|FREDERICK, JAMES - Clemson University|
|Watts, Donald - Don|
|KARLEN, DOUGLAS - Retired ARS Employee|
Submitted to: Sustainability
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/14/2021
Publication Date: 4/15/2021
Citation: Novak, J.M., Frederick, J.R., Watts, D.W., Ducey, T.F., Karlen, D.L. 2021. Corn stover removal responses on soil test P and K levels in Coastal Plain Ultisols. Sustainability. 13:4401. https://doi.org//10.3390/su13084401.
Interpretive Summary: Corn stover is often removed from fields for bioenergy production. Removing corn stover from the field, however, can result in soil fertility declines because plant nutrients such as phosphorus (P) and potassium (K) are not recycled back into soil. This is not a sustainable practice, so there is a need for information on how much P and K are removed with harvested corn stover. Thus, we conducted a study that determined impacts of crop stover removal (0, 25, 50, 75 and 100 percent by weight) on soil P and K concentrations. After 5 years of field experimentation, we found that removing between 25 and 100 percent corn stover increased soil P and K removal by 2 to 7 and 37 to 97 kilograms per hectare. Our results showed that significant P and K concentration reductions occurred with removal of greater than 50 percent stover. We concluded that additional P and K as fertilizer should be added to soil especially if greater than 50 percent corn stover is removed.
Technical Abstract: Corn (Zea mays L.) stover is used as a biofuel feedstock in the U.S. Selection of stover harvest rates for soils is problematic, however, because excessive stover removal may have consequences on plant available phosphorus (P) and potassium (K) concentrations. Our objective was to quantify stover harvest impact on soil P and K concentrations in the southeastern U.S. Coastal Plain. Five stover harvest rates (0, 25, 50, 75 and 100 percent by weight) were removed for five years (2008 to 2012) from replicated plots on highly weathered, toposequential Coastal Plain Ultisols. Grain and stover mass with P and K concentration data were used to calculate nutrient removal. Mehlich 1 (M1) extractable P and K concentrations and bulk density were used to monitor changes within the soil. Grain alone removed an average of 13 to 15 kilograms per hectare (kg/ha) P and 15 to 18 kg/ha of K each year, resulting in a cumulative removal of 71 and 85 kg ha-1 or 78 and 38 percent of the P and K fertilizer application, respectively. Harvesting stover increased nutrient removal such that when combined with grain removed a total of 88% to 115% of the applied P and 82 to 215% of fertilizer K. This caused soil M1 P and K levels to decline significantly the first year and even with annual fertilization to remain relatively static thereafter. We conclude P and K fertilizer recommendations should be reviewed and that stover harvest of > 50% by weight will significantly decrease soil test M1 P and K concentrations.