Train the youth! Effect of water stress and intercropping on peach tree growth after plantation

Abstract

The successful performance and stability of agroforestry systems relies on reduced competitionfor light and soil resources between trees and the intercrop. One management strategy couldtherefore be to ensure that the crop roots are well distributed in the upper soil horizons, whiletree roots are encouraged to forage in deeper horizons. In order for the latter to happen, thetree roots must have optimal growing conditions and at the same time be excluded by intensecompetition with crop roots from the upper soil horizons. One way of favouring optimal rootgrowth is to diminish the shoot carbon demand so that carbon is diverted towards roots insteadof shoots. Then combining shoot growth reduction with cover crop competition in the upper soilshould force tree roots to grow deeper.Shoot growth can be diminished through water stress, but net photosynthesis must remain at itsmaximum in order to maintain carbon fixation and allocation to roots. Our hypothesis is thatthere is a level of moderate water stress at which photosynthesis is not diminished while shootgrowth is (Pellegrino et al, 2006). This study aims to investigate the effects of moderate waterstress and grass intercrop competition on early shoot growth and net photosynthesis of peachtrees during the first two growing seasons after plantation