Developing high seed yielding perennial polycultures as a mimic of mid-grass prairie

Abstract:

Over the past two decades, work at The Land Institute has aimed to develop sustainable farming as a functional mimic of mid-grass prairie. Ecological studies of unploughed prairie suggested that an agricultural mimic should contain representatives of four main groups: warm season perennial grasses (C4), cool season perennial grasses (C3), perennial legumes and perennial members of the sunflower family. Then followed a systematic search of the literature and germplasm collections for suitable species within those target groups. Biological studies were carried out on six candidate species, the C3 grass, Leymus racemosus [Lam.] Tsvelev, legumes wild senna (Cassia marilandica L.) and Illinois bundleflower (Desmanthus illinoensis [Michx.] MacM), the C4 grasses Tripsacum dactyloides [L.] L., and the hybrid Sorghum halapense (L. Persoo) x S. bicolor (L. Moench), and the perennial sunflower Helianthus maximilianii Schrad. Experiments involving these species in monocultures and various polyculture combinations have set out to answer four questions; Can herbaceous perennialism and high seed yield go together? Can a polyculture of perennial seed producers outyield the same species in monoculture? Can a perennial polyculture provide most of its own fertility? Can a perennial polyculture successfully manage insects, pathogens, and weeds? To the first question, evidence is presented that the long held view that there is a necessary trade-off in resource allocation between seed production and survival does not necessarily hold. It is suggested that other insights of value to managed ecosystems in general will flow from an evolutionary ecological approach to sustainable agriculture that uses nature as model.

Presented at the “Agriculture as a Mimic of Natural Ecosystems” workshop held at Munthoola, Williams, Western Australia, September 2-6, 1997.

Jackson, W. and L.L. Jackson (1999). Developing high seed yielding perennial polycultures as a mimic of mid-grass prairie. In R. LeFroy (Ed.), E.C. Lefroy, R.J. Hobbs, M.H. O’Connor, J.S. Pate, Agriculture as a Mimic of Natural Ecosystems. Netherlands: Kluwer Academic Publishers, pp. 1-37.

Abstract reprinted with permission from Kluwer Academic Publishers.