Sandy Soil Areas Research Articles

The occurrence of the hazel dormouse,Muscardinus avellanarius, in the south-western Baltic region and its biogeographical implications

The occurrence of hazel dormice on some islands in the Baltic Sea raises the question about the origin of these long isolated populations. The spread of hazel dormice from their Pleistocene shelters in southern Europe to the north was facilitated by a rapid spread of hazel during the Boreal after 10800 cal. yr BP and subsequently hazel dominated woodlands in central Europe. The immigration of the hazel dormouse from central Germany to Ruegen is not supported by findings and seems to be unlikely due to habitat fragmentation in the north-eastern German mainland. This is indicated by areas of poor sandy soils with poor pine forests besides wide and sandy river valleys and wetlands. In contrast, immigration via Denmark is rather possible considering the post-glacial development of the south-western Baltic Sea region. Especially the Darss Sill could have been used as a land bridge between south-eastern Denmark and north-eastern Germany about 9800 to 8800 cal. yr BP. A further migration of the species towards the east, e.g. to Bornholm, might be prohibited by the existence of the vast Oder River valley.

Soil Moisture Movement during the Dry Season in the Sandy Soil Area of Northeast Thailand

Soil Moisture Movement during the Dry Season in the Sandy Soil Area of Northeast Thailand

Atmospheric precipitation on the soils of Belarusian Polesye

The article considers the influence of atmospheric precipitation in the form of dust and dry residue with rain and snow in the formation of technogenic situations in the soils of the Belarusian Polesye. Anthropogenic impact on the soil is formed as a result of entering into the soil of technogenesis product, is made up of atmospheric precipitation in the form of dust and rain, as well as key components of chemical reclamation (Ca, Mg, K, N, P) of soil. Based on field research and data of the Hydrometeorological Service of Belarus there was generalized the information and disclosed the regularities of dust deposition and mineral residue precipitation in Belarusian Polesye. Mapping the anthropogenic impact on the soil was performed using software packages ESRI ArcView and ESRI ArcGIS. It is set a noticeable spatial heterogeneity in the level of anthropogenic impact on the soil of the Belarusian Polesye, ranging from 6,3 t/ha per year in the district of Gantsevichi to 17,6 t/ha in Malorita district, Brest region. There is a general tendency of increasing of the given parameter in the direction from north-east to south-west of Polesye. The level of anthropogenic impact is largely dependent on natural (soil properties and structure of the soil) and economic (level of development and specialization of industry and agriculture) factors. The lowest value of the anthropogenic impact (less than 7,5 t/ha per year) is characteristic for areas with underdeveloped industry and a high proportion of drained peat soils: Gantsevichi, Oktyabrsky, Narovlya and Zhitkovichi. For the western part of the Belarusian Polesye (Malorita, Stolin, Ivanovo, Berezovsky, Drogichin areas) other than large areas of sandy soils, characterized by increased loads on agropochvy (12,1 or more t/ha per year), the largest contribution falls on the organic fertilizers. Technogenic situation in the soils was estimated based on the amount of annual agrotechnogenic load on the soil, air emissions from stationary sources and the level of radioactive contamination, formed as a result of the Chernobyl accident. As a result, we allocated favorable, satisfactory, conflict, tension, and critical situation. Favorable technogenic situation is typical for soils under forests and within specially protected areas (national parks and nature reserves) with anthropogenic load of less than 1 t/ha, not contaminated and distant from industrial centers. Such conditions correspond to 15 % of the Belarusian Polesye near major rivers and their tributaries in the region (the area between the Dnieper and the Sozh, the middle flow for the Pripyat and its tributaries Sluch, Yaselda, Ubort). A satisfactory situation has developed for 28,5 % of the territory, mainly within the northern part of the Pripyat Polesye due to a moderate level of anthropogenic pressure, in part – in the border of forest and wetland areas due to contamination with radionuclides. The conflict situation is typical for the northern part of Brest and Mozyr Polesye, on the right bank of the Dnieper and Berezina rivers, as well as in the area between Pina and Goryn rivers (27,7 %). In the southern part of the Brest Polesye, as well as in the countryside and along the Goryn river valley there is a tense situation (22,2 %), due to high anthropogenic pressure and intensive agricultural activities, in the latter case – also complicated by radioactive contamination. Critical man-made situation (7 %), which is observed in the south-east of Polesye, is due to high levels of radioactive contamination within the Polesye State Radiation Ecological Reserve and adjacent areas, despite the relatively low levels of air and agrotechnogenic pollution.

Assessment of plant biodiversity on and off mature stands of Androstachys johnsonii Prain and Colophospermum mopane (J.Kirk ex Benth.) J. Leonard

The species that were growing on the stands of C. mopane and on open space stands weighed more than those on the stands of A. johnsonii in both loam and sandy soil areas. This is probably an indication that there are some toxic chemicals that are excreted from various parts of A. johnsonii that caused the suffering and hence lesser weights of the understory species of A. johnsonii. The conditions were found to be unfavorable for the majority of the understory species to grow and flourish well under the canopies of A. johnsonii. This therefore, might imply that even though A. johnsonii possess allelochemical materials, some understory species may adapt to such conditions in the proximity of its vicinity. The decomposition of different parts of the plant on the ground surface under A. johnsonii canopies probably results in relatively highest concentration of allelochemical materials in the soil on A. johnsonii stands. Limiting factors like shading, temperature, water availability, and soil type may not necessarily be causes of the observed differences as the investigation was carried out from the same areas. The present investigation revealed that A. johnsonii in woodlands chokes its understory plants and such plants might eventually die out. Key words: Allelochemical materials, Androstachys johnsonii, Colophospermum mopane, biodiversity, impact.

Effect of nutrients and plant growth regulators on growth and yield of black gram in sandy loam soils of Cauvery new delta zone, India

AbstractPulse productivity is very low in some of the sandy soil areas where, soils are having poor water and nutrient holding capacity. To improve the pulse productivity, field experiments were conducted at Agricultural Research Station, Tamil Nadu for two consecutive years to study the effect of phosphorus sources (mono- and diammonium phosphate) with brassinolide and salicylic acid on growth and yield of black gram in sandy loam soils. The experiment was carried out in a randomized block design with three replications during kharif season. The treatments include 100% recommended dose of NPK along with foliar application of monoammonium phosphate (MAP), diammonium phosphate (DAP), brassinolide (0.25 ppm), and salicylic acid (100 ppm) along with the combination of these treatments. TNAU pulse wonder at 5.0 kg ha−1 and TNAU micronutrient mixture (MN) at 5 kg ha−1 were also tried. The results revealed that application of 100% recommended dose of NPK + DAP 2% + TNAU pulse wonder 5.0 kg ha−1 was statisticall...

The Abundance of Pioneer Vegetation and Their Interaction with Endomycorrhiza at Different Land Qualities after Merapi Eruption

Eruption of Merapi volcano caused accumulation of lahar materials that led to extensive land degradation. This research was to study the population of pioneer plants and their correlation with endomycorrhiza population at different land qualities after Merapi eruption. Samples of soil, pioneer plants, and endomycorrhiza were collected from Merapi volcano, 1 year after eruption, using stratified sampling method based on plant densities, with the following categories: dense vegetation, moderately dense vegetation, sparse vegetation, and control (bare land), with 3 replications for each category. Pioneer plants and endomycorrhiza were identified. Plant biomass, soil pH, total-C,-N, and exchangeable-K, -Ca, -Mg, -Fe were analyzed. The abundance of pioneer plants and their interaction with mycorrhiza was strongly correlated with depth of eruption material, quantity of sandy texture, soil pH, total-C and total-N, exchangeable-K, exchangeable-Ca, exchangeable-Mg, and exchangeable-Fe. Among the 12 identified pioneer plants, only Acacia villosa, Fiurena ciliaris, and Bidens pilosa were recommended as plant-remediator to improve soil chemical, physical and biological properties. Among the 3 genera of endomycorrhiza (Acaulospora, Gigaspora, Glomus), only Acaulospora was recommended to be a biological agent to rehabilitate sandy soil area. This research indicated that adaptive pioneer plants and endomycorrhiza were likely to be suitable for biological agents to stimulate recovery of degraded land through improvement of physical, chemical, and biological properties, that will stimulate plant growth and biodiversity.

Interspecific variation in leaf water use associated with drought tolerance in four emergent dipterocarp species of a tropical rain forest in Borneo

By use of tree-tower and canopy-crane systems we studied variations in the water use, including transpiration, stomatal conductance, and leaf water potential, of the uppermost sun-exposed canopy leaves of four emergent dipterocarp species in an aseasonal tropical rain forest in Sarawak, Malaysia. Midday depression in stomatal conductance and leaf water potential was observed in all the species studied. Interspecific differences were clearly observed in the maxima of transpiration rates and stomatal conductance and the minima of leaf water potential among the four dipterocarp species. These interspecific variations were closely related to wood density and to factors affecting ecological patterns of distribution. Specifically, Shorea parvifolia and S. smithiana, both of which have a relatively low wood density for Dipterocarpaceae and are found on clay-rich soil, had a high transpiration rate in the daytime but had a large midday depression and a low leaf water potential. In contrast, Dryobalanops aromatica, which has a high wood density and is found in sandy soil areas, consumed less water even during the daytime. Dipterocarpus pachyphyllus, which has a high wood density and is found on clay-rich soil, stood intermediate between Shorea and D. aromatica in leaf water use. The two Shorea species had higher mortality than the others during the severe drought associated with El Niño in 1998, so daily pattern of leaf water use in each dipterocarp species might be correlated with its susceptibility to unusual drought events.

Impact of manure and slurry applications on soil nitrate in a maize–triticale rotation: Field study and long term simulation analysis

Estimation of nitrate leaching from agricultural systems is critical to environment impact studies. Simulation models can help to assess and understand the dynamics of nitrates in the soil and in relation to fertilizer types and agronomical management. The main hypothesis of this study was that the long term annual application of mineral and organic N fertilizers, in irrigated sandy soil areas increases dramatically the quantity of NO3− in the soil for potential nitrate leaching. The main objectives of this research were then to quantify inorganic N concentration in soil layers affected by mineral and organic N (manure and slurry) fertilizers; and to test the SALUS crop simulation model to identify the best N management strategy able to minimize NO3− leaching without compromising crop growth and yields. A first set of rotational simulations were carried out for the 2007 and 2008 experiments, with the goal of comparing measured and simulated results. A second set of rotational simulations were carried out for a long term assessment (50years) of the two treatments in comparisons. Additional long term rotational simulation runs were carried out considering two different fertilization strategies based on the maize crop uptake in 2007 (276kgNha−1) and on the PUA (“Best Nitrogen Management with manures”) which defines the fertilization practices adopted in the nitrate vulnerable zones (no more than 170kgNha−1year−1). Measured data showed that in the manure treatment, the highest nitrate-N concentration was 627.3mgkg−1 at 0.10m depth on August 2008, while the lowest was 2.50mgkg−1 at 1.40m depth on July 2007. In the slurry treatment, the maximum nitrate N concentration was 344.6mgkg−1 at 0.10m depth on August 2008 and the minimum was 8.9mgkg−1 at 0.60cm depth on September 2007. The model was able to closely reproduce the measured results. The simulation results of the inorganic soil N were 1228kgha−1 and 1370kgha−1 for the manure and slurry treatment respectively versus the measured soil inorganic N content at the beginning of the experiment of 1267kgha−1 for the manure treatment and 1323kgha−1 for the slurry treatment. The simulated cumulative amount of nitrate leaching was 9251kgha−1 for the manure treatment and 11,101kgha−1 for the slurry treatment for the 50years simulations.The simulations results also showed that when the inorganic N was used alone, the amount of leaching and soil N were significantly reduced.

Distribution, frequency and occurrence of cereal nematodes on the Central Anatolian Plateau in Turkey and their relationship with soil physicochemical properties

The distribution of important plant-parasitic and free-living nematodes in the cereal production areas of the Central Anatolian Plateau (CAP) of Turkey was investigated with systematic surveys. Two important plant-parasitic nematode groups were found widely distributed; cereal-cyst nematodes (78.3%) and root-lesion nematodes (42.6%). Cereal cyst nematodes (CCN) were identified as Heterodera filipjevi in 18 provinces. Heterodera latipons was found in only one province. Pratylenchus thornei and P. neglectus were the most widely distributed species of root-lesion nematodes. Other frequently recorded plant-parasitic nematodes belonged to the genera Geocenamus (52.4%), Pratylenchoides (35.6%), Helicotylenchus (29.7%) and Paratylenchus (19.2%). Konya on the southern CAP had a significantly high incidence of P. neglectus as well as free-living nematodes. The incidence of CCN was greatest in areas of sandy soils on the CAP, with densities of up to 95 cysts (100 g soil)−1. Population densities of Geocenamus, Pratylenchus and Pratylenchoides were high in some locations. Soil physicochemical properties were investigated for their relationship to nematode distribution. There was a slight positive correlation of P. thornei and clay content; conversely, there was a significant negative correlation of P. neglectus with clay and a positive correlation with sand. Electrical conductivity (EC) was positively correlated with P. neglectus. Nematodes in the genera Helicotylenchus, Paratylenchus, Trophurus and Tylenchorhynchus were only recorded at low population densities in the sampled area. By contrast, nematodes in the genera Aphelenchus, Aphelenchoides, Ditylenchus, Dorylaimus, Tylenchus and bacterivorous genera had relatively high populations. Total free-living nematodes were positively correlated with EC and zinc (Zn) concentration. The Zn content of soil was generally at a level deficient for plant growth.

Analyzing the efficiency of soil amendments and irrigation for plant production on heterogeneous sandy soils under greenhouse conditions

AbstractVariability in soil properties is a complication for fertilization, irrigation, and amendment application. However, only limited progress has been made in managing soil variability for uniform productivity and increased water‐use efficiency. This study was designed to ameliorate the poor‐productivity areas of the variable sandy soils in Florida citrus groves by using frequent small irrigations and applying organic and inorganic soil amendments. Two greenhouse experiments were set up with sorghum and radish as bioassay crops in a randomized complete block design (RCBD). The factors studied were two soil‐productivity classes (very poor and very good), two water contents (50% and 100% of field capacity), two amendments (phosphatic clay and Fe humate), and two amendment rates (10 and 25 g kg–1 for sorghum and 50 and 100 g kg–1 for radish). Amendments applied at 50 and 100 g kg–1 increased the water‐holding capacity (WHC) of poor soil by 2‐ to 6‐fold, respectively. The lower rates (10 and 25 g kg–1) of amendments were not effective in enhancing sorghum growth. The higher rates (50 and 100 g kg–1) doubled the radish growth as compared to the control. The results indicate that rates greater than 50 g kg–1 of both amendments were effective in improving water retention and increasing productivity. Irrigation treatment of 100% of field capacity (FC) increased the sorghum and radish growth by about 2‐fold as compared with the 50%–water content treatment. The results suggest that the root‐zone water content should be maintained near FC by frequent small irrigations to enhance water availability in excessively drained sandy soils. In addition, application of soil amendments in the root zone can enhance the water retention of these soils. Furthermore, managing variable sandy soils with WHC‐based irrigation can increase water uptake and crop production in the poor areas of the grove.

Una Nueva Especie de Boyania (Melastomataceae) de Colombia

Boyania colombiana Humberto Mend. (Melastomataceae) is described and illustrated from an area of sandy soils in the department of Caqueta, Colombia. It is a disjunct species in a monotypic genus known from the Guayana Shield in Guyana. Boyania colombiana is distinguished from B. ayangannae Wurdack by the shape of the leaf base, the petiole longer than 2 cm, the shortened internodes, and the absence of a dorsal connective appendix. Boyania colombiana is compared to other genera of the tribe Bertolonieae, and the generic position of the new species is discussed.

Changes of woody plant interaction and spatial distribution between rocky and sandy soil areas in a semi-arid savanna, South Africa

We examined the impact of shrub–shrub interactions and soil type (rocky or sandy) on growth and spatial distribution of the two savanna shrub species Tarchonanthus camphoratus and Acacia mellifera. To explore plant interactions, we compared the size of juvenile and mature T. camphoratus shrubs between different locations (under the subcanopy of A. mellifera and in the open). Juvenile T. camphoratus shrubs had similar sizes regardless of location; however, in rocky soil, mature shrubs in the open were larger than those near A. mellifera, implying an inter-specific competitive effect of A. mellifera on T. camphoratus. Juvenile T. camphoratus shrubs grew faster in the sandy than in the rocky area. Furthermore, we used the Wiegand–Moloney O-ring statistics to explore the spatial distribution of T. camphoratus. T. camphoratus showed spatial aggregation, but in the rocky area T. camphoratus juveniles were positively associated with A. mellifera (indicating facilitation as the pattern-creating process), whereas in the sandy area they were positively associated with mature T. camphoratus shrubs (indicating seed dispersal as the pattern-creating process). T. camphoratus exhibited encroachment potential in the sandy area. We showed how spatial pattern analysis can help to explore processes determining woody plant spacing and recommend its further use.

Identification of groundwater recharge sources and processes in a heterogeneous alluvial aquifer: results from multi‐level monitoring of hydrochemistry and environmental isotopes in a riverside agricultural area in Korea

AbstractWe evaluated sources and pathways of groundwater recharge for a heterogeneous alluvial aquifer beneath an agricultural field, based on multi‐level monitoring of hydrochemistry and environmental isotopes of a riverside groundwater system at Buyeo, Korea. Two distinct groundwater zones were identified with depth: (1) a shallow oxic groundwater zone, characterized by elevated concentrations of NO3− and (2) a deeper (>10–14 m from the ground surface) sub‐oxic groundwater zone with high concentrations of dissolved Fe, silica, and HCO3−, but little nitrate. The change of redox zones occurred at a depth where the aquifer sediments change from an upper sandy stratum to a silty stratum with mud caps. The δ18O and δ2H values of groundwater were also different between the two zones. Hydrochemical and δ18Oδ2H data of oxic groundwater are similar to those of soil water. This illustrates that recharge of oxic groundwater mainly occurs through direct infiltration of rain and irrigation water in the sandy soil area where vegetable cropping with abundant fertilizer use is predominant. Oxic groundwater is therefore severely contaminated by agrochemical pollutants such as nitrate. In contrast, deeper sub‐oxic groundwater contains only small amounts of dissolved oxygen (DO) and NO3−. The 3H contents and elevated silica concentrations in sub‐oxic groundwater indicate a somewhat longer mean residence time of groundwater within this part of the aquifer. Sub‐oxic groundwater was also characterized by higher δ18O and δ2H values and lower d‐excess values, indicating significant evaporation during recharge. We suggest that recharge of sub‐oxic groundwater occurs in the areas of paddy rice fields where standing irrigation and rain water are affected by strong evaporation, and that reducing conditions develop during subsequent sub‐surface infiltration. This study illustrates the existence of two groundwater bodies with different recharge processes within an alluvial aquifer. Copyright © 2009 John Wiley & Sons, Ltd.

Population size and habitat relationships of Black-bellied SandgrousePterocles orientalisin the Canary Islands, Spain

SummaryWe estimated the breeding population size and assess the habitat relationships of Black-bellied Sandgrouse in the Eastern Canary Islands (Fuerteventura, Lanzarote and La Graciosa, Spain) by means of a survey based on 1,787 0.5-km line transects and distance sampling done in 2005 and 2006. The population comprised 2,906 individuals (90% CI: 2,363–3,562), which is much higher than the numbers estimated in previous reports based on partial surveys, and constitutes 20% of the total Spanish population. Sandgrouse in the Canaries are currently restricted to Fuerteventura, where 70% of the population gathers in four areas that encompass just 16.7 % of the island and are largely within Special Protection Areas classified under the EU Birds Directive (except the area of Tefia-Ampuyenta, first in absolute number of individuals). The environmental characteristics that maximize the probability of occurrence of the sandgrouse in Fuerteventura (probability = 0.196) are: treeless non-cultivated areas of sandy soils without bare bedrock, with a rock cover less than 44%, located in non-coastal areas with an average terrain slope less than 27.5%, at more than 400 m from the nearest urban area, with less than 795 m of dirt roads per 20 ha, with at least 0.9% of shrub cover and a NDVI index higher than 53. Sandgrouse were closer to human settlements in midsummer than in March, perhaps being attracted to artificial pools surrounding villages. Similar habitat characteristics exist in nearby Lanzarote, where the species could hypothetically reach densities as high as 4–5 birds km−2. Possible reasons for the absence of sandgrouse in this island are discussed.

Two New Species of Lizards of The Genus Bachia (Squamata, Gymnophthalmidae) from Central Brazil

Two new species of Bachia of the bresslaui group are described from the central Brazilian Cerrados, state of Tocantins. The two species are most similar to Bachia bresslaui and Bachia cacerensis from which they differ in limb morphology and head scalation. In both, the snout is more prominent than that of previously known species, suggesting more pronounced adaptations to fossoriality. One of the new species has stiliform forelimbs and four clawed short toes in the hind limb, an opposite pattern to the condition observed in the genus where limb reduction is more pronounced in hind limbs. The two new species were obtained in relictual sandy soil areas covered by semidecidual or open dry forest vegetation. Considering the relictual condition of these sandy areas, the possible endemism to those areas, and the high level of disturbance of the Cerrados, we strongly suggest that these areas should be the target of special conservation efforts.

Coupling effects of depth of film-bottomed tillage and amount of irrigation and nitrogen fertilizer on spring wheat yield

The crop cultivation with film-bottomed tillage may benefit more, but little is known about the coupling effects of depth of film-bottomed tillage (DFBT) and amount of irrigation and nitrogen (N) fertilizer on spring wheat yield. A field quadratic regression orthogonal design experiment was conducted to determine the effects of DFBT, irrigation and N fertilization on seed yield of spring wheat ( Triticum aestivum L.) in the Hexi Corridor, China from 2002 to 2005. Five levels of irrigation (143, 165, 225, 285, and 306 mm), five levels of N (45, 70, 140, 210, and 235 kg N ha −1) and five DFBT (46, 60, 70, 80, and 94 cm) were investigated. Irrigation (44 mm ≤ irrigation ≤ 300 mm), DFBT (46 cm ≤ DFBT ≤ 80 cm), and N (≤160 kg N ha −1) significantly increased wheat yield. DFBT, N and irrigation had a positive effect on wheat yield, in the order: irrigation > N > DFBT. The coupling between DFBT × N and, between N × irrigation had a synergistic effect on spring wheat yield. The coefficient of DFBT × irrigation was negative showing the coupling of DFBT × irrigation had a reciprocal inhibition or substitution effect. The findings suggest that spring wheat should be irrigated with 300 mm of water, with an application of 160 kg N ha −1 and a 70 cm DFBT in the arid climate and sandy soil areas of China, to obtain the highest wheat yield with maximum economic benefit. The assessment with respect to N fertilizer use efficiency, environmental pollution need further research.

The Topography and Gross Anatomy of the Gastrointestinal Tract of the Cape Dune Mole‐rat (Bathyergus suillus)

The Cape dune mole-rat, Bathyergus suillus, is the largest truly subterranean rodent in the world and is restricted to sandy soil areas of the southern and South-western Cape Province. These animals are herbivorous, feeding mostly on the below ground portions of grass and geophytes. The present study was undertaken to explore whether there are any gross anatomical gastrointestinal adaptations associated with the herbivorous diet of the Cape dune mole-rat and to provide a basis for further investigations into the nutrition and ecology of this animal. The stomach was unilocular (simple) and the entire internal aspect displayed macroscopically visible glandular epithelium. The caecum was voluminous and arranged into a spiral of approximately one and a half turns. The tip of the caecum resembled a vermiform appendix and lay against the left lateral abdominal wall. The ascending colon consisted of proximal and distal portions, arranged in a large double loop and attached to each other by a fat-filled mesenteric fold. The looped, folded ascending colon filled the right side of the abdominal cavity, lying against the right dorsal, lateral and ventral abdominal wall. The internal structure of the ascending colon revealed a shallow groove, lined on either side by a row of papillae. The simple, glandular stomach in conjunction with a prominent caecum and a greatly enlarged ascending colon suggests that this animal is a hindgut fermenting herbivore, rather than a caecal fermenter, as is the case in most rodent species.

Best Management Practices for Florida Citrus

Best management practices (BMPs) started in Florida citrus (Citrus spp.) in the 1990s and have evolved to play a major role in production practices today. One of the earliest BMPs in Florida arose from concerns over nitrate-nitrogen concentrations in some surficial groundwater aquifers exceeding the 10 mg·L-1 drinking water standard. This occurred in an area of well-drained sandy soils known as the Central Florida Ridge that extends north and south through the central part of the Florida peninsula. State agencies could have used a strictly regulatory approach and restricted how much nitrogen growers could apply. Instead of setting arbitrary regulations, the agencies promoted a scientific-based BMP approach. A nitrogen BMP for Central Florida Ridge citrus was established, and research is now validating the earlier groundwater work on more grower field sites. The purpose of this BMP was to minimize the risk of leaching nitrates from fertilizer into the groundwater. Several important aspects of the BMP involve: 1) limiting the amount of nitrogen fertilizer applied at any one time, 2) increasing the frequency of fertilizer applications, 3) reducing fertilizer applications during the summer rainy season, and 4) managing irrigation to reduce leaching below the root zone. Since this Central Florida Ridge nitrogen BMP was established, major BMP actions to improve water quality and reduce the quantity of runoff water have taken place in the Indian River production area of Florida's east coast. BMPs continue to be set up in other parts of the state for a variety of plant and animal agricultural practices. In some cases, cost-share funds have been provided to help implement BMPs. With voluntary BMPs, growers have scientifically based guidelines, a waiver of liability, and an avoidance of arbitrary regulations.

Nutrient Leaching in Undisturbed Cores of an Acidic Sandy Podosol Following Simultaneous Potassium Chloride and Di-Ammonium Phosphate Application

In south-east Queensland, Australia, extensive areas of sandy soils (Podosols) with shallow (<1 m) watertables are used for exotic pine tree production. Despite concerns that surface-applied fertilisers (di-ammonium phosphate (DAP) and potassium chloride (KCl)) may be contributing to a decline in local groundwater quality, published information on nutrient leaching in these Podosols is scarce. Large (0.3 m i.d. ×0.85 m long) undisturbed soil cores were intermittently leached with deionised water following a single surface application of KCl in combination with DAP. Potassium was applied at rates (equivalent on a surface area basis) of 0 (K0), 50 (K50), 100 (K100) and 300 (K300) kg K+/ha, and DAP was applied at a rate equivalent to 50 kg P ha−1. Applied ions appeared in the leachate very quickly after surface application, and reactive ions leached at the same rate as non-reactive ions. This behaviour was attributed to preferential soil–water flow, and limited ion sorption. About 30, 35, 100 and 25 percent of the applied K+, phosphorus (P), chloride (Cl−) and ammonium (NH4 +) was leached from the soil cores. Cation exchange was the major mechanism responsible for K+ and NH4 + retention, although nitrification may have also contributed to NH4 + losses. Findings indicate that significant amounts of surface-applied fertiliser ions can potentially be rapidly leached below the tree root-zone, and into the underlying groundwater. Immobile water regions were estimated to comprise nearly 50% of the soil–water. Intermittent leaching resulted in secondary concentration peaks along the trailing edge of the ion breakthrough curves (BTCs). This was attributed to diffusion of solute from immobile water regions into mobile water regions during periods of no-flow.

The effects of different input data and their spatial resolution on the results obtained from a conceptual nutrient emissions model: the River Stör case study

AbstractThis paper focuses on the influences of different data sources, and the variation in spatial resolution of input data and analysis, on the calculated nutrient emissions using the conceptual model MONERIS. MONERIS calculates both nitrogen and phosphorus emissions from point and diffuse sources and the riverine nutrient retention. By subtracting the retention from the emissions, a riverine nutrient load was estimated and compared with the observed nutrient river load. All calculations were conducted for the period from 1991 to 1993.The River Stör, with a catchment area of 1135 km2, located in a postglacial lowland landscape in northern Germany, was chosen as a case study area. Two different data sets (e.g. land use, soil type or wastewater treatment plant inventory) were used: a commonly available standard data set (German or European maps) and a more detailed set with a higher spatial resolution derived from several studies at the Ecosystem Research Centre in Kiel. Initially, both data sets were used to apply MONERIS to the total catchment. The results were compared to adapt some of the free model‐parameters to the conditions in the relatively small lowland river catchment.Using the standard data set, total nutrient emissions of 2320 tons year−1 of nitrogen and 96 tons year−1 phosphorus were calculated. The detailed data set yielded slightly higher emissions for nitrogen (2420 tons year−1) and for phosphorus (102 tons year−1). According to the spatial resolution, the proportion of the area of tile drainages and sandy soils derived from the different data sets varies considerably. This causes great differences in the total nutrient emissions estimated by the two approaches. Comparing the observed and the calculated nutrient loads, reliable results for catchments larger than 50 km2, or third‐order streams, could be shown. Copyright © 2005 John Wiley &amp; Sons, Ltd.