Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 6/1/2003
Publication Date: 11/1/2003
Citation: Glover, J.D., Huggins, D.R., Dehaan, L.R. 2003. Nutrient export from annual monoculture and perennial polyculture production systems [abstract]. Agronomy Abstracts. Paper no. S06-glover56902-oral.
Technical Abstract: Shrinking global resources and a growing human population places agriculture as this century's number one social and environmental challenge. Perennial grain systems (Natural Systems Agriculture) have been proposed as a viable way to meet that challenge. The objective of this study was to determine the ability of perennial polycultures, relative to annual monocultures, to sustain long-term nutrient yields and maintain soil quality. The study included 3 pairs of adjacent Kansas hay meadows (unfertilized) and wheat fields (fertilized). All sites have been in production for more than 75 yrs. Cumulative 75-yr nitrogen (N), phosphorus (P), and potassium (K) yields from county hay meadows are 100%, 75%, and 500%, respectively, of those from county wheat fields. Current annual N, P, and K yields from the study's hay meadows are 68%, 52%, and 348%, respectively, of the study's wheat fields. The wheat fields have 30-40% lower soil organic matter and total soil N levels (0-50 cm) than the hay meadows. The difference in kg total soil N per ha between wheat fields and hay meadows roughly equals the amount exported in grain over the past 75 yrs. Perennial polycultures can sustain high, long-term nutrient exports and maintain higher soil quality than annual monocultures. If high-yielding perennial grain crops are developed they have great potential to meet the need for truly sustainable farming practices.