addition to a yield sensor a moisture sensor 122 may also be placed inside the clean grain tank 110 there are various ways to implement a moisture sensor 122 available in the art one such common type of moisture sensor 122 is a capacitive sensor a capacitive sensor measures moisture by monitoring the change in the dielectric properties of grain another common type of moisture sensor 122 uses near infrared nir wavelengths of light to detect moisture this is done by shining two different wavelengths of nir on a sample one of the wavelengths is calibrated for moisture and the other as a reference the ratio of the two signals is derived electronically to calculate the moisture content the convoluted nature of nir spectra can require broadband illumination a spectrometer and chemo metric calibration methods to accurately extract moisture often the moisture sensor 122 collects samples of crop 405 in the clean grain tank 110 in a funnel shaped cup performs the analysis and then releases the crop 405 such that it drops to the bottom of the tank 110 and can be offloaded subsequently by an unloading auger 402 one improvement on the prior art use of nir moisture measurement is the used of two or more.