- Agronomic: cotton, grass (misc. perennial), hay
- Animal Products: dairy
- Animal Production: pasture fertility, pasture renovation, feed/forage
- Crop Production: nutrient cycling, application rate management
- Education and Training: demonstration
- Farm Business Management: new enterprise development, value added, whole farm planning
- Soil Management: composting, soil analysis, nutrient mineralization, soil chemistry, organic matter, soil quality/health
- Sustainable Communities: new business opportunities, sustainability measures
Dairy manure was composted with cotton gin byproduct (CGB) at a ratio of three parts dairy manure to two parts CGB using standard composting procedures. At six months the matured compost was sent to an analytical laboratory for standard analysis. Prior to compost application on bermudagrass, the grass leaves were analyzed for nutrient content. In August 2011 the grass was cut and bales were counted and weighed. Later in August 2011 the compost was applied at three different rates. The bermudagrass was sampled again six weeks later for nutrient content. Bales once again were weighed and counted.
Unfortunate limiting impacts of the 2011-2012 drought and a resulting drop in the well’s static level created an unavoidable limiting factor which prevented a fully successful outcome.
Due to water limitations, overall grass production decreased 16% in the composted fields compared to pre-compost production. Nitrogen content of the compost alone was insufficient to grow the bermudagrass; however, the compost did appear to positively impact zinc, iron, manganese and possibly copper within bermudagrass tissue.
Over the period of the study, another impact of the drought became apparent. Whereas the cost of CGB in early 2011 was $17/ton, by the beginning of 2012 the cost had increased to $64/ton, since the CGB was now being avidly bought by the dairies to feed dry cows in place of other more expensive feeds.
The increased cost of CGB made its use in composting economically impractical. Despite this, CGB might yet provide a useful carbon and nutrient source for compounding in the future. It cannot adequately supply nitrogen, however.
My farm is located in the Chihuahua Desert, about 15 miles across the Franklin Mountains from large dairy and cotton producers in the lower Rio Grande Valley of Dona Ana County, New Mexico. Because the major soil deficiency I encounter is the lack of organic material, I proposed to transport dairy manure and CGB to my farm, compost it to maturity and apply it at three different rates to my bermudagrass pastures. I would use identical and uniform nitrogen and water applications, varying only the rates of compost. Compost nutrient content and baseline bermudagrass tissue content would be determined and baseline weights and bale number measured before compost application. The same values would be repeated after compost application. The goals were to determine if this compost improved bermudagrass production and was economically feasible.
1. Determine if compost from dairy manure and CGB can provide adequate nitrogen for bermudagrass production
2. Determine if the compost can provide sufficient other nutrients for bermudagrass production
3. Compare the production and nutrient content of bermudagrass before and after compost application at three different rates.