The effects of CO 2 enrichment on photosynthesis and ribulose‐1,5‐bisphosphate carboxylase/ oxygenase (Rubisco) in current year 1‐year‐old needles the same branch were studied Pinus radiata D. Don. trees growing for 4 years large, open‐top chambers at ambient (36 Pa) elevated (65 partial pressures. At this age 3·5–4 m tall. Measurements made late cycle (March) showed that photosynthetic rates growth concentration [( p ) a ] lower grown concentrations than those ( . V cmax (maximum...

• Here we develop and test a method to scale sap velocity measurements from individual trees canopy transpiration (Ec) in low-productivity, old-growth rainforest dominated by the conifer Dacrydium cupressinum. Further, Ec as component of ecosystem water balance is quantified relation forest floor evaporation rates using eddy covariance (Eeco) conditions when was dry partly wet. Thermal dissipation probes were used measure trees, scaled at level dividing into classes based on sapwood density...

In preparation for an investigation of the effects elevated carbon dioxide (CO2) concentration on two tree species Pinus radiata D. Don and Nothofagus fusca (Hook. f.) Oerst, environmental conditions inside sixteen open-top chambers, design described by Heagle et al. (1989), were measured compared with those outside. During a period in late summer, both air temperature saturation deficit greater mean increases 0.3?C 0.1 kPa, respectively. The closely related to solar irradiance, reaching...

The CO₂ respired by darkened, light-adapted, leaves is enriched in ¹³C during the first minutes, and this effect may be related to rapid changes leaf respiratory biochemistry upon darkening. We hypothesized that would evident at ecosystem scale. High temporal resolution measurements of carbon isotope composition respiration were made over 28 diel periods an abandoned temperate pasture, compared with leaf-level differing levels pre-illumination. At level, darkened had been preadapted high...

While the temperature response of soil respiration (RS) has been well studied, partitioning heterotrophic (RH) by microbes from autotrophic (RA) roots, known to have distinct sensitivities, problematic. Further complexity stems presence roots affecting RH, rhizosphere priming effect. In this study short-term responses RA and RH in relation are investigated. Temperature RA, were assessed microcosms Poa cita using a natural abundance δ13C discrimination approach. The RS was found be regulated...

Responses of photosynthesis to carbon dioxide (CO2) partial pressure and irradiance were measured on leaves 39-year-old trees manuka (Leptospermum scoparium J. R. Forst. & G. Forst.) kanuka (Kunzea ericoides var. (A. Rich.) Thompson) at a field site, young grown three nitrogen supply rates in nursery, determine values for parameters model estimate annual net uptake. These secondary successional species belong the same family commonly co-occur. Mean (+/- standard error) maximum rate...

Reversion of agricultural land to native woody vegetation can sequester carbon (C), influencing regional and global C budgets. We examined whole-ecosystem differences in nitrogen (N) storage distribution, sapwood - leaf area relationships a scrubland chronosequence New Zealand dominated by manuka (Leptospermum scoparium J.R. et G. Forst) kanuka (Kunzea ericoides var. (A. Rich.) J. Thompson). At 25 years, dominated, was 6.5 kg C·m -2 . In the 55-year-old stand, stem density similar for two...

A novel, large area, repacked rectangular shipping container lysimeter (13.8 m2) was compared with those from undisturbed monolith barrel lysimeters (c. 3.1 m2), to evaluate their utility for measuring leaching under soil multiple urine patch depositions. In July 2015, the and three had 31 7 patches, respectively, of synthetic cow applied at 3.24 g N L−1, covering 52% surface area. The then remained fallow while receiving rainfall irrigation. Drainage dynamics were monitored until June 2016....

Reversion of agricultural land to native woody vegetation can sequester carbon (C), influencing regional and global C budgets. We examined whole-ecosystem differences in nitrogen (N) storage ...

Monthly measurements of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) fluxes were made at 3 sites along a sequence naturally regenerating Kunzea ericoides shrubland in New Zealand, consisting unimproved pasture (UP), young (8–12 years) trees (YK), old (80 (OK). The CO2 flux base temperature 10°C was highest the OK site (0.51 g CO2/m2.h) lowest UP (0.26 CO2/m2.h). Values regulated by soil (Ts) throughout year, water availability modified response to Ts when root-zone content,...

Improved process understanding of temporal change in soil hydraulic, water retention, and physical properties is required to improve modelling soil-water dynamics. This study reports on trends for intensive till no irrigated wheat, from autumn sowing summer harvest. There were significant bulk density, readily available capacity, unsaturated hydraulic conductivity (at three matric potentials). Using a simple two-parameter exponential model conductivity, the coefficients appeared increase...

The dynamics of internal cycling nitrogen were studied in the southern hemisphere conifer miro [Prumnopitys ferruginea (G. Benn. ex D. Don) de Laub.], which has an indeterminate growth habit. In a 2-year experiment, P. seedlings supplied with nutrient solutions consisting two different concentrations (5 and 0.5 mM) phosphorus (1.33 0.133 first year, 0.5�mM) 15N-labelled solution second year. Growth content new foliage shown to be largely dependent on seedling status at end only weakly supply...

Abstract We measured the plasticity of response photosynthesis to nutrient supply in seedlings dominant four conifer and broadleaved angiosperm tree species from an indigenous forest South‐westland, New Zealand. hypothesized that conifers differing would be less than for angiosperms because greater adaptation low fertility conditions. In Prumnopitys ferruginea (D. Don) de Laub. maximum velocity electron transport, J max , doubled with a 10‐fold increase concentration nitrogen supply....

A thermal imaging technique to assess spatial and temporal stomatal conductance was studied in a field trial Australia during the 2003-04 growing season. Images on shaded side of canopy were obtained using an infrared portable camera (Therma CAM PM575, FLIR Systems). Dry wet leaves used as reference surfaces obtain temperature thresholds eliminate non-leaf material temperatures analysis. An index (Ig) proportional leaf compared with average measured by gas exchange (Li-Cor 6400). Midday stem...

The biodiversity and structure of deep agricultural soil communities are poorly understood, especially for eukaryotes. Using DNA metabarcoding co-occurrence networks, we tested whether prokaryote, fungal, protist, nematode declines with increasing depth (0-0.1, 0.3-0.5, 1.1-1.7m) in pastoral soil; organisms subsets those at the surface; multi-kingdom networks become more interconnected depth. Depth-related richness were observed almost all detected fungal classes, protist phyla, orders, but...

Water is a scarce resource worldwide and particular problem for producers of wine grapes in Australia, where drought occurrences are frequent, determining severe limitations to vine growth productivity. Consequently, most vineyards irrigated the development efficient water nutrient management monitoring practices required. This research presents preliminary results application soil-plant-atmosphere approach accurately assess uptake on grapevines (Vitis vinifera L. var. Shiraz) located...

Nitrogen (N) inputs to agricultural systems contribute substantially soil nitrate (NO3−) concentrations, which increase NO3− leaching and contamination of groundwater. The influence microbes in regulating concentrations the topsoil are well studied but it is often assumed that microbial regulation subsoil negligible. aim this study was test assumption by determining relationships between properties both topsoil. We measured size mineralizable N (Nm) pool, (microbial biomass, bacterial...

The extent of phosphorus (P) loss from soils under deep rooting crops such as lucerne is currently unknown. This study used large lysimeters (2.0 by 1.5 m) to quantify the amounts and forms P in drainage two sites, a non-irrigated dairy system an irrigated that also received farm effluent (FDE). Results showed despite greater inputs compared site, there was no difference total concentrations drainage. There were differences lost between which dominated particulate (48%–52%). More (0.262 kg...