Introduction

This trial was conducted to compare no-till annual pastures to a reduced tillage corn silage system. This study was replicated for four consecutive years from 1992-1996. The primary objective of this study was to develop a program of establishing no-till ryegrass that could be utilized as grazing from November through mid-May. Earlier work with no-till ryegrass was in perennial sods, such as bermuda or bahia, which produced forage for grazing in the spring only. This was because the ryegrass was planted in late fall after the summer perennials were dormant. In our study, an application of glyplosate (Roundup®) in mid summer replaced traditional summer fallowing with a disk. Glyplosate killed all actively growing summer annual grasses. This stopped removal of soil moisture by the plants, and allowed dead vegetation to serve as a mulch, conserving moisture for early planted ryegrass.

Procedure

One hundred and twenty lactating Holstein cows were randomly allotted to either a pasture or silage treatment. In each year of the study, cows in the pasture system began grazing oats during the last week in October. They were rotated to ryegrass grazing in mid-November and utilized these cool season grasses until mid-May. After the oats and ryegrass were gone, there was a four week transition period of hay feeding before summer annuals were available to graze. The summer annual grasses that volunteered into the ryegrass stubble were signalgrass and crabgrass. These grasses were fertilized with nitrogen and provided 4 to 8 weeks of grazing annually. In early August, the summer annuals were sprayed with glyphosate as preparation for no-till seeding of ryegrass in mid-September. During the transition from warm to cool seasons, early August until late October (12 weeks), hay was fed to the cows on the pasture treatment. In late October, cool season grazing was again available.

The corn for silage in this system was planted no-till one year and minimum till the following year. No cultivation was performed in either of these years. This method of producing corn was not successful on a long-term basis due to encroachment of bermuda. As the years progressed, our corn yields were lower and lower from this acreage due to volunteer establishment of bermudagrass. The two methods of controlling these grasses is tillage or corn/soybean crop rotation. On many dairy operations, crop rotation with soybeans is not an alternative since all available land must be used for forage production. Another problem associated with corn for silage (tilled and no-tilled) is the long period of time after the harvest and before frost that gives perennial grasses and other vegetation time to develop good hearty rhizomes. This makes no-till and minimum till corn production on a sustaining basis very difficult to achieve. We have had much greater success in establishing grazing forages no-till than we have corn for silage.

Conclusion

Table 1 shows the average annual milk production for each period of the year for no-till pasture and no-till/minimum till corn silage feeding during last three years of this study.

Table 1. Three Year Average Daily Milk Yield for Different Periods of the Year

Income over feed cost were calculated for each treatment during each season of the year. The forage planning budgets were used as a basis for budgeting each different feeding regime. Table 2 shows the income over feed cost for each system by season of the year.

Table 2. Three Year Average Daily Income Over Feed Cost

Tables 1 and 2 show that milk production during the cool season appears to be similar between cool season grazing and corn silage systems. IOFC is greatest for the pasture system during the cool season. During the remainder of the year, cows on corn silage had higher levels of production and greater IOFC than the pasture group.

The data we have from these trials indicate that overall differences between silage and pasture systems may be in the area of economics rather than production. While production may be related more to level of management than to the forage system on a particular dairy operation, profitability cannot always be linked to production. There are many factors to consider when selecting the forages to be utilized on a dairy operation. This study shows that income-over feed cost is greatest for cows on cool-season annuals for seven months of the year. The remaining five months, IOFC is greater for corn silage based diets. The grazing forages that were produced using the no-till system described above have been very successful throughout this study. The corn produced using no-till techniques without a crop rotation has not been successful. Managing pastures so that cows do not have to travel great distances, especially in hot weather, is a factor to consider when planning these grazing systems. Producers need to consider land capabilities, equipment and time investment in each system, and last but not least, the practicality of day to day activities involved in forage management.