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This study investigated long-term fertilisation effects on soil microbiological characteristics of hydromorphic paddy soils. The study was conducted in 30-year-old experimental plots with various treatments involving chemical fertiliser (nitrogen, phosphorus, and potassium) alone or in combination with manure in relation to a control in a rice-rice-fallow system at the farm at Jiangxi Academy of Agricultural Science. The soil microbial biomass carbon (SMBC) and nitrogen (SMBN), microbial enzyme activity, and microbial community structure were analysed. Changes in levels of SMBC and SMBN in response to combinations of organic-inorganic fertilisers were significantly higher than for inorganic fertiliser treatment. Furthermore, activities of microbial enzymes (sucrase, urease, proteinase, acid phosphatase, and catalase) were significantly higher in combined than in inorganic fertiliser and control treatments. Additionally, the richness and evenness of soil bacteria were decreased by long-term fertilisation, especially inorganic, whereas the Shannon-Weiner and richness indexes of soil fungi were higher. Long-term fertilisation with high doses of combined organic-inorganic input significantly increased microbial biomass, enzyme activity, and fungal community diversity. However, the same input decreased bacterial community diversity. This study will be useful for improving fertilisation management in hydromorphic paddy soils. Additional keywords: chemical fertiliser; fertilisation; manure; microbiology. Received 22 May 2018, accepted 6 January 2019, published online 6 June 2019, Introduction Organic matter transformation represents one of the most important attributes for the management of soil fertility (Lalnunzira and Tripathi 2018), and is regulated by the activity of soil microorganisms [...]

To meet the global food demand in the coming decades, crop yields per unit area must increase. This can only be achieved by a further intensification of existing cropping systems and will require even higher inputs of N fertilisers, which may result in increased losses of nitrous oxide ([N.sub.2]O) from cropped soils. Enhanced efficiency fertilisers (EEFs) have been promoted as a potential strategy to mitigate [N.sub.2]O emissions and improve nitrogen use efficiency (NUE) in cereal cropping systems. However, only limited data are currently available on the use of different EEF products in sub-tropical cereal systems. A field experiment was conducted to investigate the effect of three different EEFs on [N.sub.2]O emissions, NUE and yield in a sub-tropical summer cereal cropping system in Australia. Over an entire year soil [N.sub.2]O fluxes were monitored continuously (3 h sampling frequency) with a fully-automated measuring system. The experimental site was fertilised with different nitrogen (N) fertilisers applied at 170 kg N [ha.sup.-1], namely conventional urea (Urea), urea with the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP), polymer-coated urea (PCU), and urea with the nitrification inhibitor nitrapyrin (Nitrapyrin). Nitrous oxide emissions were highly episodic and mainly controlled by heavy rainfall events within two months of planting and fertiliser N application. Annual [N.sub.2]O emissions in the four treatments amounted to 2.31, 0.40, 0.69 and 1.58 kg [N.sub.2]O-N [ha.sup.-1] [year.sup.-1] for Urea, DMPP, PCU and Nitrapyrin treatments, respectively, while unfertilised plots produced an average of 0.16 kg [N.sub.2]O-N [ha.sup.-1] [year.sup.-1]. Two of the tested products (DMPP and PCU) were found to be highly effective, decreasing annual [N.sub.2]O losses by 83% and 70%, respectively, but did not affect yield or NUE. This study shows that EEFs have a high potential to decrease [N.sub.2]O emissions from sub-tropical cereal cropping systems. More research is needed to assess if the increased costs of EEFs can be compensated by lower fertiliser application rates and/or yield increases., Introduction Nitrogen (N) fertiliser is a key input to achieve global food security and has made a crucial contribution to increasing food production over the past 50 years. Today the [...]

The world's coastal ecosystems are under stress. The numbers tell the story: Over 50 percent of the global population resides within 100 kilometers of a coastline, a thin ribbon of [...]

Fifteen years of N and P fertilizer addition to an Alaskan moist tundra increased aboveground biomass and primary production by 2.5 times. Species composition of the fertilized vegetation also changed dramatically, from a mix of graminoid, evergreen, deciduous, and moss species to strong dominance by a single, deciduous shrub species, Betula nana. Analysis of these simultaneous changes allows insights into the interactions between changes in resource availability and changes in species composition in regulating vegetation biomass, production, and element use. By the 15th year (1995), both new leaf production and total leaf mass were lower in fertilized than in control plots, although leaf area in fertilized plots was twice that of controls. This occurred because Betula produced thinner leaves than other species, with a high specific leaf area (SLA, leaf area per unit leaf mass). Woody stem mass also increased dramatically in fertilized plots, with secondary growth accounting for over half of aboveground net primary production, NPP. The large increase in wood production was made possible, in part, by the low cost of production of Betula's thin leaves, allowing greater allocation to secondary growth. Wood also had lower N concentrations than leaves, allowing large accumulations of wood at low N cost. Overall, aboveground N concentration in Betula did not change in fertilized relative to control plots, because its low-N wood mass increased more than its high-N leaf mass (with high SLA). Because Betula was so strongly dominant on the fertilized plots and was better able to dilute its greater N supply with new growth, community production and biomass in fertilized plots were higher, and N concentration was lower, than would have been the case if species composition had not changed. Aboveground biomass and leaf area of individual species and functional types were predicted accurately by regression against the number of hits per point-flame pin across the full range of data, including both treatments. Changes in overall canopy structure and leaf display due to fertilization were thus due mainly to changes in species composition, with no detectable effect of treatment on size/structure relationships within species or functional types. Key words: allocation; Arctic; biomass; Brooks Range, Alaska; fertilizer; nutrients; primary production; secondary growth; species composition; specific leaf area; tundra productivity.

Nutrient flows related to agricultural development in the Baltic States and Sweden after 1988 and the change from collective farms to a market economy with family farms are discussed. Changes in nitrogen and phosphorus flows in agriculture and into the Baltic Sea after independence from Russia came to the Baltic States are compared to changes in Sweden in the same time period.

1 The rhizome growth patterns of the clonal plant Solidatto altissima were studied in response to mowing and fertilizer application in a field experiment. Rhizome systems of 120 clonal fragments were harvested in the spring of 1993, after 6 years of mowing (1987-92) and 2 years of fertilizer application (1991-92). The results were interpreted in the light of plant foraging theory. 2 The ages of the individual rhizomes comprising each rhizome system were determined and their length, number of offspring rhizomes, branching angles and the height of emerging shoots measured. Rhizomes were then washed, dried and weighed. 3 Persistent rhizomes, i.e. rhizomes that survived more than 1 year, were shorter and less numerous in mown plots and their dry mass was less than 50% of that in unmown plots. Thus, repeated mowing depleted the rhizomes of their stored resources and has been used as a measure to control the further spread of S. altissima. 4 In contrast, rhizomes established in 1992 produced 10% more daughter rhizomes, which were also 23% longer in mown than in unmown plots. 5 There was little evidence that the length, and no evidence that the number of rhizomes, was increased by fertilizer application. Nevertheless, fertilizer application increased the dry mass and decreased the specific length (length per unit dry mass) of rhizomes. 6 Rhizome branching angles were not consistently altered by the treatments. However, there was a significant interaction, i.e. angles increased in response to fertilizer in unmown but not in mown plots. 7 The observed rhizome growth patterns (3-5) could be explained by adaptive growth plasticity, i.e. foraging, in the first year followed by differential survival of long rhizomes in later years. However, the greater length of newly formed rhizomes in mown plots could also have been due to increased soil temperatures caused by the removal of standing biomass and litter, which increased irradiance at the soil surface. This suggests that the observed growth responses of the rhizome systems to mowing and fertilizer application were due to 'passive growth' rather than adaptive foraging. Keywords: clonal growth, plant foraging, plasticity, rhizome architecture

Many questions faced by forestry scientists are also faced by those concerned about basic ecology. Scientists have tried to develop ecosystem-based management approaches that maintain the complexity and function of a system. They often act in nontraditional roles at the biology/sociology/policy interface. In the US two approaches with very different goals and scientific priorities have emerged in forestry. In most industrial lands the emphasis is on greater productivity of wood fiber. Federal forest management focuses on protecting diversity and water. Long-term sustainability are important for any owner, private or public. Productive genotype selection, fertilization, harvesting practices that compact soil, pest problems related to intensive forestry and the potential of loss of species with no commercial value are issues to be faced. Biology, soils and hydrology are emphasized, but other aspects of forestry are reviewed.

For decades, farmers in Montana and the Dakotas have produced impressive yields of barley and wheat. But that bounty has come at a cost. Tilling the soil in the region's [...]

SUMMARY (1) In the Vechtplassen area of The Netherlands, small fens are scattered in an agricultural landscape which is used for dairy production. Fens in groundwater discharge areas have been less affected by eutrophication than those in groundwater recharge area. (2) Hydrological and nutrient budgets (nitrogen, phosphorus, potassium) were measured in two fens from 1985 to 1987. (3) One fen, located in a groundwater recharge area, received polluted river water which compensated for evaporative and groundwater losses during the summer. This inflow, and precipitation, were the major inputs of water. Major hydrological outputs were evapotranspiration (summer) and subsurface outflow (winter). The second fen was located in a groundwater discharge area. It received river water only occasionally and the main hydrological inputs were groundwater discharge and precipitation. Evapotranspiration and subsurface outflow were the major hydrological outputs. (4) Although nutrient inputs, especially nitrogen, were enhanced as a result of agricultural activities, summer harvesting of above-ground vegetation resulted in a net loss of potassium and phosphorus from the fens. Nitrogen inputs almost equalled outputs. (5) Differences between the fens in their overall nutrient budgets were small. Annual differences in production of biomass and in nutrient uptake by the vegetation could not be explained by differences in the nutrient budgets. Primary production and nutrient uptake reflected differences in mineralization rates of nitrogen and phosphorus. The mineralization process is regulated by the amount of organic nutrient substrates which may be mineralized as well as by the substrate composition and the ionic composition of the fen water. (6) The young fens are primarily fed by external nutrient inputs and are characterized by nutrient accumulation in peat. In mature fens, the peat which has developed isolates the fen from its environs, and plant growth is driven by re-mineralization of nutrients that have accumulated in former periods. (7) Harvesting of vegetation effectively reduces phosphorus and potassium in the soil. Over the long term, a shift from nitrogen limitation towards phosphorus or potassium limitation is to be expected in the fens. However, regional land-use control is necessary to prevent a further increase in nutrient inputs.

The American Association of Plant Food Control Officials (AAPFCO) adopted standard language for Bulk Compost Rules and Regulations. It allows composters to reduce the risk to marketers of bulk compost when making nutrient claims.

ABSTRACT: We investigated the effects of rain infiltration rate and manure application rate on the quality of leachate and runoff from four soils. Tall fescue (Festuca arundinacea Schreber) plots received [...]