Diagnostic leaf nutrient standards for low-chill peaches in subtropical Australia

Abstract

Summary. A leaf nutrient survey was conducted of the low-chill peach cultivars, Flordaprince (October maturing) and Flordagold (mid November–early December maturing) at 3 commercial sites in both northern New South Wales and southern Queensland. Recently mature leaves from the middle third of a current season’s fruiting lateral (spring flush) were sampled at stone hardening and 2-weeks postharvest and of a non-fruiting lateral at maturity of the summer flush (after summer pruning) during the 1992–93 and 1993–94 seasons. At an additional site in New South Wales (Alstonville), leaf nutrient concentrations were also determined on cv. Flordagem (early November maturing) at 2-week intervals during both seasons. Soil (0–30 cm) chemical determinations were conducted at all sites at 2-weeks postharvest Seasonal trends in leaf nutrient composition were associated with a leaf age–maturity effect. As flush leaves matured during spring, and as mature leaves aged after hardening of the summer flush, nitrogen (N) concentration declined and calcium (Ca) concentration increased. Nitrogen and Ca concentrations increased when young leaves produced from the summer flush were sampled. Time of sampling produced the most consistently significant (P<0.05) main effects on leaf nutrient concentration. The 2-week postharvest period was selected as a convenient time to sample—when leaves were of a consistent age and maturity, and the effect of crop load on tree nutrient reserves was still present. Paclobutrazol, which reduces vegetative growth in stonefruit, was applied to all Queensland sites and, as a consequence, mid lateral leaves contained higher (P<0.05) Ca, magnesium (Mg) and chloride (Cl) and lower (P<0.05) N and phosphorus (P) concentrations than leaves from New South Wales sites. State effects can therefore be interpreted as paclobutrazol effects. Cultivar effects (P<0.05) occurred for many leaf nutrients, however, at the 2-week postharvest sampling, concentrations were sufficiently similar to combine as a narrow adequate concentration range for both cultivars. The diagnostic adequate leaf nutrient concentrations were within the range developed for high-chill peaches (Leece et al. 1971) with the exception of lower Ca, lower Mg for New South Wales (both cultivars), lower iron for Flordaprince (both states), higher P for Flordaprince in New South Wales and higher manganese values for Queensland (both cultivars). Regression analyses were conducted between leaf and fruit nutrient concentrations and soil chemical properties. The only consistent result demonstrated that as the soil Ca : Mg ratio increased, leaf Mg concentration decreased exponentially (P<0.001), indicating that the practice of heavy annual agricultural limestone or gypsum applications in the absence of Mg fertiliser, which had been adopted by several growers in the survey, is associated with lower leaf Mg concentrations.

Response of Growth Inhibitor Paclobutrazol in Fruit Crops

“…Calcium: Increased concentration of foliar Ca with paclobutrazol application was observed in Nemaguard [84], Flordaprince [85], Flordaprince and Flordagold peach cultivars [86] and Red Spur Delicious and Vance Delicious apples [87]. Similar observations regarding the increase in foliar Ca concentrations in various apple cultivars were made by Bonomo et al [91].…”

“…Nitrogen: Paclobutrazol application reduced foliar N concentration in Nemaguard [84], Flordaprince [85], Flordaprince and Flordagold peach cultivars [86] and Red Spur Delicious and Vance Delicious apples [87]. However, Sharma and Joolka [40] recorded reduced leaf N content with paclobutrazol in nonpareil almond plants.…”

Enhancement of Nitrogen and Phosphorus Removal in Pilot-Scale Vertical Subsurface Flow-Constructed Wetlands Using Polypropylene Pellets

“…The results were then converted to gram dry mass. The separated biomass was powdered and analyzed for total nitrogen and total phosphorus content according to the method of Huett (1997). The results were then converted to mg N and mg P per g of dry stem or leaves.…”

Nutrient Removal in Pilot-Scale Constructed Wetlands Treating Eutrophic River Water: Assessment of Plants, Intermittent Artificial Aeration and Polyhedron Hollow Polypropylene Balls

“…After dividing the biomass into stems (no flower stems were noted in November) and leaves, they were subsequently oven-dried for approximately 48 h at 80°C (Fraser et al 2004). Subsample of dried stems and leaves were powdered, wet digested and analyzed for TN and TP content according to the method provided by Huett (1997). Due to the high biomass yield, utilization of T. latifolia biomass as biofuel has been recommended by Ciria et al (2005).…”