Nutrient Export From Annual Monoculture and Perennial Polyculture Production Systems. (S06-glover569602-oral)
Authors:
J.D. Glover* - The Land Institute
D.L. Huggins - Washington State University L.R. DeHaan - The Land Institute
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.
Speaker Information: Jerry Glover, The Land Institute, 2440 E. Water Well Road, Salina, KS 67401;
Phone: 785-823-5376; E-mail: [email protected]
Session Information: Thursday, November 6, 2003, 7:55 AM-9:15 AM Presentation Start: 8:30 AM
Keywords: perennial polyculture; soil organic matter; soil nitrogen; Natural Systems Agriculture
