Root distribution and demography in an avocado (Persea americana) orchard under groundcover management systems

Abstract

The effect of groundcover management systems on root demography and distribution of newly planted avocado (Persea americana Mill) trees was examined using minirhizotron techniques. We evaluated three groundcover systems: (1) bare soil (BS), pre- and post-emergence herbicides; (2) vegetation strip (VS), post-emergence herbicide applied in a 1-m wide strip centred on the tree row plus a groundcover mixture seeded between tree rows; and (3) complete groundcover (GC), covering the entire surface of the plots. Root production was higher in the non-bearing year (2009–10) than in the bearing year (2010–11). Trees in the BS plots had more roots of bigger diameter in the top 30 cm of soil and trees in VS and GC plots had more roots in the 30–60 cm depth and of smaller diameter. Lifespan of spring-born roots were 61 and 59% greater than those born during autumn and summer, respectively and soil depth and root diameter were positively correlated with root longevity. Lifespan of thinner roots (<0.2 mm) in the BS and VS plots were 49 and 33% greater than GC respectively. Avocado trees grown in contrasting condition compared with their native habitat show high morphological root plasticity, in response to resource and non-resource competition when grown in mixed stands.

Root-zone management practices impact above and belowground growth in Cabernet Franc grapevines

“…, Atucha et al. ). The area around the MR was kept weed‐free, weeds were manually pulled when they appeared throughout the season; therefore, only grapevine or cover crop fine roots were observed.…”

“…The hazard is defined as ‘the mortality rate for a root at time t , where t is the product of a baseline hazard function of k covariates’ (Atucha et al. ). In addition, within the AR and BW treatments, the Cox proportional hazards regression model was run to test the effect of neighbouring cover crops, that is cover crop fine root that was present along with a grapevine fine root in the same MR window, on the grapevine lifespan.…”

“…, Atucha et al. ). In order to understand the means by which RZM may control vine size and affect physiological processes, it is crucial to provide information on fine root dynamics and lifespan, as fine roots are responsible for the majority of water and nutrient uptake (Atucha et al.…”

“…, Atucha et al. ). We are not aware, however, if the use of annual cover crops will induce a similar response due to the shorter period of time they are in the vineyard, that is 5 or 6 months before growers hill‐up the soil from around the graft union.…”

“…In order to understand the means by which RZM may control vine size and affect physiological processes, it is crucial to provide information on fine root dynamics and lifespan, as fine roots are responsible for the majority of water and nutrient uptake (Atucha et al. ). Under‐trellis cover crops may cause a substantial variation in the spatial resource availability in the soil profile, as well as in the soil health (Sánchez et al.…”