Calcium Inputs for Soil Quality Improvement
Studies were established to evaluate the potential benefits of lime and gypsum on soil quality factors and crop production. Results to this point indicate soybean yields have been best with 4 ton per acre or with 1400 pounds gypsum per acre. Corn yield data is limited at this point in the study, but seems to be less affected by lime or gypsum application. Liming improved soil aggregate stability. Neither lime nor gypsum has altered water infiltration rates or the soil bulk density. Changes may occur with more time.
Demonstrate the effects of calcium amendments on soil quality and corn/ soybean yields.
Establish a database for advising farm regarding the benefits of using calcium soil amendments.
Facilitate measurement of soil quality factors in farmer-initiated field experiments with calcium amendments.
Establish a total of six farmer cooperator fields with calcium treatments for intensive study of effects on soil quality properties and corn yield.
Provide advice and yield analysis for other farmer-managed lime/gypsum demonstration sites in Mid-Michigan.
Enhanced awareness of soil and watershed quality issues.
Enhanced awareness of the effects of calcium in soil quality.
Five field sites have been established to evaluate and demonstrate the effects of calcium additions on soil quality and crop production. Two of the study sites had Calcitic lime spread and incorporated (chisel plow) at 0, 2, 4 and 8 tons per acre in the fall of 2000. One site had gypsum spread at 0, 200, 1400 and 2100 pounds per acre in the spring of 2002. Gypsum was spread at the same four rates on two additional fields during 2004, one in the spring and one in the fall. Each of the treatments was spread in strips completely across the fields. The strips were randomly assigned in a randomized complete block design. Each field has at least four replications of the treatments. Soil samples have been collected from plot areas in all fields to track changes in extractable calcium values. Soil cores have been collected in the two limed fields to evaluate soil bulk density and strength of soil aggregates. Water infiltration measurements were taken in two fields in the fall of 2004. Crop yields have been determined by yield monitors on the farmers’ combines. Application of gypsum (2100 lb/A) increased the calcium test value 81 ppm and decreased the magnesium test value 31 ppm changing the Ca:Mg ratio form 4.0 to 4.7 over a period of 8 months. Application of 2100 lb gypsum/A or 8 ton of lime/A had no significant effect on the soil bulk density over 8 month and 2 year periods, respectively. Water infiltration measurements were quite variable among the three clustered measurement sites within each treatment strip location. Hence, differences were hard to evaluate and no obvious differences occurred. Stability of various size aggregates, measured with a slaking method, was better for aggregates in areas treated with 8 tons lime/A in 2000 compared with aggregates no receiving lime. When the aggregates were humidified first there was less difference in apparent stability. Soybean yields were variable for treatments across replications, but there has been a trend for yield to increase with lime rate. In the field where gypsum was applied in early spring 2004, the average soybean yield was highest with 1400 lb gypsum/A (43.5 bu/A vs 40.6 bu/A with no gypsum). Corn yields tended to be less affected by the application of lime or gypsum.
Impacts and Contributions/Outcomes
Impact and Contributions:
Effects of calcium additions on soil quality need time to be manifested so short term results (1 year) may not be indicative of the eventual observations. Application of calcium as Calcitic lime or gypsum has had limited effects on soil quality. The primary impact of calcium additions has been the trend toward higher soybean yields, 2 to 6 bushels per acre. For this practice to provide monetary gain the effects need to be valued over at least 3 years. Collection of cumulative data over the next two years will provide more value to this study.