Forest Fertilization Research Articles

NiepoŁomice forest—a gis analysis of ecosystem response to industrial pollution

The Niepołomice Forest is located near the city of Kraków (Southern Poland). Since the erection of large iron works in the 1950’s, the forest has suffered from heavy pollution with SO 2 and industrial dusts containing heavy metals. During the last 10 years this impact was significantly reduced. In the same period the Niepołomice Forest ecology has been intensively studied. With the advent of modern, computer intensive techniques, data gathered in the past are being reanalysed with respect to the spatial and temporal variation of the forest ecosystem response to the industrial pollution. To that end, the effects of natural conditions (soil, vegetation) and of industrial pollution (heavy metals, sulphur dioxide) upon the pine stands (tree volume increment, crown injuries) in the Niepołomice Forest were studied using a geographic information system. Procedures of statistical analysis involving bootstrapping were developed. Results suggest fertilization of forest stands due to industrial pollution, an effect not revealed in former studies.

Acidification: its impact on the environment and mitigation strategies

The effect of acidification on ecosystems is reviewed. About 30% of the world land area is acidified mostly by natural processes. Only a small part of it is acidified from pollution which leads to extensive forest and surface water deterioration in Europe and North America. The damage is especially visible in areas of poor soil quality. The acid deposition pattern is characterized, with a special emphasis on Poland. It was shown that strategies for mitigation of ecosystem acidification lead to a decrease of SO 2 emissions due to the use of lower sulphur content fuels and application of desulphurisation methods. Also, a decrease in NO x emissions is observed due to use of catalysts and application of NO x removal technologies. However, since about 50% of NO x emission is from vehicles, this improvement is offset by a continuously increasing vehicle population. The application of liming, forest fertilisation and suitable land use for mitigation of ecosystem acidification is also reviewed.

An Ecological Perspective on Human Densities in the Central African Forest

1. The factors determining human densities in the central African forests are examined and compared with the predictions from an agronomic model by the Food and Agriculture Organization, United Nations Fund for Population Activities and International Institute for Applied Systems Analysis (FAO/UNFPA/IIASA). 2. Published data on crop yields, wild and domestic herbivore densities and human densities are compared along the rainfall gradient and between three broad geological classes representing low, medium and high soil nutrient availability. 3. Crop yields show no increase with rainfall; both manioc and maize may decrease at higher rainfall levels. The lowest yields are seen on the geological class which underlies the central African forests. 4. Wild herbivore biomass increases steeply with rainfall on volcanics and marine sediments and also on sedimentary rocks (high and medium soil nutrient availability, respectively). On basement and Kalahari sand (low soil nutrient availability), most sites show a decrease in herbivore biomass at high rainfall, suggesting that soil nutrients are limiting. 5. There are large differences between geological classes in cattle density. Within each class cattle densities increase along the rainfall gradient and then decline. The lowest densities are in central Africa. 6. Within each geological class human densities increase with rainfall. The steepest slope is on volcanics and marine sediments. The slopes on the other two classes are less steep. The lowest human densities are on basement and Kalahari sand. Geology and rainfall together explain three-quarters of the variance in human densities over much of sub-Saharan Africa (33 out of 40 countries). 7. Cultivation of carbohydrate staples by forest-dwellers in north-eastern Gabon could theoretically support 20-28 people km -2 . Game resources support 0.3 people km -2 . 8. The predictions from FAO/UNFPA/IIASA's agronomic model are very different from the actual patterns revealed by the analyses of crop yields, wild and domestic herbivores and humans in relation to geology and soils. 9. The carrying capacity of the forest for humans is governed by soil nutrients, agricultural pests and the low protein harvest from game. Game resources are the limiting factor for humans. 10. Understanding the relationships between soils, rainfall, biological resources and human populations has important implications for development projects, the replacement of forests by cattle pastures and the management of refugees. The illusion of rain forest fertility, propagated by the FAO/UNFPA/IIASA model, will result in inappropriate land use policies for the forest zone.

Symptoms of nitrogen saturation in two central Appalachian hardwood forest ecosystems

By synthesizing more than twenty years of research at the Fernow Experimental Forest, we have documented 7 symptoms of nitrogen saturation in two adjacent watersheds. The symptoms include: 1) high relative rates of net nitrification, 2) long-term increases in stream-water concentrations of nitrate and base cations, 3) relatively high nitrate concentrations in solution losses, 4) little seasonal variability in stream-water nitrate concentrations, 5) a high discharge of nitrate from a young aggrading forest, 6) a rapid increase in nitrate loss following fertilization of a young aggrading forest, and 7) low retention of inorganic nitrogen when compared with other forested sites. These data support current conceptual models of nitrogen saturation and provide a strong, and perhaps the best, example of nitrogen saturation in the United States.

Phosphorus adsorption by peat from drained mires in southern Finland

The phosphorus adsorption capacity of 20 peat soils and those soil properties likely to influence it (Al, Fe, Ca, Mg, pH, ash content) were studied. Phosphorus adsorption was correlated only weakly to the site type classification of peatlands. However, the P adsorption was strongly correlated with the concentration of Fe in the peat. Thus, soil chemical analysis should be used to support site type classification in order to assess the effectiveness of peatlands to adsorb P. When expressed on a volume basis, the P adsorption capacity varied from 7 kg ha‐1 to 673 kg ha‐1 in the 0–30 cm layer. Compared with the amounts of P used in practical peatland forest fertilization in Finland (40–45 kg ha‐1), the P adsorption capacity of several peat soils studied was substantially lower. It was thus concluded that slowly soluble P fertilizers or applications <40–45 kg ha‐1 should be used where the P adsorption capacity is low.

Principles of forest fertilisation - illustrated by New Zealand experience

Principles of forest fertilisation - illustrated by New Zealand experience

Soil microbial activity in eleven Swedish coniferous forests in relation to site fertility and nitrogen fertilization

The effect of forest fertilization on soil microbial activity and biomass was studied in 11 coniferous forests with different site fertility. Soil microbial activity was measured as respiration rate and the microbial biomass was estimated using ATP content and substrate‐induced respiration rate (SIR). At all sites, except those with the highest site fertility, the microbial activity and biomass were reduced in the fertilized treatments compared with the control. The general trend indicated that the lower the site fertility, the more pronounced was the reduction of microbial biomass and activity. Some possible explanations for this effect are discussed.

Abundance of Tylospora fibrillosa ectomycorrhizas in a South Swedish spruce forest measured by RFLP analysis of the PCR-amplified rDNA ITS region

Polymerase chain reaction (PCR) amplification of the internal transcribed spacer (ITS) region of the ribosomal DNA, subsequent cutting with the endonuclease Hinf I and restriction fragment length polymorphism (RFLP) analysis have previously proved to be a good method for distinguishing the ectomycorrhizal Tylospora fibrillosa from a large number of other basidiomycetes. In the present study this method was used to screen single mycorrhizas sampled in a Norway spruce forest in South Sweden. In this forest 98% of randomly collected mycorrhizas had the macroscopical features of T. fibrillosa mycorrhizas. Fungal ITS was successfully amplified from 93% of the sampled mycorrhizas. Five major, distinct fungal RFLP patterns were found, clearly demonstrating the benefit of the molecular method. The T. fibrillosa RFLP pattern was present in 21%, type 1 in 27%, type 2 in 20%, type 3 in 11% and type 4 in 3% of the mycorrhizas. Fungal ITS of more than one origin was found in 22% of the amplifications. It can be concluded that T. fibrillosa is one of the main mycorrhizal fungi in the studied site and it is therefore likely to be of significant ecological importance. These results suggest that T. fibrillosa would be a suitable ‘model mycorrhiza’ for studies of anthropogenic influence, such as pollution, liming or forest fertilization, on population structure of spruce mycorrhizas in southern Sweden.

Effect of nitrogen, phosphorus and magnesium fertilizers on growth of a semimature jack pine forest, northwestern Ontario

In the spring of 1969, an experiment to test response (mean DBH, BA, BA%, and total and merchantable volume increments) to nitrogen (N), phosphorus (P) and magnesium (Mg) fertilizers, singly and in combination, was established in a semimature jack pine (Pinus banksiana Lamb.) forest on a Site Class III sandy site in the Dryden-Sioux Lookout area of northwestern Ontario, Canada. Analysis of variance of 10-year increments revealed highly significant (P = 0.01) responses of mean DBH increment, BA and percent BA increments, and total and merchantable volume increments to N, but no response to either P or Mg. An interaction between N and P was noted, however, in relation to BA and to total and merchantable volume increments. The best treatment in terms of total volume increment over that of the control was 151 kg N ha−1 plus 62 kg Mg ha−1, which produced ca. 16 m3 ha−1 of extra wood over 10 years. Key words: forest fertilization, nitrogen, phosphorus, magnesium fertilizers, jack pine growth response

A GIS evaluation of land use dynamics and forest soil fertility in a watershed in Nepal

Abstract A geographical information system (GIS) based study was carried out in a densely-populated watershed in Nepal. An evaluation of land use change between 1972 and 1990 indicated that there has been an increase in forest and agricultural land area and a decrease in shrubland and grassland area. GIS techniques were used to produce single and composite fertility index maps, which can be used for problem identification and planning. These maps indicate that forest soil fertility is generally poor in the watershed. GIS was found to be very beneficial in addressing critical resource issues in small watersheds in developing countries.

Effects of forest fertilization on nitrogen leaching and soil microbial properties in the Northern Calcareous Alps of Austria

Several boreal and alpine forests are depleted in nutrients due to acidification. Fertilization may be a remedy, but rapidly-soluble salts (N, P, K, Mg) may pose nitrate problems for the groundwater or decrease microbial activity. With the aim to investigate potential nitrogen leaching after fertilization we set up an experiment employing intact soil cores (11 cm diameter, 20–40 cm long) from a mixed forest and a Picea abies stand (soil type Rendsina) in the Northern Calcareous Alps of Austria. The cores were fertilized with a commercial NPK fertilizer or a methylene-urea-apatite-biotite (MuAB) fertilizer at a rate corresponding to 300 kg N ha-1 and incubated for 28 weeks together with unfertilized controls. Both soil water (retrieved 5 cm below the soil surface) and leachate were analyzed for nitrate and ammonium in regular intervals. After the incubation, soil microbial biomass and basal repiration were determined and a nitrogen mineralization assay was performed. For the control, in the soil water and leachate maximum NH4 + and NO3 - concentrations of 5 and 11 mg N L-1, respectively, were found. Compared to that, MuAB fertilizer resulted in a slow increase of NH4 + and NO3 - in the soil water (up to 11 and 35 mg N L-1 respectively) and in the leachate (4 mg NH4 +-N L-1 and 44 mg NO3 --N L-1). Highest nitrogen loads were found for the fast release NPK fertilizer, with NH4 + and NO3 - concentrations up to 170 and 270 mg N L-1, respectively, in the soil water. NH4 +-N levels in the leachate remained below 5, while NO3-N levels were up to 190 mg L-1. Fast- release NPK caused a significant decrease of microbial biomass and basal respiration. These parameters were not affected by MuAB fertilizer. The results suggest that the MuAB fertilizer may be an ecologically appropriate alternative to fast-release mineral fertilizers for improving forest soils.

Use of Nutrient Diffusing Substrata to Assess Nutrient Limitation in a Stream Impacted by Agriculture and Silviculture

ABSTRACT The nutrient status or streams impacted by agriculture and silviculture is little known, especially in Oklahoma and Arkansas. USA. In this research we assessed the impact of nutrients on biofilms in the Glover River, Oklahoma, which drains a watershed impacted by poultry manure, clear-cutting, and forest fertilization. We used nutrient diffusing substrata with two independent measures of biomass and N:P ratios to assess N and P limitation in this stream during 1988–1990. The substrata data revealed limitation by N. However, N:P supply ratios indicated P limitation during 1990. The nutrient regime, turbidity and discharge changed radically during the study. Caution is advised in use of nutrient diffusing substrata in streams impacted by high turbidity and high discharge.

Modeling the Global Carbon Cycle: Nitrogen fertilization of the terrestrial biosphere and the “missing” CO2 sink

The discrepancy between estimates of net terrestrial CO2 emissions derived from (1) inverse modeling of the ocean/atmosphere system and (2) modeling of land use change, better known as the “missing” CO2 sink, suggests that some changing environmental factor, such as CO2, anthropogenic N emissions, or climate, has fertilized terrestrial ecosystems. To address this question, we herein describe and apply GLOCO, a global carbon cycle model. GLOCO's ocean submodel combines a box diffusion model with representations of chemical equilibria and biological processes to simulate the distributions and cycling of inorganic and organic carbon, phosphate, and alkalinity. The terrestrial submodel divides the biosphere into seven natural biomes with dynamic carbon and nitrogen cycling in both vegetation and soils. Anthropogenic influences on the functioning of the carbon and nitrogen cycles, such as fossil fuel combustion, forestry, and agricultural development, are also incorporated in the model. Our analysis confirms previous suggestions that because temperate and boreal forests are N limited, CO2 fertilization of these forests is less than predicted by short‐term CO2 response factors. Modeling of temperate/boreal forest fertilization by anthropogenic N deposition suggests that CO2 is initially sequestered at a C:N ratio of ∼100, rather than the steady state value for the ecosystem of ∼30. If N deposition is to account for the 40–70% of the fertilization of the terrestrial biosphere not explainable by CO2 fertilization and temperature increases, then we estimate that 26‐30 Tg N yr−1 of anthropogenic deposition in the temperate and boreal zones would be required. Recent anthropogenic NOx and NH3 deposition fluxes at northern temperate latitudes have been estimated to be 20–28 Tg N yr−1. Thus fertilization by anthropogenic N emissions likely constitutes a significant portion of the missing CO2 sink.

The effects of sewage sludge application to a heathland site prior to planting with Sitka spruce

New outlets are being sought for sewage sludge which is currently disposed of at sea. Sewage sludge has long been used as a fertiliser in agriculture, and a research programme is now evaluating the potential of sludge as a forest fertiliser. Single applications of sludge (13 and 26 Mg dry solids ha −1) before planting have enabled a pure Sitka spruce crop to be established on a heathland site where large inputs of conventional fertilisers and herbicides would have been required. Sludge applications reduced the amount of heather in the ground vegetation which would otherwise have resulted in reduced growth of the spruce. At age 7 years the mean tree heights in plots treated with sewage sludge are significantly greater than in those plots receiving conventional treatments. Foliar nitrogen concentrations have now declined from satisfactory to deficient in the sludge treated plots and the conventionally fertilised plots which have not received nitrogen treatments. Phosphorus concentrations remain satisfactory. Metal additions from the sludge applications were well within limits set for agricultural use and could largely be accounted for in the top 75 mm of the soil 5 years after the sludge was applied. Although some increases in the concentration of metals in the spruce foliage were observed, levels were below those at which any phytotoxic effects could be expected. The quality of water draining from the site was also monitored and found to be satisfactory immediately following sludge application. In subsequent months low levels of nutrient leaching occurred only after heavy rainfall, but levels were still within the quality standards for surface water intended for abstraction for drinking water.

Evaluation of eight forest fertilizer response estimators by means of a simulation study

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Response of young Douglas-fir to urea fertilizer applied on and off snow

The effects of 200 kg N ha−1 applied as urea fertilizer on 50 cm of snow or on bare ground were studied in an 11-year-old Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) plantation on Vancouver Island. Analysis was done on all trees per plot and on 20 selected dominant trees per plot. Up to 2 years after fertilization, urea significantly increased absolute DBH increments over controls in all trees and the 20 selected trees per plot; response to fertilization on snow was equal to that on bare ground. Between the 3rd and 9th year following fertilization, mean DBH increments were not significantly different for any treatment. Four-year absolute volume increments were 63 and 87% greater than the controls for bare-ground and on-snow applications, respectively. A positive and quantitatively similar response is expected in wetter coastal Douglas-fir stands whether urea is applied on snow or under better conditions during other seasons. Key words: Forest fertilization, season of application, nitrogen, tree response, Pseudotsuga menziesii (Mirb.) Franco

15N abundance of soils and plants along an experimentally induced forest nitrogen supply gradient.

15N abundances of soils and a grass species (Deschampsia flexuosa (L.) Trin.) were analysed in a forest fertilization experiment 10 years after the last fertilization. Nitrogen had been given as urea, at seven doses, ranging from 0 to 2400 kg N ha-1. Previously, we have shown that plants in systems experiencing large losses of N become enriched with 15N. This was explained by the fact that processes leading to loss of N, e.g. ammonia volatilization, nitrification followed by leaching or denitrification and denitrification itself, tend to fractionate against 15N. In this experiment, 15N abundance increased with dose of N applied in both grass and soil total-N, but more so in the grass. This was interpreted to be due to the grass sampling small but active pools of N subject to losses. In contrast, soil total-N largely consists of inactive N that does not immediately exchange with pools of N from which fractionating losses occur. Hence, soil total-N shows a large pretreatment 15N memory effect, and is, therefore, and integrator of the long-term N balance. When short-term changes (years, decades) in N balances are monitored using variations in 15N abundance, plants are more suitable indicators of such change than is soil total-N.

Effect of base cation addition on soil chemistry in a sugar maple forest of the Lower Laurentians, Quebec

Forest fertilization has been adopted as the primary means of controlling sugar maple (Acersaccharum Marsh.) dieback in southern Quebec. Following foliar analysis, treatments containing appropriate mixtures of K, Ca, Mg, and (or) P have been used on commercial sugar groves. This study was undertaken to identify the impact of base cation additions on nutrient cycling in a sugar maple stand in the Lower Laurentians, Quebec, and to quantify the amounts of added nutrients that were retained in the stand or lost by leaching. In 1988, six 40 × 40 m plots were established; three were kept as controls and the other three received a mixture of 500 kg•ha−1 of K2SO4, 250 kg•ha−1 of Ca,Mg(CO3)2 and 250 kg•ha−1 of CaCO3 applied as fine particulate matter in June 1989. Soil solutions were collected weekly during the spring and fall from October 1988 until November 1992. Soil solution chemistry indicated that there was increased biocycling of both K and Mg as a result of the treatment. The application of appropriate mixtures of base cation will improve the fertility of the soils and decrease nutrient imbalances. The amount of added material lost from the rooting zone was a small proportion of the amount added: over a 4-year period following treatment only 12.1, 9.5, and 1.4% of added Ca, Mg, and K were lost, respectively.

Nutritional assessment of a forest fertilisation experiment in northern Sweden by root bioassays

Roots were excised from long-term nitrogen, phosphorus and potassium fertilisation experiments in a Pinus sylvestris plantation in northern Sweden, and tested for their ability to take up 15N, 32P or 86Rb from solutions of ammonium chloride, potassium dihydrogen phosphate and rubidium chloride. High levels of uptake in these tests indicate low nutrient status. At this site, lower uptake rates in the trees from the fertilised treatments showed they had responded to the addition of all three nutrients, although the nitrogen test could not detect a difference in root response between trees from the two higher nitrogen treatments, which, according to other criteria, were high enough to create nitrogen-saturated conditions. There was no evidence from the nitrogen uptake measured that this was affected by phosphorus or potassium fertiliser treatment, suggesting that correcting the supply of these elements did not induce further nitrogen demand. Conversely, trees receiving high nitrogen additions did not show any increased demand for phosphorus or potassium. This is in agreement with data on tree growth and nitrogen retention of the stands. Trees from plots treated with acid 16–21 years previously or lime 21 years previously did not respond differently from trees in control plots, unless nitrogen, phosphorus and potassium fertiliser were also added, when demand for the three nutrients was reduced. The results suggest that, in spite of difficulties in sampling tree roots in an area with a rich ground flora, the method is a useful test of the long-term nutrient status in forest fertilisation experiments.

Evaluation of eight forest fertilizer response estimators by means of a simulation study

Eight estimators of total fertilizer response (simple difference, ratio, covariance, and regression estimators) commonly used to determine the results of fertilization experiments were evaluated using a simulation study. An individual tree model based on equations developed for Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) was used to project the growth of fertilized and unfertilized plots under several different experimental conditions. The effects of number of plots, plot size, initial plot variability, stand age at the time of fertilization, length of response period, and differing growth responses to fertilization on the relative performance of the estimators were evaluated. Covariance and regression estimators provided the best estimates as long as there was sufficient data to determine model parameters. In almost all cases measures of growth were preferable to measures of yield. For the simple difference and ratio estimators strong linear relationships were observed between bias and pre-treatment differences in yield or growth between fertilized and unfertilized experimental units. Variability in growth response to fertilization did not influence the relative performance of the estimators. The more critical factor was the variability in unfertilized growth as this is what must be predicted in order to estimate fertilizer response.