The Law of Maximum also known as Law of the Maximum is a principle developed by Arthur Wallace which states that total growth of a crop or a plant is proportional to about 70 growth factors. Growth will not be greater than the aggregate values of the growth factors. Without the correction of the limiting growth factors, nutrients, waters and other inputs are not fully or judicially used resulting in wasted resources. [1] [2] [3]
The factors range from 0 for no growth to 1 for maximum growth. Actual growth is calculated by the total multiplication of each growth factor. For example, if three factors had a value of 0.5, the actual growth would be:
If each of the three factors had a value of 0.9 the actual growth would be:
Hence the need to achieve maximal value for each factor is critical in order to obtain maximal growth.
The following demonstrates the Law of the Maximum. For the various crops listed below, one, two or three factors were limiting while all the other factors were 1. When two or three factors were simultaneously limiting, predicted growth of the two or three factors was similar to the actual growth when the two or three factors were limits individually and then multiplied together.
Percent of Optimum growth (Measured growth) | predicted growth (calculated growth) | |
---|---|---|
Soybeans | ||
Low phosphorus | 83% | |
Low nitrogen | 71% | |
Both low phosphorus | actual result 57% | 59% (83% x 71%) |
and low nitrogen | ||
Wheat | ||
Low moisture | 66% | |
Low nitrogen | 27% | |
Both low moisture | actual 18% | 18% (66% x 27%) |
and low nitrogen | ||
Bush beans | ||
Nickel addition | 42% | |
Copper addition | 71% | |
Vanadium addition | 39% | |
All 3 metals | actual 10% | 11% (42% x 70% x 39%) |
Tomato | ||
Presence of insects | 37% | |
Nutrient deficiencies | 78% | |
Both presence of insects and nutrient deficiencies | actual 29% | 29% (37% x 78%) |
Tomato – poor physical soil conditions | ||
Correction with organic matter | 43% | |
Correction with P.A.M. | 82% | |
No corrections | 33% | 18% (66% x 27%) |
Corrections with both organic matter and P.A.M. | 100% |
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Hydroponics is a type of horticulture and a subset of hydroculture which involves growing plants, usually crops or medicinal plants, without soil, by using water-based mineral nutrient solutions in an artificial environment. Terrestrial or aquatic plants may grow freely with their roots exposed to the nutritious liquid or the roots may be mechanically supported by an inert medium such as perlite, gravel, or other substrates.
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The Three Sisters are the three main agricultural crops of various indigenous peoples of Central and North America: squash, maize ("corn"), and climbing beans. In a technique known as companion planting, the maize and beans are often planted together in mounds formed by hilling soil around the base of the plants each year; squash is typically planted between the mounds. The cornstalk serves as a trellis for climbing beans, the beans fix nitrogen in their root nodules and stabilize the maize in high winds, and the wide leaves of the squash plant shade the ground, keeping the soil moist and helping prevent the establishment of weeds.
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Arthur Wallace, was a soil scientist.
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