针对目前该课程全英教学实践中遇到的问题,重点讨论如何从改进教学方法、完善反馈机制两个方面对宏观经济学全英课教学工作进行探索与改革。  相似文献   

10.
A field experiment was conducted to study the response of individual leaf spectral reflectance to five levels of nitrogen fertilizer treatments in rice (Oriza sativa L.) plants. Sampling was combined through a rice canopy at upper, medium and low levels for biomass, nitrogen and water content measurements with spectral signals from the leaves. The vertical gradients of leaf biomass, nitrogen and water contents were associated with the nitrogen availability during tillering, panicle formation, initial heading and heading. Rice plants treated with the lowest rate of N could be characterized with the lowest value of gradient in leaf biomass and leaf water content and the highest value of gradient in leaf N concentration. A spectral gradient of single reflectance (R), ratio (RVI) and normalized difference (ND) of two individual reflectances was defined as this yielded a better relationship between the spectral data and leaf nitrogen concentration. The results suggested the spectral gradients may be used as an improved diagnostic tool for nitrogen status. Project (49771056) supported by Natural Science Foundation of China(NSFC).  相似文献   

11.
A series of laboratory and pot experiments carried out to examine the role of soil microbial biomass in red soils' nitrogen availability and productivity showed that soil available N (NA), dry matter yield (DMY) of ryegrass, and plant uptake of nitrogen were each closely correlated with microbial biomass-C (Cmic) or -N (Nmic), suggesting that soil microbial biomass is a very important nitrogen pool available to plants in red soils. After correction for the substrate effect, the computed turnover of the Nmic in three tested soils ranged from 63 to 250 days. Soils with low Nmic or light texture generally had higher Nmic turnover rate than those with high Nmic or heavy texture. These results showed that soils with low Nmic, microbial biomass could also play an important role in the availability of nitrogen to plants due to these soils' high turnover rate.  相似文献   

12.
那刚  白骏 《教育教学论坛》2019,(21):145-146
党的"十九大"以来,我国政府大力发展高等职业教育的战略决策,为社会经济发展和实现高等教育大众化做出了重要的贡献。政府提出了高职教育人才培养模式适时转型的一系列指导思想,确立了高职教育要培养高级应用型人才的教学目标这一高职院校的人才培养目标。为了更好地培养出色的表演应用型人才,浙江艺术职业学院戏剧影视表演专业提出了"163"教学模式,相对于以往的培养模式,"163"教学模式既注重基础性理论知识的传授,更侧重实践知识的要求,强化学生的实际表演工作能力,为社会培养实用型人才,进而让我专业与社会上广大企业之间的联系更加紧密。  相似文献   

13.
Acute pancreatitis （AP） is a common acute abdomen in clinic with a rapid onset and dangerous pathogenetic condition AP can cause an injury of intestinal mucosa barrier, leading to translocation of bacteria or endotoxin through multiple routes, bacterial translocation （BT）, gutorigin endotoxaemia, and secondary infection of pancreatic tissue, and then cause systemic inflammatory response syndrome （SIRS） or multiple organ dysfunction syndrome （MODS）, which are important factors influencing AP＇s severity and mortality. Meanwhile, the injury of intestinal mucosa barrier plays a key role in AP＇s process. Therefore, it is clinically important to study the relationship between the injury of intestinal mucosa barrier and AP. In addition, many factors such as microcirculation disturbance, ischemical reperfusion injury, excessive release of inflammatory mediators and apoptosis may also play important roles in the damage of intestinal mucosa barrier. In this review, we summarize studies on mechanisms of AP.  相似文献   

14.
The effects of CO2 enrichment on the growth and glucosinolate (GS) concentrations in the bolting stem of Chinese kale (Brassioa alboglabra L.) treated with three nitrogen (N) concentrations (5, 10, and 20 mmol/L) were investigated. Height,stem thickness, and dry weights of the total aerial parts, bolting stems, and roots, as well as the root to shoot ratio, significantly increased as CO2 concentration was elevated from 350 to 800 μl/L at each N concentration. In the edible part of the bolting stem,11 individual GSs were identified, including 7 aliphatic and 4 indolyl GSs. GS concentration was affected by the elevated CO2 concentration, N concentration, and CO2×N interaction. At 5 and 10 mmol N/L, the concentrations of aliphatic GSs and total GSs significantly increased, whereas those of indolyl GSs were not affected, by elevated atmospheric CO2. However, at 20 mmol N/L,elevated CO2 had no significant effects on the concentrations of total GSs and total indolyl GSs, but the concentrations of total aliphatic GSs significantly increased. Moreover, the bolting stem carbon (C) content increased, whereas the N and sulfur (S) contents decreased under elevated CO2 concentration in the three N treatments, resulting in changes in the C/N and N/S ratios.Also the C/N ratio is not a reliable predictor of change of GS concentration, while the changes in N and S contents and the N/S ratio at the elevated CO2 concentration may influence the GS concentration in Chinese kale bolting stems. The results demonstrate that high nitrogen supply is beneficial for the growth of Chinese kale, but not for the GS concentration in bolting stems, under elevated CO2 condition.  相似文献   

15.
The effects of CO2 enrichment on the growth and glucosinolate (GS) concentrations in the bolting stem of Chinese kale (Brassica alboglabra L.) treated with three nitrogen (N) concentrations (5, 10, and 20 mmol/L) were investigated. Height, stem thickness, and dry weights of the total aerial parts, bolting stems, and roots, as well as the root to shoot ratio, significantly increased as CO2 concentration was elevated from 350 to 800 μl/L at each N concentration. In the edible part of the bolting stem, 11 individual GSs were identified, including 7 aliphatic and 4 indolyl GSs. GS concentration was affected by the elevated CO2 concentration, N concentration, and CO2×N interaction. At 5 and 10 mmol N/L, the concentrations of aliphatic GSs and total GSs significantly increased, whereas those of indolyl GSs were not affected, by elevated atmospheric CO2. However, at 20 mmol N/L, elevated CO2 had no significant effects on the concentrations of total GSs and total indolyl GSs, but the concentrations of total aliphatic GSs significantly increased. Moreover, the bolting stem carbon (C) content increased, whereas the N and sulfur (S) contents decreased under elevated CO2 concentration in the three N treatments, resulting in changes in the C/N and N/S ratios. Also the C/N ratio is not a reliable predictor of change of GS concentration, while the changes in N and S contents and the N/S ratio at the elevated CO2 concentration may influence the GS concentration in Chinese kale bolting stems. The results demonstrate that high nitrogen supply is beneficial for the growth of Chinese kale, but not for the GS concentration in bolting stems, under elevated CO2 condition. Project (No. 2007CB109305) supported by the National Basic Research Program (973) of China  相似文献   

16.
Tocopherols (Tocs) are vital scavengers of reactive oxygen species (ROS) and important seed oil quality indicators. Nitrogen (N) is one of the most important fertilizers in promoting biomass and grain yield in crop production. However, the effect of different sources and application rates of N on seed Toc contents in oilseed rape is poorly understood. In this study, pot trials were conducted to evaluate the effect of two sources of N fertilizer (urea and ammonium nitrate). Each source was applied to five oilseed rape genotypes (Zheshuang 72, Jiu-Er-1358, Zheshuang 758, Shiralee, and Pakola) at three different application rates (0.41 g/pot (N1), 0.81 g/pot (N2), and 1.20 g/pot (N3)). Results indicated that urea increased α-, γ-, and total Toc (T-Toc) more than did ammonium nitrate. N3 was proven as the most efficient application rate, which yielded high contents of γ-Toc and T-Toc. Highly significant correlations were observed between Toc isomers, T-Toc, and α-/γ-Toc ratio. These results clearly demonstrate that N sources and application rates significantly affect seed Toc contents in oilseed rape.  相似文献   

17.
Hyperspectral reflectance (350~2500 nm) data were recorded at two different sites of rice in two experiment fields including two cultivars, and three levels of nitrogen (N) application. Twenty-five Vegetation Indices (VIs) were used to predict the rice agronomic parameters including Leaf Area Index (LAI, m2 green leaf/m2 soil) and Green Leaf Chlorophyll Density (GLCD, mg chlorophyll/m2 soil) by the traditional regression models and Radial Basis Function Neural Network (RBF). RBF emerged as a variant of Artificial Neural Networks (ANNs) in the late 1980’s. A large variety of training algorithms has been tested for training RBF networks. In this study, Original RBF (ORBF), Gradient Descent RBF (GDRBF), and Generalized Regression Neural Network (GRNN) were employed. Results showed that green waveband Normalized Difference Vegetation Index (NDVIgreen) and TCARI/OSAVI have the best prediction power for LAI by exponent model and ORBF respectively, and that TCARI/OSAVI has the best prediction power for GLCD by exponent model and GDRBF. The best performances of RBF are compared with the traditional models, showing that the relationship between VIs and agronomic variables are further improved when RBF is used. Compared with the best traditional models, ORBF using TCARI/OSAVI improves the prediction power for LAI by lowering the Root Mean Square Error (RMSE) for 0.1119, and GDRBF using TCARI/OSAVI improves the prediction power for GLCD by lowering the RMSE for 26.7853. It is concluded that RBF provides a useful exploratory and predictive tool when applied to the sensitive VIs.  相似文献   

18.
Fertilization increases paddy soil organic carbon density   总被引：5，自引：0，他引：5  
Field experiments provide an opportunity to study the effects of fertilization on soil organic carbon (SOC) sequestration. We sampled soils from a long-term (25 years) paddy experiment in subtropical China. The experiment included eight treatments: (1) check, (2) PK, (3) NP, (4) NK, (5) NPK, (6) 7F:3M (N, P, K inorganic fertilizers+30% organic N), (7) 5F:5M (N, P, K inorganic fertilizers+50% organic N), (8) 3F:7M (N, P, K inorganic fertilizers+70% organic N). Fertilization increased SOC content in the plow layers compared to the non-fertilized check treatment. The SOC density in the top 100 cm of soil ranged from 73.12 to 91.36 Mg/ha. The SOC densities of all fertilizer treatments were greater than that of the check. Those treatments that combined inorganic fertilizers and organic amendments had greater SOC densities than those receiving only inorganic fertilizers. The SOC density was closely correlated to the sum of the soil carbon converted from organic amendments and rice residues. Carbon sequestration in paddy soils could be achieved by balanced and combined fertilization. Fertilization combining both inorganic fertilizers and organic amendments is an effective sustainable practice to sequestrate SOC.  相似文献   

19.
Polychlorinated dibenzo-p-dioxins and furans （PCDD/Fs） emissions in flue gas from two types of municipal solid waste incinerators （MSWIs） most commonly used in China were investigated in this study. The selected incinerators include two grate-type MSWIs： MSWI-A （350 t/d） and MSWI-B 050 t/d）, and two fluidized bed MSWIs： MSWI-C （400 t/d） and MSWI-D （400 t/d）, which are all equipped with semi-dry lime scrubber and bag filter except MSWI-D equipped with cyclone and wet scrubber （WS） as air pollutant control device （APCD）. Results indicated that the emission concentration and the international toxic equivalents （I-TEQs） of the PCDD/Fs from the stacks were in the range of 1.210-10.273 ng/Nm^3 and 0.019-0.201 ng I-TEQ/Nm^3, respectively. They were greatly lower than the emission regulation standard of PCDD/Fs in China （1.0 ng I-TEQ/Nm^3）. However, only the PCDD/Fs emission level from MSWI-C was below 0.1 ng I-TEQ/Nm^3. Although the homologue profiles were distinct, the contributions of the 2,3,7,8-subsituted congeners to the total I-TEQ were similar among all the investigated MSWIs. Two major 2,3,7,8-substituted congeners, 2,3,4,7,8-PeCDF and 1,2,3,7,8-PeCDD, account for 47% and 9% （average values） of the total I-TEQ values, respectively. The correlation between PCDD/Fs levels and composition of flue gas was also discussed.  相似文献   

20.
Lovastatin production by Aspergillus terreus ATCC 20542 in solid-state fermentation (SSF) was studied. Various substrates were used to evaluate the ability of A. terreus to produce lovastatin. The results showed that either rice or wheat bran was suitable substrate for lovastatin production in SSF. The maximum yield of lovastatin (2.9 mg/g dry substrate) using rice as substrate was achieved after incubating for 11 d at the following optimized process parameters: 50%～60% initial moisture content,pH 5.5,incubation temperature 28 °C.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号