黄土高塬沟壑区水土流失综合治理范式   总被引：3，自引：0，他引：3       下载免费PDF全文

毕华兴  刘立斌  刘斌 《中国水土保持科学》2010,8(4):27-33

 黄土高原是中华农耕文化的发祥地,其主要地貌类型区之一的黄土高塬沟壑区,其农业发展有着比黄土高原其他地区优越的自然条件。但长期以来,由于自然和人为因素的双重作用,该区水土流失十分严重,塬面径流下沟导致沟头不断前进,塬面逐年萎缩。由于沟坡坡度大而导致重力侵蚀异常活跃,侵蚀强度逐渐加强。在特殊的自然环境、人口压力以及经济发展需求的条件下,探索黄土高塬沟壑区水土流失综合治理范式成为水土保持领域科技人员和当地政府急需解决的问题之一。在解析黄土高塬沟壑区自然地理特征、水土流失特点以及社会经济发展需求的基础上,通过对该区现有的水土流失综合治理模式进行梳理,结合范式的概念,提出黄土高塬沟壑区水土流失综合治理范式。  相似文献   

紫花苕挤压出水营养损失及干燥节能研究     

裴成江  石开齐  许万里 《饲料博览》2009,(9):5-7

试验对紫花苕挤压出水40%和50%后烘干与原草直接烘干和晒干进行比较,结果表明,挤压出水40%和50%后烘干比原草直接烘干缩短烘干时间12和13h;比晒干缩短66和67h;DM获得率比原草直接烘干低0.02%和0.19%,比晒制干草高7.9%和3.8%;挤压出水40%后烘干的DM、CP、EE、CF、CA、Ca损失率分别为2.05%、4.22%、7.92%、1.09%、7.94%、9.44%;挤压出水50%后烘干的DM、CP、EE、CF、CA、Ca损失率分别为6.15%、9.32%、26.16%、4.28%、15.17%、15.89%;晒干的DM、CP、EE、CF、CA、Ca损失率分别为9.74%、14.45%、42.94%、16.15%、15.67%、17.07%。且挤压出水40%和50%后烘干相比,经济效益分别提高了177.67%和176.72%。  相似文献   

Leaching and Recovering of Nitrogen Following N Fertilizers Application to the Soil in a Laboratory Study     

Sulian Junkes Dal Molin  Paulo Roberto Ernani  Pâmella Soldatelli  Paulo Cezar Cassol 《Communications in Soil Science and Plant Analysis》2018,49(9):1099-1106

Following soil fertilization, nitrogen (N) is partially lost. The objective of this study was to evaluate leaching and recovery of N after addition of fertilizers to the soil. Two experiments were conducted in leaching columns submitted to frequent water percolations. In the leaching experiment, urea, ammonium nitrate, and six coated N fertilizers were utilized; in the N recovery experiment, treatments consisted of urea, potassium nitrate, ammonium sulfate, and ammonium nitrate, combined or not with percolation. Percolations were performed weekly with quantification of ammonium and nitrate in the percolated. The recovered N was obtained by summing total N percolated with N in the soil. Nitrate leaching was highest from amide-N fertilizers, with no differences between them showing that coating urea was not efficient to decrease N leaching. Nitric fertilizers had the lowest recovery of N, probably due to the occurrence of denitrification caused by the frequent water percolation.  相似文献   

Estimation of economic threshold level of alligator weed (Alternanthera philoxeroides (Mart.) Griseb.) to Tackle Grain quality and yield Losses in Rice     

Azhar Mehmood  Asif Tanveer  Muhammad Mansoor Javed  Muhammad Ather Nadeem  Muhammad Naeem 《Archives of Agronomy and Soil Science》2018,64(2):208-218

Alligator weed (Alternanthera philoxeroides) is the most troublesome invasive weed in transplanted rice ecosystems worldwide. A two-year field study was conducted to estimate economic threshold levels and the season long competitive effect of six alligator weed densities (0, 2, 4, 8, 16, and 32 plants m^?2) on yield and quality traits of transplanted rice. A gradual linear incline in dry weight of alligator weed was observed with an increase in its density from 2 to 32 plants m^?2. Maximum N (15.93–18.26 kg ha^?1), P (15.10–16.46 kg ha^?1) and K (16.34–17.81 kg ha^?1) uptake by alligator weed was recorded at its density of 32 plants m^?2. More micronutrient loss to the tune of 6.53, 47.92, 19.99, and 38.42 mg kg^?1 for Cu, Fe, Zn, and Mn, respectively was observed at the same density. Increasing density of alligator weed caused more losses in paddy yield (up to 21.37–23.78%), amylose and rice grain protein contents. According to a nonlinear hyperbolic regression model, maximum paddy yield loss of rice at asymptotic value of alligator weed density was 38.8% during 2011 and 42.4% during 2012. Economic threshold value of alligator weed was estimated 1.5 and 1.3 plants per m² during 2011 and 2012, respectively.  相似文献   

基于描述性统计分析的销售环节粮食损失影响因素研究     

臧秋霞  吴林海 《安徽农业科学》2017,45(14)

以粮食销售商为研究对象,调查了全国9省51市销售环节粮食损失情况,并以获取的1 864个样本为基础数据,分析了我国粮食销售商的基本特征以及销售阶段各环节粮食损失的影响因素。结果表明,我国粮食经营者的主要特征为男性略多于女性,年龄为36~45岁,大部分为中学学历,从业时间为6~10年;粮食销售商多为个体工商户,店铺面积普遍为20~50 m2,年销售额普遍为10万~50万元;存储环节中各因素对粮食销售损失的影响最大,装卸、搬运环节次之,展销环节对粮食损失影响最小。  相似文献   

"十二五"期间凤城市5种主要林业有害生物灾害损失评估     

杨庆寅 《安徽农业科学》2017,45(20)

根据凤城市"十二五"期间林业有害生物发生情况,筛选出美国白蛾、日本蚣干蚧、栗山天牛、杨干象、杨树烂皮病5种主要林业有害生物作为灾害损失评估对象,进行直接和间接经济损失评估计算。结果表明,凤城地区"十二五"期间5种主要林业有害生物造成的年均损失为61 376.777万元,其中,直接经济损失87.218万元,间接经济损失为61 289.559万元。  相似文献   

供给侧改革中的湖北粮食发展思考   总被引：1，自引：0，他引：1  

王雅鹏  文清 《农业现代化研究》2017,38(1):1-7

湖北粮食在十二年连续增产之后,受全国"三量齐增"局势的影响,也需要进行供给侧改革。本文根据湖北省粮食生产比较效益低、供给结构与消费需求结构吻合度低,以及粮食产量压库存和占用资金等问题,提出按照去库存、保产能、提质增效的原则,抓好结构调整、藏粮于技、藏粮于地,实施生产组织制度改革和降本增效战略,使其稳步发展。回答了为什么要进行供给侧改革,如何进行供给侧改革的问题。  相似文献   

Losses of 15N-nitrogen by plant–soil system after herbicide application on black oat     

V. Damin  P. C. O. Trivelin  L. A. C. Moraes  I. P. Bruno  L. A. Figueiredo  A. B. Lima 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2017,67(3):202-207

Recent studies have demonstrated that the use of glyphosate or glufosinate-ammonium herbicides for some cover crop desiccation in conservationist systems could favor nitrogen (N) losses from the soil–plant system. In this context, the objective of this study was to evaluate the losses of N by the plant–soil system after the desiccation of black oat (Avena strigosa Schreb.) with the application of herbicides glyphosate, glufosinate-ammonium, or paraquat. Two greenhouse experiments were implemented using black oat plants fertilized with labeled (¹⁵N) ammonium nitrogen, and the N loss of the plant–soil system was quantified. The desiccation of black oat with glyphosate caused a reduction in root dry mass by approximately 60% in both experiments. The glyphosate and glufosinate-ammonium reduced the amount of N present in the aboveground portion; however, the paraquat herbicide did not modify it. None of the herbicides applied affected N losses in the black oat plant–soil system. However, 5–15% of the N applied as fertilizer was lost up to harvest. The results suggest that black oat can be used as a cover crop in direct sowing in order to avoid nitrogen losses in the soil–plant system.  相似文献   

玉米褪绿斑驳病毒入侵损失指标体系及直接经济损失评估   总被引：3，自引：0，他引：3  

饶玉燕  尤扬  朱水芳  严进  黄冠胜  魏国荣 《植物检疫》2010,24(2)

玉米褪绿斑驳病毒(Maize chlorotic mottle virus)是我国进境检疫性病毒,严重危害玉米的生长,给玉米生产带来巨大经济损失。文中根据科学性、系统优化、通用可比及实用性原则,结合玉米褪绿斑驳病毒特点,系统构建了玉米褪绿斑驳病毒损失评判指标体系,共1个一级指标、3个二级指标、11个三级指标。并对其在我国可能造成的直接经济损失作出初步评估,经估算,玉米褪绿斑驳病毒对我国造成的潜在直接经济损失达140.95亿人民币。  相似文献   

紫色土丘陵区非耕作季节不同种植模式下N P流失模型     

罗艺  吴福忠  杨万勤  王旭熙 《农业环境科学学报》2010,29(4)

为了解长江上游紫色土丘陵区非耕作季节N、P的流失特征,以长江上游紫色土丘陵区4种典型种植模式为研究对象,采用野外调查、室内分析和模型模拟相结合的方法,于2008年11月1日至12月31日研究了耕作季节后不同种植模式在每次降雨后的N、P流失特征及不完全混合模型的综合应用效果。结果表明,非耕作季节,紫色农耕地均表现出较大的N、P流失量,最大分别达到(0.491±0.079)kg·hm-2和(12.604±13.173)×10-3kg·hm-2。N的流失量均大于P的流失量,并且N、P主要通过地表径流流失。不同种植模式间N、P流失量有较大的差异,其中生姜种植模式的N、P流失量最大,大豆种植模式最小。不完全混合模型可很好应用于研究区域农耕地N、P流失。模型的有效系数均达到0.6以上,其中模拟N流失的有效系数高达0.958。这表明,非耕作季节农耕地N、P流失是区域农业面源污染的重要来源,不完全混合模型可成为该区域N、P流失预报和面源污染控制的重要手段。  相似文献