RES 061 Draft 01 2010-2012 - Laserfiche WebLink

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Physical Resources The archipelago of Hawaii is the most remote land on earth—more isolated from any continental landmass than any other island chain. This isolation has figured prominently in its ecology, settlement, and the development of the people and economy of this place. Three key components for agriculture production include land, climate, and water. Each component is discussed briefly in the following sections. Land and Soils Hawaii Island consists of four volcanic mountains extending from the Pacific Basin to heights approaching 14,000 feet above sea level. Three of the four volcanic peaks are considered to be active, with eruptions within the past two centuries; one has been continuously erupting for the past 25 years. This volcanic origin creates the geologically young nature of the island. The island, approximately 2,500 miles from the nearest part of the continental United States contains approximately 4,028 square miles of land and is growing constantly in response to new volcanic activity. For comparison purposes, it approximates the size of Connecticut in land area. Falling below the Tropic of Capricorn, Hawaii Island's native vegetation and soils are similar to other tropical regions of the earth. The volcanic origin results in shallow to non-existent soils in some areas (notably the Kona Coffee Belt), contrasted with areas of volcanic cinder or ash deposits resulting in deep and well -textured mineral soils in Kohala and the Hamakua regions, among others. As is true for most tropical soils, the soils of Hawaii Island tend to be under- developed and highly oxidized with minimal organic material. The combination of soil chemistry and temperature/moisture regimes ideal for microbial activity result in the rapid oxidation of any organic soil nutrients, with the result that most organic materials on a given site will be contained in living tissue. This is in sharp contrast to the highly productive soils of the great plains of the Continental United States and Canada, where colder temperatures and variable moisture result in a soil matrix with most organic matter on a specific site contained in the deep loam soils and available for plant growth during the growing season. Large scale continuous cropping and burning of sugar cane over the past century has not increased the carbon reservoirs or nutrient availability in those soils, nor has conversion to eucalyptus groves. Tropical soils are normally considered low in nutrients, quickly depleted under continuous cropping, and highly susceptible to rapid erosion from tropical rainfall events if plant cover is removed. Hawai`i's soils share these characteristics and limitations with tropical regions around the world. Climate Steep and varied mountainous terrain deflects the trade winds in unique patterns that result in 11 of the 13 recognized terrestrial ecosystem types on the earth being present. These variable climates with varying elevation and exposure create virtually unlimited potential for crops or livestock. Unfortunately, they also provide perfect conditions for the establishment of invasive species and pathogens as described later. The prevailing trade winds and the surrounding Pacific Ocean, as well as the location on the northern boundary of the tropical zone, provide the island with moderate weather and 7