|
|
|
| Registros recuperados: 193 | |
|
| |
|
| |
|
| |
|
| |
|
| |
|
| |
|
| |
|
| |
|
| |
|
| |
|
| |
|
| |
|
| |
|
| |
|
|
| Robinson, A.R.; Lauritzen, C.W.; Muckel, D.C.; Phelan, Jack. |
| An irrigation system should be designed to provide correct distribution, control, and measurement of the irrigation water. Usually a farmer takes his irrigation water from a canal through a headgate. Or he may receive it from a pipeline regulated by a valve, or perhaps from his own well and pump. Open ditches are most commonly used to carry the water to the fields. Water control structures are used to get it out of the ditches and onto the fields. Measurement devices are needed so the farmer can tell how much water he has applied to his field at any irrigation or over the season. Several types of structures are used to divert, convey, control, or measure irrigation water. Some of these are described, and their functions... |
| Tipo: Technical Bulletin |
Palavras-chave: Irrigation control; Research methodology; Mass Import - autoclassified (may be erroneous). |
| Ano: 1963 |
URL: http://eprints.nwisrl.ars.usda.gov/1140/1/7.pdf |
| |
|
| |
|
| |
|
| |
|
|
| Westermann, D.T.. |
| Plant analysis historic beginnings are generally attributed to T. de Saussure (1804) following studies by van Helmont, Joseph Priestly, Henry Cavenish, and Antonine Lavoisier. de Saussure showed that the composition of plant ash varied with the part analyzed, with the age of the plant, and with the soil upon which the plant grew. The ash was chiefly composed of alkalis and phosphates. Erasmus Darwin in his 1800 book, Phytogia: The Philosophy of Agriculture and Gardening (London, J. Johnson) wrote that both nitrogen (N) and phosphorus (P) were essential components of plants. In 1833, the Fifth Duke of Richmond showed that the value of bone meal fertilizing was due to its P component rather than calcium (Ca), although Justus von Liebig (1852) is... |
| Tipo: Book Section |
Palavras-chave: Research methodology; Mass Import - autoclassified (may be erroneous). |
| Ano: 2005 |
URL: http://eprints.nwisrl.ars.usda.gov/738/1/1170.pdf |
| |
|
| |
| Registros recuperados: 193 | |
|
|
|
