Cover Cropping with the Penn State Interseeder is all about Downstream
Posted: August 20, 2012
Cory Dillon from Penn State’s Agronomy Research Farm interseeds a cover crop in a corn field on the Hottenstein Farm in Forks Township, Sullivan County.
Farmers that have conscientiously planted cover crops between their cash crops for a number of years have come to recognize the accumulation of benefits over the long term and have become more passionate about the practice. The added bonus of cover crops is improved water quality for all of us that live downstream.
Cover cropping involves the establishment of a crop following the harvest of a cash crop such as corn or other commodity. By design, the cover crops create a ‘green bridge’ between the cash crops and in doing so support the biotic environment of the soil with living roots. Living roots and the accumulation or retention of organic matter largely account for the utility of the practice.
Various plants can be used as cover crops depending on the specific and desired purpose for the cover crop. Legumes, like clover for example, can create and add nitrogen to the soil that is available later to the cash crop. Small grains like winter rye, a common cover crop, or annual ryegrass can scavenge nutrients and retain them for subsequent use. Other crops, like radish with its deep taproot configuration, are believed to loosen soil and improve soil structure. All cover crops can be expected to intercept the soil-dislodging power of rainfall and therefore mitigate topsoil erosion.
Using cover crops isn’t without management complexities and added costs. The weather conditions in any given year can have a profound impact on field operations in terms of planting date or harvest opportunity for the cash crop and cover crop management needs to adaptable to these seasonal uncertainties. The length of growing season in a particular area will also have an impact on what cover crops can be grown and how it is established. In northern areas of the state, where corn silage and hay rotations predominate, producers typically attempt to optimize corn yields by planting hybrids that utilize as much of the (shorter) growing season as possible, leaving less of a window for cover crop planting in the fall than what would be considered ideal for establishment. Establishing cover crops also commonly requires an additional pass across the field and possibly additional equipment requirements for the farm.
Recently, the Penn State Extension Field and Forage Crops team with some support from the Northeast Sustainable Agriculture Research and Education Consortium (NESARE) launched an effort to address these challenges. In conjunction with staff at Penn State Agronomy Research Farm who developed a specialized interseeding machine, the researchers and cooperators in this project are evaluating the planting of cover crops in a standing corn crop several weeks after the corn has been planted. Trials have been established as part of this project in Centre, Sullivan and Bradford Counties. Establishing ‘relay crops’ in this manner, could provide for well-established cover crops without impacting the yield and growth of the primary crop. Similar studies at other institutions, where cover crop establishment was delayed until after the crop was up and growing, have shown favorable results but these studies were conducted on tilled fields.
The patent-pending Penn State interseeder is designed to function in notill and reduced-tillage fields with minimal disruption to the soil surface. And, since interseeding often coincides with sidedressing and postemergent herbicide applications, the Research Farm staff added these capabilities to the machine. The goal with the design of the interseeder was to develop an affordable machine that could do the interseeding effectively as well as improve the application of the fertilizer and herbicide. With the interseeder, a producer could combine the fertilization and spraying into one operation and seed a cover crop at the same time, eliminating the extra cost of seeding.
Use of the machine on the research farm over past year has been promising and on-farm evaluations across Pennsylvania are underway. Four planters have been built and deployed. The hope and expectations are that the interseeders will be able to improve crop yields, reduced runoff and leaching and increase farm profits at the same time.
County Agricultural Agent