Abstract: The term ecological balance or its equivalents may not exist in many biolo-gical and ecological books and dictionaries, but their pages are full of treatments on energy flow, nutrient cycling, trophic levels, biotic potential and environmental resistance, balances between vegetation, herbivores and carnivores, and between competing species,etc. This signifies what is important is not the term, but investigations with the concept in mind on the processes at work in ecosystems. As most of the processes are governed by the law of conservation of energy and matter, serious studies are more often than not characterized by quantification on a sound observational and experimental basis. As an example, the CO₂ transfer between the atmosphere and terrestrial ecosystem is discussed in brief.The most important measure for this purpose is the net ecosystem production of carbon=net primary production minus heterotrophic respiration, a figure varies widely with a host of factors. The scarcity of data can hardly bring out a global picture. In recent publications in China, one ton of CO₂ per hectare per day has repeatedly been quoted as a representative estimate of absorption of broad leaved forests during the growing season. In the light of present knowledge of carbon cycle, the acceptance of this would lead one to go amis. A fashionable term and superficial talk are of little use to problem solution. Much of geographic research in China should be focussed on agricultural problems. The notions of ecological balance and ecosystem are in close connection with this pursuit and should help geographers to correlate and coordinate various components and processes of the agricultural industry. Also in vogue are such terms as utilization and conservation of natural resources,environment protection, environmental system, physical planning, etc. In conceptual framework, they are not synonymous and investigations are differently oriented. But there is no great difference in the majority of information to be acquired. A cursory survey of geographic publications-since the latter half of the nineteenth century will not fail to find these concepts at least in their rude form, although geographers have contributed not much in their elaboration. In the geographic studies of agriculture, we have to learn from neighbouring sciences,weld together the foremention-ed concepts and broaden our scope to include physical, biological, economic, social and environmental implications. Our work should provide answers to two questions. (1) for any piece of land, which use or uses would offer the greatest advantages? and (2) for any use or uses of a piece of land, how can the potential productivity be retained or improved?