Selecting seeding rates for diverse summer annual forage crop mixtures

View the project final report

• 2014 annual report
• 2015 annual report

Commodities

• Agronomic: peas (field, cowpeas), sorghum (milo)

Practices

• Crop Production: seeding rates

One way to make agriculture in the Northeast more sustainable is to change the context of annual forage crop mixtures from emergency to everyday.  Often planted as a result of bad weather, diverse annual forage crop mixtures are more productive than monocultures, use resources more efficiently, and reduce the risk of a subsequent crop failure.  In order to further adoption, seeding rate recommendations must be provided. Seeding rates are based on species, climate, and management practice.  Sow too many seeds in a field you have created a competitive environment, limiting the potential of the plants.  Sow too few, than you have wasted the potential of the land.  Complications arise when planting multiple species at the same time, as is done when seeding summer annual forage crop mixtures. This research examines the biomass production of four annual forage species (two grasses and two legumes) when they are seeded at various rates in monoculture, biculture, and polyculture. The experiment will be planted at two field sites in New York for two years to determine the effect of environment on annual forage crop mixtures and optimal seeding rates.  The biomass and plant density of the plots will be modelled to better understand intra- and interspecific competition in these mixtures and mixtures of other species.  Besides yield, other factors like seed cost and potential milk production will also be examined.  The goal is to provide optimal seeding rates for mixtures that maximize the land’s productivity, the plants’ forage quality, and the farmer’s profitability.

The ultimate goal of this project is to provide farmers seeding recommendations for diverse annual summer forage crop mixtures.  Using the four species model system with numerous seeding rates and seeding ratios between species, the effects of plant stature and nitrogen acquisition traits will be measured.  The characteristics of the different species will be further examined using a biomass-density competition model to better understand how plant densities of different species affect biomass production.  We will also conduct an economic analysis that integrates seed costs and potential milk production, to assess how worthwhile a suggested mixture might be to farmers. We aim to increase farmer adoption of diverse annual forage crop mixtures rates by identifying optimal seeding rates that maximize production, quality, and profitability.

Our project has four objectives:

1. 1. Quantify the effects of functional diversity of crop mixtures on productivity and weed suppression.

1. 1. Model the intraspecific and interspecific competition of the different species in each mixture based on their biomass-density relationship.

1. 1. Determine the effect of environment on annual forage crop mixtures and optimal seeding rates.

1. 1. Perform an economic analysis of the suggested practice and examine the potential for widespread adoption.