CLIMATE AND CLASSIC LANDSCAPE PROFILES
Humid, arid and continental climates
Volcanic, islands high and low, coasts, flatlands, wetlands. Arid, dunes, basement and erg
Climate Differences
As a designer we must have a very clear understanding of exactly which climate we are working in, and the possible fluctuations within that climate zone.
Three basic divisions: Cold/hot/dry or Temperate/tropical/Arid, plus continental climate, which is a long way inland.
Temperate has wet winters and dry summers, topsoil is usually deep and contains nutrients and elements, and cultivation is cautiously possible on contour in small area fields. Mulch naturally develops with the yearly flush annual herbs and deciduous tree leaves adding to the soil ever autumn. Small areas should be mulched, larger areas cut/grazed in cycles. The amount of humus in the soil determines the fertility. Fields need to be small with deep-rooted deciduous trees to ensure nutrient cycling plus new nutrient deposits. The best strategy for cropping is no tillage systems of overlapping crops winter to summer, each crop mulched by the previous crop residue. Winter is often a dormant period with little if any growth and sterilization of the soil. The spring breaks into a great flush of herbaceous growth, which makes up most of the summer fresh cut mulch with the previous autumns composted leaf fall. At the extremes of the main temperate climate zones of Earth we have the Sub-Arctic with permafrost, through to cold temperate, cool temperate, warm temperate what is called a Mediterranean climate.
Tropical zones have wet summers and dry winters. The topsoil’s are usually thin and most nutrients 80-90% held in suspension above the soil in life systems mainly plants. Plow agriculture is a disaster and usually a quick failure. Very little mulch develops under the forest, as decomposition is continuous and fungi action rapid. Biomass (plant and animal mass) is crucial to stability of landscape and fertility of soils. Bare soil leads to the development of caliches, concrete-like layers below the soil and severe erosion results with heavy tropical rains. Nitrogenous ground covers are an essential precursor to agriculture summer ground covers and winter ground covers until nitrogenous pioneer tree cover is established and is shading the majority of the soil. Eventually establishing 4-6 large long-lived uncut leguminous trees to the acre, the smaller nitrogenous trees then being pollarded for continuous branch, twig, leaf and seed pod mulch to the soil, as an in crop nutrient recycling strategy. It is essential to cut the woody mulch required in the tropics starting at the beginning of the wet season in summer and stopping well before end of summer. The re-growth of the pollarded tree inter crop provides essential partial shade for the dry season crops when water stress is at the highest. Dry periods and water competition during establishment may be solved by the use of drip irrigation, and selective small animal grazing in advanced tree crops. It is essential to incorporate as much tree crop as possible; otherwise aquaculture and paddy crop where nutrients are bound up in algae and mud. At the extremes of the tropics we have the sub-tropics through to dry tropics (which are part the arid zone), wet-dry tropics and the equatorial wet tropics.
Arid zones have much greater annual evaporation rate than rainfall, the rains come in just a few quick large intense events usually in mid winter. Soils usually contain plenty of nutrients but need humus and water to be released. The concentration must be on increasing soil life cycles with plants cycles that decrease evaporation through shade, wind buffering and mulch additions which in turn increases the efficiency of the water cycles as all these are crucial for establishment in an arid environment. Desert strategies primarily are all about reducing evaporation, which means they are water-connected. Great attention and detail must be paid to wastewater in mulched home gardens, flood flow during the few large yearly events and runoff from all hard surfaces natural or manmade. Deep rooted pioneer trees need mulch and drip irrigation in establishment for shading, wind buffering leading to mulch production when established that can be can and added to for crops and fruit trees. At the first rains of winter most tree mulch is cut allowing plenty of time for re-growth for summer shaded. Summer is the slow period of the year where often heat and water stress are extreme. Fertilizer additions are mainly made during the winter months in milder time of year.
The major arid zone deserts of Earth are in the sub-tropics at the extreme end of the path of the vertical sun, the Tropic of Capricorn at latitude 23 south and Tropic of Cancer at latitude 23 north. There are cold and hot arid zone occurring at high altitudes through to lowest landscapes on Earth at 400 meters below sea level.
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