Total Nutrient Inputs Research Articles

Nutrient balance in forests of northern Tasmania. 1. Atmospheric inputs and within-stand cycles

Eucalypt forest soils in northeastern Tasmania are ammonifying and contain low concentrations of extractable P, inorganic N and exchangeable cations, irrespective of underlying geology. Litterfall was proportional to productivity and could be described by a climatic index. Nutrient return in litterfall was unaffected by soil type and was the dominant transfer of N, P and Ca. Significant amounts of N (up to 8 kg ha −1 year −1) and other nutrients were added to the forests in rain. Although rainwater quality varied with distance from the coast, total nutrient input was dominated by rainwater quantity. Nutrient cycles and inputs were comparable with those found in other Australian forests of similar productivity. Soil in a cool-temperate rainforest was more organic than eucalypt forest and soils and contained higher concentrations of extractable P, inorganic N and other nutrients. Litterfall in the rainforest was rich in P, relative to the eucalypt forests, but poor in Mg. Nutrient absorption by the rainforest root mat was more effective than that in eucalypt forests.

Nutrient Loading to Norwegian Coastal Waters and Its Contribution to the Pollution of the North Sea

The North Sea Declaration aims at reducing the load of nutrients to the North Sea by the order of 50 per cent between 1985 and 1995. This paper gives an overview of the nutrient loading to the Norwegian coastal waters, and an estimate of how much of this loading reaches the local Skagerrak coast and the North Sea. The average annual nutrient load to coastal waters from land-based sources along the Norwegian North Sea coastline (from the Swedish border to 62°N) is approximately 3,600 tons of phosphorus and 70,000 tons of nitrogen. Municipal wastewater is the main source of phosphorus (44 per cent), while agriculture contributes with 20 per cent of the total load. Background runoff, i.e. runoff from forested areas and uplands, including effects of acid precipitation, is the main source of nitrogen inputs (40 per cent). Agriculture is the second major source (32 per cent). Our calculations indicate that deposits of airborne nitrogen via precipitation contribute approximately 15-20,000 tons of nitrogen inputs on the coastal watersheds draining to this coast. The Norwegian loading amounts to 3-4 % of the total nutrient inputs to the North Sea from the surrounding countries. Taking into consideration the dominating current systems in the North Sea and along the Norwegian coast, only a small part of this load reaches the middle and southern parts of the North Sea susceptible to eutrophication. This implies that the Norwegian nutrient input has minimal effects on the eutrophication of the North Sea. There is a considerable need for developing standard methods for estimating nutrient inputs to the North Sea. Emphasis should be put on preparing guidelines for assessing comparable nutrient input data from all North Sea countries.

Growth and production dynamics of boreal mosses over climatic, chemical and topographic gradients

Three basic questions arc addressed in this paper. Each of them considers a separate aspect of moss growth and production. A common theme throughout is that moss populations are dynamic, highly active entities. The study of these dynamics can tell us not only about the mosses themselves but also about the systems in which they live. The following conclusions are reached. (1) Moss populations are organized into complex canopies, some having at least 6000 leaves cm“‘. Drought-tolerant mosses may achieve high rates of growth when moist, but generally are dry and inactive a large percentage of lime. (2) For the ectohydric, drought-tolerant moss, Hylocomium splendens, growth is highly variable over its North American boreal range and can be related to precipitation and continentality. However, for the endohydric, less drought-tolerant moss, Polytrichum strictum, growth is more constant over its North American range and is not as distinctly related to broad macroclimatic patterns. It may have nutrient limited growth, whereas Hylocomium splendens may have climatically limited growth. (3) (a) In mires, calcium, magnesium, sodium and hydrogen ions are important chemical factors that are closely correlated to mire type. Available amounts of nitrate, ammonium, phosphorus and total organic nitrogen in surface waters do not correlate with mire type; likewise, they do not increase across the bog-rich fen gradient. Extreme-rich fens and bogs have about the same concentrations of these components, but water-flow differences may modify the total nutrient input during a season in fens, (b) Moss production in extreme-rich fens is similar to, or somewhat less than, in bogs and poor fens. However, decomposition is much greater in extreme-rich fens. Peat accumulation may, therefore, be greater in bogs and poor fens than in extreme-rich fens, (c) Net production on bog hummocks is about half that of hollows, whereas in poor fens and rich fens, production on hummocks is greater than or equal to that in the hollows. Decomposition in poor fens and bogs is much less on hummocks, while there are few differences between height extremes in rich fens. Hummocks appear to be maintained in bogs due to low decomposition rates, while in rich fens they are maintained by relatively high production, (d) Production rates of Sphagnum species are generally similar to or higher than those of brown mosses. Different species of Sphagnum dominate different parts of the chemical and topographic gradients in bogs while different brown moss species dominate parts of comparable gradients in rich fens.

Precipitation Nutrient Inputs in Semiarid Environments

AbstractSeasonal and spatial variations in precipitation nutrient inputs were suggested by differences in storm type and air mass origin into southeastern Arizona. Wet precipitation NO3‐N, NH4‐N, PO4‐P, and K inputs were collected at seven sites to determine seasonal and spatial variations in nutrient inputs. Total nutrient inputs and concentrations in summer precipitation were significantly greater than in winter precipitation. Higher summer total inputs and concentrations were attributed to storm type and air mass origin rather than precipitation amount, as summer precipitation accounted for 56% of the precipitation and 79, 69, 66, and 73% of the NO3‐N, NH4‐N, PO4‐P, and K, respectively. Spatial variability in nutrient inputs was limited to specific nutrients, seasons, and sites and attributed to precipitation variability and localized sources. Generally, the air masses and storm types that produced seasonal differences in nutrient inputs and concentrations affected all sites uniformly.

Effects of intensive harvesting on nutrient capitals of three forest types in New England

Effects of whole-tree clearcutting are being studied in three major forest types in the northeastern United States: a spruce-fir forest in central Maine, a northern hardwood forest in New Hampshire, and a central hardwood forest in Connecticut. At each site we sampled total and extractable nutrient capitals, inputs and outputs of nutrient ions in precipitation and streamflow, nutrient removals in harvested products, and nutrient accumulation in regrowth. Depending upon location, combined losses of nutrients in harvested products and increased leaching to streams were in the ranges of 374–558 kg ha −1 for Ca, 135–253 kg ha −1 for K, 50–65 kg ha −1 for Mg, 248–379 kg ha −1 for N, and 19–54 kg ha −1 for P. Opportunities for replacing these losses over the next rotation are best for N. Data on inputs in precipitation versus outputs in streamflow indicate that, once effects of harvest subside, most N in precipitation will stay within the forest. By contrast, Ca shows a net output of 8–15 kg ha −1 year −1 from uncut watersheds, and the added leaching losses due to harvest may have a serious impact on Ca capital. This is especially the case for the Connecticut site, where total site capital for Ca is only about 4000 kg ha −1.

A mathematical model for predicting annual fertiliser requirements of kiwifruit vines

A mathematical model for predicting fertiliser requirements in commercial kiwifruit orchards is presented. The model assumes allometric distribution of dry weight amongst vine components for all levels of productivity, and uses a prediction of fruit yield to estimate vine dry weight, annual growth and hence nutrient uptake. The efficiency of nutrient recovery is used to estimate the total nutrient inputs to the soil required to maintain an equilibrium of the soil nutrient pools. Atmospheric inputs and nutrients cycled in senesced or pruned plant material are then deducted from the total nutrient requirement to calculate a nutrient deficit or fertiliser requirement. Leaf analysis is used to detect nutrient deficiencies or excesses that can be addressed in corrective fertiliser dressings. Sensitivity analysis showed that estimates of fruit yield and the efficiency of nutrient recovery had the greatest impact on predictions of fertiliser requirement. The validity of initial estimates of these parameters is discussed. Application of the model to a mature orchard and a developing orchard revealed that nitrogen fertiliser rates much less than those recommended did not lead to evidence of nitrogen deficiency, suggesting contributions to uptake from soil nitrogen reserves and/or incorrect assessment of the efficiency of nitrogen recovery. Potassium deficiency occurred in the mature orchard following low potassium fertiliser rates, and also in the developing orchard in spite of apparently high potassium fertiliser rates, highlighting the importance of this disorder for kiwifruit. For other nutrients, deficiencies or excesses followed fertiliser rates respectively lower or higher than those recommended.

Nutrient cycling in two traditional Central American agroforestry systems

A preliminary nutrient cycling study quantified total and temporal nutrient inputs via litterfall and pruning residues in two agroforestry systems: (1) Coffea arabica (perennial crop)-Erythrina poeppigiana (leguminous shade tree); and (2) C. arabica-E. poeppigiana-Cordia alliodora with emphasis on the effect of the timber tree C. alliodora. The total annual input of litterfall plus pruning residues was similar in both associations. Total annual input from E. poeppigiana was less than half in the association with C. alliodora than without, but the litterfall from this latter species compensated for the loss. Large differences in the total annual nutrient input of K, Ca and Mg was found between associations, but not for N or P. The amount of nutrients recycled by the associated trees reached the recommended level of fertilizer required for coffee production. The inclusion of C. alliodora within the C. arabica-E. poeppigiana association resulted in a more evenly distributed annual nutrient input.

Nutrient budget of a marine fish pond in Eilat, Israel

Monthly budgets for nitrogen and phosphorus for a marine fish pond in Eilat were determined for the period September 1983 to June 1984. The ponds are operated as a semi-open system, 41% of the pond water being replaced each day by water from a nearby seawater well. Only 29% of the phosphorus and 36% of the nitrogen are incorporated into harvestable fish flesh ( Sparus aurata or Mugil sp.). The remainder reaches the pond as uneaten food, fish faeces or excreted matter, and it is then available to support high levels of phytoplankton and heterotrophic activity. The total input of nutrients supplied to the ponds showed a seasonal trend, with the lowest amount being supplied at the beginning of the sampling period (October) (5.2 moles N/day, 0.25 moles P/day), and increasing in June to 10.6 moles N/day, 0.57 moles P/day. All the increase was due to the amount of food fed. A large proportion (70–80%) of the excess nutrients was exported from the system as dissolved or particulate matter in the overflow. Because of this the water quality of the ponds has remained at levels which have enabled 6.5–12 tons fish/ha to be cultured without regular drying of the ponds. Oysters have been grown on the plankton carried out with the overflow. The ponds have a surplus of nutrient inflow in October/November (1.9 moles N/day, 0.06 moles P/day), a small deficit of N (0.4 moles/day), and surplus of P (0.01 moles/day) in spring, and a large surplus again in May and June of 1.3 moles N/day, 0.11 moles P/day. In all, 60–120% of the nutrient inputs are directly accounted for.

Atmospheric nutrient inputs to three forest types in East Texas

The effect of forest type on atmospheric nutrient inputs to the forest ecosystem was measured for individual storm events for 1 year in three East Texas forest types: beechmagnolia, pine-mixed hardwoods and loblolly pine plantation. Total annual bulk precipitation inputs (kg/ha) for Ca, Mg, N, K and Na were, respectively: 5.0, 1.1, 4.1, 3.3 and 9.9. Total througfall inputs were increased by forest type, but the magnitude differed with each nutrient. Over 3 4 of the total K and 1 2 the total Mg throughfall input were due to the forest canopy. However 2 3 of the Ca and most of the Na throughfall input resulted from bulk precipitation. Although stemflow nutrient concentrations (ppm) were higher than throughfall and bulk precipitation, total annual stemflow nutrient inputs were only a minor component of the loblolly pine plantation ecosystem.

Effects of the Spawning Migration of the Alewife, Alosa Pseudoharengus, on Freshwater Ecosystems

The influx of large numbers of alewife, Alosa pseudoharengus, into relatively small freshwater systems may have a considerable impact upon pre—established food chains and nutrient cycles. We estimate the total nutrient input to Pausacaco Pond, Rhode Island, USA, from alewives amounted to 0.43 g P, 2.7 g N, and 16.8 g/Cm2 over a 2—mo period. This is largely through mortality of the spawning fish, and to a lesser extent through excretion. These inputs were much greater than the eventual nutrient loss to the system through emigration of juvenile fish. In tank experiments using pond microcosms, the initial response to the addition of the fish was a large phytoplankton bloom and an increase in litter respiration. The phytoplankton bloom was short—lived, and the most lasting effort was an increase in production and respiration in the leaf litter. This increased production in the litter community would support a long lasting supply of insect and benthic invertebrate food for young fish. The respiration rate of autumn leaves incubated in alewife streams during the migration was significantly higher than that of leaves incubated simultaneously in a stream which had no alewife run. Respiration rates of leaves incubated in the same streams before the arrival of alewives did not differ significantly. The increase in litter respiration, an indication of microbial and invertebrate activity on the leaf surface, was attributed to the additional nutrients supplied by the fish.

NUTRIENT FLUXES IN PRECIPITATION, THROUGHFALL, AND STEMFLOW IN AN OAK‐HICKORY FOREST1

ABSTRACT: Nutrient fluxes in precipitation, throughfall, and stemflow were studied in an oak‐hickory forest in southern Illinois for a three‐year period beginning in 1973. Nutrient inputs in these water related pathways were approximately one‐half those of litterfall; a major nutrient return mechanism. Considering these water carried nutrients (116 kg/ha/yr), 38% was contributed by precipitation, 35% by throughfall and approximately 27% by stemflow. Although the total nutrient input is only one‐half that of litterfall, the net impact on short‐term nutrient requirements is considerable because of their immediate availability. Nutrient inputs in litter represent a delayed return mechanism because of the relatively slow decomposition process.

Seasonal Nutrient Dynamics of Litter in a Subtropical Eucalypt Forest, North Stradbroke Island

The plant components and chemical composition of litter fall and the litter layer in a forest growing on deep, nutrient-poor sands were examined on North Stradbroke Island, south-eastern Queensland. The seasonal distribution of litter fall was examined over a 26-month period. While the total litter fall was greatest during summer months, the dominant tree species differed in their individual patterns of litter fall. Eucalyptus signata showed a single summer peak for leaf fall while E. umbra exhibited one peak in early summer and another in autumn. The possibility is discussed that these and other temporal differences are evolutionary expressions of niche differentiatibn to reduce competition between species in the ecosystem. The total litter fall averaged 640 g m-1 yr-1 and the accumulated forest floor mass totalled 2700 g m-2. Total nutrient pools and nutrient inputs in litter fall are presented. A litter half-life of 2.9 years is estimated, a figure close to the half-life of most of the nutrients in the litter. Manganese appears to be markedly concentrated in eucalypt leaves before they fall. Only sodium, potassium, copper and chloride appear to be leached easily from leaves slashed from trees and left on the forest floor. Patterns of litter production and decay in this subtropical forest fit within trends extrapolated from temperate Eucalyptus-dominated communities studied to date.

Nitrogen and Phosphorus Levels in Water Associated with a Channel Catfish (Ictalurus punctatus) Feeding Operation

Abstract Nitrogen and phosphorus budgets for two catfish raceways near Durant, Oklahoma, during 1972 and 1973, indicated that 18 to 64% of the total nutrient inputs accumulated in the raceways' sediment. Both N and P inflow/outflow levels were relatively constant throughout the study. Levels of nitrite-N, nitrate-N, ammonium-N, and organic-N were generally higher in the outflow than the inflow, but were typically within recommended water quality limits. Similarly, average total and soluble P concentrations increased in the raceways, doubling from inflow to outflow. Nevertheless, the increased N and P levels did not result in serious problems due to algae or other aquatic growths. Moreover, the health and growth of the catfish remained good. Present raceway management and catfish production practices seem to pose no particular water quality problem.