Winter rye cover cropping to improve water quality in corn-based cropping systems

Abstract

Winter rye (Secale cereale L.) cover cropping as a best management practice aimed at improving surface water quality by providing more ground cover, retaining nutrients, and preventing movement of surface water that carries nitrogen, phosphorus, and sediment to rivers, lakes, and streams. These four studies evaluated winter rye effects on surface water quality using different seeding methods in a variety of cropping systems. The first study (chapter 1) evaluated surface water quality under a one hour simulated rainfall event using different seeding methods of establishing winter rye following soybean (Glycine max L.) in fall and spring. Aerial, airflow, and broadcast seeding methods provided optimal winter rye ground cover to reduce surface runoff, NO3-N, NH4-N, phosphorus, and sediment compared to fallow. The second study (chapter 2) evaluated surface water quality under a one hour simulated rainfall event using different management practices of winter rye following corn (Zea mays L.) stover removal for silage in spring of 2010 and 2011. Standing and harvested rye treatments reduced surface runoff, NO3-N, NH4-N, phosphorus, and sediment compared to fallow, with standing rye being superior to harvested rye. Harvesting the rye for forage or bedding still provided exceptional environmental benefits for improving water quality compared to fallow. The last two studies (chapters 3 and 4) monitored and evaluated surface runoff in a paired watershed design. The longitudinal limitations of these studies provided insufficient results to conclude if winter rye was effective at reducing surface runoff and improving water quality at the field edge. Overall, simulated rainfall studies showed that winter rye was effective at reducing surface runoff and improving water quality, but the results of field scale studies were less clear.