摘要:

Two field trials were performed to assess a variety of control methods for larvae of diamondback moth,Plutella xylostella(L.) and cabbage white butterfly,Pieris rapae(L.) on cabbage. The possibility of reducing the number of synthetic insecticide applications, by spraying according to action thresholds, was also studied. The plant-based product rotenone, the bacteriumBacillus thuringiensisBerliner and a lightweight netting barrier successfully controlled the pests and produced cabbage of marketable quality. Pyrethrum, garlic, soap and combinations of these products did not prevent larval feeding damage. Use of action thresholds reduced numbers of synthetic insecticide applications, in one season, without compromising yield or quality. Results of these trials show that there is potential for reducing synthetic insecticide input in the production of quality cabbage crops.

ISSN:0144-8765    

DOI:10.1080/01448765.1992.9754594

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Fruit yield of cantaloup (Cucumis melol.cv. PSF 189) was not affected by the application of clear (C) or (B) plastic mulches, in comparison to unmulched soil (U), when grown inside an unheated greenhouse located in the Mediterranean mountains in a region with a cold early spring. Marketable yields of 30.5, 28.06 and 25.03 t/ha were achieved under the C, B and U treatments, respectively, during 1990. These yields were not significantly different (P>0.05). The mulches enhanced vegetative growth during the cold early spring; fully expanded leaves were 2.5 times more under C mulch, and 1.8 times more under the B mulch, than under the U treatment, by the fifth week after planting. Fruiting occurred later on when the weather warmed and thus no significant effect on yield occurred due to the mulches. Soil temperature at 10 cm depth under the C treatment was warmer by 1–2°C and 7–10°C than temperature under the B and U treatments respectively, when the plant canopy did not cover the mulches but became comparable among the mulches when they became covered by the plant canopy.

ISSN:0144-8765    

DOI:10.1080/01448765.1992.9754595

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The latex of four plants belonging to the family Euphorbiaceae viz.Jatropha gossypifolia, Euphorbia royleana, Euphorbia antisyphliticaandEuphorbia lactea cristatacaused significant reductions in the acid and alkaline phosphatase activity in nervous tissue of the snailLymnaea acuminata.The reduction in the activity of both the phosphatases was time and dose dependent; the order of effectiveness was as follows:Euphorbia lactea cristata > Euphorbia antisyphlitica > Euphorbia royleana > Jatropha gossypifolia.

ISSN:0144-8765    

DOI:10.1080/01448765.1992.9754596

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

As an addition to analytical methods, food preference tests represent a new approach in the investigation of food quality. This method was put to a test with common beets from biological and conventional farming systems and with different kinds of bread containing improving or debasing substances (milk thistle, ground sunflower seeds, ergot, undigestible roughages) and different proportions of wheat and rye.

ISSN:0144-8765    

DOI:10.1080/01448765.1992.9754597

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Locating research on a commercial farm is essential for three types of investigation: studies involving 1) management histories and physical conditions not available on experiment stations; 2) farmer management, especially of innovative systems; and 3) ecological effects of whole-farm changes. On-farm research with the farmer involved beyond assisting with operations has advantages in the design, implementation, and dissemination stages. These benefits may warrant locating a project on a commercial farm even if it could also be done on-station. Misunderstandings about the value of on-farm research are often due to its promotion in conjunction with sustainable agriculture and greater political power for farmers. On-farm research, especially with high farmer involvement, is more appropriate for answering some questions critical to developing more sustainable agricultural systems; but other aspects of sustainable agriculture are more suitably studied at experiment station sites. Greater involvement of farmers in all stages of a project is conducive to improving communication and cooperation with agricultural researchers and administrators. However, not all research on farms should have this kind of farmer involvement; and simply increasing the amount of on-farm research does not necessarily augment farmers' political power.

ISSN:0144-8765    

DOI:10.1080/01448765.1992.9754598

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

A farm-level trial was conducted at Mgbidi and Umuowa in the Orlu Agricultural zone of Imo State, Nigeria. The productivity of and income from single, alternative and double row intercropping arrangements for yam (Dioscorea rotunda ta)/maize (Zea ways)/Egusi (Citrulus vulgaris)/cassava (Manihot esculentaCrantz) intercrop were compared against the farmers' intercropping arrangements in a randomized complete block design with five replications. Analysis of variance was used to assess crop yields, productivity assessed by energy values, gross margins, return on capital, benefit/cost and return to labour.

ISSN:0144-8765    

DOI:10.1080/01448765.1992.9754599

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

ISSN:0144-8765    

DOI:10.1080/01448765.1992.9754601

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

ISSN:0144-8765    

DOI:10.1080/01448765.1992.9754602

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

ISSN:0144-8765    

DOI:10.1080/01448765.1992.9754603

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

ISSN:0144-8765    

DOI:10.1080/01448765.1992.9754604

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor