Foreground: continuous cotton, no legumes, over 126 years; background cotton- 3 yr rotation includes winter legumes
The “Old Rotation” trial at Auburn University, AL has been continuously managed since 1896 (126 years) and is one of 3 of the oldest running research plots in the USA (in Europe, the Rothamsted plots have been running 160 years). Recent monitoring of the Auburn plots reveals the great value to soil quality (and nutrient mineralization potential) of inclusion of soil building crops (winter legumes) in the rotation. Without proper crop and nutrient management, the study shows soil quality and crop yields will decline steadily to very low levels. The more remarkable feature is the fact that soil degradation is as slow as soil building – in other words, good soil care and rotations (which might include composts or farm manure as do the Rothamsted plots) takes time to improve soils. According to published reports, soil organic carbon (SOC) was “dramatically affected by conservation tillage and crop rotations”. Woods End’s Brinton visited the plots and previously worked on long-term trials in Sweden as part of his Masters in Agriculture. Brinton stressed the value of the long term studies to understand realistically the benefits of organic matter to soil quality. Woods End plans to work with scientists on the long term plots to show how soil respiration is an excellent overall indicator of soil quality improvements. Sadly, continuance of the long term plots is threatened by budget cuts.