मृदा नमी स्थिरांक: क्षेत्र क्षमता, स्थायी म्लानि बिंदु एवं उपलब्ध जल

A sample of moist soil with a wet mass of 1.0 kg and a volume of 0.64 liters (\(6.4 \times 10^{-4}\text{ m}^3\)) was dried in the oven and found to have a dry mass of 0.8 kg. Assuming the typical value of particle density (\(2650\text{ kg/m}^3\)) for a mineral soil, what will be the volumetric moisture content?

What is the equivalent depth of water contained in a soil profile of 1 m deep, if the mass wetness of the upper 0.4 m is 15% and that of the lower 0.6 m is 25%? Assume a bulk density of \(1200\text{ kg/m}^3\) in the upper layer and \(1400\text{ kg/m}^3\) in the lower layer:

Which of the following term represents an empirical measurement supposed to represent the soil profile's ability to retain water after the process of internal drainage has ceased?