摘要:

Weeding has traditionally been a labour intensive operation in crop production. The use of herbicides was rapidly accepted by many farmers and became an accepted part of crop husbandry, although a few farmers always questioned the widespread use of chemicals in farming, and the concept of organic farming necessitated a non-chemical approach to weed control.

ISSN:0144-8765    

DOI:10.1080/01448765.1990.9754540

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Mycorrhizal colonization of strawberry roots was studied for two agricultural management systems on the California central coast, one conventional and one in transition to organic. Low levels of VAM colonization early in the first year of the experiment may be the result of past management practices, which included conventional production of a non-mycorrhizal crop with high levels of phosphorus inputs. In the second year colonization levels were higher in the transitional organic plots. Annual use of a fumigant and a fungicide in the conventional plots was implicated with depleting the VAM inoculum reservoir and maintaining low colonization levels. Inoculation of organically managed plots withGlomus intraradicesat the second planting did not change colonization levels. Soil analyses showed that available soil phosphorus levels remained high (range 62 to 101 ppm) in both treatments throughout the study. In both years colonization increased during the spring and summer harvest season, and it is hypothesized that the high phosphorus demand of strawberries during the reproductive growth stage may create a microzone of phosphorus depletion around roots, even in soil with high levels of phosphorus. If present, this depletion microzone would enhance the formation and potential benefits of mycorrhiza.

ISSN:0144-8765    

DOI:10.1080/01448765.1990.9754541

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Slurries of manures from sheep, dairy cows and poultry and their composts with peat moss, and composts made from fish and crab scraps with peat moss or brown peat, were characterized for the distribution of different N forms. The total-N in the composts varied from 1.09 to 3.72%, with the fish scrap composts being the richest. The mature composts contained 13 to 44% of the total N as NH4−and NO−3+ions, immediately available to plants. The crab scrap composts were richest in mineral N.

ISSN:0144-8765    

DOI:10.1080/01448765.1990.9754542

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The relationship between the position of the moon and crop growth is an issue that was viewed as being of great consequence in antiquity but has become controversial or viewed as superstitious in our time. In 1924 Rudolf Steiner, the founder of biodynamic farming, suggested that healthy agriculture should not only consider factors such as crop rotations, sound stocking rates, and organic manuring, but also cosmic factors. Based on his observations he indicated a relationship between the position of the moon relative to the sun (synodic rhythm), planting dates, and crop growth. A number of studies were carried out in the 1930's and 1940's to test this relationship; these studies produced varying results.

ISSN:0144-8765    

DOI:10.1080/01448765.1990.9754543

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

This report of a three-year study of the effects of lunar rhythms on the growth of radish supplements a companion report on rye (Spiess, 1990a). In 1979 and 1980, plantings with radish were carried out on a daily basis over a four-week period in April and May. In 1982, plantings were carried out every second day for an eight-week period from April to June. These field plantings were carried out on a biodynamic farm in randomized, complete-block designs with four replications per planting date. Leaves and roots were harvested when the same constellation in which planting took place had returned. Seeds were harvested when physiologically Nature. Curves fitted from polynomial regressions of yields against seeding dates were used to indicate general trends associated with the dominating primary growth factors such as weather. The magnitudes of effects associated with planting at a specific lunar position were measured by the deviations from the trend curve.

ISSN:0144-8765    

DOI:10.1080/01448765.1990.9754544

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Vesicular-arbuscular mycorrhiza (VAM) can improve phosphorus uptake of wheat plants and may be very effective in agricultural low external input systems, where low concentrations of plant available P are often found in the soil. Levels of VAM-infection were studied in four varieties of winter wheat of different periods of release from 1985 to 1986. These varieties differed greatly concerning rooting patterns and above ground development.

ISSN:0144-8765    

DOI:10.1080/01448765.1990.9754545

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

ISSN:0144-8765    

DOI:10.1080/01448765.1990.9754546

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

ISSN:0144-8765    

DOI:10.1080/01448765.1990.9754547

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

ISSN:0144-8765    

DOI:10.1080/01448765.1990.9754548

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

ISSN:0144-8765    

DOI:10.1080/01448765.1990.9754549

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor