Floating lysimeters were used to measure evaporation from bare soil and evapotranspiration from a potato crop during three consecutive seasons. Evaporation from bare soil amounted to 87.5% of the water lost by evapotranspiration from the crop. Moisture loss from the bare and cropped areas differed only for a short period of time at mid-season. It was concluded that, during this period, plant roots utilized moisture stored at depths beyond which water was available for evaporation. Later in the season when this source of water was exhausted losses from the two areas were again equal. Moisture conservation by summer-fallow was limited to that amount which was stored at a depth penetrated by plant roots but unavailable to evaporation from the bare surface. The amount of water conserved in these experiments was small but probably dependent upon the moisture characteristics of the soil, the depth of root penetration, and the frequency with which the soil moisture reservoir was recharged during the growing season.
A Novel Simplified Algorithm for Bare Surface Soil Moisture Retrieval Using L-Band Radiometer