Advantages of Perennial Grain

Several claims have been published:

  1. Greater access to resources through a longer season. Perennial plants typically emerge earlier than annuals in the spring and go dormant in the autumn well after annual plants have died. The longer growing season allows greater interception of sunlight and rainfall. For example, In Minnesota, annual soybean seedlings emerge from the soil in early June. By this time perennial alfalfa has grown so much that it is ready for the first harvest. Therefore, by the time a soybean crop has just begun to photosynthesize, a field of alfalfa has already produced about 40% of the season’s production.
  2. Greater access to resources through a deeper rooting zone. Most long--lived plants construct larger, deeper root systems than short-lived plants adapted to the same region. Deeper roots enable perennials to "mine" a larger volume of soil each year. A larger volume of soil also available for exploitation per unit of cropland also means a larger volume of soil water serves as a reservoir for periods without rainfall.
  3. More efficient use of soil nutrients. Leaching of nitrogen from fertilizer has been found to be much lower under perennial crops such as alfalfa (lucerne) than annual crops such as maize. A similar phenomenon is seen in unfertilized fields harvested for wild hay. While adjacent wheat fields required annual inputs of fertilizer, the wild perennial grasses continued to produce nitrogen-rich hay for 75 to 100 years with no appreciable decline in productivity or soil fertility. Presumably, the larger root systems of the perennial plants and the microbial community they support intercept and cycle nutrients passing through the system much more efficiently than do the ephemeral root systems of crop plants.
  4. Sustainable production on marginal lands. Cassman et al. (2003) wrote that for large areas in poor regions of the world, “annual cereal cropping ... is not likely to be sustainable over the longer term because of severe erosion risk. Perennial crops and agroforestry systems are better suited to these environments.” Current perennial crops and agroforestry systems do not produce grain. Grain provides greater food security than forage or fruit because it can be eaten directly by humans (unlike forage) andit can be stored (unlike fruit) for consumption during the winter or dry season.

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Perennial Grain".