Sunday, 13 July 2008

Organic agriculture is not enough: we must replace annual with perennial crops

by Dr. Stan Cox from Institute of Science in Society Humans now directly manage 27 percent of the Earth's surface area, harvesting more than 40 percent of the planet's biological productivity for our own uses. Yet food production per person is on the decline, and agriculture worldwide is doing more than ever to worsen the global ecological crisis. Like the Hindu god Shiva, today's agriculture is both a creator and a destroyer, partly as the consequence of conscious decisions taken by farmers, agribusiness executives, government officials, and food buyers. But the productivity and ecological impact of agriculture are also inherent in the crops and cropping methods that humans have relied upon for 10 000 years. The problem of agriculture Since its inception, agriculture has relied on annual plants that are grown from seed every year and harvested for their seed. That requires tilling of the soil, which can be done on a small scale without causing great harm, as in small, intensively hand-managed plots or on annually flooded land along a river. But every civilization that has practised tillage on a large scale has suffered the often catastrophic consequences of soil erosion. Industrialization has compounded the problem through burning fossil fuels and chemical contamination. The world's natural landscapes are covered mostly by perennial plants growing in mixed stands, whereas more than two-thirds of global cropland is sown to monocultures of annual crops. Conversion from natural to agricultural landscapes dramatically alters ecological conditions. Across the planet, more land has been converted from perennial to annual cover since 1950 than in the previous 150 years. This recent expansion of cropland has made it more and more necessary to apply chemical fertilizers and pesticides, which disrupt natural nutrient cycles and erode biodiversity. Perennial plants are highly efficient and responsive micromanagers of soil, nutrients, and water. Annual crops are not; they require churning of the soil, precisely timed inputs and management, and favourable weather at just the right time. With shorter growing seasons and ephemeral, often small root systems, annual crops provide less protection against soil erosion, wasting water and nutrients, storing less carbon below ground, and are less tolerant of pests than are perennial plant communities. Read the rest of this article here

No comments: