Agroecological Intensification of Warm-season Pastures for Improved Productivity and Quality and Ecosystem Services

View the project final report

Commodities

• Agronomic: grass (misc. perennial)

Practices

• Animal Production: feed/forage, pasture fertility
• Crop Production: cover crops
• Soil Management: organic matter

Bahiagrass pastures (Paspalum notatum Flugge; BG) dominate Florida grazing land. Grown on over one million hectares, this warm-season perennial grass produces abundant, low-quality forage. Seasonal dormancy and low soil fertility limit BG production and require feed and fertilizer inputs to support forage production and quality. However, high input costs and scrutiny of the carbon footprint associated with fertilizer and feed production and transport highlight the need for sustainable alternatives. Integrating legumes and over-seeding cool-season annual forages into BG pastures supplies N through biological N2-fixation while cool-season annuals extend the grazing season, thus reducing the need for fertilizer N and stored feed. Species diversification of BG pastures over time and space, referred to here as agroecological intensification (AEI), may enhance soil organic matter (SOM) and improve nutrient cycling by changing the quality, quantity and timing of organic inputs. Despite advances in mixed BG-rhizoma peanut (Arachis glabrata Benth; RP) research, the influence of RP proportion and other forage species on below-ground responses linked to SOM formation and nutrient cycling remains understudied. This project aims to evaluate increasingly intensified pasture systems for forage productivity and quality and to understand root-rhizome and microbial outcomes of intensification and pasture composition. Ultimately, it seeks to maximize pasture productivity, promote on-farm resource use efficiency and enhance ecosystem services by supporting SOM and year-round plant growth to reduce external inputs.

1. To evaluate the productivity and quality of forage systems along a gradient of AEI. Specifically, we will examine both overall productivity and quality as well as the smoothness of their seasonal distribution (i.e. ability to reduce seasonal over/under-supply), given the large importance of the latter to realizing production benefits in practice.
2. To evaluate root and rhizome production along a gradient of AEI, and to link these below-ground responses to SOM formation and soil fertility indicators.
3. To explore how variations in legume proportion, soil quality (indexed by baseline SOM) and soil resource supply (including fertility and soil moisture) relate to variations in the realized production and ecological benefits of AEI.