Submitted to: New Phytologist
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/24/2005
Publication Date: 8/1/2005
Citation: Comas, L.H., Anderson, L.J., Lakso, A.N., Eissenstat, D.M. 2005. Canopy and environmental control of root dynamics in a long-term study of Concord grape. New Phytologist. 167(3):829-840. Interpretive Summary: Information on root production and lifespan has important implications for water and nutrient uptake, crop productivity and below-ground carbon and nitrogen cycling. This study looked at how irrigation and pruning practices affected the production, death, and decomposition of Concord grape roots. Minimal canopy pruning resulted in earlier canopy development and caused peak root production to occur one month earlier than under conventional pruning. Roots were also concentrated at shallower soil depths under minimal pruning. Root production in non-irrigated treatments was limited in the later part of the season and roots were distributed more deeply in the soil profile than under irrigation. There did not appear to be any relationship between crop yield and current season root production. Heavy crop yield stimulated early season root production in the following year. The pruning and irrigation treatments had little or no effect on root death and decomposition . Minimal canopy pruning is a relative new cultural practice that could reduce plant stress and grower labor costs. This study suggests that minimal pruning will not have adverse effects on roots.
Technical Abstract: Minirhizotron techniques were used to examine root dynamics and distribution in Vitis labruscana (Concord grape) under two levels of winter pruning (minimal and heavy/'balanced') and irrigation (with and without). Timing of production, pigmentation, death and disappearance of roots down to a 110 cm depth of soil were determined over four years (1997-2000) of varying rainfall. Peak root production under minimal canopy pruning occurred approximately one month earlier than root production under conventional pruning, corresponding to the earlier canopy development under minimal pruning. Under minimal canopy removal treatment, roots were produced in shallower soil depths, likely due to higher soil temperatures in more shallow than deeper soil layers in the early season. As expected, root production in dry years without irrigation was limited in the later part of the season. Roots in non-irrigated treatments were produced more deeply in the soil. Surprisingly, root distribution in dry years did not have lasting effects in subsequent wet years. Canopy removal and irrigation regimes did not affect timing of pigmentation and death of fine roots. Root decomposition was affected by these treatments only in one year when a dry year followed a wet year with high root production. Heavy crop yield stimulated early season root production in the following year. There did not appear to be any relationship with crop yields and current season root production. These results are relevant to fertile sites with seasonal but generally adequate rainfall.