Portable forecasting ruler for crude protein of alfalfa grass land

A portable forecasting ruler for crude protein of an alfalfa grass land comprises a plurality of short rulers, wherein a pin shaft is arranged at the end part of each short ruler; the plurality of short rulers can be sequentially connected in a rotating manner through the pin shafts, so that the forecasting ruler can be folded and unfolded; length scales and crude protein content scales corresponding to the length scales are arranged on the surface of the forecasting ruler; a gasket for preventing the abrasion of each pin shaft is arranged between each pin shaft and each short ruler, and is clung to the surface of each short ruler; the length and width of the plurality of short rulers are the same; and the short rulers are made of stainless steel material. According to the portable forecasting ruler, the operation is convenient, the forecast is precise, and the portable forecasting ruler is suitable for the application of professionals of grassland farming and pratacultural science.