ROOT DISTRIBUTION MODELS APPLIED TO PEANUTS

Greater understanding of root distribution and water uptake can lead t o improved modeling of water transport processes in the soil-plant-atm osphere system. Peanuts (Arachis hypogaea L.) were grown in the field under both well-irrigated and limited-irrigated conditions. On four di fferent sampling dates, root length density (RLD) data were obtained a t eight depths and in three locations relative to the crop row. The RL D tended to be substantially greater at shallow depths in the crop row , and to be more uniform with depth for sampling locations away from t he crop row. Linear and exponential models were developed for represen ting the spatial distribution of roots in either one or two dimensions . The exponential model better described the observed peanut root dist ributions. A normalized root length density was used to determine rela tive root distributions over four equal depth increments.