The concept of sustainable agriculture has received increasing amounts of attention in recent years; there is wide spread realization that much of modern agriculture has become an extractive process with production being taken at the expense of losses in soil health and increasing amounts of inputs from outside the system. Loss of soil organic content and soil erosion are common on most of our cultivated land and these degraded soils require ever greater quantities of fertilizer, energy and irrigation to maintain good production. There are a number of factors contributing to the loss of soil health but one of the prime culprits is that animals have been removed from the farm. A farm without animals loses the manure that for centuries has been the basis of soil health – the manure is now generated at feedlots and confinement housing where it becomes a waste product with a disposal cost. Without animals to convert crop residues into food for soil life and give value to pasture and cover crops, the loss of soil organic matter and the soil life that this material sustains increases with each passing year. The movement of animals off of the farm was done in the name of efficiency of production and while a farmer can sell more bushels of grain off of a farm than when much of a farms production of grain, hay and pasture was sold through animals, it is debatable as to whether the farmer is better off under the new system. Aside from soil health, cropping without animals increases both financial and ecological risk. Having several different crops to sell increases financial stability – if all you sell is corn, a cheap corn market hurts. If you have several crops plus livestock both bad weather and bad markets have much less impact on the farm as a whole. One of the most successful farming programs ever devised is the Argentinean system of grazing high legume content pasture for four to six years before plowing the forage down and cropping the area for two years before seeding it back to pasture. This program requires a minimum of outside inputs – weeds, insect pests and diseases of both crops and pasture are greatly reduced and little or no fertilizer is required. For many years this program has been very profitable even though cattle prices were very low compared to those in the US and prices for most inputs like machinery, fuel and fertilizer were much higher. Argentinean beef – almost all totally grass fed – was widely regarded as some of the finest in the world. Lately the Argentinean government – with help from the US State Department (egged on by US chemical companies) has pressured Argentinean ranchers to move toward continuous row crop – they want grain to export.Results have not been good – beef a staple of the Argentinean diet has shot up in price and once profitable ranches are losing money due to high input costs and reduced yields. What is happening now in the pampas of Argentina has already occurred to most agricultural soils.Most agricultural land in the world is degraded; without large infusions of outside inputs yields are low, the nutritional content of the food produced is poor and both floods and droughts are more prevalent since low organic content soils are unable to take in and store large amounts of water.
There is a feasible way to reverse all of these maladies – planned high stock density grazing. When grazing animals are concentrated on an area of forage (works best with a dense stand) that is in advanced growth stage II (boot stage or beyond) for a short period of time and then moved (not to return until the forage has completely recovered) to fresh pasture leaving at least fifty to sixty percent of the forage behind some very good things happen. The animals do very well – they are constantly moving to fresh pasture with a lot of forage on offer and can select their diet. Forage growth increases dramatically due to soil improvement and to the large amount of functioning leaf left on the plants.The soil surface is covered with a mulch of trampled forage and manure which creates an ideal habitat for micro life from bacteria and fungi to earth worms and dung beetles ; it is this micro life that does the heavy lifting of soil formation. Moisture is conserved by the insulation effect of the mulch and by the fact that the decomposition of the mulch increases carbon dioxide levels in the plant canopy so that plants lose less water to transpiration as they can keep the stomata where they take in CO2 open for shorter periods of time. In an, at first, seemingly illogical act, grazed forage pumps root exudates (mostly carbohydrates) out into the area around their feeder roots; this feast of sugars and starches brings about an explosion of bacteria which causes the populations of predator microbes to increase greatly. As the predators consume the bacteria they take in more protein than they need and excrete the excess nitrogen (in a plant usable form) out right where the plant that contributed the carbohydrates can grab it to produce new growth. All of this activity (the life and death of billions of organisms) plus the root growth of properly grazed forage swards creates the fertile and biological active top soil that is the real solution to sustainable, productive and profitable agriculture. This is not just theory; good graziers all over the world are creating top soil at a rapid rate. Sustainable agriculture is a step up but what is truly needed is the wide spread practice of regenerative agriculture.