A Model for Long-Term, Large-Scale Systems Research Directed Toward Agricultural Sustainability

A Model for Long-Term, Large-Scale Systems Research Directed Toward Agricultural Sustainability

Summary

Objectives
This project is located at the Center for Environmental Farming Systems, near Goldsboro. N.C. Through the collaboration of a broad coalition stakeholders, (N. C. State University, N. C. A&T Sate University, and N. C. Department of Agriculture, NGO groups and farmers) this three year project is to establish, in perpetuity, a multidisciplinary systems research project evaluating five diverse systems.

Objectives include:
1. Selection of sites and conduct of baseline sampling.
2. Formation of a Research Advisory Board.
3. Establishment of systems and begin data collection.
4. Construction of a procedural model for systems research.
5. Outreach and information dissemination of project outcomes.

Approach
The systems are being evaluated on numerous integrating parameters including, energy and nutrient flows within the plant-soil system, biological-based shifts, and economic performance evaluations. Cover-crop rye was planted in October 1999 and data collection began in March with baseline soil sampling. Soil samples were collected on 3/99, 10/99, 3/00, and 10/00.Composite soil samples were taken at geo-referenced points so that the same point was sampled at each date. The same sample was used for chemical (pH, organic C, N03 and NH4-N) analyses and for quantifying entomopathogenic nematode and bacterial (Psuedomonas) populations. Additional measurements included gravimetric soil water content, bulk density, infiltration time and soil respiration as measured by C02 evolution (Doran and Parkin, 1996). The goal of the Soil Quality work is to develop a set of key soil quality indicators (chemical, physical, and biological) that reflect current and future systems performance potential.

Results
Statistically significant differences were found for both infiltration rate and carbon content both between systems and sampling date. Differences in the carbon concentrations are most apparent between the conventional and no-till subplots in the BMP system. These differences were greatest in the dryer 1999-growing season. Carbon concentrations (kg C/ha/day) in the no-till subplots were 3.5, 2.5 and 1.5 times greater than concentrations in the conventional subplots in May, July and October 1999 respectively. Carbon concentrations in the successional ecosystems were approximately equal to no-till concentrations and were statistically similar on all sampling dates.

System treatment effects on infiltration rate were masked by the differences in soil type between reps and the variability within the plots.

Soil arthropods were extracted from a portion of soil from each treatment and sample point. We have completed sorting and mounting arthropods from the first three sample dates, and are currently sorting and mounting specimens collected from the last date. An aliquot of each soil sample was bioassayed for the presence of beneficial insect-pathogenic nematodes and fungi. Three types of beneficial nematodes and two types of beneficial fungi were identified from the samples. These and data, consisting of numbers of mites, collembola, and other arthropods for completed dates were transmitted to the statistician and the database manager.

These data will be used in correlations to determine if their presence is associated with higher yield and/or lower crop damage than where they do not occur, and whether particular systems favor the occurrence of beneficial soil organisms.

Summaries of this work were presented at the Agronomy Society annual meeting, the CEFS Field Day, the Entomology Society of America annual meeting, the Sustainable Agriculture annual meeting, and meetings for NCDA and NCSU administrative personnel, and Clemson faculty and administrators.

A second soil sampling was completed in November 1999. Crop rotations in 2000 included peanut, wheat/soybeans, sweet potatoes and pasture. were initiated in April and May with planting of corn, pastures and soybeans. At the writing of this report, yield data from the cropping systems were still being processed.

Collaborators: