拖拉机耕深自动监测与控制   总被引：2，自引：3，他引：2  

吴国桢  程文祥 《农业机械学报》1993,24(1):31-36

拖拉机耕深采用伺服和微机根据负荷及耕深的大小进行自动控制,使拖拉机处于最佳工况,提高作业质量和经济性。由耕作阻力的力信号和耕深变化的位移信号相叠加并和设定耕深相比较输入伺服放大器或计算机,然后输出控制信号,控制电液伺服阀的工作,改变控制阀的行程和方向,以改变输入拖拉机提升油缸的油量和流向,达到控制耕深的目的。 所组成的 TMD-1 型微机拖拉机耕深控制系统成功地进行了模拟试验和田间试验,取得了满意的结果。  相似文献   

Predicting effects of drainage water management in Iowa's subsurface drained landscapes     

R. Singh  M.J. Helmers  D.W. Lemke 《Agricultural Water Management》2007,92(3):162-170

Long-term hydrologic simulations are presented predicting the effects of drainage water management on subsurface drainage, surface runoff and crop production in Iowa's subsurface drained landscapes. The deterministic hydrologic model, DRAINMOD was used to simulate Webster (fine-loamy, mixed, superactive, mesic) soil in a Continuous Corn rotation (WEBS_CC) with different drain depths from 0.75 to 1.20 m and drain spacing from 10 to 50 m in a combination of free and controlled drainage over a weather record of 60 (1945-2004) years. Shallow drainage is defined as drains installed at a drain depth of 0.75 m, and controlled drainage with a drain depth of 1.20 m restricts flow at the drain outlet to maintain a water table at 0.60 m below surface level during the winter (November-March) and summer (June-August) months. These drainage design and management modifications were evaluated against conventional drainage system installed at a drain depth of 1.20 m with free drainage at the drain outlet. The simulation results indicate the potential of a tradeoff between subsurface drainage and surface runoff as a pathway to remove excess water from the system. While a reduction of subsurface drainage may occur through the use of shallow and controlled drainage, these practices may increase surface runoff in Iowa's subsurface drained landscapes. The simulations also indicate that shallow and controlled drainage might increase the excess water stress on crop production, and thereby result in slightly lower relative yields. Field experiments are needed to examine the pathways of water movement, total water balance, and crop production under shallow and controlled drainage in Iowa's subsurface drained landscapes.  相似文献   

浅水芹夏秋轻简栽培技术研究     

陆志新  濮焕中  路广  邵珊  吴洁云  杨慧玉  黄金福 《长江蔬菜》2014,(12):27-29

为探索浅水芹夏秋轻简栽培技术,研究了不同稻草覆盖量和覆盖方式对水芹生长的影响。试验结果表明,浅水芹夏秋栽培宜采用免催芽直接排种;覆盖方式以遮阳网大棚覆盖为最佳,其次为稻草覆盖,最适宜的稻草覆盖量为200~250 kg/667 m2。  相似文献   

不同灌溉处理寒地井灌稻田地温和产量构成要素研究     

聂晓  王毅勇  刘兴土 《安徽农业科学》2014,42(36):12840-12842

通过田同试验研究了浅水-间歇灌溉（SIT）、湿润-间歇灌溉（MIT）、淹灌（CSF）条件下寒地稻田的0～ 15 cm地温和水稻产量构成因素.结果表明,SrT、MIT田间建立浅水层或无水层,有利于0～ 15 cm的土壤温度的提升.由于Srr和MIT处理显著提高了每穴有效穗数,因而最终分别较CSF增产8.6％和11.9％,但SIT和MIT处理间差异不显著.  相似文献   

Effects of tillage on productivity of a winter wheat-vetch rotation under dryland Mediterranean conditions     

Sakine Ozpinar   《Soil & Tillage Research》2006,89(2):258-265

An experiment was conducted to determine the effects of three tillage systems on crop yield in a winter wheat-vetch (Vicia sativa L.) rotation during 3-year growing seasons on a clay-loam soil in the northwest region of Turkey. The three tillage treatments were: (1) conventional tillage (CT); (2) shallow tillage (ST); (3) double disk tillage (DD).The wheat grain yield was significantly affected by tillage when averaged across years. The highest wheat grain yield was obtained with shallow tillage treatment. The year affected wheat grain yield significantly, mainly due to the distribution of rainfall through the growing season and probably due to the wheat-vetch rotation. Heads density and head length increased significantly with shallow tillage when compared with conventional tillage. Tillage practices had no significant influence on thousand kernel weight. Results from this study indicated that for a dryland wheat-vetch rotation cropping system, shallow tillage had higher wheat grain yields than that obtained from conventional tillage. Furthermore, mouldboard ploughing tillage in this crop rotation could be replaced by shallow tillage that would increase yield and would be likely to improve soil properties in the long-term. On the other hand, double disk tillage proved to be a promising soil management practice to improve vetch grain yield when compared with conventional tillage.  相似文献   

Agricultural studies of GM maize and the field experimental infrastructure of ECOGEN   总被引：4，自引：9，他引：4  

Mathias Neumann Andersen  Christophe Sausse  Bernard Lacroix  Sandra Caul  Antoine Messan 《Pedobiologia》2007,51(3):175-ECOGEN

Within the ECOGEN project, long-term field experiments with genetically modified maize, Zea mays L. were conducted to study agro-ecological effects on the soil fauna and agro-economic implications of the technology. Here, we describe the study-sites, experimental layout and results of agro-economic relevance. Experiments were conducted during 2002–2005 in Denmark (Foulum), northern France (Varois) and the Midi-Pyrenees region of southern France (Narbons). MON810 Bacillus thuringiensis (Bt)-varieties expressing the Cry1Ab protein, and a T25 glufosinate-ammonium (Basta) tolerant variety expressing the pat-gene encoding phosphinotrinacetyl-transferase were compared with near-isogenic non-Bt varieties, and conventional maize varieties. At Foulum, the maize was harvested for silage. There were no significant differences in yield between Bt-maize and a near-isogenic non-Bt variety, while a small difference in N-concentration of dry matter was detected in 1 year in a range of a measured quality parameters. Similar yield and quality were found in ploughed and reduced tillage treatments in all varieties. At Varois, the maize was harvested at ripeness and no significant differences in grain yield between Bt-maize and near-isogenic non-Bt varieties were found. These results were expected, as only Narbons harbours significant corn-borer populations. At Narbons, the number of Sesamia and Ostrinia corn-borer larvae were significantly lower in the Bt-maize than in a near-isogenic non-Bt variety and for Sesamia even less than in conventional varieties sprayed with pesticides to control corn-borer infestation. Here, Bt-maize produced a higher grain yield and grain size than a near-isogenic non-Bt variety or allowed a significant reduction in pesticide use. Concentrations of Cry1Ab in the Bt-varieties were sufficient to effectively control corn-borer larvae. In soil, Cry1Ab was close to the limit of detection and the protein did not accumulate in the soil year on year.  相似文献   

Unusual soil nematode communities on karst mountain peaks in southwest China     

《Soil biology & biochemistry》2015

On karst mountain peaks in southwest China, soils are very shallow and vegetation cover is very low. Although the subtropical monsoon climate provides abundant rainfall, the soils experience severe dry–wet cycles and extremely high temperatures in summer (wet season). We determined the composition of soil nematode communities along a vegetation succession sere of four common plant communities (i.e., moss crust, moss crust with sparse grasses, sparse grasses, and sparse dwarf shrubs) on karst mountain peaks in the wet and dry seasons. The results showed that the nematode communities were unusual. Specifically, Rhabdolaimus was the most abundant nematode genus. Rhabdolaimus is a common aquatic nematode genus that has been detected in hot springs but has not been previously reported as the dominant genus in relatively arid and semi-arid soils. Therefore, tolerance to extremely high soil temperatures and rapid wet–dry cycles may help explain why Rhabdolaimus dominates the nematode communities in the soils of karst mountain peaks in southwest China.  相似文献   

试论中国犁耕技术进步的推动力     

胡泽学 《古今农业》2006,(4):42-51

犁是中国传统农具中最具代表性的生产工具。犁耕技术的发展、进步,与生产力的进步和社会制度的更迭、历代统治者的重农与革新、土地利用方式的增加、相关行业技术的进步、人口迁移与生产环境的变化、科技文化交流与民族文化交融等有着非常密切的关系。正是这些因素的推动,使我国古代犁的形制一次次改变,犁耕技术一次次取得重大突破,犁在社会发展和农业生产中的作用一次次提升。  相似文献   

棕点石斑鱼网箱养殖试验研究     

严俊贤  许小华  梁晓春  梁盛  冯永勤  王世锋 《安徽农业科学》2012,40(11):6524-6526

[目的]开发利用浅海网箱人工养殖棕点石斑鱼技术,并提高棕点石斑鱼的产量。[方法]利用浅海网箱进行棕点石斑鱼的人工养殖试验,探讨棕点石斑鱼网箱养殖的可行性和经济效益。[结果]放养9万尾鱼苗,经过18个月的网箱养殖试验,共养成体重为485～520 g的商品鱼73 297尾,平均成活率达81.4%,共获利润5 401 200元。[结论]通过浅海网箱养殖棕点石斑鱼是可行的,并可获得很好的经济效益。  相似文献   

亚热带典型地貌下旱地和水田可溶性有机物化学组成特征   总被引：3，自引：1，他引：2  

郑小东  陈香碧  胡亚军  苏以荣 《土壤》2019,51(6):1114-1121

阐明亚热带典型地貌下旱地与水田土壤可溶性有机物(DOM)化学组成差异可为农田土壤DOM稳定性评价提供理论依据。研究采用XAD-8树脂分组和热裂解气质联用仪(Py-GCMS)技术,分析比较休闲期、耕作期亚热带喀斯特山区、丘陵区及平原湖区旱地和水田土壤DOM化学组成特征。结果表明:休闲期,亲、疏水性可溶性有机碳(DOC)含量以水田(10.2、33.4 mg/kg)显著高于旱地(4.15、12.8 mg/kg),耕作期无显著性差异。与休闲期相比,耕作期水田亲、疏水性DOC含量均显著降低,而旱地亲、疏水性组分DOC含量在两个时期间保持相对稳定。休闲期旱地和水田土壤DOM中有机酸相对比例分别为31.9%、35.6%,耕作期显著降至17.9%、20.0%(P0.05)。脂类相对比例趋势与有机酸相反,旱地和水田土壤DOM中脂类相对比例在休闲期分别为55.0%、49.5%,耕作期显著增至70.1%、62.9%(P0.05)。Adonis分析表明,亲、疏水性DOC含量在旱地和水田、休闲期和耕作期差异显著(P0.05);DOM化学组成在不同时期(休闲期和耕作期)及地貌(喀斯特山区和丘陵区、丘陵区和平原湖区)差异显著(P0.05)。Random Forest分析表明,有机酸和脂类参与微生物代谢过程,在休闲期和耕作期差异显著(P0.05);芳香化合物作为DOM稳定性组分,在不同地貌区差异较大(P0.05)。总体上,田间条件下水田DOC比旱地DOC对时期响应更敏感,且土壤DOM中微生物代谢相关组分(有机酸、脂类)和稳定性组分(芳香族化合物)在不同时期及地貌区的差异性不同,这对评价旱地和水田土壤DOM稳定性及土壤有机碳积累具有一定的参考意义。  相似文献