Potassium Dynamics in US Coastal Plain Soils

作者：Mitchell Charles C^*; Huluka Gobena

来源：Communications in Soil Science and Plant Analysis, 2016, 47(sup1): 54-63.

DOI：10.1080/00103624.2016.1232096

• Long-term experiment
• potassium accumulation
• Potassium depletion
• potassium mineralization
• potassium movement
• soil test K
• subsoil K

Potassium (K) deficiency in crops in southern US Coastal Plain soils has been documented since the l880s. Long-term soil fertility studies such as Alabama's Cullars Rotation experiment (circa 1911) have been conducted with K since 1911. Other Alabama long-term experiments on several Coastal Plain and related Hapludults, Paleudults, and Kandiudults also contain K variable treatments which have been monitored since 1929. Soil test data from these long-term experiments have allowed us to answer some practical questions regarding K dynamics in Coastal Plain soils. Potassium movement through the soil profile is dependent on the soil's cation exchange capacity (CEC) but relative accumulation is greater in the plow layer regardless of soil CEC. While subsoil K testing may be useful for identifying situations where subsoil K has been depleted, this extra effort and expense is not necessary for most cropping situations. A crop will remove most of its K from the plow layer if it is present in sufficient quantity based on soil test. Crop depletion of plow-layer K to the point where yield may be reduced is gradual and may take 10-15years or more depending upon soil CEC and initial soil K concentration. Depletion is most rapid in low CEC soils as would be expected. However, soil test K can vary considerably during the course of a crop season with the lowest soil test K concentrations occurring immediately after harvest.

• 出版日期2016