By looking at the following pictures, picture one is soybean stubble that was tilled last fall and this spring on 4/24, picture two where there was a rye cover crop planted into soybean stubble last fall, the rye is about 7 inches tall, which treatment would you guess had the higher 2 inch soil temperature overall the last few days when there was air temps in the 37-52 degree range? 

(hovdes near data logger 4 24 2016.jpg)

(larkins north soybean stubble rye cover 7 in high 4 29 2016.jpg)

hovdes near data logger 4 24 2016.jpg (151KB - 122 downloads)

larkins north soybean stubble rye cover 7 in high 4 29 2016.jpg (170KB - 113 downloads)