An alternative planting strategy for establishing clover in pastures

View the project final report

• 2006 annual report
• 2007 annual report

Commodities

• Agronomic: grass (misc. perennial), hay
• Animals: bovine

Practices

• Animal Production: grazing - continuous, pasture renovation, grazing - rotational, feed/forage
• Crop Production: no-till
• Education and Training: demonstration, extension, on-farm/ranch research
• Production Systems: integrated crop and livestock systems

Nitrogen fertilizer costs have skyrocketed in recent years making it difficult for producers to sustain adequate pasture productivity in grass monoculture systems. Additionally hay production costs have increased dramatically. Establishing and maintaining clover in cool-season grass pastures helps improve sustainability through improved animal performance and a reduction in fertilizer inputs. Benefits of clover include the reduction of toxic endophyte infected fescue effects on livestock and reduction in production costs by reducing the need for expensive N fertilizer (Ball, et al., 2002).However, over-reliance on continuous grazing, N fertilizer applications, and lack of understanding of the planting and establishment process has limited addition of clover by many Arkansas producers.
Planting practices include either broadcast or no-till planting clover seed in dormant grass sod across the entire pasture. In theory, planting clover over 100% of the pasture should result in an even distribution of clover over the field, but in practice, uniform stands of clover are seldom achieved using these methods. When clover is planted into an existing grass pasture, the resulting clover stand is considered good at 25% of the total pasture sward. But, the percentages obtained are often under 20% due to droughty soils, variable fertility, and heavy grass sod. When clover establishment is less than expected, producers revert to typical practices, including N fertilization and continuous grazing, which reduce survival of any remaining clover.
When planting new expensive forage varieties, accurate calibration is very important to reduce cost and to encourage producers to accept the new forage. Most clover that is planted is mixed with fertilizer and broadcast. Calibrating broadcast seeders and fertilizer spreaders is more difficult than for drills. No-till drills work very well when planting legumes into grass sods since seed depth and rate can be readily controlled. White clover is planted at very low seeding rates, usually 1-3 lbs per acre. Most pasture drills are difficult to calibrate for these extremely low seeding rates. This decreases the likelihood of producers planting with no-till drills.

The broadcast approach to establishing additional forages into existing pastures is often recommended but does not always work well due to pasture variability. Conversely, producers have historically noted good establishment of certain forage and weed species from seed in mature hay where the hay was unrolled during feeding. This concentration of seed from the hay and nutrients in animal manure deposited in the feeding area creates a favorable environment for seedling establishment. Forages and weeds that become established in this natural “strip-seeding” manner often spread throughout the pasture over time. This project will use a modified “strip-seeding” approach as a means of encouraging producers to adopt clover into their grazing systems for improved sustainability. Because it is difficult to calibrate planters for low seeding rates and because clover planted at low rates often becomes established from the initial planting in less than 25% of the pasture, it may be more cost-effective to plant clover at a higher seeding rate only in the areas of the field best suited for clover or in areas that can be best managed for clover and let both vegetative spread and grazing disperse clover into other areas of the pasture. In theory, 100% of the recommended clover seed for a field could be planted on only 25% of the area (4X rate), thus increasing likelihood of establishment while reducing labor and planting costs. Many grain and no-till drills are difficult to calibrate for a recommended 1-3 lb per acre seeding rate but are much easier to calibrate for a 6-8 lb per acre seeding rate, especially with worn equipment. White clover spreads readily from stolons and produces a percentage of hard seed that can pass through the digestive tract of grazing animals (Caradus, 1990; Gibson and Cope, 1985). Rotational grazing is beneficial to persistence of legumes in pastures and has been shown to improve distribution of manure across a pasture compared to continuous grazing systems (Joost, 1997). Over time the clover would be dispersed across the field via vegetative stolons and seed dispersal by livestock. Producers will manage what they can see so the likelihood of managing to favor a sustainable clover/grass mixture increases if successful establishment is observed.

The objective of this study is: 1) to compare two strategies for establishing clover into dormant grass sod (1x seeding rate over the entire pasture vs. 4x seeding rate on 25% of the pasture).