The hectare is frequently used for area of fields in agriculture. The are either alone or with any other prefix is rarely used. Prefixes less than one seem extremely confusing with the are (much as with the tonne) and IMO should not be used. My recommendation for increasing areas, square meters to 9999 m², then 1 - 99.9 ha, then square kilometers. The two yards (international and survey) differ by only two parts per million. Given that the accepted closure standard for surveys is 1 part in 10000 for urban land, 1 part in 5000 for rural, worry about 2 parts in a million for the yard seems a bit "off." Probably the most common example of easy calculation is 1 mm of rain falling on 1 m² is 1 L. This scales to 10000 L (or 10 m³) on 1 ha. Similarly, a yield of 1 kg/m² or a chemical application of 1 g/m² scales to 10 t/ha or 10 kg/ha, respectively. Try that on square yards and acres, using ounces, pounds, and tons. Still, I don't farm. I believe Jim Frysinger does and may have better examples.
________________________________ From: Natalia Permiakova <[email protected]> To: U.S. Metric Association <[email protected]> Sent: Tuesday, June 25, 2013 7:26 PM Subject: [USMA:52986] Re: Si and Agriculture examples all looks incredibly easy: Comparison of Area units Unit SI 1 ca 1 m2 1 a 100 m2 1 ha 10,000 m2 100 ha 1 km2 (from http://en.wikipedia.org/wiki/Hectare#Are) vs. One acre equals 0.0015625 square miles, 4,840 square yards, 43,560 square feet[1] or about 4,047 square metres (0.405 hectares) (see below). While all modern variants of the acre contain 4,840 square yards, there are alternative definitions of a yard, so the exact size of an acre depends on which yard it is based on. (from http://en.wikipedia.org/wiki/Acre) even converting feet to yards sounds like nightmare to me, not mentioning cups per sq foot to gallons per acre (sorry if it is not useful in agriculture task, i am not an expert in this field ) thanks, Natalie ________________________________ From: "[email protected]" <[email protected]> To: U.S. Metric Association <[email protected]> Sent: Tuesday, June 25, 2013 7:12 PM Subject: [USMA:52985] Si and Agriculture examples Hello Everyone: >I am writing an article about the benefits of using SI units in Agriculture. I need concrete, real world examples of easy calculations such water needed per square meter or any other interesting, persuasive examples. >I know I have seen many examples associated with different topics. >Many thanks, >Bridget
