Soil Health Status Baseline Development Using Soil pH Monitoring on Three Hilltop Soil Map Units at Prairie View A&M University
Armondo D. Waters Mentor: Dr. Richard W. Griffin Cooperative Agricultural Research Center Agriculture, Nutrition, and Human Ecology Department Introduction: Soil pH, also known as soil reaction, is a measure of the acidity or alkalinity (basicity) of the sample. The results can provide some indication of the potential availability of nutrients to plants, if the soil nutrient level is adequate for plant growth (Shoeneberger et al., 2012). Soil pH is a primary indicator for soil health as well as soil quality, since it provides a reflection of growth potential for beneficial plants such as row crops (annual), pasture (grazing or hay), shrubs and trees (permaculture). This project provided an opportunity for an agriculture student to gain practical, technical, and “hands on” knowledge about an important chemical indicator (pH) of soil and water conditions that can also be used to infer additional knowledge about soil health status and the growth potential for beneficial plant and weed species. Materials and Methods: Soil pH was measured using the 1:1 soil to deionized water method described in the USDA NSSL methods manual (USDA NRCS, 2004). The Water pH was measured using a portable probe that was calibrated using the 3point standardization method. The soil samples were collected from 7 locations in the Hockley, Kenney, Mentz, and Mockley soil units at the following depths (inches): a) 0-4, in soil pits with water and at 72 inches in soil pits that were dry, in order to access the pH conditions in the following locations: topsoil and subsoil. Triplicate (3) samples of soil and water, from each Soil Pit, were used to produce the mean and standard deviation values for the statistical analyses. Results and Discussion: Soil pH data from the 6 Soil Pits and 1 Pond Dam samples within the individual soil units provided spatial variability information that assists the overall project goals of baseline assessment with an aim of providing higher quality land management in future agricultural operations. Water pH data from 3 Soil Pits and 1 Pond adjacent to the property were monitored to compare with the soil pH values surrounding the same sites. In addition, data from a previous study by UGRA student, Zulfa Eisa, was used as an additional comparison to determine spatial variability by landscape position, soil type, and elevation on the property. Note: The following discussion will use these abbreviations: 1-6 represent the Soil Pit numbers; Pa – Pond adjacent to the 90-acre property; Pd – Pond dam on 90-Acre property; Pe – Pond East sampling site from ZEisa study; Pn – Pond North sampling site from ZEisa study; Ps – Pond South sampling site from ZEisa study; and Pw – Pond West sampling site from ZEisa study. A statistical comparison of Soil Pit Soil and Water pH Values indicated that at Soil Pits 1, 3, and 5, the Soil pH values (7.55, 6.49, and 7.96, respectively) were significantly lower (p<0.05) than the Water pH values (8.88, 7.15, and 9.34, respectively). In addition, at the Pond Dam and Pond Adjacent to the 90-acre property, the Soil pH value (6.20) was significantly lower (p<0.05) than the Water pH value (7.56). A comparison of Soil Pit Soil and Water pH Values by Elevation (Ordered) indicated that the elevations ranged from 265 to 289 feet above mean sea level. A comparison of Soil Pit Soil and Water pH Values (Ordered) by Elevation indicated that the highest Water pH value (9.34) occurred at Soil Pit 5 at the highest elevation (289). A comparison of Soil Pit Soil (Ordered) and Water pH Values by Elevation indicated that the highest Soil pH value (7.96) occurred at Soil Pit 5 at the highest elevation (289).
Conclusions: The most important conclusions at this point within the research project include: 1) Soil pH values at Soil Pits 1, 3, and 5 were significantly lower (p<0.05) than the Water pH values as well as at the Pond Dam compared to the Pond Adjacent to the 90acre property; 2) This observation indicated that the acidity of the soil is not significantly lowering the pH of the water in the ponds either on or adjacent to the property; 3) The highest Water pH value (9.34) occurred at Soil Pit 5 at the highest elevation (289); and 4) The highest Soil pH value (7.96) occurred at Soil Pit 5 at the highest elevation (289). Future Research Project Work: The project was continued in the Spring 2021 semester with additional sampling of the Soil Pits, the surrounding surface soils, and ephemeral surface water that may be present during the winter and early spring periods. The additional data was analyzed Page 108 statistically and compared to the previously collected and analyzed dataset. of 3
