Protect Your Investment by Eliminating Tillage and Keeping Residue

This fall, field observations with significant amounts of intensive tillage and residue removal provide an opportunity to rethink such practices by considering research proven practices such as no-tillage (NT) and strip-tillage (ST), which have demonstrated their effectiveness in many parts of the state and across the Midwest. Many studies from the Midwest and elsewhere have documented the economic benefits of NT and ST for both corn and soybean, where the conventional tillage input cost was greater than that of NT and ST by $15-25/acre in a study covering 14 years of tillage and crop rotations in Iowa

Development of a Soil Carbon Index for Iowa Mineral Soils

A carbon index (Cl) is one of many soil quality indicators that depends on organic carbon concentration. One of the values of a soil carbon index is in determining the impact of agriculture practices (i.e., tillage, crop rotation, N management, etc.) on soil organic matter status of mineral soils. Interactions of climate, parent material, topography, time, and organisms including human activities influence soil organic carbon (SOC). This study developed a soil carbon index for mineral soil map units in Iowa using data collected by the Iowa Cooperative Soil Survey Laboratory and the USDA Soil Survey Laboratory for over 2,300 soil map units across the state in the past 20-30 years. The results show that the soil CI is highly influenced by soil forming factors. The highest soil carbon index was associated with soil map units of soils that are poorly drained, have moderately fine textures, and are on relatively flat topography as in the Clarion-Nicollet-Webster soils association area in north-central Iowa. Additionally, there was a negative correlation between the number of hectares of soils formed under deciduous forest vegetation and CI values within a county. The CI is also related to soil productivity in the state. Fifty five percent of the variability of the corn suitability ratings was explained by the CI. The CI is a valuable tool in evaluating soil organic matter status, productivity of Iowa soils, and land valu