Big Picture Agriculture

It wasn’t until motorized pumps powered by fossil fuels were used to irrigate from underground water sources, that aquifers and groundwater sources could be pumped beyond natural replenishment rates. This has led to unsustainable drops in aquifer levels in India, China, and the U.S.

But, there are simple, nonmotorized methods to pump water from underground sustainably that are immensely valuable to small farmers in undeveloped regions of the world.

Treadle pumps: Bamboo (or metal) treadle water pumps have enabled poor farmers in places like Bangladesh to access groundwater during the dry season. Treadle pumps draw groundwater to the surface using a manually powered suction system. They can be made locally and there have been programs to supply them in certain areas. Today, there are more than two million of these that have been distributed world wide. They can be used to fill containers used for micro-irrigation or bucket drip irrigation systems. These are viewed as a stepping stone between hand lifting water and obtaining motorized pumps.

Hip Pumps: According to KickStart, this $30 pump which began selling in 2008 can irrigate an acre or more. It can pull water from 7 meters and push water an additional 14 meters above the pump. These micro-irrigation pumps are available in Africa, Asia, and Latin America.

Solar Pumps: Solar and wind energy can be used to power pumps for irrigation as can small biomass plants, and micro-hydroelectric plants.

Motorized Pumps: China has been exporting around four million pumps annually, after decreasing the weight and the cost of small irrigation pumps. Now, more than 60 percent of India’s irrigation is being done by smallholder farmers pumping groundwater.

The plastic netting is a coarse woven mesh, used to shade fruit trees. It is inexpensive and readily available. Various collection methods can be constructed, to fit the specific setting.

In addition to gaining potable water for drinking, collecting water from fog can be used for agriculture and starting trees for reforestation, too. Nets have been used to provide direct irrigation to quinoa in South America.

The areas with the best climatic and geographic conditions for collecting seasonal fog include some mountainous areas, the Atlantic coast of southern Africa and South Africa, Oman, Sri Lanka, China, Nepal, Mexico, Kenya, Morocco, Yemen, Guatemala, Chile, Peru, and Ecuador. In Chile, this method has been used for over 30 years.

In deficit irrigation, the goal is to obtain maximum crop water productivity rather than maximum yield. By irrigating less than a crop’s optimal full requirement, you might reduce the yield by 10%, but save 50% of the water. With supplemental irrigation to rainfed crops in dry lands, a little irrigation is selectively applied during rainfall shortages and during the drought-sensitive growth stages of a crop. (These important stages are the vegetative stages and the late ripening period.)

The end goal is to maximize irrigation water productivity, even if it means some loss of production. As a success story example, results from using deficit irrigation have been quite dramatic for wheat production in Turkey.

This fungus increases the drought tolerance of plants and can reduce water needs by 25 percent. It increases the fruit and flowering of plants while reducing the need for water and fertilizer. It also enables plants to grow in salty or contaminated soils and increases the temperature stress tolerance for plants. It helps protect plants from disease, and helps store carbon in the soil. Mycorrhiza has the potential to bring poor and degraded lands back into cultivation.

It is possible to encourage mycorrhiza growth in soils by adding compost to your garden soil, by not using synthetic chemicals, using minimum tillage, rotating crops, and growing cover crops. By cold composting, or mulching your garden with shredded leaves each fall, you can promote optimal Mycorrhizal fungi growth. Or, it can be purchased and added directly to sterile potting soils, or degraded soil.

Traditional rice varieties tend to have lower yields and longer crop cycles but they require less fertilizer, use less expensive seeds, and are preferred by consumers, bringing a higher price. Because of higher input costs and lower market values for high-yield rice varieties, farmers often opt to plant traditional rice varieties instead.

Ecologists have labeled five categories of rice plants according to water needs as being rainfed lowland, deep water, tidal wetland, rainfed upland and irrigated rice. Researchers have been investigating improved ways of growing rice with less inputs and/or water.

Below, are some ways found to reduce water use in rice growing.

1. System of Rice Intensification (SRI) (See #5 in this series.)

2. Alternate Wetting and Drying [AWD] lets fields fall dry for a number of days before re-irrigating them, which can maintain yields with 15 to 30 percent of water savings. In Bangladesh, the AWD technique reduced water consumption by 30 to 50 percent.

3. Aerobic Rice is grown in water-scarce regions, without ponded water and saturated soil. It uses 50 percent less water, and produces 20-30 percent less yield. These are high-yielding varieties that grow under non-flooded conditions in non-puddled, unsaturated (aerobic) soil. They rely on irrigation water, greater fertilizer application, and greater use of pesticides. The shorter growth cycle of these varieties enables farmers to grow other crops (rice or other plants) after the rice crop is harvested.

4. New varieties like short-season rice significantly reduce water use. Rice produced 40 to 45 years ago required 160 days from seed to harvest, compared to 135 days for short-season varieties which has reduced the amount of water needed by about 20 percent over the last 30 years.

5. Pioneered by China, hybrid rice – a cross-bred robust variety – has increased land and yield productivity while reducing water use. It is taking China about 1,750 liters of water to produce 1 kilogram of rice as compared to 3,500 liters in India.

6. Genetic modification might be able to improve water efficiency of rice by another 30 to 40 percent.

7. Good land management, using laser leveling of compact soil fields with channels and dikes helps save water in California.

8. In Australia, rice grown with saturated soil culture used 32 percent less irrigation water than conventional methods in wet and dry seasons.

9. ACIAR is supporting trials of permanent raised beds in mixed cropping systems (rice–wheat and other combinations) in India, Pakistan and China.

10. About 13 percent of global rice area is dryland rice. Yields are quite low and it is mostly grown for subsistence. In Southeast Asia, most dryland rice is grown on rolling or mountainous land. Some newer rainfed rice varieties can achieve yields close to those of irrigated fields, however.

11. A newer variety of flood tolerant rice has also been shown to withstand drought better. About 8 percent of the world’s rice is classified as flood prone.

Some of the above methods also reduce methane emissions from rice growing, significantly.

Finally, to achieve more ‘crop per drop,’ wheat and crops that do not grow in flooded areas have the potential to produce food with less water. A rice field takes 2 to 3 times more water than a wheat or corn field. So, it is possible that in the future wheat might supply a growing share of the world’s staple grain.

By monitoring soil moisture conditions, yield increases can be dramatic through careful water applications during the most critical plant growth stages.

By watering less, plant roots grow deeper and there is less disease.

Moisture sensors can be used for commodity crop farming, vegetable farming, or orchards.

The probes are made up of multiple soil moisture sensors. They range in price, with the higher priced models generally more accurate.

Some center pivot irrigation systems combine soil moisture sensors with a computer that controls the operation of the pivot.

The University of Nebraska now provides a Crop Water App for the iPhone and iPad based on Watermark sensors from IRROMETER® which are installed at depths of 1, 2 and 3 feet.

Soil compaction reduces the amount of pore space in soils and results in soil that will not drain quickly. This affects plant growth because plant roots require air. Most plants cannot survive for too long under water or in damp soils. Poor drainage causes diseases and root rot. It not only affects the returns to the producer but also can result in increased runoff during heavy rainfall events, therefore increasing water erosion.

When trying to improve damaged land that is saline or waterlogged, moving soil, installing drainage pipes, and mulching can help. Other methods of improving drainage include good crop rotation practices, adding manure and compost to improve macropores in the soil, and reduced tillage.

Chinampas: This farming system is thousands of years old from the Aztecs of Mexico’s lake country. Chinampas are long narrow patches of ground, called “floating gardens”, bordered by canals on each side. Approximately 98 feet by 8 feet (30 meters by 2.5 meters), they are man-made by building up earth during canal excavation through stacking alternate layers of canal muck and rotting vegetation.

One system of agroforestry mixes livestock with trees and forage. The animals benefit from shade and the trees can provide nuts or timber or fruit.

Intercropping with trees can produce honey, fruits, nuts, maple syrup, medicinal plants such as ginseng, and mushrooms.

As field windbreaks, trees help to control wind erosion, provide wildlife habitat, control soil erosion, and protect livestock.

Although not meant to produce a large amount of a single crop, these systems can provide good yields with a variety of outputs. By mixing trees, shrubs and seasonal crops there is more resilience to insects, diseases, drought, and wind damage.

When processed food gets thrown away, all of the water, energy, and labor used to process, transport, refrigerate, and distribute that food was wasted. When fresh produce or meat is thrown away, everything that went into the production and cooking of those foods was wasted.

Some waste in a food system is normal, and it can be put to good use as compost to create rich soils for growing next year’s food. It would be great if all food that is not consumed could be recycled into compost. The “huge” problem of obesity results in the squandering of both food and health.

In the developing world, small, local storage silos can greatly reduce rot, waste, and rodent damage to crops. Refrigeration, improved communication, and distribution infrastructure advancements will also help.

We must embrace smart practices and have government regulations in place that protect our water from becoming contaminated. Agriculture is guilty of water contamination from unsustainable land overuse practices that result in the runoff of fertilizers, manure, pesticides, soil, and herbicides.

Industrial agriculture runoff has contributed to the Dead Zones in various coastal locations around the world. Here in the U.S., our Dead Zone is located in the Gulf of Mexico and is a hypoxic water area the size of New Jersey. It results from agricultural and municipal waste runoff that funnels into the Mississippi River.

Overuse of nitrogen fertilizer has contaminated large amounts of ground water in regions such as Minnesota, where industrial agriculture is practiced. This has resulted in the loss of safe drinking water from underground wells for the families who live in these areas.

Poor farming practices that lead to soil erosion and harmful chemical runoffs not only degrade the land, but contaminate streams, lakes, and rivers. By nurturing wetlands, keeping waterways natural with buffered areas, incorporating grassy and woody buffer strips into farmed land, and building terraces or contours on slopes, farmers can help to keep their local water clean. By using methods which keep soil healthy — including organic farming, minimum tillage, rotational grazing, and crop rotations — soil absorbs and keeps water pure.