Nitrogen Rate Comparison in Corn Following Green Manure Cover Crop Mixes
In a Nutshell
Various green manure cover crop mixes can successfully be established following the harvest of a small grain crop in mid-summer. Following cereal rye seed harvest in July 2015, farmer-cooperator Tim Sieren seeded a brassica mix into one field and a legume mix into another field. He then compared 2016 corn yields resulting from a Low and High N fertilizer rate that followed the green manure mixes in the separate fields.
Regardless of the green manure mix it followed, corn yields were significantly greater with the 145 lb N/ac (High) rate compared to the 95 lb N/ac (Low) rate. Wet summer months likely contributed to the superiority of the High N rate in terms of both yield and financial returns in 2016.