Saline Agriculture in the 21st Century: Using Salt Contaminated Resources to Cope Food Requirements

With the continue increase of the world population the requirements for food, freshwater, and fuel are bigger every day. This way an urgent necessity to develop, create, and practice a new type of agriculture, which has to be environmentally sustainable and adequate to the soils, is arising. Among the stresses in plant agriculture worldwide, the increase of soil salinity is considered the major stress. This is particularly emerging in developing countries that present the highest population growth rates, and often the high rates of soil degradation. Therefore, salt-tolerant plants provide a sensible alternative for many developing countries. These plants have the capacity to grow using land and water unsuitable for conventional crops producing food, fuel, fodder, fibber, resin, essential oils, and pharmaceutical products. In addition to their production capabilities they can be used simultaneously for landscape reintegration and soil rehabilitation. This review will cover important subjects concerning saline agriculture and the crop potential of halophytes to use salt-contaminated resources to manage food requirements. 1. Human Population Growth and Agriculture Challenges in the 21st Century It is estimated that in November 2011, the mankind has reached the 7 thousand million people, and the United Nations (2008) predicted a population increase up to 8.01 thousand million people in 2025. This represents a duplication of human population in approximately 50 years. So, agriculture strategies for feeding all people represent one of the most important challenges in the 21st century. Therefore, there is enormous demographic and economic pressure to rise, within the next 40 years, leading to an increase of the crop production by about 50% years in a sustainable manner to fulfil the world food necessities [1, 2]. Some other facts are aggravating this demand, namely, (a) the increase of land occupation for biofuel supply that deviates arable soils from food crops [3], (b) the challenges posed by increasing occasional episodes of extreme environmental conditions and even natural disasters often associated with the generally called “climate change events”, (c) some excesses in soil pressure posed by postgreen revolution practices; (d) the raise of soil degradation and/or the increase of saline soils is growing dramatically, reducing the area of arable land. The duality faced by mankind concerning food supply was summarized by Rudel [4] stating “our ability to supply the growing global demand for food, fiber, and fuel, while maintaining a landscape able to provide