Forest production responses to irrigation and fertilization are not explained by shifts in allocation

Abstract

Production increases in intensively managed forests have been obtained by improving resource availability through water and nutrient amendments. Increased stem production has been attributed to shifts in growth from roots to shoot, and such shifts would have important implications for belowground carbon sequestration. We examined above and belowground growth and biomass accumulation and distribution in two eastern cottonwood clones and American sycamore receiving irrigation (I), fertilization (F), or irrigation + fertilization (IF) and compared with non-treated controls (C). Aboveground growth and biomass accumulation responded positively to both I and F in all genotypes. After three growing seasons, the largest trees were sycamore receiving the IF treatment, with a total mean annual biomass production of 9.4 Mg ha À1 yr À1. Total cottonwood mean annual biomass production in both clones was >5.0 Mg ha À1 yr À1 in the IF treatment. Aboveground biomass production was 6.3 and >3.1 Mg ha À1 yr À1 for sycamore and cottonwoods, respectively. Total root mass fraction was lower in high resource treatments and declined as stands aged. To compare allocation in trees of equal size, we used allometric relationships between above and belowground tissue. Allometric relationships between woody perennial tissues rarely differed among treatments. Improved resource availability caused large increases in growth and consequently accelerated development, but it had little effect on belowground allocation that was not explained by development. Reports of shifting belowground allocation due to soil resource availability must account for developmental effects if they are to accurately evaluate direct impacts of soil resources. #

Biochar as a Substitute for Vermiculite in Potting Mix for Hybrid Poplar

“…5), they may be important for other species which are prone to specific nutrient deficiencies (e.g., Ca in tomatoes) or sensitivities (e.g., Na in beans), and therefore additional research with a wider variety of poplar clones and other crops is recommended. Such studies should account for the initial cutting diameter and changes in biomass allocation associated with plant development, which were found to have significant influences on tree growth in this study and are consistent with previous research [29,30]. While vector analysis suggested possible pre-fertilizer transfer of N (biochar and vermiculite treatments) and Ca (vermiculite treatment) from the shoots to other tissues (see Fig.…”

“…In addition, the nutrient content of each tissue (determined by multiplying the measured nutrient concentration by the dry weight of the tissue) and total biomass (determined by summing the dry weights of the tissues) were similarly evaluated, again with initial cutting diameter as a covariate. For shoot/root biomass ratio, shoot biomass was used as the covariate based on previous research showing the influence of tree development on biomass allocation [30]. The potting mixes were tested for differences in pH, CEC, ECEC, and nutrient concentrations and contents.…”

Effects of salt stress on eco-physiological characteristics in Robinia pseudoacacia based on salt-soil rhizosphere

“…The similar result was also found by Fernández-García et al (2014) and Glaeser et al (2016). However, Li et al (2016) didn't find the significant change in root/shoot ration for R. chinensis, which may be controlled by the genes in plants (Coyle and Coleman, 2005).…”

Spatial and temporal patterns of root distribution in developing stands of four woody crop species grown with drip irrigation and fertilization

“…Lateral roots in the 1 m2 area surrounding the stump are not included in this study of spatial distribution. The stump and attached lateral roots in the central squaremeter were included in total belowground biomass and previously reported with aboveground biomass (Coyle and Coleman 2005).…”

“…Forest growth process models commonly predict lower relative amounts of root tissue in response to high resource conditions (e.g. Landsberg and Waring 1997;Reynolds and Thomley 1982), yet observations are not always consistent with those predictions (Coyle and Coleman 2005). Defining primary production responses in relation to soil resource acquisition or understanding environmental controls of belowground carbon allocation requires greater understanding of root distribution under various levels of resource availability.…”