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Forest Research Institute Bulletin No. 97 entitled „Nutrient deficiencies and fertiliser use in New
Zealand exotic forests‟ was published in 1985. It brought together information collected from
over 30 years of research on forest nutrition, and was produced as a practical guide for the
identification and correction of nutrient deficiencies. A subst...
Citations
... Several handbooks provide images of S-deficient row-crops (Bryson and Mills 2014; Grant and Hawkesford 2015) but photographs of S-deficient pine plantations are not available from Ireland, United Kingdom, Europe, New Zealand and the United States (Baule and Fricker 1970;van Goor 1970;Binns et al. 1980;Landis et al. 1989;Davis et al. 2015). This indicates rain typically contains sufficient S for adequate growth of most pine species. ...
During the 20th century, managers at sandy nurseries utilized sulphur (S) to lower soil pH and mitigate the risk of iron deficiency. During that time, however, applying S as a fertilizer was a rare event. At many nurseries, S in rain and irrigation water was sufficient to avoid visual deficiency symptoms. The S status of soil and foliage was typically unknown, and many researchers did not test for S due to the additional cost. Consequently, S became the most neglected macronutrient. While a few nursery trials demonstrated that elemental S reduced damping-off and increased height growth, a majority showed no benefit after applying S at rates lower than 100 kg ha-1. Even so, by 1980, S-deficiencies occurred at bareroot nurseries in Alabama, Oklahoma, Virginia, Wisconsin, the United Kingdom, and likely in North Dakota and New York. The risk of a deficiency increases when N-only fertilizers are applied to seedbeds. Due to research, experience and the precautionary principle, several managers transitioned to using ammonium sulfate instead of, less expensive, N-only nitrogen fertilizers. After soil tests became affordable, managers began to ask questions about the need to apply S to seedbeds. Only a few hydroponic trials with small pine seedlings have been used to estimate “threshold” or “critical values” for foliar S. Since an initial 1,500 μg g-1 S value is “unreliable” for pine seedlings, some authors lowered the value to 1,100 μg g-1 and even as low as 500 μg g-1 S. Others ignore all estimates based on total S concentrations and, instead, monitor only foliar SO4 levels.
... There are numerous photos of Ca-deficient crops but few if any photos illustrating symptoms on pine in irrigated bareroot seedbeds. In addition, there are no photos of Ca-deficient pines in either New Zealand Davis et al. 2015), United Kingdom (Binns et al. 1980) or the United States. In contrast, photos from greenhouse trials have been published (Table 7). ...
Bareroot nursery managers may apply dolomite, gypsum, or Ca-nitrate to increase Ca in nursery soils. Although a few managers follow S.A. Wilde’s recommendations and maintain soil at levels of 500 to 1,000 μg g-1 Ca, there is no need to keep Ca levels this high. In contrast, managers at sandy nurseries apply Ca when soil tests drop below 200 μg g-1 Ca. In fact, acceptable pine seedlings have been produced in irrigated soil with <100 μg g-1 available Ca. In plantations, asymptomatic wildlings grow when topsoil contains 17 μg g-1 Ca. In sandy soils, applying too much gypsum can result in a temporary Mg deficiency and too much lime will result in chlorotic needles. Managers apply Ca when foliar levels fall below a published “critical value.” The belief that the critical value for Ca varies by stock type is not valid. In fact, numerous “critical” values are invalid since they were not determined using growth response curves. Critical values determined for small seedlings using CaCl2 in sand are apparently not valid for use in bareroot nurseries. At bareroot nurseries, the soil extractable Ca level can decline during a year by 30 μg g-1 or more. Harvesting 1.7 million pine seedlings may remove 20 kg ha-1 of Ca but irrigation can replace this amount or more. When water contains 5 mg l-1 Ca, 600 mm of irrigation will add 30 kg ha-1 Ca. In some areas, 1,000 mm of rainfall will supply 7 kg ha-1 Ca. Even when a Mehlich 1 test shows no exchangeable Ca in the topsoil, pine needles on tall trees may exceed 2,000 μg g-1 Ca due to root growth in subsoil. There are few documented cases of deficient pine needles (<300 μg g-1 Ca) in irrigated nurseries in Australia, New Zealand, Scotland and in the Americas. Even when soil fumigation delays the inoculation of ectomycorrhiza, bareroot pines have adequate levels of Ca. Typically, foliage samples from pine nurseries contain at least 1,000 μg g-1 Ca. Samples from 9-month-old seedlings range from 300 to 11,000 μg g-1 Ca. Although the “critical value” for Pinus echinata foliage is not known, 1-0 seedlings with 300 μg g-1 Ca were not stunted and apparently grew well after ouplanting.
... Increasing production to meet that demand can be achieved through a number of forest management options, including the use of mineral fertiliser to improve site nutrition and forest growth (Clinton 2018;Powers 1999). The addition of mineral fertiliser, in particular N, which is often limiting for forest growth (Davis et al. 2015;Fox et al. 2007;Littke et al. 2014), has been used to increase forest productivity at an operational scale (Chappell et al. 1991;Fox et al. 2007). However, the response of a forest stand to N fertiliser addition can be highly variable, resulting in low confidence in N fertiliser as a forest management option to increase production (Smaill and Clinton 2016;Sucre et al. 2008). ...
... These forests are dominated by Pinus radiata D. Don (90% planted forest land area) and have a range in site fertility from low fertility sand dunes through to very fertile intensively developed pastoral soils (Beets et al. 2019;Garrett et al. 2022;Ross et al. 2009;Watt et al. 2008). The New Zealand forestry sector has traditionally managed forest nutrition exclusively to reduce nutrient deficiency (Davis et al. 2015;Mead and Gadgil 1978); however, there is now a greater interest in managing soil nutrition to achieve productivity gains (Clinton 2018;NZFOA 2019). The New Zealand forest industry currently predicts a productivity response with N fertiliser addition using a basic grid of foliage N concentration deficiency and stand thinning or openness (Hunter 1982). ...
The fertiliser growth response of planted forests can vary due to differences in site-specific factors like climate and soil fertility. We identified when forest stands responded to a standard, single application of nitrogen (N) fertiliser and employed a machine learning random forest model to test the use of natural abundance stable isotopic N (δ¹⁵N) to predict site response. Pinus radiata growth response was calculated as the change in periodic annual increment of basal area (PAI BA) from replicated control and treatment (~ 200 kg N ha⁻¹) plots within trials across New Zealand. Variables in the analysis were climate, silviculture, soil, and foliage chemical properties, including natural abundance δ¹⁵N values as integrators of historical patterns in N cycling. Our Random Forest model explained 78% of the variation in growth with tree age and the δ¹⁵N enrichment factor (δ¹⁵Nfoliage − δ¹⁵Nsoil) showing more than 50% relative importance to the model. Tree growth rates generally decreased with more negative δ¹⁵N enrichment factors. Growth response to N fertiliser was highly variable. If a response was going to occur, it was most likely within 1–3 years after fertiliser addition. The Random Forest model predicts that younger stands (< 15 years old) with the freedom to grow and sites with more negative δ¹⁵N isotopic enrichment factors will exhibit the biggest growth response to N fertiliser. Supporting the challenge of forest nutrient management, these findings provide a novel decision-support tool to guide the intensification of nutrient additions.
... The most common nutrient limitations that can occur in production forests are nitrogen and phosphorus (Binkley, 1986). Typically forest managers have used visual tree crown assessments and foliage chemistry testing in lieu of soil testing to assess the nutrition status of a forest due to ease of sample collection and the results can then be used to inform nutrition management of which the addition of fertiliser is one management tool (Birk, 1994;Davis, et al., 2015;Mead, et al., 2012;Will, 1985). The longterm assessment of nutrient sustainability within a forest cannot rely on tree productivity metrics alone, as new and improved tree genetics and silviculture may result in a hidden decline of soil nutrient pools (Garrett, et al., 2021). ...
... The New Zealand planted forestry industry is now transitioning the focus of forest productivity from management of deficiencies (NZFOA, 2019b) towards realising potential productivity potential within modern silviculture and genetics by ensuring macro and micronutrients are available on a stand-by-stand basis. While there is some information available for planted forest soil property values at a national level (Beets, et al., 2019;Ross, et al., 2009;Watt, et al., 2008), there is very limited data on thresholds to inform nutrition management (Davis, et al., 2015). The use of MIR spectroscopy as a rapid testing method can advance New Zealand's ability to achieve a comprehensive understanding of forestry nutrition. ...
... Soil samples selected were mostly from Pinus radiata (D.Don) (98% of samples) and a smaller set from other planted exotic species. Foliage samples only came from P. radiata planted forests and were dominated by samples collected in late summer to inform on nutrition management practices (Davis, et al., 2015) and a smaller number were sourced from tree crown biomass samples taken in winter. Some samples were sourced from experimental trials which included a control and fertiliser treatment, where there would be a wide range in soil and foliar chemical properties within the same site. ...
Soil nutrient supply is one of several environmental and biotic drivers of planted forest productivity and testing the soil and tree foliage can inform nutrient management decisions. For many forest companies and research organisations the collection and analysis of a large number of soil samples for chemical properties has previously been considered expensive if not cost-prohibitive. Consequently, site nutrition status may not be measured or, as is the case with many forestry managers, efforts are directed towards foliar sampling to assess tree health and vigour. Diffuse reflectance infrared spectroscopy has emerged as a quick, cost-effective, and non-destructive method for the analysis of many soil properties. Because of the advances in diffuse reflectance spectroscopy, we see potential advantages to the forest industry and research organisations by utilising this method as a cost-effective means of analysing forest soil and foliage nutrient status. In this study we build a New Zealand planted-forest specific mid-infrared spectral training library for soil and foliage chemical properties. Nationally applicable partial least squares regression models for soil and foliage chemical properties were built from the respective libraries and were applied to an independent national data set to test their robustness. The soil properties with good (R² >0.8) and fair (R² 0.5-0.8) predictions on the independent data set were soil pH, total carbon, total nitrogen, total phosphorus, available aluminium, available calcium, CEC (cation exchange capacity), base saturation, and the following elemental totals: aluminium, calcium, iron, potassium, magnesium, nickel, and zinc. The foliage properties with fair predictions (R² 0.5-0.8) were total calcium, total potassium and total phosphorus. Total nitrogen had an R² of 0.47 which was a result of a narrow range in nitrogen values within the test set. The root mean squared error (RMSE) for foliage nitrogen was acceptable. Most of the key planted forest soil and tree foliage nutrient properties were able to be predicted using MIR (mid infrared) spectroscopy. However, some soil available macro-nutrients and all measured soil available micro-nutrients and foliage micro-nutrients predictions were unreliable (R² <0.5). The high throughput of samples and efficiency of analysis when using MIR spectroscopy will result in cost savings whereby forest companies and research organisations can afford to routinely analyse soil and foliar samples for their nutrient status that will then benefit the industry in their quest for productive and sustainable planted forests.
... Calcium (Ca), potassium (K), magnesium (Mg), phosphorus (P), and boron (B) were measured in subsamples by ICP-MS after Mehlich 3 extraction, again using a set of calibration standards. This suite of nutrients were assessed as they are considered the most critical to P. radiata performance in New Zealand (Davis et al., 2010). ...
... Trees used in the study did not exhibit any visual symptom of nutrient deficiency (data not shown). Soil pH values were all within acceptable levels for P. radiata (Davis et al., 2010). ...
Effective symbiosis with ectomycorrhizal (ECM) fungi is important for the successful growth and establishment of Pinus radiata. However, the structure of ECM communities varies across soil (edaphic) and environmental conditions, and thus affects the potential range of symbiotic associations. To improve our understanding of these factors, we characterised the range of ECM fungi present across six sites varying in edaphic properties. We also assessed ECM fungi in root tips of P. radiata planted two years earlier at these sites to assess the extent in overlap between root and soil ECM communities. The structure of the ECM community varied substantially with site. Across all sites, correlations were identified between soil pH and metrics describing ECM community structure in both soil and root samples, indicating soil pH was contributing to the differences in the fungal communities between sites. Mineralisable nitrogen, soil carbon, and phosphorus content also varied with site, but were not significantly related to descriptors of the ECM communities. Root tips and surrounding soils shared some taxa but were inhabited by diverse communities of fungi, and a number of ECM P. radiata associations unique to New Zealand were identified. It is possible that the establishment of linkages between metrics could provide an opportunity to begin predicting the response of ECM populations to site modification, and potentially increase the growth of radiata pine and improve forest health through enhanced resilience to disturbance.
Pines with visible magnesium (Mg) deficiencies (i.e. yellow tips on needles) occur in bareroot nurseries throughout the world. The occurrence of “yellow-tips” is rare when soil pH is above 6.5 but they have occurred on sands (pH < 6.0) with less than 25 μg g-1 Mg. If yellow-tips occur in the summer, the foliar content of yellow tips is usually less than 1,000 μg g-1 Mg. Some nurseries do not produce “yellow-tip” seedlings when irrigation water contains sufficient Mg. Factors favoring a deficiency include low soil pH, high calcium in irrigation water, frequent fertilization with nitrogen and potassium and applying too much gypsum. Although various Mg fertilizers are available, many nursery managers apply dolomite or potassium-magnesium sulfate before sowing seeds and a few also apply magnesium sulfate in July or August. Soil tests are used to determine when to fertilize before sowing and foliage tests determine when to apply Mg to green seedlings. Nursery managers who follow S.A. Wilde’s forest-based soil recommendations may apply magnesium sulfate to green seedlings even when seedbeds contain adequate levels of Mg. When deficiency is minor, chlorosis on needle tips usually disappears before the fall equinox and, when applied at this time, Mg fertilizers have little or no effect on height growth. This paper reviews some of the past and current uses of Mg in bareroot nurseries and highlights a need for additional research.
Copper has been used by nursery managers for more than 100 years to suppress fungi and as a fertilizer for more than 50 years. Consequently, nursery seedlings with copper deficiencies are rare, especially for broadleaf species. In many nurseries, soil contains <10 μg-Cu g-1 and in greenhouse trials, pine seedlings are relatively tolerant of soil levels with 35 μg-Cu g-1. A million bareroot pine seedlings may contain 50 to 100 g-Cu and, when soil tests indicate low copper levels, managers might apply 1 kg-Cu per million seedlings. In contrast, it may take only 15 g-Cu to produce one million container-grown seedlings. Copper fertilization is typically not required when 30 cm of applied irrigation water contains 0.1 μg-Cu g-1 (supplying 0.3 kg-Cu ha-1). This review highlights some of the past and current uses of copper in bareroot and container nurseries with a focus on deficiency and toxicity effects as well as the impact of various copper-based products and provides recommendations on ideal soil and foliar ranges.
