Case Study Background
This case study was developed for the J Alvin Lee Farm, LLC (Lee Farm) located in the Delta Region of the central eastern part of Arkansas, where most of the state’s row crop farms are concentrated. The landforms in the area are level or depressional to very gently undulating alluvial plains, backswamps, oxbows, natural levees, and terraces. Arkansas’s climate is classified as humid, subtropical, with mild, cool winters that sometimes dip below freezing; springs that can experience late season frosts and freezing; warm, humid summers where temperatures often exceed 100° F, and occasionally exceed 110° F in the southern part of the state; and mild autumns that are generally the driest part of the year. The Lee Farm has been in operation since 2008 and is 100% row crop production, including: corn, milo (grain sorghum), rice, soybeans, and winter wheat. Crops are managed under a crop rotation that typically rotates a high residue crop (corn, milo, rice, and winter wheat) with a low residue crop (soybeans). In this system, crop residue is left in the field after harvest to help cycle plant nutrients back into the soil, improve water holding capacity, and protect exposed soil. 65% of the cropland is managed under irrigation while 35% is managed as dryland. Fields are managed using flood irrigation when rice is produced.
The management goals for the Lee Farm are to:
- Reduce the amount of water required for crop production by adopting more advanced irrigation techniques, such as low-energy precision application irrigation or furrow-dikes.
- Abandon conventional tillage and adopt both reduced till and no-till with cover crops to protect the soil, build organic matter, and conserve soil moisture.
- Improve wildlife habitats for migratory birds, deer, and rabbits for hunting and recreation (a secondary desire). The L’Anguille River, Coffee Creek, and Flat Fork Creek border the northern and eastern side of some areas of the farm, and provide excellent habits for migratory birds, such as ducks and geese. Additionally, we’ve seen that implementing no-till when planting multi-year cover crops helps increase deer and rabbit populations.
Climate Change Impacts:
The impact of a changing climate is not going unnoticed on Lee Farm, as weather patterns are markedly different from one year to the next. While the average annual temperature in Arkansas was highly variable during the 20th century, there has been an upward trend since the 1970s that is projected to continue. This will result in increased heat stress and soil moisture loss. Extreme rainfall events are not uncommon in Arkansas; however, changing rainfall patterns (heavier rain events followed by more extended dry periods) will continue to challenge agricultural producers.
Climate change and variability have the potential to affect operations on the Lee Farm in several ways:
- Warmer summer temperatures are projected to increase across the southeast and will result in more untimely heat spikes. The unpredictability of the heat spikes can have a detrimental impact on crop yields, especially soybeans, corn, and milo, when they occur during plant flowering and pollination. Warmer temperatures can also result in lower soil moisture availability due to higher evapotranspiration rates.
- Growing seasons will be longer, with the freeze-free season projected to increase 20 to 30 days by mid-century. This could allow for additional crops to be harvested during one, longer growing season, depending on water availability and the occurrence and severity of heat spikes.
- Summer precipitation is expected to fluctuate, with both increases and decreases in precipitation varying across the region. Altered rainfall patterns will increase the occurrence and severity of extreme events, including flooding and drought, which will impair many of these crops through altered water availability (too much or too little or at the wrong time) and soil conditions (saturated, dry, eroding).
Climate Change Challenges and Opportunities:
Climate change and variability will continue to be a challenge on Lee Farm. Many of the challenges are similar to those faced by other warm-season crop farmers, primarily increasing temperatures and too much (flooding) or too little (drought) precipitation. Warmer temperatures could result in lower yields (for crops and residues) if soil organic matter respiration rates increase, and higher water demand outpaces availability. Higher variability in precipitation can also negatively impact crop productivity through drought, flooding, and increased pests and disease. Lee Farm can reduce their risk to high temperatures and variable precipitation rates by 1) choosing crop varieties and planting dates based on forecasted precipitation and soil moisture levels, 2) planting high residue crops and cover crops to improve soil health, increase soil organic matter and infiltration, and reduce soil moisture and carbon loss, 3) using no-till farming and a controlled traffic system to reduce soil compaction and improve soil structure, and 4) expanding irrigation to areas not receiving enough moisture.
A) First year no-till farming reduced standing wheat stubble so B) soybeans could be planted as a low residue crop. C) Cover crops, such as black oats, clover crimson, and turnips were planted in between harvests to improve soil nitrogen and reduce carbon loss, and D) second year soybean production was noticeably higher.
The Adaptation Workbook was used during a brainstorming session to identify potential approaches and tactics that can be implemented on Lee Farm to increase resilience to climate change and variability. Numerous potential actions were identified to increase farm resilience in the near-term, and several additional actions were identified to enhance the ability of the farm to cope with longer-term changing conditions. For example, increasing soil organic matter through crop rotation, cover crops, no-till farming, residue retention, and other practices has increased the farm’s resilience to both drought and extreme precipitation in the near-term and under a changing climate. Additional adaptation tactics include:
- Lowering the density of corn planted in non-irrigated fields if drier conditions are expected.
- Utilizing controlled traffic patterns (such as confining machinery to the same row) to reduce soil compaction.
- Planting cover crop mixes with grasses that sequester carbon and complement cash crops.
- Using legume cover crops after wheat in years that are projected to have wetter conditions to help retain soil moisture and reduce runoff and erosion.
- Planting sorghum when wet springs are forecast, and corn planting would be delayed. Sorghum is also more drought tolerant.
- Planting high carbon cover crops following wheat harvest to increase soil organic matter and residue retention.
- Diversifying crops to reduce pest and disease pressure and provide additional opportunities to rotate high residue cash crops with low residue cash crops.
- Substituting crops. As the climate changes, alternative crops or rotations might be more suitable to the changing conditions. For example, sorghum could replace corn in the rotation under warmer and drier conditions and would maintain the preferred high-residue-low residue crop rotation.
- Increasing the number of acres managed under irrigation to reduce drought risks and improve the sustainability of the farm.
As the climate changes in the Delta Region of Arkansas, Lee Farm will continually monitor their management decisions and how those decisions impact challenges and opportunities in production agriculture and farm health. Specifically, they will evaluate their crop productivity as they switch between crop types, varieties, and planting times of alternate crops that can reduce risks when weather conditions are not favorable. One good indicator that the selected management systems are working will be any increases in farm sustainability. Increases in crop yields and reductions in costs (e.g., less sediment removal from drainage ditches, less water usage) will serve as indicators of improved sustainability. The use of farm production records documenting improvements in soil nutrient levels via soil testing will give some ideas about improvements made on the farm. Maintaining good farm records for multiple years will also provide opportunities to track improvements though the years. Likewise, on-farm crop yields can be compared to county or local averages to evaluate the performance of Lee Farm relative to neighboring farms, particularly those with similar soils and management histories.
Lee Farm 2-page fact sheet