Fostering climate-friendly sustainable farming through integration of biochar and cover crops in Texas and Florida

Commodities

• Vegetables: peppers

Practices

• Crop Production: cover crops

This three-year project is a multi-state (Texas and Florida) and
multi-university (Texas A&M University – Kingsville,
University of Florida, Texas A&M AgriLife Research/extension
center, and UF Extension Center – Immokalee) collaborative
approach for fostering climate-friendly agricultural practices.
Major agricultural soils in Texas (South Texas and the Lower Rio
Grande Valley) and Florida (South and Central Florida) are low in
organic matter content (less than 2%) and consequently encounter
reduced crop yield, soil quality issues, nutrient loss, and
eventually economic losses during production. We received several
requests from vegetable growers of Texas and Florida to apply
regenerative agricultural practices for production resiliency,
climate friendly ecosystem, and improved soil health. Our initial
survey indicates that about 67% growers in Texas and Florida are
motivated to use or try sustainable farming (specifically biochar
and cover crops) in their farms. Biochar, often called as super
charcoal, are capable of increasing crop yield by providing
nutrients in the soil, improving soil water retention capacity,
promoting seed germination, increasing cation/anion exchange
capacity of soil, and promoting soil biodiversity. Similarly,
cover crops (CC) are capable to provide ecosystem services
including addition of soil organic matter and other nutrients,
improve soil structure, increase soil water retention, and more.
Also, under EQIP program by NRCS, a CC mixture can provide
$76/acre incentive to the growers. Application of cover crops and
biochar in the field will improve soil nutrient efficiency and
reduce major greenhouse gas emissions: a climate-friendly
approach while improving production efficiency.

We recognized that research works on CC and soil health analysis
are well documented, however, the effect of sub-tropical CC in
combination with biochar on crop yield and soil quality
assessment is still limited. Specifically, we are producing
biochar from invasive plant-feedstocks which is therefore
expected to reduce competition of soil nutrients for main
agricultural crops. We will grow sunn hemp (SH) and velvet bean
(VB) as CC in bell pepper (Capsicum sp) field and the
biochar will be produced from invasive plant-feedstocks that are
abundant in Texas and Florida.

A preliminary study on physicochemical properties of biochar made
from invasive plant feedstocks indicates high cation exchange
capacity (8 to 17 cmol/kg), organic matter contents (95 to 97%),
and improve soil pH to near neutral (pH 7.3 to 7.8).

On another note, this project will also encourage diversity by
engaging more historically underserved farmers of TX and FL in
sustainable farming. Texas has the largest number of Hispanic,
Spanish, or Latino origin (HSL) growers in the United States. As
of 2017, more than 41,000 agricultural growers in Texas are HSL
which contribute about 37% of the total HSL in the US. Similarly,
more than 30% Florida farmers are socially disadvantaged among
which about 29% farmers are HSL.

We expect the major outcomes of this project will be efficient
vegetable production (increased yield due to addition of soil
nutrients), reduction in greenhouse gas emissions, improved soil
health (high CEC from biochar and organic matter addition from
CC), and educational benefits to growers and students on
sustainable farming systems.  

Project objectives

This is a multi-state (Texas and Florida) and multi-agency
coordinated research, extension, and educational project. A
strong collaboration between university partners and vegetable
industry stakeholders has been established to promote
climate-friendly agricultural farming and improve overall
sustainability during production. Experiences from growers, other
stakeholders, and our advisory committee members in discussing
the current problems and expectations were invaluable and we
outlined our project objectives and hypotheses accordingly
(support letters are attached). Overall, this project will
integrate research and extension components through system-based,
trans-disciplinary approach where optimum pepper yield will be
obtained through application of cover crops and biochar in
farmer’s field.

A thorough literature analysis has been carried out and the
objectives were carefully devised to avoid duplication of effort
with similar activities by others.

Specific objectives of this project are:

1) To evaluate the individual and combined effects of
high biomass producing cover crops (sunn hemp and velvet bean)
and biochar for pepper (Capsicum sp; Variety: Red Knight)
production

We will quantify yield and physiological parameters of pepper at
different plant growth stages both at the University farm (Texas
A&M University – Kingsville; TAMUK greenhouse and UF research
station) and in field trials (collaborative farmer’s field). We
hypothesize that the application of biochar and growing high
biomass producing cover crops will improve soil fertility, pepper
fruit quality, and increase overall crop production.

2) To foster climate-friendly practices by analyzing
the efficacy of cover crop and biochar treatments (individual and
combined) in accumulating soil carbon and reducing greenhouse gas
emissions

Hypothesis 2A: Cover crop mixtures will have positive impact on
soil carbon balance (net C accumulation) and reducing greenhouse
gas (CO₂, CH₄, and N₂O)
emissions in the field compared to the plots have no cover crops.
The extracellular exudates released by cover crop roots in the
soil will improve overall soil health components (soil aggregate
stability, soil bulk density, and water holding capacity).

Hypothesis 2B: Biochar (from invasive feedstocks) in combination
with cover crop treatments (biochar + cover crop) will provide
higher organic matter, soil nutrients, improve soil structure
than individual biochar and cover crop treatments. We also
hypothesize that biochar application will reduce the emission of
greenhouse gases compared to conventional farming system.

3) To measure the economic benefits (using stochastic
models) of cover crops and biochar on pepper
production

We will run stochastic economic models to integrate inputs
(seeds, fertilizer, labor etc.) and outputs (crop yield, price,
market demand etc.) for assessing the economic benefits of cover
crops and biochar in pepper productions. We realize that there
are uncertainties with crop yields, costs, and market prices
under both conventional and proposed sustainable farming
approaches. The stochastic economic model will utilize a Monte
Carlo approach to account for the above uncertainties and help
assess incremental (additional) net profits and variability in
returns.

We hypothesize that our proposed sustainable farming approach
(biochar and cover crops) will generate higher profits as well as
lower economic variability (risks) for growers than conventional
farming practices.

4) To develop and evaluate a remote sensing based
expert system utilizing UAV technology for plant and soil health
analysis

The research studies will be conducted in about five different
field sites across South Florida. Geo-coordinates of each soil
sampling point will be recorded using the Trimble GeoExplorer
(Trimble Navigation Limited, CA, USA) global positioning system
(GPS) receiver. All the soil samples will be collected soon after
the satellite (Landsat and Sentinel) overpass. The results of
this study will improve our knowledge on the soil nutrient
dynamics which is critical to calculate nutrient inventory and to
improve soil nutrient management through appropriate combination
of Cover crop and biochar amendments.

5) To provide educational benefits to the
stakeholders and students (both Texas and Florida) on
regenerative and sustainable farming system

This project will provide experimental and experiential learning
opportunities for agroecology undergraduate and graduate students
in Texas and Florida. Series of training workshops and field days
during this project will be able to properly disseminate the
knowledge acquired through experiments. The newly acquired
knowledge about cover crops and biochar integration will help the
stakeholders for sustainable agriculture planning and management.