摘要:

On the basis of what is known from the literature an attempt has been made to estimate the yields in an agricultural system that is supplied with nitrogen from natural sources. For this purpose a model of Dutch agriculture is developed in which only nitrogen is considered as a variable and all other production factors (like phosphate, potassium, water, plant variety, and the skills of the farmer) are considered to contribute to productivity in their usual manner.

ISSN:0144-8765    

DOI:10.1080/01448765.1987.9755103

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

In a four-month investigation of litter fall and its decay as well as soil respiration underChromolaena odoratacanopy, 1970 kg ha−1of dry matter were collected. There was a significant negative correlation (r = −0.62; P< 0.01) between litter fall and atmospheric relative humidity. Of the 43.9% of the litter degraded from litter bags, 35.7% of it was lost in the first month. A significant correlation (r = 0.93; P<0.01) between CO2evolution from the vegetation floor and litter degradation was obtained.

ISSN:0144-8765    

DOI:10.1080/01448765.1987.9755104

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The rates of decomposition of litter from five plant species common to West Africa namely:Chromolaena odorata(Siam weed),Anacardium occidentale(cashew),Acioa batteri, Imperata cylindrica(spear grass) andPentaclethra macrophylla(oil bean) were investigated in the laboratory and the field during the dry season using respiration and litter bag techniques.

ISSN:0144-8765    

DOI:10.1080/01448765.1987.9755105

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A field trial was carried out to compare the performance of three species of overwintering leguminous green manure crops with a fallow. White clover produced the greatest amounts of nitrogen (45–60 kg/ha). Subterranean clover produced the greatest amount of dry matter (1600 kg/ha). Trefoil had the deepest root system but did not nodulate. The concentrations of soil nitrate were significantly higher under the white clover sward than under the other legume and fallow swards.

ISSN:0144-8765    

DOI:10.1080/01448765.1987.9755106

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Unfinished composts prepared from peat, fish scrap, crab scrap and seaweeds were found by tissue-culture tests to contain some toxic components present or formed in starting materials. However, no toxins tested were present in the mature composts. The data thus revealed the usefulness of the tests, and high hygienic quality of the composts.

ISSN:0144-8765    

DOI:10.1080/01448765.1987.9755107

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

ISSN:0144-8765    

DOI:10.1080/01448765.1987.9755108

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

ISSN:0144-8765    

DOI:10.1080/01448765.1987.9755109

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

ISSN:0144-8765    

DOI:10.1080/01448765.1987.9755110

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

ISSN:0144-8765    

DOI:10.1080/01448765.1987.9755102

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor