摆动平底从动件盘形凸轮廓解析设计的应用     

殷珍荣  张凤举  刘金国 《扬州大学学报(农业与生命科学版)》1989,(3)

本文根据具体机器动作协调性要求及其具体空间几何条件,采用了摆动从动件盘形凸轮机构。其摆杆推程在O°～52°及52°～62°范围内分别采用了等加速——等速合理拼接运动规律。回程在62°～153°范围内采用了正弦加速度运动规律。用极坐标矢量分析法建立方程、微分,通过电脑程序计算,设计制造出凸轮轮廓,用于禾苗移植机的擒纵机构处,完全符合生产要求,获得了理想的效果。  相似文献   

Physiological Analysis of Yield Variation in Mungbean (Vigna radiata [Roxb.] Wilczek)     

D. B. Patel    K. R. Purohit  R. R. Shah 《Journal of Agronomy and Crop Science》1992,168(2):128-132

Two mungbean varieties, Guj-1 and PIMS-1 differing in their productivity potential, were examined to investigate their photosynthetic system at various stages of growth in relation to yield with two different dates of sowing. Vertical leaves were found to be beneficial. On the other hand, excessive leaf area during the later stages of growth may be detrimental to yield. Lower LAD at seedling stage and overall high NAR values may be reflected in higher grain yield. NAR declined as season progressed and this, in turn, may be related with increase in LAI. The grain yield was considerably more at the first date of sowing as compared to second date of sowing, the effect was being more pronounced in var. PIMS-1 . Various environmental factors recorded at two different dates of sowing and at various stages of growth indicated that these factors may have influenced the yield potential at two different dates of sowing.  相似文献   

分期播种下拟高粱生育进程的温光特性     

陈才夫  梁祖铎 《草业科学》1992,9(6):27-30

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春小麦、紫花苜蓿混播植物群落地上生物量季节动态   总被引：1，自引：0，他引：1  

仓生海  李晓明  杨慧青  尕切江  祁迎林  彭宏春  牛东玲 《青海草业》2001,10(1):7-10

通过对小麦 +紫花苜蓿混播当年植物群落地上生物量的测定表明 :植物在生长季节 ,各类群的地上生物量有明显差异 ,地上生物量积累最多的是小麦 ,其次是杂草 ,混播当年紫花苜蓿的地上生物量很小。小麦和杂草的地上生物量季节生长速率高峰期出现在 7月下旬 ,紫花苜蓿在 8月下旬。  相似文献   

Weeding techniques in transplanted and direct wet-seeded rice in Pakistan     

MOHAMMAD SAFDAR BALOCH  GUL HASSAN  TETSUO MORIMOTO 《Weed Biology and Management》2005,5(4):190-196

Field studies were undertaken to explore the weed management strategies for transplanted and direct wet-seeded rice in the Dera Ismail Khan district of North-west Frontier Province, Pakistan. The experimental design was a randomized complete block with a split plot arrangement. The main plots consisted of two planting techniques (transplantation and direct seeding), while weed control practises assigned to the subplots included the use of the granular herbicide Sunstar 15WG (ethoxy sulfuron), Machete 60EC (butachlor), conventional hand weeding, and the weedy check (untreated control). Data were recorded on weed dynamics and the agronomic parameters of the rice crop. Economic analyses on the data were also run. The weed density and biomass were lower in the transplantation plots than the direct-seeding plots. The herbicides ethoxy sulfuron and butachlor reduced the density over the weedy check, with a density comparable to hand weeding in 2002, but slightly higher in 2003. As a result of weed management by hand weeding and herbicides, the paddy yield and its components were significantly higher for the transplanted method compared to the direct-seeded method. The comparable yield of herbicides with hand weeding offers an option for the use of herbicides as an alternative management tool. In light of our findings, it is concluded that for good economic returns, rice crops may be transplanted rather than direct-seeded. The herbicides ethoxy sulfuron and butachlor offer a weed control cover comparable with hand weeding under the transplantation method, while butachlor is good for controlling weeds even under the direct-seeded conditions in the agroclimatic conditions of the area.  相似文献   

充足底墒播后不灌水时肥料和播期组合对小麦生长和耗水的影响   总被引：2，自引：1，他引：2  

薛绪掌  王志敏  秦勇 《干旱地区农业研究》2003,21(4):78-83

在充足底墒播后不灌水条件下,进行了适当晚播(10月15日播)与超晚播条件下的小麦肥料试验。主要结果为:(1)播后不灌水条件下超晚播减产严重,主要是单位面积总粒数下降太多,通过适当提高穗密度难以补偿;(2)高施磷条件下(施磷二铵450kg/hm2),随施氮量的增加,开花前的耗水量没有增加,而灌浆期的耗水量则随氮肥用量增加而增加;(3)控制花前无效生长,降低花前耗水,优化开花后的群体结构,提高灌浆期的灌浆强度是降低总耗水、提高水分利用效率的基本途径。  相似文献   

The effect of sowing date, stale seedbed, row width and mechanical weed control on weeds and yields of organic winter wheat   总被引：1，自引：0，他引：1  

I A Rasmussen 《Weed Research》2004,44(1):12-20

Three field experiments were carried out in organically grown winter wheat in Denmark. The treatments were sowing time (normal or late sowing) and false seedbed, row width (12 and 24 cm) and weed control method [untreated; mechanical weed control (weed harrowing at 12 cm supplemented with inter‐row hoeing at 24 cm); and herbicide weed control]. Weed biomass in midsummer was greatest on plots sown at the normal sowing time (compared with delayed sowing) and was reduced by mechanical or chemical weed control (compared with untreated plots). Row width alone had no influence on weed biomass, but in the experiment with high weed pressure, the more intensive mechanical weed control used at a row width of 24 cm reduced weed biomass. Normal sowing time tended to give higher yields, but this was only statistically significant in one of the three experiments. Wide rows gave a yield decrease in the experiment with low weed pressure. The effect of weed control on yield was dependent on the weed pressure. At low weed pressure, mechanical weed control caused a yield decrease compared with untreated or herbicide treated. At intermediate weed levels there were no differences, whereas at high weed pressure, mechanical weed control and herbicide treatment caused a yield increase compared with untreated. False seedbeds were shown to contribute to a decrease in the soil seed reserve.  相似文献   

Effect of Sowing Date on Agronomic Traits and Starch Physicochemical Properties of Proso Millet   总被引：1，自引：1，他引：0  

LUO Yan  QU Yang  YANG QingHua  ZHANG WeiLi  GONG XiangWei  LI Jing  GAO XiaoLi  GAO JinFeng  YANG Pu  WANG PengKe  FENG BaiLi 《中国农业科学》2019,52(22):4154-4165

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种植密度对滴灌马铃薯生长、产量的影响   总被引：1，自引：0，他引：1  

王岩  刘畅  李云开  顾涛  苏艳平 《排灌机械工程学报》2020,38(1):90-94

为了了解耕培土滴灌条件下种植密度对马铃薯生长、产量以及水分利用效率的影响.试验共设密度分别为7.28×10⁴ 株/hm²(RS25),6.67×10⁴ 株/hm²(RS35),5.55×10⁴ 株/hm²(CK)3个处理.结果表明:随着种植密度的增加,株高、茎粗、干物质积累量以及商品薯率均有降低的趋势;产量、水分利用效率随种植密度的增加表现出先增大后减少,其中RS35处理产量和水分利用效率均表现最高,分别达到47 325 kg/hm²和12.05 kg/m³;在马铃薯品质方面,种植密度对马铃薯粗蛋白含量的影响不具有统计学意义;淀粉和维生素C随着密度的大幅增加而降低,其中RS25处理的淀粉较CK降低了5.57%,RS25处理的维生素C较CK降低了7.96%,同时RS35与CK处理不具有统计学意义.综上所述,种植密度为6.67×10⁴ 株/hm²的RS35处理马铃薯高产优质,且水分利用效率最高,为黑龙江地区滴灌马铃薯较为适宜的种植密度.  相似文献   

Effects of Wheat Seeding Rate with Nitrogen Fertilizer Application Reduction on Soil Microbial Biomass Carbon,Nitrogen and Enzyme Activities in Fluvo-Aquic Soil in Huang-Huai Plain   总被引：1，自引：0，他引：1  

SHI Ke  DONG ShiGang  SHEN FengMin  LONG Qian  JIANG GuiYing  LIU Fang  LIU ShiLiang 《中国农业科学》2019,52(15):2646-2663

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