We investigated the effects of growing media amendment with organic fertilizers and vegetable species on soil temperature (T), thermal conductivity (K), thermal resistivity (R), thermal diffusivity (D) and volumetric heat capacity (C). The study was conducted from June to September 2011in a greenhouse at Lincoln University. One hundred and twenty pots were filled with Fafard organic soil and amended with three organic fertilizers: Cottonseed meal (6-2-1), Dried Blood (12-0-0), Garden Food (4-3-2) and NPK(13-13-13). A control treatment made of non-amended Fafard organic soil was also included in the study. The experimental design was a completely randomized block with 5 fertilizers treatments and 3 vegetables replicated 8 times. T, K, R, D and C were monitored throughout the four months of this study using a KD2-Pro Thermal Meter. Soil moisture and soil water potential were also measured. Results showed that soil thermal properties were: 29.81oC, 0.34 W/moK, 3.56 moK/W-1, 0.16 mm/s and 2.09 MJ/m3oK for T, K, R, D, C respectively at the beginning of this study in June 2011 and slightly increased (T, K, C) and decrease (R, D) after four months of study in September 2011. Fertilizers did not significantly affect soil thermal properties. However, vegetable type significantly affected R (p=0.002) during the second month, and also K (p=0.022), R (p = 0.0001) and C (p=0.004) during the fourth month of this greenhouse study. More studies are needed for a better understanding of the effects soil amendment and plant growth on soil properties of the growing media.
Asbtract of oral presentation at Missouri Academy of Science, 2012 (April 4) University of Missouri-Columbia