NMR is based on the interaction between nuclear magnetic moments and applied static and radio frequency magnetic fields [1]. The magnetic nuclear spins are aligned using a constant magnetic field and perturbed using a radio frequency pulse at a certain frequency. Different nuclei (e.g. hydrogen) require different resonant frequencies for perturbation and so the energy absorbed at a set resonant frequency can be related to quantity.
Measurement of subsurface free water properties [2].
A tractor mounted NMR instrument has been developed for soil water content [3].
Hardware requirements (large size and high cost)
Research.
1. Paetzold, R.F., Matzkanin, G.A. and De Los Santos, A. 1985. Surface soil-water content measurements using pulsed nuclear magnetic resonance techniques. Soil Science Society of America Journal, 49: 537–540.
2. Lubczynski M, Roy J. 2004. Magnetic resonance sounding: new method for ground water assessment. Ground Water 42: 291–303.
3. Paetzold, R.F., Matzkanin, G.A. and De Los Santos, A. 1985. Surface soil-water content measurements using pulsed nuclear magnetic resonance techniques. Soil Science Society of America Journal, 49: 537–540.