Environmental Problems, Their Causes, and Sustainability 1

14 Foodand Soil ResourcesSoilBiodiversityCASE STUDYGrowing Perennial Cropson the Kansas Prairieby Copying NatureThink about farms in Kansas and you probably pictureseemingly endless fields of wheat or corn plowedup and planted each year. By 2040, the picture mightchange, thanks to pioneering research at the nonprofitLand Institute near Salina, Kansas.The institute, headed by plant geneticist WesJackson, is experimenting with an ecological approachto agriculture on the midwestern prairie. It relies onplanting a mixture of different crops in the same area,a technique called polyculture. This involves planting amix of perennial grasses (Figure 14-1, right), legumes(a source of nitrogen fertilizer, Figure 14-1, left), sunflowers,grain crops, and plants that provide naturalinsecticides in the same field.The goal is to raise food by mimicking many ofthe natural conditions of the prairie without losingfertile grassland soil. Institute researchers believe thatperennial polyculture can be blended with modern monocultureto help reduce the latter’s harmful environmentaleffects.Because these plants are perennials, there is noneed to plow up and prepare the soil each year to replantthem. This takes much less labor than conventionalmonoculture or diversified organic farms thatgrow annual crops. It also reduces soil erosion becausethe unplowed soil is not exposed to wind andrain. And it reduces the need for irrigation becausethe deep roots of such perennials retain more waterthan annuals. There is also less pollution from chemicalfertilizers and pesticides. This sounds like a winwinsolution.Thirty-six years of research by the institute haveshown that various mixtures of perennials grown inparts of the midwestern prairie could be used as importantsources of food. One such mix of perennialcrops includes eastern grama grass (a warm-seasongrass that is a relative of corn with three times asmuch protein as corn and twice as much as wheat;Figure 14-1, right), mammoth wildrye (a cool-seasongrass distantly related to rye, wheat, and barley), Illinoisbundleflower (a wild nitrogen-producing legumethat can enrich the soil and whose seeds can serve aslivestock feed; Figure 14-1, left), and Maximilian sunflower(which produces seeds with as much protein assoybeans).This important research may eventually helpus come closer to producing and distributing enoughfood to meet everyone’s basic nutritional needs anddoing this without degrading the soil, water, air,and biodiversity that support all food production.However, this will require more evaluation of thecosts involved and the feasibility of integrating suchpractices into conventional agricultural productionsystems.Figure 14-1 Solutions: The Land Institute in Salina,Kansas, is a farm, a prairie laboratory, and a schooldedicated to changing the way we grow food. It advocatesgrowing a diverse mixture (polyculture) of edibleperennial plants to supplement traditional annualmonoculture crops. Two of these perennial crops areeastern grama grass (bottom) and the Illinois bundleflower(top left).