A Comparison of Methods of Measuring Soil Moisture under Field Conditions¹

Latitudinal variation in behaviors linked to risk tolerance is driven by nest-site competition and spatial distribution in the ant Temnothorax rugatulus

“…However, it had not rained for a minimum of 5 days before soil samples were collected, minimizing the effect of recent precipitation. Samples were weighed before and after being placed in an oven at 105°C for 5 h. This process allows for a measure of soil water content (Kelley et al 1946). Canopy cover (environmental stressor)…”

Evaluation of the Intrinsic Performance of Electrical-Resistance Units for Measuring Soil Moisture

“…Uniformity and precision are other desirable characteristics of moisture blocks. Kelly et al (7) said that it was important that the pore-size distribution of all blocks be very similar because water drains faster from the larger pores at lower tensions (higher water potential) than from smaller pores. Anderson and Edlefsen (1) suggested that, to ensure unquestioned simi-larity iii characteristics of the blocks, such factors as mix-proportion, mixing time, and pouring time must be carefully reproduced in the construction of each block.…”

A Comparison of Electric Resistance Units for Making a Continuous Measurement of Soil Moisture Under Field Conditions

“…Hydrologic research2 (16), war production problems involving guayule culture (11,12), and many other investigations ranging from field irrigation to greenhouse studies have made use of this technique. Briefly, the method consists of imbedding within the soil a plaster of Paris block containing two electrodes.…”

“…At a constant temperature, the electrical resistance of this absorbent material varies with its moisture content, which, in turn, varies according to the magnitude of the forces exerted by the surrounding soil. A determination of block resistance thus gives a measure of these soil moisture forces, a measurement which can be made with a high degree of accuracy and reproducibility within the moisture range that is of significant importance to growing plants (12).…”