No‐Till Corn/Soybean Systems Including Winter Cover Crops

Abstract

The use of winter cover crops (WCC) such as hairy vetch (Vicia villosa Roth) and cereal rye (Secale cereale L.), in a corn (Zea mays L.)–soybean [Glycine max (L.) Merr.] rotation provides long‐term benefits that are generally overlooked. There is a particular lack of information regarding the effects of WCC on soil physical and chemical properties. The objective of this study was to assess the effects of four crop sequences (C/S, corn‐fallow/soybean‐fallow; C‐R/S‐R, corn‐rye/soybean‐rye; C‐R/S‐V, corn‐rye/soybean‐vetch; and C‐R/S‐VR, corn‐rye/soybean‐vetch and rye) under no‐till on several soil physical and chemical properties. Soil chemical properties included soil organic matter (SOM), pH, total nitrogen (TN), nitrates (NO3–N), and available phosphorus (P). The analyzed soil physical properties analyzed were: water‐aggregate stability (WAS), bulk density (Db), penetration resistance (PR), total porosity (TP), pore‐size distribution, water retention properties, and saturated hydraulic conductivity (Ksat). The experimental design was a split‐split‐plot where whole‐plot treatments (sampling period) had a Latin square design and subplot treatments (crop sequences) were arranged in a randomized complete block design with four replications. Compared with winter fallow, crop sequences that included WCC provided substantial benefits from the soil productivity standpoint. Specifically, the use of the C‐R/S‐V or C‐R/S‐VR increased SOM down to 30 cm. All WCC sequences improved WAS with increases of 9, 13, and 17% for C‐R/S‐R, C‐R/S‐V, and C‐R/S‐VR, respectively. Winter cover crop sequences reduced Db and PR of the soil surface and increased total and storage porosity along with plant available water. While the C‐R/S‐V sequence was the most effective in reducing soil NO3–N, the C‐R/S‐R sequence was the most effective in fixing soil P.