Fertilizer trees are used in agroforestry to improve the condition of soils used for farming. As woody legumes, they capture nitrogen from the air and put it in the soil through their roots and falling leaves. [1] They can also bring nutrients from deep in the soil up to the surface for crops with roots that cannot reach that depth. [2] Fertilizer trees are further useful for preventing fertilizer erosion, soil degradation and related desertification, and improving water usage for crops. [1]
Sesbania , Gliricidia , Tephrosia , and Faidherbia albida are known as fertilizer trees. Tree lucerne or tagasaste ( Cytisus proliferus ) is able to fix more than 587 kg. of nitrogen per hectare per year. It can increase maize (corn) yields from 1 ton per hectare per year to more than 10 tons per ha/year in areas with more than 850 mm. of rain per year or a perched water table. Tree lucerne is also used to create and maintain terra preta.
The use of Faidherbia albida in Malawi and Zambia has resulted in a doubling or even tripling of maize yields. [3] As part of evergreen agriculture, use of fertilizer trees is proposed as a means to improve food security. Niger has more than 4.8 million hectares of predominantly Faidherbia agroforests, while Zambia has 300,000 hectares. [3] In Zambia and Malawi, farmers plant the trees in a checkerboard pattern every 30 feet. [4]
Fertilizer trees are used to prevent the expansion of desert, and to keep agriculture viable in arid lands in many African countries. [5]
A fertilizer or fertiliser is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from liming materials or other non-nutrient soil amendments. Many sources of fertilizer exist, both natural and industrially produced. For most modern agricultural practices, fertilization focuses on three main macro nutrients: nitrogen (N), phosphorus (P), and potassium (K) with occasional addition of supplements like rock flour for micronutrients. Farmers apply these fertilizers in a variety of ways: through dry or pelletized or liquid application processes, using large agricultural equipment or hand-tool methods.
Crop rotation is the practice of growing a series of different types of crops in the same area across a sequence of growing seasons. This practice reduces the reliance of crops on one set of nutrients, pest and weed pressure, along with the probability of developing resistant pests and weeds.
The Green Revolution, or the Third Agricultural Revolution, was a period of technology transfer initiatives that saw greatly increased crop yields. These changes in agriculture began in developed countries in the early 20th century and spread globally until the late 1980s. In the late 1960s, farmers began incorporating new technologies such as high-yielding varieties of cereals, particularly dwarf wheat and rice, and the widespread use of chemical fertilizers, pesticides, and controlled irrigation.
Organic farming, also known as ecological farming or biological farming, is an agricultural system that uses fertilizers of organic origin such as compost manure, green manure, and bone meal and places emphasis on techniques such as crop rotation and companion planting. It originated early in the 20th century in reaction to rapidly changing farming practices. Certified organic agriculture accounts for 70 million hectares globally, with over half of that total in Australia. Biological pest control, mixed cropping, and the fostering of insect predators are encouraged. Organic standards are designed to allow the use of naturally-occurring substances while prohibiting or strictly limiting synthetic substances. For instance, naturally-occurring pesticides such as pyrethrin are permitted, while synthetic fertilizers and pesticides are generally prohibited. Synthetic substances that are allowed include, for example, copper sulfate, elemental sulfur, and veterinary drugs. Genetically modified organisms, nanomaterials, human sewage sludge, plant growth regulators, hormones, and antibiotic use in livestock husbandry are prohibited. Organic farming advocates claim advantages in sustainability, openness, self-sufficiency, autonomy and independence, health, food security, and food safety.
Legumes are plants in the family Fabaceae, or the fruit or seeds of such plants. When used as a dry grain for human consumption, the seeds are also called pulses. Legumes are grown agriculturally, primarily for human consumption; for livestock forage and silage; and as soil-enhancing green manure. Well-known legumes include beans, chickpeas, peanuts, lentils, lupins, mesquite, carob, tamarind, alfalfa, and clover. Legumes produce a botanically unique type of fruit – a simple dry fruit that develops from a simple carpel and usually dehisces on two sides.
In agriculture, polyculture is the practice of growing more than one crop species together in the same place at the same time, in contrast to monoculture, which had become the dominant approach in developed countries by 1950. Traditional examples include the intercropping of the Three Sisters, namely maize, beans, and squashes, by indigenous peoples of Central and North America, the rice-fish systems of Asia, and the complex mixed cropping systems of Nigeria.
Vigna subterranea is a member of the family Fabaceae. Its name is derived from the Bambara ethnic group. The plant originated in West Africa. As a food and source of income, the Bambara groundnut is considered to be the third most important leguminous crop in those African countries where it is grown, after peanut and cowpea. The crop is mainly cultivated, sold and processed by women, and is, thus, particularly valuable for female subsistence farmers.
Nutrient management is the science and practice directed to link soil, crop, weather, and hydrologic factors with cultural, irrigation, and soil and water conservation practices to achieve optimal nutrient use efficiency, crop yields, crop quality, and economic returns, while reducing off-site transport of nutrients (fertilizer) that may impact the environment. It involves matching a specific field soil, climate, and crop management conditions to rate, source, timing, and place of nutrient application.
Agroforestry is a land use management system that integrates trees with crops or pasture. It combines agricultural and forestry technologies. As a polyculture system, an agroforestry system can produce timber and wood products, fruits, nuts, other edible plant products, edible mushrooms, medicinal plants, ornamental plants, animals and animal products, and other products from both domesticated and wild species.
Soil conservation is the prevention of loss of the topmost layer of the soil from erosion or prevention of reduced fertility caused by over usage, acidification, salinization or other chemical soil contamination.
In agriculture, a living mulch is a cover crop interplanted or undersown with a main crop, and intended to serve the purposes of a mulch, such as weed suppression and regulation of soil temperature. Living mulches grow for a long time with the main crops, whereas cover crops are incorporated into the soil or killed with herbicides.
Worldwide more human beings gain their livelihood from agriculture than any other endeavor; the majority are self-employed subsistence farmers living in the tropics. While growing food for local consumption is the core of tropical agriculture, cash crops are also included in the definition.
Cytisus proliferus, tagasaste or tree lucerne, is a small spreading evergreen tree that grows 3–4 m (10–13 ft) high. It is a well known fertilizer tree. It is a member of the Fabaceae (pea) family and is indigenous to the dry volcanic slopes of the Canary Islands, but it is now grown in Australia, New Zealand and many other parts of the world as a fodder crop.
Tithonia diversifolia is a species of flowering plant in the family Asteraceae that is commonly known as the tree marigold, Mexican tournesol, Mexican sunflower, Japanese sunflower or Nitobe chrysanthemum. It is native to Mexico and Central America but has a nearly pantropical distribution as an introduced species. Depending on the area they may be either annual or perennial. It has shown great potential in raising the soil fertility in soils depleted in nutrients.
Faidherbia is a genus of leguminous plants containing one species, Faidherbia albida, which was formerly widely included in the genus Acacia as Acacia albida. The species is native to Africa and the Middle East and has also been introduced to Pakistan and India. Common names include apple-ring acacia, white acacia, and winter thorn. The South African name is ana tree.
The main economic products of Malawi are tobacco, tea, cotton, groundnuts, sugar and coffee. These have been among the main cash crops for the last century, but tobacco has become increasingly predominant in the last quarter-century, with a production in 2011 of 175,000 tonnes. Over the last century, tea and groundnuts have increased in relative importance while cotton has decreased. The main food crops are maize, cassava, sweet potatoes, sorghum, bananas, rice, and Irish potatoes and cattle, sheep and goats are raised. The main industries deal with agricultural processing of tobacco, tea and sugar and timber products. The industrial production growth rate is estimated at 10% (2009).
Tephrosia vogelii, the Vogel's tephrosia, fish-poison-bean or Vogel tephrosia (English), tefrósia (Portuguese) or barbasco guineano (Spanish), is a flowering plant species in the genus Tephrosia.
Sesbania rostrata is a small semi-aquatic leguminous tree, in the genus Sesbania. It forms a symbiotic relationship with Gram-negative rhizobia which leads to the formation of nitrogen fixing nodules on both stem and roots. It is mainly used as green manure to improve soil fertility due to its fast growth, high biomass production and ability to convert large amounts of atmospheric nitrogen into a usable form for plants. Other applications include production of high quality forage for livestock and it is a source of fuel-wood.
Sorghum is an important staple crop for more than 500 million people in sub-Saharan Africa and South Asia, including many people in Nepal. In statistics collected from 1992 to 1994 about general millet, Nepal had an area of 0.21 million ha, with a yield rate of 1.14 (t/ha), and produced around 0.24 million tons of sorghum. The entirety of the crop is highly valued, with both the grain and the stem being utilized. The Terai region of Nepal tends to be more tropical which is ideal for the growth of sorghum. It tolerates hot climates better than maize or soybeans. For subsistence farmers, like those in Nepal, fertilizers are not necessary and the crop is frequently harvested by hand.
Chickpeas are a major pulse legume grown in Nepal, either by themselves or as an intercrop with maize or rice. Chickpeas are an important legume to the population, as it is the primary protein source for nearly 2 million Nepalese people. In 2013, Nepal imported approximately US$10.1 million in dried shelled chickpeas, mostly from Australia and also from Canada, creating a need to increase production for its own people and to balance bilateral trade. Chickpeas are an excellent source of protein, especially when compared to other legume pulses. They are high in unsaturated fatty acids and minerals, including calcium, magnesium, phosphorus and potassium.