A comparison between minirhizotron and soil coring methods of estimating root distribution in young almond trees under trickle irrigation

SummaryThe minirhizotron method and the soil coring method were used to study the development of the root system (down to 105 cm) of almond trees cv. Atocha on ‘Pestaneta’ almond rootstock. The study was carried out during the first years of development of the trees under trickle irrigation. Most of the roots (about 80%) developed within the wetted zone of the trickle line in the top 60 cm of soil. The greatest root length density (RLD) was within 30 cm of the soil surface but decreased rapidly with depth. Outside the wetted zone, the greatest root development occurred at about 60 cm depth. When the RLD values obtained by the minirhizotron and soil coring methods were compared, the former was seen to underestimate the RLD values particularly in the top layers of soil so much so that the root distribution patterns established by the methods were not comparable. However, a significant relationship was established between the measurements obtained by both methods at different soil depths.