浅谈黑龙江省黑土地保土耕作法的机理及效应

水土保持耕作措施对于防治水土流失、促进农业增产具有明显的作用。黑龙江省水保科研机构在黑土区多年来研究推广的横坡垄作、垄作区田、少耕免耕、间混作、深松耕法、鼠道耕法等措施 ,投资少 ,见效快 ,适宜进一步推广。若将耕作措施与植物措施、田间工程措施科学配置 ,则水土保持措施的作用将更加显著     

水土保持耕作法应用趋势

水土保持耕作法(Conservation Tillage)既是种植法,又是种植以后保留至少百分之三十土壤表面作物残茬覆盖层的耕作法.这些方法包括免耕或间作、垄作、条耕.覆盖耕作、少耕和几乎不耕.最近,美国农业部承担的1983年农业生产费用调查(FPES)是1984年春天进行的,经过对全国11000多农民阶层的调查,在应用水土保持耕作法的措施方面,加深了对全国和许多地区的情况了解.包括诸如应用范围与位置、耕作、耕作范围、耕作坡度、使用权、采纳原因和接受政府援助等方面情况.     

东北垄作区机械免耕播种工艺(英文)

为了建立东北地区垄作保护性耕作工艺模式,并为其配套机具的优化设计提供理论指导。该文针对东北垄作区的保护性耕作,论述了国内外垄作耕法的概况。该文论述了国内外垄作耕法的概况。在调查研究的基础上,结合课题科研实践提出了垄作耕法的垄形断面图,构建了机械免耕播种种床土壤耕作的几何模型与相关尺寸。从田间调查与测试结果,以几何模型为依据,对2种形式(滚动圆盘式,条带旋耕式)玉米垄作免耕播种机进行了研究、分析与评价。研究表明,滚动圆盘式破茬与清垄方案符合玉米垄作几何模型要求,但仍需研发新型破茬圆盘犁刀以减小工作阻力,研发新的加载技术,保持机器对下压力的需求。该研究可为垄作免耕播种机的创新设计、改进与评价提供科学依据与方法。     

基于文献统计的CSLE模型中耕作措施因子的确定

为了研究CSLE模型中T因子的确定方法,收集并筛选了关于全国各水土保持区不同保护性耕作措施与传统耕作相比减少侵蚀的研究成果,利用文献统计的方法,计算并得出了我国6种保护性耕作措施在6个水土保持区的T因子取值。结果表明:(1)东北黑土区免耕秸秆覆盖、等高耕作和垄作区田3种保护性耕作措施下,T因子分别为:0.20±0.14,0.52±0.25,0.15±0.12;(2)北方土石山区免耕、垄作区田和等高耕作+植物篱3种保护性耕作措施下,T因子分别为:0.51±0.25,0.46±0.24,0.17±0.09;(3)西北黄土高原区免耕、免耕秸秆覆盖和等高耕作3种保护性耕作措施下,T因子分别为:0.73±0.17,0.69±0.22,0.27±0.22;(4)南方红壤区免耕秸秆覆盖和等高耕作2种保护性耕作措施下,T因子分别为:0.11±0.08,0.54±0.32;(5)西南紫色土区免耕秸秆覆盖、等高耕作、等高耕作+植物篱和聚土免耕4种保护性耕作措施下,T因子分别为:0.44±0.29,0.48±0.27,0.47±0.24,0.32±0.15;(6)西南岩溶区免耕和等高耕作2种保护性耕作措施下,T因子分别为:0.49±0.33,0.38±033。由此可知,在同一水土保持区,不同耕作方式的T因子取值不同,相同的水土保持耕作措施在不同的水土保持区的T因子取值也有较大差异。     

东北黑土区不同耕作措施保水保土效应研究

采用标准径流小区试验方法对东北黑土区顺坡垄作和横坡垄作两种耕作措施在天然降雨下的径流量、土壤侵蚀量及蓄水保土效应进行了研究。结果表明,3°、5°坡按径流量大小排序为顺坡垄作+种植大豆小区>裸地小区>横坡垄作+种植大豆小区,3°坡按土壤侵蚀量大小排序为裸地小区>顺坡垄作+种植大豆小区>横坡垄作+种植大豆小区,5°坡按土壤侵蚀量大小排序为顺坡垄作+种植大豆小区>裸地小区>横坡垄作+种植大豆小区。可见,横坡垄作是东北黑土区适宜的水土保持耕作措施。     

东北黑土区不同地形垄向坡度的相对水土保持效益研究

垄作是东北黑土区一种非常普遍而重要的耕作措施,具有一定的水土保持效益,但几乎没有学者对其进行研究。探讨黑土区不同地形垄作方向在空间上的分布规律及其具有的水土保持效益具有重要研究价值。以黑龙江省宾县为研究区,用分层抽样的方法提取168个野外调查单元并进行实地填图调查,根据坡度因子和垄向坡度计算公式,利用ArcMAP、SPSS和Excel等软件进行了室内数据分析统计,结果表明:平原区、丘陵区、山区的平均地面坡度分别为1.92°,6.20°,8.27°;平均垄向坡度分别为1.33°,4.52°,6.45°,分别为平均地面坡度的70%,73%,78%;垄作坡度引起的平均土壤流失相对量分别为地面坡度的55%,69%,67%,垄作的相对水土保持效益明显。在此基础上,对垄作现状的原因进行了分析,并提出一些改进措施。研究成果有助于了解东北黑土区不同地形耕地垄作方向的分布情况及其水土保持效益状况,对当地水土保持措施的布设也具有重要的指导意义。     

中国主要水土保持耕作措施因子

水土保持耕作措施因子是中国土壤流失方程参数之一,确定全国范围主要措施的因子值,是计算土壤水蚀模数的基础工作,可为开展全国土壤侵蚀强度评价奠定基础。以收集的文献资料和监测资料为基础,计算了全国水蚀区等高沟垄种植、垄作区田和免耕等5种耕作措施因子值,并基于区域差异不显著分析结果,确定了最终的全国统一因子值,为模型的推广应用提供了数据基础。     

坡度对农业耕作措施水土保持作用的影响

农业耕作措施是水土保持三大措施之一,在坡耕地水土保持中起关键作用。利用人工模拟降雨试验方法,对不同坡度条件下农业耕作措施水土保持作用进行了研究。农业耕作措施包括等高耕作、人工掏挖和人工锄耕,以平整坡面为对照措施;降雨试验在长4m,宽1m的径流小区完成;坡度为5°,10°,15°,20°,25°;降雨强度为1,1.5,2mm/min。结果表明:与平整坡面相比,等高耕作、人工掏挖和人工锄耕分别减小产流量38.19%,32.25%和15.84%;减小产沙量均在50%以上,说明农业耕作措施具有明显的水土保持作用。通过对坡度与产流量、产沙量关系分析表明,在耕作坡面,坡度会影响产流量,但是大坡度与小坡度之间差异不显著。相反,坡度对产沙量具有显著影响,在小坡度条件下,产沙量受坡度的影响较小。当坡度大于15°后,坡度每增加1°,等高耕作、人工掏挖和人工锄耕耕作措施保土作用平均降低3.08%,4.74%和7.61%。回归分析表明产沙量与坡度之间存在指数函数关系。可见,坡度对农业耕作措施保水作用和保土作用的影响不同。     

基于人工模拟降雨试验的垄作区田水土保持效益的变化研究

[目的]研究垄作区田在不同降雨条件下发生溢流和损毁的情况和水土保持效益的变化,为实施垄作区田的适宜条件评价和水土保持效益的评价提供依据。[方法]对垄作区田和顺垄耕作实施不同雨强的人工模拟降雨实验,分析二者的产流产沙过程和水土保持效益变化。[结果]雨强大于60mm/h时,区田有溢流产生,但土档不会损毁,水土保持效益略有降低;雨强大于60mm/h时,区田土档在溢流后很快损毁,水土保持效益有明显的下降。区田未损毁情况下的蓄水效益为87.5%,保土效益为88.2%;区田损毁后的蓄水效益降至34.1%,保土效益降至21.0%。[结论]垄作区田在60mm/h雨强下具有良好的水土保持效益,超过60mm/h时,由于土档在溢流后容易损毁,从而使其水土保持效益显著下降,丧失了拦蓄径流和泥沙的能力。     

灌区实施水保耕作的防蚀作用及效益

为防止灌溉引起沟蚀的发生,采取水土保持耕作措施。合理的水保耕作制度可使土壤侵蚀降低47%以上,作物产量可持续不变。5年后,能使农民单位面积土地收入平均增加125美元/hm~2·a。     

贵州草海耕地土壤与农作物中DDTs和HCHs残留及污染特征

采集草海流域周边成熟期整株农作物及土壤样品,分析测试其中DDTs和HCHs的含量,对比研究了土壤和作物中DDTs和HCHs污染水平及其在作物中富集能力。结果表明：研究区域土壤中HCHs和DDTs残留检出率均为100％,残留范围分别为0．06～16．66μg·kg^-1和0．08-39．77μg·kg^-1,土壤中HCHs和DDTs的残留量均小于国家土壤环境质量一级标准;三种农作物中DDTs、HCHs及∑（DDTs,HCHs）残留量差异显著,HCHs含量最高的是玉米,DDTs和（DDTs,HCHs）最高的是马铃薯;三种农作物中HCHs和DDTs残留的风险系数均为1．1,属于低度风险,农作物中DDTs、HCHs及∑（DDTs,HCHs）的安全指数IFSc均小于1,DDTs和HCHs残留量对三种农作物安全影响的风险是可以接受的。     

陇陕片预警减灾工作的成效与做法

自 1991年长江上游水土保持重点防治区滑坡、泥石流预警系统运作以来 ,陇南陕南片成功预报和处理滑坡、泥石流险情 10 3处 ,保护人口 11 6 8万 ,避免经济和财产损失 11879 6 5万元 ,取得了良好的社会效益。主要做法及经验是 :依靠各级政府 ,健全预警网络 ;广泛深入宣传 ,增强防灾意识 ;健全管理制度 ,落实岗位职责 ;强化技术培训 ,提高业务技能 ;加强检查指导 ,现场解决问题 ;及时调查险情 ,做好技术服务 ;预防治理结合 ,注重减灾实效。     

Changes in yield and gas exchange parameters in Festulolium and alfalfa grown in pure sowing and in mixture under drought stress

Crop performance and yield are the results of genotypic expression as modulated by continuous interaction with the environment. Among environmental factors, water is globally one of the most limiting for crop production. Water resources in the world are steadily diminishing and in many areas, including Poland, more frequent periods of drought are being observed. The aim of the study was to compare the yields and gas exchange parameters of Festulolium hybrid (Festulolium braunii (K. Richt) A. Camus) and alfalfa (Medicago?×?varia T. Martyn) under different levels of soil moisture (well-watered conditions and drought stress) and cultivation method (pure stand and mixture). The study has shown that all the measured parameters were affected by drought stress. Net photosynthetic rate, transpiration rate, stomatal conductance and dry mass yield were significantly lower under drought stress than under well-watered conditions in all treatment types. Alfalfa grown in a pure sowing showed the strongest reaction to stress, while hybrid Festulolium grown in mixture showed the weakest. It was also found that under stress, grass assimilated CO₂ and evaporated water much more intensively in mixture cultivation than in pure sowing. Higher water use efficiency (WUE) was observed in alfalfa and Festulolium growing in mixture only in the first year of the study.     

Cadmium Effects in Sunflower: Membrane Permeability and Changes in Catalase and Peroxidase Activity in Leaves and Calluses

Mechanisms preventing oxidative burst in cells exposed to high metal concentrations are crucial for cell survival. In this report, sunflower (Helianthus annuus L.) was used as a model species to investigate: (a) how cadmium (Cd) affects plant defense pathways (in particular, those involved in preventing oxidative stress), and (b) whether antioxidative enzymes of plants and of in vitro cell culture (calluses) have similar responses to Cd exposure. For this experiment, plants (grown hydroponically on Long Ashton medium) and calluses (grown on Murashige and Skoog medium) were exposed for three weeks to different Cd concentrations (0, 5, 50, and 500 μ M). Solute and electrolyte leakage increased significantly with the increase in Cd concentration in the external medium and in exposed leaves, and less in exposed calluses. Cadmium exposure also reduced significantly soluble protein contents in both leaves and calluses. The activities of catalase and peroxidase decreased significantly in 50 and 500 μ M-exposed leaves compared with the control, but increased in 5 μ M-exposed calluses, decreasing in the calluses exposed 500 μ M Cd. The decrease in antioxidative enzymes activities is congruent with the decrease in membrane integrity and suggests that calluses develop antioxidant mechanisms that respond better to Cd stress than do leaves. On average, 100% of plants exposed for 21 d to 500 μ M and 95% of plants exposed for 45 d to 50 μ M Cd were dead. After 45 d, only 53% of 50 μ M-exposed calluses had died. These surviving calluses were maintained on 50 μ M for six months. Six-month-old exposed calluses had higher activities of peroxidase and catalase when compared with control calluses, as well as lower membrane degradation. These data show that calluses are more tolerant than plants to Cd exposure, and that antioxidant mechanisms under Cd exposure may differ between the two cell systems and vary with time.     

肯尼亚和中国农业资源投入与农业单产水平变化

当前,肯尼亚和中国在生产足够粮食以保障粮食安全方面都面临着严峻的挑战。尤其是对于肯尼亚而言,因为其2100年预测的人口将达到2018年的1.4倍,且其粮食生产在过去并没有大幅度的改善。而中国近些年粮食生产能力显著提高。本文系统分析了肯尼亚和中国农业资源投入、种植业和畜牧业单产水平的历史变化,以及农业资源投入与产量之间的关系,为肯尼亚粮食危机和消灭贫困提供更多的理论支撑。研究结果表明,在20世纪60年代,肯尼亚耕地、草地和降水等自然资源人均占有量比中国高2~3倍,且人均食物能量和蛋白质供应显著高于中国。当前,肯尼亚人均资源拥有量仍高出中国约30%,但是其人均食品供应和粮食自给率却远低于中国平均水平。这是由于与肯尼亚相比,中国在种植业和畜牧业长期持续的投入,大幅度地增加了种植业和畜牧业能量或蛋白质单产水平。1961-2017年,中国和肯尼亚作物蛋白的平均单产分别增加282%和44%。中国的数据表明,种植业和畜牧业单产水平与肥料、精饲料、机械和农药的投入具有显著正相关性;农牧业生产结构对单产水平的变化影响也很大,如种植业中蔬菜和水果播种面积占比,畜牧业中单胃动物饲养占比等。总的来说,农业资源投入和农业结构对生产力的提高都有很大的影响,这可能是肯尼亚提高农业生产力的潜在选择。     

Fungal abundance and diversity in earthworm casts and in uningested soil

Earthworm casts and adjacent uningested soil from 30 different locations were compared to determine the abundance and diversity of fungal species. The casts contained larger fungal populations (g^-1 dry soil weight) and numbers of fungal species than the soil. Variations in these parameters between casts and soil were statistically significant (P=0.05). Fungal populations and the number of fungal species in casts and soil also varied significantly (P=0.05) between samples from different locations. A total of 27 fungal species were recorded from the casts and soil. Indices of dominance (0.084 casts; 0.14 soil) and general diversity (2.53 casts; 2.02 soil) demonstrated that the casts displayed more diverse fungal flora than the soil. The diversity of fungal species increased in earthworm casts after passing through the earthworm gut.     

云南省开展水土保持的做法与成效

云南省各级党政领导重视和支持水土保持 ,积极出台有关法规、政策 ,为搞好水土保持工作提供了保障。治理中坚持高起点要求 ,有力地推动了水保产业化建设。适应市场经济要求 ,大力发展水土保持专业户、重点户 ,调动社会各方面力量参与水土流失治理开发。介绍了具体的做法、成效及今后做好水保工作的思路。     

1,4-Dimethoxyglucobrassicin in Barbarea and 4-hydroxyglucobrassicin in Arabidopsis and Brassica

A novel indole glucosinolate, 1,4-dimethoxyglucobrassicin (1,4-dimethoxyindol-3-ylmethylglucosinolate), was isolated as the desulfo derivative from roots of the P-type of Barbarea vulgaris ssp. arcuata, and its structure was determined by spectroscopy including 2D NMR spectroscopy. 4-Hydroxyglucobrassicin (4-hydroxyindol-3-ylmethylglucosinolate) was isolated as the desulfo derivative from green siliques (fruits) of Arabidopsis thaliana and identified by comparison of its (1)H NMR spectrum with the spectrum of the known desulfoglucosinolate from Brassica napus. The delayed elution of desulfo indole glucosinolates from the DEAE Sephadex column used in sample preparation was examined, and the diode-array UV spectra of desulfo indole glucosinolates were measured, to ensure a reliable determination of 1,4-dimethoxyglucobrassicin and 4-hydroxyglucobrassicin with the existing analysis method based on the HPLC of desulfoglucosinolates. 1,4-Dimethoxyglucobrassicin was not detected in 10 other Arabidopsis, Brassica, and Barbarea species, indicating an evolutionarily recent mutation in the indole glucosinolate biosynthesis in B. vulgaris ssp. arcuata type P.     

Aorta and liver changes in rats fed cholesterol-containing and raw vegetable-supplemented diets: experiments in vitro and in vivo

The aim of this investigation was to compare the liver and aorta changes in rats fed cholesterol-containing diets and the possible improvement when diets would be supplemented with frequently used raw vegetables. The phenolic compounds of three vegetables in methanol-water (1:1) fraction were characterized using electrospray ionization mass spectra (ESI-MS). Results showed that the content of polyphenols, flavonoids, quercetin, flavanols, tannins, and ascorbic acid varied for garlic and white and red onions ranging from 6.68 to 18.08 mg GAE/g DW, 490.4-701.0 μg CE/g DW, 281.2-1100.0 μg, 32.40-41.30 μg CE/g DW, 2.88-3.12 mg CE/g DW, 1.87-2.33 mg AA/g DW, 1388.2-1442.3 μg CGE/g DW, respectively. The radical scavenging capacities (μM TE/g DW) for the same investigated vegetables for ABTS, FRAP, CUPRAC, and DPPH assays ranged from 48.78 to 92.42, 9.41-28.56, 3.06-10.41, and 6.49-23.42, respectively. Good correlations were observed between the phenolic contents and the radical scavenging capacities of the vegetables. The interaction between BSA and quercetin, BSA and garlic and onions extracts was measured by 3-dimensional fluorescence (3D-FL) and Fourier transform infrared (FT-IR) spectroscopy. The highest polyphenol content was found in methanol/water fraction of onions and garlic; therefore, for the investigation of in vitro interactions with BSA only polyphenols of this fraction were used. For in vivo studies, 30 male Wistar rats were divided into 5 groups each of 6 and named Control, Chol, Chol/Garlic, Chol/OnionRed, and Chol/OnionWhite. During 6 weeks, the rats of all 5 groups were fed a basal diet (BD). The rats of the Control group were fed the BD only. The BD of the Chol group was supplemented with 10 g/kg of nonoxidized cholesterol (NOC). Each of the other three groups was supplemented with 10 g/kg of NOC and 500 mg of raw fresh garlic, 500 mg of raw fresh red onion, and 500 mg of raw fresh white onion on 1 kg of body weight for Chol/Garlic, Chol/OnionRed, and Chol/OnionWhite diet groups, respectively. In order to detect the changes in the liver and aorta, a histological procedure was applied, and the liver enzymes were determined and compared. It was found that the main changes vs the Control group were in the liver of rats fed the cholesterol-containing diet without vegetable supplementation. Significantly less histological changes in the liver and lower level of liver enzymes vs those of the Chol group were detected in rats of the Chol/Garlic group (P < 0.05). The interaction between the polyphenol extract of garlic and BSA in vitro showed its strong ability comparable with that of quercetin to quench the intrinsic fluorescence of BSA. In conclusion, all studied vegetables showed protective effects, but raw garlic supplemented with cholesterol-containing diets significantly prevented the aorta and liver damages of rats.