ISSN:0143-6147    

DOI:10.1080/09670878509370935

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Spinning disc sprayers have been in widespread use in some countries for a number of years. Whilst the machines have become somewhat more economical in battery usage, the cost of disposable batteries has increased markedly. Erratic supplies of poor quality disposable batteries in some areas has also restricted the growth of this spraying method. This paper discusses the merits and problems relating to primary (disposable) and secondary, (rechargeable) cells together with a variety of possible recharging methods. A series of tables summarizes information presented in the text to permit easy comparison of the features of each power source and recharging method where appropriate. Further tables give costing examples (U.K. values) for various power source/recharging combinations and show the range of costs, relative to hydraulic spraying per hectare per annum when taking labour costs, batteries etc. into consideration. The possibility of recharging existing primary cells is considered but is thought likely to be impractical in most situations. However, resting batteries to increase useful life is likely to be of benefit.

ISSN:0143-6147    

DOI:10.1080/09670878509370936

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Lever‐operated knapsack sprayers are used in many countries for the application of pesticides. Various methods have been used to evaluate the performance of knapsack sprayers. A number of features, including design, performance, durability, operation and maintenance, are discussed. This paper assists purchasers in selecting a suitable sprayer and provides a list of manufacturers.

ISSN:0143-6147    

DOI:10.1080/09670878509370937

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

A manually pushed granular herbicide distributor was made from a garden cultivator by adding bicycle parts and granular attachments from a tractor‐pulled planting machine. At normal walking speed, delivery of chloramben granules (9% a.e.) was uniform and highly reproducible over a range of 2.7 to 18.2 kg granules/10 km row. Treated bands were 35 cm wide with a herbicide diffuser and 14 cm wide when an insecticide diffuser was used to spread granules laterally.

ISSN:0143-6147    

DOI:10.1080/09670878509370938

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

An experiment was conducted at Umudike in 1981 and 1982 on a sandy loam soil in the rain forest zone of Nigeria, to determine the critical weed‐free requirement and the critical duration of weed interference in cocoyam/sweet potato/maize intercrop combination. The major weeds present in the weedy control crop mixture during the 2 years included grasses, broad‐leaves and sedges. The grasses were mainlyCynodon dactylon, Digitaria horizontalis, Eleusine indica, Panicum maximumandPaspalum scrobiculatum.The dominant broadleaved weeds includedCommelina benghalensis, lpomoea involucrata, Tridax procumbens, Mimosa pudica, Icacina trichantha, Vernonia cinerea, Calapogonium mucunoidesandChromolaena odorata.The major sedges comprised,Cyperus esculentus, Cyperus distans, Fimbristylis barteriandMariscus alternifollus.Uncontrolled weed growth caused a 2 year average yield loss of?1731.00 (? = Nigerian shillings) or 76% in cocoyam/sweet potato/maize intercrop combination compared with the yield (? 2260.00) of the mixture weeded every 28 days after planting. Intercropping the three crops significantly out‐yielded any of the sole crop components on per unit area basis. The yield of the crop mixture was most seriously impaired by weed interference during the first 28 days after planting but also caused serious yield reduction in the crop mixture if not removed during the first 56 days after planting.

ISSN:0143-6147    

DOI:10.1080/09670878509370939

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Field experiments on sorghum,Sorghum bicolor(L.) Moench., hybrid CSH‐6, demonstrated the importance of in‐the‐row weed management in this crop when grown under rainfed conditions in south‐central India. In‐the‐row weeds reduced sorghum grain yields by up to 30% when only inter‐row weeding was carried out. A single hand weeding at any time between 2 and 5 weeks after crop sowing was equal to repeated hand weeding in maintaining high grain yields. Atrazine applied pre‐emergence to the crop or isoproturon applied 3 weeks after crop sowing resulted in sorghum grain yields equal to those obtained from hand weeding. Over the row band applications of these herbicides were equal to broadcast applications, provided two interrow cultivations were carried out; and herbicide costs were reduced by two‐thirds.

ISSN:0143-6147    

DOI:10.1080/09670878509370940

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Field experiments were conducted on a heavy clay soil of Central Sudan to study the effectiveness of some pre‐planting and pre‐emergence herbicides on kenaf,Hibiscus cannabinusL. Pre‐planting application of trifluralin at 1.2 to 2.4 kg/ha and pendimethalin at 1.2 to 2.4 kg/ha were found to be the most promising herbicides for weed control; nitralin at 1.2 kg/ha was less effective, while EPTC at 3.6 kg/ha caused crop damage with significant reduction in yield. Among the pre‐emergence herbicides fluorodifen at 3.6 to 4.8 kg/ha and pendimethalin at 1.2 to 2.4 kg/ha were the best. Oxadiazon and its tank mix with diuron were considered to be too damaging for recommendation to growers.

ISSN:0143-6147    

DOI:10.1080/09670878509370941

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Field trials conducted during two crop seasons in the kharif season (1981 and 1982) at the Zonal Agricultural Research Station, Raipur (M.P.). India, investigated the interrelationship between systems of rice cultivation and weed management. Direct seeding of pre‐germinated rice seed by dibbling (20 x 15 cm) produced yields on a par with the transplanting system. Amongst the different systems of weed management, cultural (hand pulling) methods and butachlor application effectively controlled weeds on plots sown by the broadcasting method. On plots sown using transplanting methods, improved weed control was only achieved using cultural methods. On plots sown by drilling and dibbling, weed control by cultural methods, butachlor and a combination of butachlor and propanil application were equally efficient. The usual practice of planting pre‐germinated rice seed under broadcast without a weed management system significantly reduced productivity.

ISSN:0143-6147    

DOI:10.1080/09670878509370942

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The importance and production of mangoes in Zambia is described. The current status of major diseases and insect pests is reported with particular reference to their relative importance and control under Zambian climatic conditions. The plant protection measures of mango orchards in Zambia are outlined and a spray programme is suggested. Further research work to enable an integrated approach to pest control in mango orchards is essential.

ISSN:0143-6147    

DOI:10.1080/09670878509370943

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Components of resistance in seven rice varieties to the Whitebacked planthopper,Sogatella furcifera(Horvath), were studied in terms of nymphal preference, adult preference, ovipositional preference, nymphal survival, nymphal duration, adult longevity, fecundity, percentage of egg hatch and population build‐up. Both nymphs and adults showed distinct non‐preference reactions to the resistant varieties for feeding, orientation and oviposition. The resistant varieties had an adverse influence on the nymphal survival and duration, as well as on the longevity and fecundity of adult females. However, resistance in rice did not have an appreciable effect on egg hatching. The adverse effects of resistant varieties had a cumulative effect on the insect population build‐up through several generations. The overall assessment in the present study indicated that resistance in rice to the Whitebacked planthopper was shown by the combined influence of non‐preference by the hopper for feeding, orientation and oviposition coupled with antibiosis.

ISSN:0143-6147    

DOI:10.1080/09670878509370944

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor