ISSN:0010-3624    

DOI:10.1080/00103629409368997

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Conventional agriculture appears to be decreasing in energy efficiency and has some adverse effects on the environment. Therefore, the marriage of agriculture and ecology is welcome, but the debate on how to achieve goals for sustainability is far from concluded. The most important aspect of sustainability is creating systems that have an indefinite future. This point is too often ignored. A number of “terrible” questions can be asked about sustainability. A list of 24 ingredients required for a sustainable agriculture is given. We want sustainable agriculture to be scientific, safe and sensible. People won't stop eating if the agriculture is not sustainable, but someday there may be little to eat unless sustainability is seriously addressed.

ISSN:0010-3624    

DOI:10.1080/00103629409368998

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

ISSN:0010-3624    

DOI:10.1080/00103629409368996

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Fifty per cent, more or less, of the soil organic matter from farm lands has been lost. The remainder is perhaps more resistant to loss and therefore is stable but that which has been lost was perhaps the most important half‐it resisted erosion, it made soils permeable, it increased water‐holding capacity and it produced healthy crops. The 50 per cent that has been lost is via two major mechanisms. One is loss per unit weight of soil by decomposition (mineralization) induced by cultivation, and the other is loss by erosion—loss by wash away and blow away of the surface soil which contains the most soil organic matter. Both mineralization and erosion are downhill processes. If they are not in equilibrium with reverse processes, the land cannot be sustainable. If agriculture is to be sustainable, we have to look at soil organic matter, first and foremost, as a means for maintaining stable‐tillable soil. Mining of soil for nutrients and letting soil organic matter levels decrease can never result in sustainable agriculture. The role of soil organic matter as a source of nitrogen and other nutrients is less important than that of providing excellent physical and biological properties of soil. Use of water‐soluble polymer soil conditioners can help.

ISSN:0010-3624    

DOI:10.1080/00103629409368999

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Burning of fossil fuels globally helps put 3 billion metric tons of carbon into the atmosphere per year more than is removed by all carbon sinks. By far the best use of that carbon would be to arrange sufficient extra plant growth and then transfer that plant growth into new stable soil organic matter. Twenty or more years of such effort would immensely improve the soils of the world. Any fraction of it would help decrease the threat of global greenhouse warming. A great worldwide goal should be to increase levels of soil organic matter levels considerably. It should be possible. The most important research relating to soil organic matter is perhaps yet to be done. Elucidation of the regulators involved in the build‐up and decomposition processes of various types of soil organic matter deserves high priority. It should be possible to develop technologies where the regulators can be managed and controlled for the beneficial purpose of increasing levels of soil organic matter. The role of calcium in stabilizing soil organic matter needs more study. Genetic engineering of specific microorganisms may be needed to increase levels of soil organic matter.

ISSN:0010-3624    

DOI:10.1080/00103629409369000

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

To avert global greenhouse warming, it is necessary to either reduce emissions of the gases which cause it and/or sequester the gases that have already accumulated in the atmosphere. By far the most important gas involved is carbon dioxide. Two major strategies to reduce emissions of carbon dioxide and five for sequestering the carbon to remove it from the active carbon cycle are discussed. There can be several more. Nine techniques are discussed to help add carbon to soil organic matter. If each of several different strategies can mitigate 5 to 10 or more percent of the problem, the problem will become small. One of the best strategies to sequester the carbon is as soil organic matter.

ISSN:0010-3624    

DOI:10.1080/00103629409369001

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

High‐precision agriculture can minimize unwanted accumulation or migration of input residues, can save money, and can avoid interactions which would decrease yields. High precision has meanings beyond the quantity of an input. It includes correct placement in the soil or on or in the plant, it includes timing of the input, it includes relationships with other inputs to create proper balances, it includes correctly leveling, draining and contouring the land, and much more. High precision directly and indirectly has or can have beneficial effects on the environment. High‐precision agriculture can make it possible to produce necessary food and fiber on much less land than is currently being used. High precision is a procedure to give maximum economic yields.

ISSN:0010-3624    

DOI:10.1080/00103629409369002

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

It is generally believed that if the foliage of plants is visibly green, iron‐deficiency problems do not exist. There are at least five conditions under which plants may respond to iron even when green: (1) If the soil solution or irrigation water contain more than 1 or 2 me/L bicarbonate, (2) If leaf concentrations of iron are below between 40 to 70 mg/kg dry weight, (3) In the new leaf growth of most trees and vines, (4) During the first one of more days in the life of a seedling, and (5) When crops are pushed to very high yields. SPAD leaf color readings or chlorophyll analyses may detect some of the possibilities. The Sufficiency Values for iron have to be less than the maximum of 1.00 in order for these iron responses to occur. Considerable programs in plant breeding and genetics are being conducted to improve the efficiency of plants for iron nutrition, but these efforts will mostly insure that iron is not a severe Liebig type limiting factor. Many or most of the physiology which relates to the five factors above, even with iron‐efficient cultivars, will continue to result in slight Mitscherlich type limiting factors that involve iron. Avoidance of environmental mismanagement will continue to be a major factor in preventing iron deficiency. Sustainable practices help avoid iron deficiency.

ISSN:0010-3624    

DOI:10.1080/00103629409369003

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Sustainable, environmentally safe, and profitable agriculture of the future will require a new generation of diagnostic laboratories capable of extreme precision in a very complicated regulated world. Analyses are only part of what is needed; the meanings of the numbers must be determined in terms of categories of disciplines and philosophies and, then, wise decisions need be made. Laboratories must participate at all levels of decision making.

ISSN:0010-3624    

DOI:10.1080/00103629409369004

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Experts believe that it will be necessary to produce grain for a total of eight billion persons before world population becomes stabilized. This is thought to be exceedingly difficult for environmental reasons and on a sustainable basis. Sound procedures are suggested to work towards such a goal. Perhaps the best way to produce that much grain is to increase the price of it sufficiently so that farmers can use high‐precision technologies that are sustainable. The needed grain will then be produced.

ISSN:0010-3624    

DOI:10.1080/00103629409369005

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor