Systems and methods for measuring the content of an element in a soil comprises: a neutron source for irradiating the soil with neutrons; a detector assembly configured to detect an INS gamma spectrum of the soil; an instrument for measuring a moisture content of the soil; and a processor in communication with the detector assembly, the processor configured to: apply a moisture calibration coefficient to calculate a net peak area of a characteristic peak of the element in the INS gamma spectrum, the moisture calibration coefficient calculated to account for the moderation of fast neutrons by hydrogen atoms of water present in the irradiated soil at the location under analysis; and generate a concentration of the element in the soil. The instrument for measuring a moisture content of the soil may comprise the detector assembly. Systems and methods incorporating a temperature-controlled housing for the gamma detector assembly are also provided.

A method for identifying a soil texture class of a soil using gamma analysis comprises: acquiring an inelastic neutron scattering (INS) gamma spectrum of the soil; calculating at least one ratio of a mass fraction of a first oxide to a mass fraction of a second oxide present in the soil, wherein the mass fraction of each of the first and second oxides is determined from calculating a contribution to a characteristic peak in the gamma spectrum of the soil by each oxide of the first and second oxides; and identifying one or more soil texture classes of the soil by identifying a contour line of a contour plot that corresponds to the calculated at least one ratio, wherein the contour line correlates the calculated at least one ratio to one or more soil texture classes. A mobile system for gamma analysis determination of soil texture is also provided.