Impact of soil compaction upon soil water balance and maize yield estimated by the SIMWASER model

The capability of the soil water balance model SIMWASER to predict the impact of soil compaction upon the yield of maize (Zea mays L.) is tested, using the results of a field experiment on the influence of soil compaction by wheel pressure upon soil structure, water regime and plant growth. The experimental site was located on an Eutric Cambisol with loamy silt soil texture at an elevation of 260 m in the northern, semi-humid sub-alpine zone of Austria. Within the experimental field a 7 m wide strip was compacted by a tractor driven trailer just before planting maize in May 1988. Compression effects due to trailer traffic resulted in distinct differences of physical and mechanical soil parameters in comparison with the uncompressed experimental plots down to a depth of about 30 cm: bulk density and penetration resistance at field capacity were increased from 1.45 to 1.85 g/cm³, and from 0.8 to 1.5 MPa, respectively, while air-filled pore space as well as infiltration rate were appreciable lowered from about 0.08–0.02 cm³/cm³ and from 50 to 0.5 cm per day, respectively. The overall effect was a clear depression of the dry matter grain yield from 7184 kg/ha of the non-compacted plot to 5272 kg/ha in the compacted field strip. The deterministic and functional model SIMWASER simulates the water balance and the crop yield for any number of crop rotations and years, provided that daily weather records (air temperature, humidity of air, global radiation, wind and precipitation) are available. Crop growth and soil water regime are coupled together by the physiological processes of transpiration and assimilation, which take place at the same time through the stomata of the plant leaves and are both reacting in the same direction to changes in the soil water availability within the rooting zone. The water availability during rainless seasons depends on the hydraulic properties of the soil profile within the rooting depth and on rooting density. Rooting depth and density are affected by both the type of the crop and the penetration resistance of the soil, which depends on the soil moisture status and may be strongly increased by soil compaction. The model SIMWASER was able to simulate these effects as shown by the calculated grain yields, which amounted in the non-compacted plot to 7512 and to 5558 kg dry matter/ha in the compacted plot.     

精细农业田间信息采样策略

为研究田间空间变异性信息和采样策略 ,对 13.3hm2 冬小麦田以 5 0 m× 5 0 m栅格测得 6 3个数据 ;设计不同采样方案 ,用克立格法插值绘空间分布图 ,用最小显著差数法检验 ,得最佳采样方案。结果表明 ,不同田间信息应选不同采样方案 ;同种信息同采样点数和间距 ,采样位置不同 ,其变异性描述也不同 ;5 0 m× 10 0 m、15 0 m× 15 0 m右和 10 0 m× 2 0 0 m采样方案对所有田间信息都适用 ,15 0 m× 15 0 m左采样方案对速效磷、含水量和土壤密度都不适用。     

网棚养殖蝗虫吸捕机设计

针对网棚养殖蝗虫的捕集问题,设计了旋风分离式蝗虫吸捕机.使用CFD软件对吸嘴和分离装置的内部气流场进行了数值模拟.样机试验表明:当吸嘴倾角为75°、吸口气流速度为14 m/s、吸嘴距地高度为40 mm、机器前进速度为0.4 m/s时,可以获得较高的吸捕率和较低的破碎率.实际作业时可根据蝗虫分布密度,灵活调节吸口风速和机器前进速度,以提高吸捕效率、降低能耗.     

5%吡虫啉乳油不同试验点防治烟蚜田间药效试验研究(英文)

该文对5%吡虫啉乳油对烟草烟蚜进行3地田间药效试验,通过对不同剂量5%吡虫啉乳油,在药后3、7、14、20 d进行差异显著性分析。结果表明5%吡虫啉乳油对烟草K326、烟草G28、云烟-87防效效果较好。证明5%吡虫啉对烟蚜有较好的防治效果。     

240g/L收乐通EC加助剂防除向日葵田禾本科杂草的效果

为了增加防除向日葵田禾本科杂草除草剂种类的选择性,便于药剂的交替使用,延缓杂草抗药性的产生,延长除草剂的使用寿命。2012年应用240g/L收乐通EC 45-100mL/667m^2,以及各处理加入等量Amigo助剂,于向日葵生长期,杂草3-6叶期进行茎叶喷雾处理防除田间禾本科杂草试验。结果表明：试验药剂单剂各处理对于一年生禾本科杂草稗草的速效性、持效性和防效均很好,药后15d、35d防效均稳定在94.3%以上,而且与10.8%高效氟吡甲禾灵EC和10%精喹禾灵EC两种对照药剂防效相当;对于多年生芦苇施药后35d鲜重防效为56.9%-76.5%,不如对照药剂10.8%高效氟吡甲禾灵EC和10%精喹禾灵EC处理88.9%、91.6%的防效。但是,收乐通各处理加入等量助剂后防效明显提高,药后35d对芦苇的鲜重防效为55.8%-98.9%,其中240g/L收乐通 EC 80mL/667m^2、100mL/667m^2处理防效均在93.1%以上,优于两种对照药剂,而且对向日葵安全。     

9种杀菌剂对枣树锈病的室内毒力及田间防效

为筛选防治枣树锈病的高效药剂,采用含毒介质法测定9种杀菌剂对枣树锈病夏孢子萌发的毒力,并进行田间防治效果评价。结果表明,抑制夏孢子萌发毒力强的有 12.5%四氟醚唑EW、85%三氯异氰尿酸SP和10%苯醚甲环唑WG,EC₅₀分别为2.657、 3.358、8.290 μg/mL;其次为40%氟硅唑EC、25%吡唑醚菌酯SC、80%戊唑醇WG和25%嘧菌酯SC,EC₅₀分别为10.406、16.501、21.047、23.046 μg/mL。田间试验结果以12.5%四氟醚唑EW防效最好,药后10 d防效为94.3%,药后20 d防效为86.3%;其次为10%苯醚甲环唑WG、80%戊唑醇WG、40%氟硅唑EC、25%嘧菌酯SC和25%吡唑醚菌酯SC,药后10 d防效分别为89.3%、86.8%、88.3%、81.2%、82.3%,药后20d防效分别为75.3%、78.8%、79.6%、75.6%、77.4%,可有效防治枣树锈病。     

13种农药对甘肃定西和武威地区小菜蛾的毒力及药效

旨在筛选对甘肃露地蔬菜小菜蛾高效且对环境安全的药剂,明确它们对小菜蛾的室内毒力和田间防效。选用四氯虫酰胺等13种药剂,采用叶片浸渍法测定其对小菜蛾的室内毒力,并进行田间防效试验。结果表明：小菜蛾相对敏感（RS）种群、定西大田种群（D-R）和武威大田种群（W-R）均对四氯虫酰胺的敏感性最强,LC₅₀分别为0.178、0.193、0.228 mg/L,其次是乙基多杀菌素和溴氰虫酰胺。筛选11种药剂进行D-R的药效试验,结果表明：1×109 PIB/mL甘蓝夜蛾核型多角体病毒悬浮剂的防效最好,药后1、3、7 d的防效分别为62.95%、65.42%、84.28%,其次是10%四氯虫酰胺悬浮剂,药后7 d防效为77.96%。选用4 种药剂对W-R 进行药效试验,结果表明：25%乙基多杀菌素水分散粒剂的防效最好,药后7 d的防效为80.93%。综上所述,两种核型多角体病毒、乙基多杀菌素及3种吡啶类杀虫剂防效较高,建议在高原夏菜生产中推广应用。     

旱作农业区不同田间集雨措施应用效果研究

分别对冬小麦和夏玉米进行了不同田间集雨措施的试验研究。结果表明,起垄可使垄背土壤变得疏松,孔隙度增大,有利于土壤通气透水,增加土壤水库容。这有利于作物根系生长,增强抗倒伏能力,并可以减少地表径流使表土土壤结构体免遭破坏。因土壤贮水能力增加、地形对降水的再分配、土壤水的运移及蒸发强度的不同,使更多水分可以被作物利用。秸秆覆盖也可以缓冲雨滴的冲击力而减弱对土壤结构体的破坏,并且可以减少土壤水的蒸发损失。冬小麦生育期由于降水较少且强度不大,田间地形对降水的再分配效果不明显;而在没有覆盖措施的情况下因加快了土壤水分的蒸发,会降低冬小麦降水利用率。垄沟种植对夏玉米有明显的增产效应,而覆盖的效应相对较小。     

Up-regulation of miR-133a expression attenuates myocardial fibrosis in spontaneously hypertensive rats

AIM: To investigate the effect of up-regulated expression of microRNA-133a (miR-133a) on myocardial fibrosis in spontaneously hypertensive rats (SHR). METHODS: Wistar-Kyoto (WKY) rats with homologous normal blood pressure served as the normal control group. SHR were divided into SHR group, SHR+ adeno-associated virus (AAV) group and SHR+miR-133a-AAV group randomly. miR-133a carried by miR-133a-AAV was transfected into SHR heart by coronary perfusion. The rat tail artery pressure was monitored. The myocardial collagen deposition was observed by Masson staining. The expression of miR-133a in myocardial tissue was detected by real-time PCR. The protein levels of transforming growth factor-β1 (TGF-β1) and connective tissue growth factor (CTGF) were determined by immunohistochemistry and Western blot. RESULTS: Compared with the WKY rats, the tail artery pressure of the SHR increased significantly. The expression of miR-133a in heart decreased, and the expression levels of TGF-β1 and CTGF increased (P<0.05), and myocardial fibrosis occurred. After up-regulating the expression level of miR-133a in the heart of SHR, the myocardial fibrosis was significantly reduced, and the expression levels of TGF-β1 and CTGF decreased (P<0.05). CONCLUSION: Up-regulation of the miR-133a expression improves myocardial fibrosis induced by hypertension, which may be related to inhibiting the protein expression of TGF-β1 and CTGF in myocardium.     

蓝剑(Echium vulgare)不同部位浸提液对5种常见大田作物种子萌发的化感效应

为探讨蓝剑(Echium vulgare)对本地大田作物是否产生化感效应,本研究以生物测定方法研究蓝剑根、茎、叶3部分的无水乙醇浸提液和水浸提液对玉米、水稻、小麦、花生和大豆5种大田作物种子萌发过程的影响。结果表明:叶的化感作用最为明显,豆科对浸提液的响应比禾本科敏感,无水乙醇浸提液和水浸提液对禾本科影响有差异。综合分析,可以判断外来种蓝剑可与本地大田作物产生较为明显的化感作用,具有一定竞争关系。可初步判断蓝蓟对常见的5种大田作物的竞争力,对大田作物合理的间混套作提供一定的科学依据。