In this presentation, Marlon WInger, NRCS Regional Soil Health Specialist and Agronomist, describes how to conduct a low-tech cost-benefit analysis using a cover cropping system.
The first few slides of this presentation are geared towards those training to become a NRCS Technical Service Provider (TSP). The slides geared for farmers start around Slide 14.
In slide 9 Marlon gives farmers a pep talk and lists some of the barriers for implementing soil health practices, including the lack of time to seed cover crop, high cost of irrigation, yield drag and overall costs.
Slide 14 Marlon shares his work doing cost-benefit analysis of cover cropping systems with farmers. His work shows that although the initial cost of cover crop seed can be $15-$60 per acre, cover cropping does show a positive Return On Investment (ROI) and does treat the root cause of the problem (e.g. compaction, reduced nutrient cycling and nutrient leaching, erosion etc.).
In Slide 15 Marlon shows how he sets up a simple cost-benefit analysis for a cover cropping system, looking at the cost-savings from reduction in weeds (reduced costs of herbicides and labor), reduced compaction (comparing the price and benefits of cover cropping with that of a subsoiler and other heavy machinery), reduce fertilizer needs (calculating the amount of reduced nutrient leaching and contribution from fixed nitrogen), reduced soil erosion (using dollar estimates from literature on the cost of soil erosion), livestock feed and reduction in the cost of equipment and labor.
On Slide 19 he reminds us how important it is to understand the succession of annual weed production and to choose a cover crop that can outcompete the weeds for the wet/dry season. Farmers who can use a cover crop to reduce their weed pressure while minimizing disturbance to the soil aggregate structure will save the cost of herbicide and labor to manage weeds during the growing season.
Slide 20- 22 Marlon sites a 33% reduction in herbicide (Willis Farms Case Study) by farmers who have integrating cover cropping into their operation. He also demonstrates a cover cropping system using Pili grass in Hawaii. He reminds us that sometimes farmers apply herbicide when establishing the cover crop, but the goal is to an overall reduction in the amount of herbicide needed.
The cost savings of reducing compaction using a cover cropping system compared to the cost of ripping a field is discussed in Slides 24-27. In these slides he shows a comparison of crop yield in systems using cover crop and a subsoiler, citing a study from Alan Sundermeier of Ohio State. He also demonstrate a design where the farmer plants his crop a couple inches from where the radish cover crop was terminated. The radish acts as a ‘subsoiler shank’. In this slide, he also reminds us that soil structure problems can be solved with cover crops. He sites an example from a CTAHR study, History of No-Tillage Farming, using Pili grass as a ‘green mulch’. Perennial grass systems create granular structures around the rhizosheaths of the grass. As the Pili grass creates soil aggregates the bulk density (the amount of soil pores and channels) of the soil is improved. Increasing the amount of air, water and life in the soil can soften the texture of the soil, making it easier for the roots of your crops to grow.
In Slide 27, Marlon reminds us that in a soil health management system, nitrogen is stored in the DNA of organisms (proteins and amino acids in microbes and plant roots). In native soils, nitrogen is not stored as a nitrate. Nitrogen stored in a nitrate form can be easily leached. Nitrogen is mineralized from crop residue and soil organic matter by the biology in the soil. This form of nitrogen (nitrate ((No3)) or ammonium ((No4)) is highly soluble (inorganic) and easily leached. Literature shows that nitrogen leaching can be 50-100lbs/acre.
The cost of nitrogen fertilizer has tripled in 2021.
In Slide 28 Marlon shows us how he calculates the cost-savings in nitrogen and phosphorus fertilizer reductions.
Slide 34, How farmers trust the nitrogen is being provided from your cover crop. Marlon demonstrates why a strip trials with zero inputs, 50% inputs and 100% inputs. When the zero inputs have no greater yields, than you’ve proven to yourself that the cover crop is providing nitrogen for your system. He why it’s important for farmers to understand how soil functions before they change their operation. He also shares how soil health innovator, Gabe Brown, measures his nitrogen using leaf tissue tests. In a biologically active soil health management system, most of nitrogen is in an organic form and not stored as a nitrate.
Slide 37 Marlon explains why farmers need to address soil erosion if they are going to start managing soil health. He provides estimates of how much nutrients and fertilizers are lost through soil erosion.
Slides 38- 42 to show the cost savings in livestock feed when they graze on cover crop.
Slide 43-47 Estimates the cost of equipment for a conventional system verses the equipment used in a system that uses strip-tiling or no-till. The slide also looks at reduced labor costs for operating machinery. Demonstrates new machinery used in a strip-tilling system. Average producers spent $136 per acre on equipment costs. Soil health innovator, Wayne Fredericks, uses a no-till cover cropping system and his equipment costs was only $70 per acre and $27 in reduced labor per acre and saved $92 per acre on equipment and labor compared to conventional system.
In Slide 48 Marlon estimates that cover crop costs $60 per per acre in seed and $20 per acre to irrigate, so the no-till, cover cropping system costs $80 per acre. He estimates that a farmer using a cover-cropping system and who has addressed erosion, can save up to $588 per acre. He also describes how to use a partial budget and how to calculate the economic return of a soil health management system.
Slide 51, Marlon sites the CTAHR study and provides an example of rolling down cane and using a no-till drill to plant in place.
Slides 64-66 speakers more to those interested in working as Technical Service Providers.
Slides 67- 74 Provides case studies from NRCS’s website. He also goes into detail on a case study with the McPeak Grass and Cattle Ranch yields from adding carbon to their system to become carbon neutral.