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Plant health, soil fertility relationships and food quality

Lookup NU author(s): Dr Kirsten BrandtORCiD



Soil quality affects the quality of plant products in terms of soil productivity, which in turn affects the plants’ allocation of nutrients and other resources. This allocation determines which compounds are formed in which tissues, such as protein, starch, secondary metabolites or lignin, and thus the composition of the harvested product. When soil productivity is low, as in subsistence farming or most uncultivated land, the plant’s resources are used for survival and reproduction, resulting in a small yield of material with high biological value. Medium productivity, as is typical of organic farming, induces the plant to increase the allocation of resources to defence mechanisms, it gives a higher yield of material with high amounts of anti-nutrients and higher content of protein, which the anti-nutrients make less available to herbivores such as humans. At even higher soil productivity levels, as in typical conventional farming, the plant growth is not limited by nutrient restriction, and fewer resources are used for defence. The yield reaches a maximum, and the material is easily digestible, but tends to be dominated by storage compounds with relatively low biological value. The value of plant foods for health depends on who the consumer is. For non-ruminant animal production, high productivity gives the most easily digestible feed, while ruminants equally well can use material from less fertile systems. For those human populations where most people have a choice of food available, the plants grown on soil of medium productivity are probably best for health, since their high content of anti-nutrients counteract the harmful consequences of too much and too nutritious food. However, foods grown on land with either low or high productivity provide the most nutrients per kg food, which can be an advantage for populations suffering from shortage in food availability.

Publication metadata

Author(s): Brandt K

Editor(s): Köpke U; Sohn SM

Publication type: Conference Proceedings (inc. Abstract)

Publication status: Published

Conference Name: Organic Agriculture in Asia

Year of Conference: 2008

Date deposited: 30/01/2011

Publisher: International Society of Organic Agriculture Research

Series Title: ISOFAR Conference Series

Sponsor(s): Governor of Gyeonggi Province