Atmospheric sciences and radiant energy. In contrast to meteorology, which studies short term weather systems lasting up to a few weeks, climatology studies the frequency and trends of those systems. It studies the periodicity of weather events over years to millennia, as well as changes in long-term average weather patterns, in relation to atmospheric conditions. Climatologists, those who practice climatology, study both the nature of climates – local, regional or global – and the natural or human-induced factors that cause climates to change. Climatology considers the past and can help predict future climate change. Phenomena of climatological interest include the atmospheric boundary
Long-term experiment environment. The Haughley Experiment was noteworthy as a rare example of a long-term experiment in organic farming without external inputs of nutrients. After about 30 years, however, it was decided to start importing manure. There is some disagreement whether a "decline in relative yields from the organic section" was due to a depletion of soil nutrients. Various short-term experiments have used legumes (in symbiosis with nitrogen-fixing rhizobia) as a nitrogen source, but good short-term yields do not prove the system is sustainable. The problem is that release of nitrogen from soil organic matter can make up any shortfall of nitrogen