Harvest Management to Maximize Dry Matter and Nutrient Yield, and Economic Return of Red Clover

Abstract

In Pennsylvania and the northeast USA, red clover (Trifolium pratense L.) is widely grown as an alternative to alfalfa. Harvest systems which maximize red clover dry matter (DM) and nutrient yield and economic return over the relatively short life of the stand have not been identified in Pennsylvania or the northeastern USA. The objectives of this research were to determine the effect of seeding-year and year-after-seeding (production year) harvest systems on total DM and nutrient yield, and economic return of red clover. Red clover was spring seeded without a companion crop and subjected to one or two harvests during the seeding year and two, three, or four harvests during the production year. Red clover harvested twice in the seeding year averaged 2230 and 1526 lb/acre greater DM and digestible dry matter (DDM) yields, respectively, over the life of the stand than red clover harvested once. Harvesting twice during the seeding year also resulted in a $79/acre greater return over the life of the stand than a single harvest. Seeding-year harvest treatment had no effect on red clover DM or DDM yield, or economic return in the production year. Average production-year DM yields were 7359, 7639, and 6512 lb/acre for the two, three, and four harvest systems, respectively. Economic returns over the life of the stand as a result of production-year harvest treatments were inconsistent but two or three harvests were always among the highest. Red clover persistence did not differ among treatments. Seeding- and production-year harvest management of red clover may vary with location; however, in Pennsylvania and regions of similar climatic conditions, two harvests in the seeding year and two or three harvests in the production year were consistently superior in DM and nutrient yield, and economic return compared to other harvest systems. Research Question Red clover's ability to establish easily and produce under conditions of low soil pH have made it a popular alternative to alfalfa in situations where short crop rotation cycles are needed for nutrient management in the northeastern USA. However, producers of red clover face the challenge of maximizing economic returns in just 2 to 3 yr. The objectives of this research were to determine the effects of seeding-year and production-year harvest schedules on total dry matter (DM) and nutrient yield and economic return for red clover. Literature Summary There have been several studies completed at different latitudes that address the effects of red clover seeding-year harvest management or harvest management during the year after seeding on DM yield. The results of these studies have been mixed, recommending one or two harvests in the seeding year and two to four harvests in the year after seeding. Unfortunately, only limited work has been conducted that addresses the effects of red clover harvest management on yield of nutrients or economic returns over the life of the stand. Study Description Red clover was band seeded at 15 lb/acre into a tilled seedbed in 1991, 1992, and 1994 near Rock Springs, PA, at the Russell E. Larson Agricultural Research Center. One or two harvests were then taken in the seeding year followed by two, three, or four harvests in the year after seeding (production year). Dry matter and forage quality were determined for each harvest. Economic evaluations of each treatment were made based on the value of the harvested forage and the costs associated with production. Applied Questions How many times should red clover be harvested during the seeding year? Two harvests during the seeding year resulted in greater DM and digestible dry matter (DDM) yields, and a $79/acre greater economic return over the life of the stand, than a single harvest (Table 1). Number of harvests during the seeding year had no affect on DM yield, forage quality, nutrient yield, or economic return during the production year. Therefore, to maximize both DM and DDM yields and economic returns over the life of a red clover stand in Pennsylvania, two harvests should be taken during the seeding year. How many times should red clover be harvested during the production year? In general, two or three harvests during the production year resulted in greater DM and DDM yield than four harvests (Table 1). However, increased yields associated with two or three harvests were not consistently parlayed into increased economic returns because of lower forage quality associated with the two or three harvests compared with four harvests in the production year. Three harvests in the production year provides a compromise in yield and quality relative to the two or four harvest system. Recommendations In Pennsylvania and in regions with similar latitude or climatic conditions, based on DM and nutrient yields and economic returns, harvesting red clover twice during the seeding year and two or three times in the production year provided the greatest economic return compared with other harvest systems. These numbers of harvests did not adversely affect red clover persistence relative to other harvest treatments. However, these conclusions must be considered in context with other red clover research. Specifically, in order to take two harvests during the seeding year and not reduce red clover DM and nutrient yield in the production year, seeding must be completed by early May. In addition, precipitation has a large influence on red clover growth. In years when moisture is not a limiting factor to growth, additional harvests in the production year may be warranted. Table 1. Effects of seeding-year and production-year harvest number on red clover dry matter (DM) and digestible dry matter (DDM) yield, and economic return over the life of the stand. Treatments Seeding + production years Year Number of harvests DM DDM Economic return ----------lb/acre---------- $/acre Seeding 1 9312† 5856 164 2 11542 7382 243 Production 2 10 667 6596 200 3 10 797 6876 215 4 9817 6386 196 † Values are the mean of three experiments seeded in 1991, 1992, and 1994.