Development Of Best Management Practices Research Articles

Diagnostics in animal health: How UC helps exclude and minimize impact of livestock pathogens

UC has a wide reach in the agriculture sector of the California economy and is well recognized for research expertise in plant diseases. Less well known is the role UC plays in animal agriculture. In 2012, the California Animal Health and Food Safety lab at UC Davis performed nearly 980,000 tests on samples from sick livestock, including cattle, horses, pigs, chickens and turkeys. The lab is prepared to respond rapidly to any disease outbreak or identification of a foreign disease. Researchers at the School of Veterinary Medicine at UC Davis are testing novel subunit vaccines to prevent pinkeye in cattle; UC ANR specialists and advisors and the staff at the Sierra Foothill Research and Extension Center were key to the development of best management practices that landowners and resource managers are using to protect their herds and public water sources against the parasite Cryptosporidium parvum; and UC veterinary scientists are part of a large team of experts, including state and federal agencies, determined to combat the endemic bluetongue virus, which can affect the state's exports.

Bioenergy and Invasive Plants: Quantifying and Mitigating Future Risks

AbstractThe United States is charging toward the largest expansion of agriculture in 10,000 years with vast acreages of primarily exotic perennial grasses planted for bioenergy that possess many traits that may confer invasiveness. Cautious integration of these crops into the bioeconomy must be accompanied by development of best management practices and regulation to mitigate the risk of invasion posed by this emerging industry. Here I review the current status of United States policy drivers for bioenergy, the status of federal and state regulation related to invasion mitigation, and survey the scant quantitative literature attempting to quantify the invasive potential of bioenergy crops. A wealth of weed risk assessments are available on exotic bioenergy crops, and generally show a high risk of invasion, but should only be a first-step in quantifying the risk of invasion. The most information exists for sterile giant miscanthus, with preliminary empirical studies and demographic models suggesting a relatively low risk of invasion. However, most important bioenergy crops are poorly studied in the context of invasion risk, which is not simply confined to the production field; but also occurs in crop selection, harvest and transport, and feedstock storage. Thus, I propose a nested-feedback risk assessment (NFRA) that considers the entire bioenergy supply chain and includes the broad components of weed risk assessment, species distribution models, and quantitative empirical studies. New information from the NFRA is continuously fed back into other components to further refine the risk assessment; for example, empirical dispersal kernels are utilized in landscape-level species distribution models, which inform habitat invasibility studies. Importantly, the NFRA results in a relative invasion risk to known species (e.g., is giant reed a higher or lower invasion risk than johnsongrass). This information is used to design robust mitigation plans that include record keeping, regular scouting and reporting, prudent harvest and transport practices that consider species biology, and eradication protocols as an ultimate precaution. Finally, a socio-political balance must be struck (i.e., a cost-benefit analysis) among our energy choices that consider the broader implications, which includes the risk of future invasions.

Managing Urban Archaeological Heritage: Latin American Case Studies

Abstract:This article focuses on the idea that archaeology aids the revaluation of cultural properties within historical centers. At the same time, it holds that the application of the Convention Concerning the Protection of the World Cultural and Natural Heritage of 1972 should imply the development of best management practices at inscribed sites. The handling of archaeological heritage in three Latin American cities is presented and discussed in this study, through the theoretical assumptions of preventive archaeology for the management of archaeological properties. It examines the different social contexts of World Heritage in these areas and concludes that the traditional vision of World Heritage impedes other historical readings of the past in these places. This conclusion is reached through a proactive vision defending the use of these UNESCO World Heritage Sites to improve management models with high public participation, the use of which should also be considered in the European community. There is, finally, a reminder of the desired objective: the improvement of archaeological management and, consequently, of urban historical discourses, whose outcomes enrich the lives of citizens.

Natural products chemistry applied to aquaculture: an interdisciplinary review

This review sought to highlight the importance of natural products versus synthetic products, as bioactive molecules, towards the development of better management practices in aquaculture. The nature, structure, activity, and applications of these naturally-occurring high value-added compounds are described, as well as the methodology used for their study. Examples include the well-known rotenone, eugenol, forskolin, isatin, malyngamide, chlorodesmine, pachydictyol, fimbrolide, and other potentially active molecules in aquaculture.

Advancing water resource management in agricultural, rural, and urbanizing watersheds: Why land-grant universities matter

Federally funded university water programs have had limited success in halting the degradation of water resources in agricultural, rural, and urbanizing watersheds for the past five decades. USDA-funded university water programs have advanced our understanding of watershed processes and the development of best management practices (BMPs; e.g., conservation tillage, nutrient management, alternative and innovative septic systems, and riparian buffers) to mitigate environmental risks from anthropogenic activities, in particular from agriculture, to our water resources; yet water degradation persists and has worsened in many watersheds (Howarth et al. 2000; Mueller and Spahr 2006). The National Research Council (2012) stresses the need for sustainable agricultural practices to reduce changes in flow regimes and water quality.

Linear disturbances on discontinuous permafrost: implications for thaw-induced changes to land cover and drainage patterns

Within the zone of discontinuous permafrost, linear disturbances such as winter roads and seismic lines severely alter the hydrology, ecology, and ground thermal regime. Continued resource exploration in this environment has created a need to better understand the processes causing permafrost thaw and concomitant changes to the terrain and ground cover, in order to efficiently reduce the environmental impact of future exploration through the development of best management practices. In a peatland 50 km south of Fort Simpson, NWT, permafrost thaw and the resulting ground surface subsidence have produced water-logged linear disturbances that appear not to be regenerating permafrost, and in many cases have altered the land cover type to resemble that of a wetland bog or fen. Subsidence alters the hydrology of plateaus, developing a fill and spill drainage pattern that allows some disturbances to be hydrologically connected with adjacent wetlands via surface flow paths during periods of high water availability. The degree of initial disturbance is an important control on the extent of permafrost thaw and thus the overall potential recovery of the linear disturbance. Low impact techniques that minimize ground surface disturbance and maintain original surface topography by eliminating windrows are needed to minimize the impact of these linear disturbances.

Assessment OF SURFACE WATER QUALITY at Large Watershed Scale: Land‐Use, Anthropogenic, and Administrative Impacts

AbstractUnderstanding the impacts that influence water quality is critical to the development of best management practices at the large watershed scale. This study describes the spatiotemporal variation in surface water quality and identifies their main impact in the Haihe River basin, China. Multivariate statistical techniques are applied to analyze the similarities among the sampling sites and to identify the main pollution sources in surface water. Results show that: (1) the basin can be clustered into two regions, water quality being better in the mountainous vs. plain regions; (2) water quality improves due to implementation of a strict state policy on environmental pollution control, prodded by the hosting of the Olympic games in the cities of Beijing and Tianjin; and (3) agricultural and residential land uses as well as livestock‐breeding are the main sources affecting water quality in the mountainous regions, whereas rural waste discharge — including domestic waste sewage, human and animal feces, and solid waste — significantly influences water quality in the plain regions. The waste discharge of industrial factories may be a significant source of water pollution in the plain regions. Results indicate that the environmental management from pollution sinks and sources, long‐lasting legal framework, and adequate economic incentives should be improved to optimize the large‐scale watershed management under the background of the rapid development of countries like China.

Phosphorus Levels Influence Plasma Membrane H+-ATPase Activity and K+, Ca2+, and Mg2+ Assimilation in Green Bean

Few studies have evaluated the changes in nutrient uptake in response to the availability of other nutrients, particularly cations [potassium (K), magnesium (Mg), and calcium (Ca)]. Therefore, the objective of the present work was to determine the effects of deficient, adequate, or excessive levels of phosphorus (P) on plasma membrane H+-ATPase activity and K+, Ca2+, and Mg2+ assimilation in green bean plants (Phaseolus vulgaris L. cv. Strike). A growth chamber study was conducted with different P levels applied to the nutrient solution: P1, 0.5 mM; P2, 1 mM; P3, 2 mM; P4, 4 mM; P5, 6 mM; and P6, 8 mM. Forms of cations analyzed were total and soluble K+, Ca2+, and Mg2+ and plasma membrane H+-ATPase (EC 3.6.1.35) activity, basal or induced with K+ (K+-ATPase), Ca2+ (Ca2+-ATPase), and Mg2+ (Mg2+-ATPase). Phosphorus treatments caused a significant and progressive increase in total and soluble K+, Ca2+, and Mg2+, with P6 registering the greatest concentration and P1 the lowest. Also, P doses significantly affected plasma membrane H+-ATPase activity, both basal ATPase and that induced with K+, Ca2+, and Mg2+. Therefore, P was the key factor enhancing plasma membrane H+-ATPase activity and improving K+, Ca2+, and Mg2+ uptake. Cations always were present in the nutritive solution; however, only increasing P concentration increased the cation uptake. The knowledge about the change in nutrient input in response to the availability of other nutrients could lead to the development of better management practices to minimize fertilizer input. Our results show that P is an important element for plasma membrane H+-ATPase activity and K+, Ca2+, and Mg2+ uptake.

Development of Best Management Practices for Controlling the Non-Point Sources of Pollution Around Lake Victoria Using SWAT Model: A Case of Simiyu Catchment Tanzania

Recent studies carried out in Lake Victoria Basin have identified major sources of Non-Point Source (NPS) of pollution in the Simiyu catchment of Lake Victoria using land-uses of 1975 and 2006 and compared the relative impact of land-use change on sediment and nutrient load (P and N) into the Lake. The main aim of this study was to identify and develop Best Management Practices to control NPS pollution in the Simiyu Catchment. The SWAT model was used to stimulate and assess the Best Management Practices Scenario for the catchment. The catchment was divided into seven (7) sub-basins. The results show that there was no intensive use of artifical fertilisers in the catchment and manure is the major type of fertiliser in use. Simulation was done for the period 2000 to 2005. High nutrient concentration was observed in Sub-basin 6; 0.558-0.779 kgN/ha/yr than in Sub-basin 7; 0.018-0.115 kgN/ha/yr, despite the larger area of coverage by the latter. This is also irrespective of the fact that Sub-basin 7 covers a larger area, 3,426.52 km 2 compared to Sub-basin 6 (72.97 km 2 ) and Sub-basin 4 (618.16 km 2 ). Relatively, considering their size, Sub-basin 6 produces higher pollution than Sub-basin 7. It was also observed that the sediment yield from the whole catchment reduced from 81,222 ton/yr to 98,400ton/yr.It was observed that to control the NPS pollution problem, Best Management Practices like reduced manure application rate, tillage and contour yielded a decrease of 1.4% in N load and 1.57% in sediment load. As a result, it was concluded that the SWAT modelling tool can be used in developing Best Management Practices because pollutant proc- esses per sub-catchment had been fully understood. With good model performance, developing management strategies to control NPS pollution around Lake Victoria can be achieved using the SWAT model. The BMPs have been devised de- pending on the sub-basin, which has a big collective reduction and control in NPS pollution in the whole catchment.

Caracterização de neossolos regolíticos da região semiárida do Estado de Pernambuco

Estudos de caracterização de solos em regiões ainda pouco exploradas, além de disponibilizarem e ampliarem a base de informações sobre as mais distintas ordens de solos do território nacional, também permitem sistematizar informações sobre suas propriedades, que poderão servir de subsídio para o desenvolvimento de práticas de manejo e uso sustentável das terras. Entre os principais solos recorrentes na região semiárida pernambucana, destacam-se os Neossolos Regolíticos, os quais perfazem aproximadamente 27 % da superfície do Estado e recobrem importantes áreas voltadas à produção agrícola, especialmente à agricultura familiar. Considerando a possibilidade de ocorrência de Neossolos Regolíticos com distintas propriedades físicas, químicas ou mineralógicas, em razão da existência de distintos contextos geológicos e climáticos ao longo do Estado de Pernambuco, o presente trabalho teve como objetivo caracterizar física, química e mineralogicamente Neossolos Regolíticos ao longo da região semiárida do Estado de Pernambuco, bem como relacionar os solos com sua litologia. Para isso, foram selecionados cinco perfis de Neossolos Regolíticos em diversos municípios do Estado de Pernambuco (P1=São Caetano, P2=Lagoa do Ouro, P3=Caetés, P4=São João e P5=Parnamirim). Os perfis foram descritos morfologicamente, coletando-se amostras de todos os horizontes do solo e da rocha do embasamento. Foram realizadas análises físicas e químicas para fins de classificação de solos, análises mineralógicas das frações grossas (cascalho e areia) por microscopia óptica e das frações silte e argila por difração de raios X, além de análises petrográficas das amostras de rochas. De acordo com os resultados, observou-se a ocorrência de solos semelhantes e com pequeno grau de desenvolvimento pedogenético, variando de medianamente a muito profundos, com sequência de horizontes A-AC-C e Cr e textura arenosa a média. Dois perfis apresentaram caráter solódico em profundidade. Todos os solos apresentaram baixos teores de matéria orgânica e P disponível. Apesar dos baixos teores de cátions trocáveis, todos os perfis são eutróficos. A assembleia mineralógica das frações cascalho, areia e silte é constituída essencialmente por quartzo, seguido de feldspatos e mica, corroborando a constituição petrográfica analisada. A caulinita é o principal argilomineral da fração argila em todos os perfis e horizontes estudados, indicando um importante processo de monossialitização em solos autóctones, em clima caracteristicamente semiárido. No perfil P2, devido à posição mais baixa do solo na paisagem, ocorreram minerais esmectíticos com misturas de fases entre montmorilonita, beidelita ou nontronita, identificados pela análise de DRX, empregando o teste de Greene-Kelly.

Assessment of Cattle Grazing Effects on E. coli Runoff

Runoff of Escherichia coli and other fecal indicator bacteria from grazing lands has been identified as a significant source of bacterial contamination. Development of best management practices to address these bacterial issues is critical to the success of watershed restoration efforts where grazing is a substantial contributor. In the present study, grazing management was evaluated to assess its effectiveness as a best management practice. Specifically, runoff from rotationally grazed and ungrazed approximately 1 ha pastures was monitored for more than two years using automated samplers. E. coli levels in runoff were enumerated by membrane filtration using modified membrane-thermotolerant Escherichia coli agar (modified mTEC). The study found that background E. coli concentrations (i.e., those from wildlife and soilborne naturalized strains) were relatively consistent among sites. Median background E. coli concentrations ranged from 3,500 to 5,500 colony forming units per 100 mL, which are not inconsequential levels related to water quality assessment and implementation efforts. Findings also indicated that rotational stocking, if timed appropriately, reduced E.coli concentrations in runoff. The impact of grazing timing in relation to runoff events was a more significant factor than stocking rate on the rotationally stocked pastures. When runoff occurred more than two weeks following grazing, E.coli levels were reduced by more than 88% compared to runoff during or soon after grazing. As a result, it is recommended that creek pastures and other hydrologically connected pastures be grazed during periods when runoff is less likely and that upland pastures be grazed during rainy seasons when runoff is more likely to occur.

Study on Water Quality Parameters of Linggi and Melaka Rivers Catchments in Malaysia

The Linggi and Melaka rivers catchments are among the most significant watersheds in the west coast of Peninsular Malaysia. However, Malaysia is a tropical country with approximately similar seasonal climate, in the monsoon period, water level of catchment is different. Recently in the supposed domain, due to raising the population and expanding urban areas, demand for water consumption is increased gradually. On the other hand, problem of water pollutions due to industrial activities have been signed out. Therefore, study on water quality and sources of pollutions in these regions became vital for public and private sections. This study was conducted to assess the water quality conditions in both rivers catchments. The observed water quality data for 5 years period (2004-2008) were obtained from Departments of Environments’ water quality monitoring stations in Malaysia. Statistical analyses have been carried out on three water quality constituents which are BOD5, NH3-N and TSS. The observed data were compared with the water quality criteria to identify the water quality violation level in both river catchments. Furthermore, the differences in water quality between base and storm flow events were examined using Box and Whisker Plots. Results of this study indicate that TSS and NH3-N are the primary causes for water quality impairment in Linggi River with concentration of about 78.3% and 81.8% respectively. However, for Melaka catchment, TSS is identified as the main cause of water quality impairment, when 64.4% of the total water samples exceed the standard. There are some point sources and non-point sources of water quality impacts in both watersheds. The results of this study would be contributed to development of best management practices for the Linggi and Melaka catchments and similar study areas.

Infiltration, Runoff, and Export of Dissolved Organic Carbon from Furrow-Irrigated Forage Fields under Cover Crop and No-Till Management in the Arid Climate of California

Development of best management practices (BMPs) such as conservation tillage and winter cover crop to mitigate runoff and reduce dissolved chemicals in irrigation runoff is an important objective for controlling surface water pollution attributable to agricultural activities. In this study, the effect of standard tillage (ST), STwith winter cover cropping (STCC), and no-till (NT) management practices on infiltration, runoff, and dissolved organic carbon (DOC) export from furrow-irrigated fields of 244-m length was investigated for summer 2007 and 2008 irrigations. The practices were implemented for 2 years. The average surface residue cover was 11, 44, and 32% for ST, STCC, and NT, respectively, for 2007 and 11, 59, and 61%, respectively, in the following year of the study. Two irrigations in each year were considered for the analysis. The runoff samples were collected from each tillage treatment using ISCO autosamplers at regular time intervals. The infiltration and runoff were estimated using a volume balance model (VBM) by considering a 0.2-m irrigation requirement. Converting from ST to STCC increased the infiltration by 14 and 43% and reduced the runoff by 48 and 43% in 2007 and 2008 irrigations, respectively; whereas, converting ST to NT enhanced the infiltration by 4% in both years and decreased the runoff by 19 and 23% in 2007 and 2008 irrigations, respectively. The authors observed only slightly higher DOC concentrations in STCC, but there was a 24% increase for NT in 2007 irrigations, and both compared to with ST ranged from 3.98 to 5:46 mg=L. The DOC concentration was not significantly different among the treatments in 2008 irrigations (3.48 to 4: 6m g=L). Combining the runoff and DOC concentration effects, the DOC export for STCC was decreased by 55% in both years; whereas, it was decreased by 4 and 27% for NT in 2007 and 2008 irrigations, respectively, compared with ST. Although STCC and NT have higher concentrations, the reduction in export in these treatments is attributable to lower runoff. These results suggest that DOC export can be controlled with STCC practice. No-till showed the same trend, although these results must be confirmed after extended implementation of this practice. DOI: 10.1061/(ASCE)IR.1943-4774.0000385. © 2012 American Society of Civil Engineers.

Hydro-physical characteristics of selected media used for containerized agriculture systems

Abstract Containerized plant production represents an extremely intensive agricultural practice with large amounts of moisture and fertilizer application. Hydro-physical characteristics such as water infiltration, texture and structure, particle size distribution affect the quality of the media used in containerized agricultural systems and the water availability to plants. Water retention characteristics depend on particle size distribution as well as the composition of the media used. Materials with coarser particles allow faster percolation of water and also retain relatively higher amounts moisture per unit weight due to higher porosity, while draining faster due to smaller surface area per unit weight. Faster drainage can result into airflow through coarser materials causing the media to dry. The objectives of this study were to characterize the selected hydro-physical properties of plant growth media that are commonly used by nurseries in South Florida. Characterization of the plant growing media can allow modeling of soil–water interactions and development of best management practices for more efficient use of water and agrochemicals by nurseries. Experimental analyses were performed to characterize the plant growth mixtures in terms of particle size distribution and hydraulic conductivity using three different methods (i.e., constant head permeability, falling head permeability test, and tension infiltrometer test). The saturated hydraulic conductivity of the mixtures measured by constant head method ranged from 0.029 to 0.042 cm/s (104–151 cm/h) and by falling head method ranged from 0.078 to 0.112 cm/s (281–403 cm/h). The saturated hydraulic conductivity of the mixtures measured by tension infiltrometer ranged from 0.02 to 0.34 cm/h. Understanding water retention and permeation characteristics of the plant growing media could assist development of best management practices (BMP) for containerized agricultural systems for efficient management of irrigation water and agrochemical use.

Use of beryllium-7 to study the effectiveness of woody trash barriers in reducing sediment delivery to streams after forest clearcutting

Reliable information on the effectiveness of control measures in reducing soil erosion and sediment delivery to streams resulting from clearcutting operations is needed to support the development of best management practices for soil and water conservation in forest areas. To address this need, an investigation of the efficiency of barriers (constructed by piling up woody trash along contours) in reducing soil loss and sediment delivery was undertaken in an area experiencing prolonged highly erosive rainfall events immediately after final forest harvest. The study sites selected were located in south-central Chile and are characterized by a wet autumn and winter and mean annual rainfall of ∼2300 mm. Using a newly developed approach for employing 7Be measurements to quantify soil redistribution over an extended wet season, soil redistribution was documented at two sites located ∼2 km apart, El Monumento (EM) and San Germán (SG), the latter exhibiting less compacted soil. For an autumn period of 82 d in 2006 associated with 989 mm rainfall at EM, the observed net soil loss from two plots bounded at the top and bottom by trash barriers with a 15 and 30 m spacing, respectively, was −0.4 ± 0.1 and −0.75 ± 0.08 kg m −2 and the sediment delivery ratio 34 and 92%. Results obtained for the SG site from three plots with 10, 15 and 30 m spacing, for a 58-d autumn period with 664 mm rainfall in 2008, were −1.0 ± 0.1, −0.7 ± 0.1 and −1.8 ± 0.1 kg m −2 net soil loss, with associated sediment delivery ratios of ∼60, 55 and 88%, respectively. These results suggest that the shorter barrier spacings (∼15 m) are more effective in reducing soil loss. At SG during a 149-d period in 2008, with an extremely high precipitation total of 2089 mm, the net erosion varied only between −5.6 ± 0.4 and −6.5 ± 0.4 kg m −2 and the sediment delivery ratio between 70 and 86% for 10, 15 and 18 m barrier spacings. These results suggest that under conditions of extreme rainfall and unconsolidated soils, the woody trash barriers are unable to retain the large amounts of sediment mobilized upslope and that much of this sediment passes through the barrier, increasing the net soil loss and sediment delivery ratio. Nevertheless, in the absence of the lower woody barrier the soil loss increases. These results emphasize the benefits of installing barriers, and the need to improve their design to maximize trapping efficiency.

Assessment of Ionic Interferences to Nitrate and Potassium Analyses with Ion-Selective Electrodes

Ion-selective electrodes (ISEs) are simple tools used for rapid measurement of nitrate nitrogen (NO3-N) and potassium (K) concentrations in plant sap. With the development of best management practices (BMPs), interest exists in using ISEs for soil leachate and soil and fertilizer solutions. Nitrate N and K concentrations in the 0 to 10,000 mg L–1 ISE working range were measured in diluted solutions of common salts to assess ionic interference of calcium (Ca2+), ammonium (NH4 +), chloride (Cl–), and sulfate (SO4 2–). The effects of meter (replication) were unexpectedly significant in one out of three ranges for NO3-N and K (P values of 0.50, 0.72, and 0.01 for NO3-N and 0.99, 0.01, and 0.74 for K, for the 0–100, 100–1,000 and 1,000–10,000 mg L–1 ranges, respectively). The responses of calculated NO3-N and K concentrations to measured NO3-N and K concentrations were linear, but slopes ranged from 0.85 to 1.54, from 0.24 to 2.72, and from 0.93 to 5.48 for NO3-N and from 0.80 to 1.01, from 0.71 to 1.39, and from 0.93 to 2.21 for K for the 0–100, 100–1,000, and 1,000–10,000 mg L–1 measuring ranges, respectively. All slopes were significantly different from zero, and several were significantly different from each other and the 1:1 line. Pairwise slope comparisons conducted with covariance analysis showed that SO4 2– alone interfered with NO3-N measurements at concentrations ranging from 34 to 171 mg L–1, which was less than the manufacturer's information, and by its presence in combination with K+, NH4 +, Ca2+, and Cl– within the medium and high concentration ranges. Potassium measurements were not subject to interference from the ions tested for all three concentration ranges. These results highlight the importance of using quality assurance / quality control (QA/QC) samples in the set of unknown samples to detect inacceptable departure from linearity in routine analysis. The increase in measurement variability from one range to the next showed the importance of keeping measurements within a single concentration range by using dilutions. Hence, ISEs may be used for field measurements of NO3-N and K concentrations in soil leachate as well as soil and nutrient solutions and are therefore a practical BMP tool. However, ISEs should not be used as substitutes for the laboratory methods when official measurements are needed.

Clinoptilolite Zeolite Influence on Inorganic Nitrogen in Silt Loam and Sandy Agricultural Soils

Development of best management practices can help improve inorganic nitrogen (N) availability to plants and reduce nitrate-nitrogen (NO3−N) leaching in soils. This study was conducted to determine the influence of the zeolite mineral clinoptilolite (CL) additions on NO3−N and ammonium-nitrogen (NH4−N) in two common Pacific Northwest soils. The effects of CL application rate (up to 26.9 Mg ha−1) either band applied or mixed with a set rate of N fertilizer on masses of NO3−N and NH4−N in leachate and soil were investigated in a column study using a Portneuf silt loam (coarse-silty mixed mesic Durixerollic Caliciorthid) and a Wolverine sand (Mixed, frigid Xeric Torripsamment). All treatments for each soil received a uniform application of N from urea fertilizer, with fertilizer banded or mixed with CL. In the Portneuf soil, band application of CL and N contained 109% more total inorganic N (NO3−N + NH4−N) in the soil/leachate system compared with mixing. In both soils, CL application rate influenced the quantity of NO3−N and NH4−N in the leachate and soil. Application of CL at rates of 6.7 to 13.4 Mg ha−1 resulted in the conservation of inorganic N in the soils. Band applying CL and N seems to conserve available inorganic N in the soil compared with mixing CL and N possibly because of decreased rates of microbial immobilization, nitrification, and denitrification.

인공강우기에 의한 밭에서의 영양물질 배출특성 모의 - 시비량 및 경사도 변화 -

Various fundamental and practical theories and technologies are needed for the development of Best Management Practices (BMPs) to manage the problems. The objectives of this paper was to investigate the effect of fertilizer and Non-point suource (NPS) pollution discharges from the field. The effect of fertilizer application was measured with respect to 10 % and 20 % slopes, respectively, using artificial rainfall simulator. The effect of fertilizer application on runoff was not significant because the effect of slope and rainfall intensity were overwhelmed. Runoff from 20 % plots was 21 % larger than that from 10 % plots. While groundwater discharge from 10 % plots was about 70 % larger than that from 20 % plots. It was concluded that runoff and groundwater discharge were largely affected by slope. T-N concentration in groundwater was much higher than that in runoff for both 10 % and 20 % plots. While T-P concentration in groundwater was lower than that in runoff. It explained that T-N moved well through soil pores without adsorption and other chemical reactions but T-P was well adsorbed on the surface of soil particles.

Simulation of land use–soil interactive effects on water and sediment yields at watershed scale

Influences of vegetation management on soil erosion have been extensively studied. However, interactive effects between land use and soil are poorly documented in literature. Given the importance of understanding such effects for successful watershed management, the objective of this study was to examine the land use–soil interactive effects on water and sediment yields for the 117,845-ha drainage area upstream of the U.S. Geological Survey flow gauging station 08101000 in the Cowhouse Creek watershed located in north central Texas. The examination was implemented using the Soil and Water Assessment Tool (SWAT), a distributed watershed model that has been widely used to tackle problems relevant to nonpoint source pollution. A SWAT model was calibrated and validated in accordance with the observed daily streamflows at this gauging station. Subsequently, the calibrated model was used to examine changes of water and sediment yields as a result of the conversion of range brush to range grasses on an individual soil basis. The results indicated that for the study area, the removal of range brush would result in an annual water yield increase of 24 mm ha −1 treated area. However, the removal on an upland soil with a moderately high permeability was predicted to increase the annual water yield by 80 mm ha −1 treated area, while it would result in a small increase of annual sediment loading (4.2 t ha −1 treated area) and a minimal alteration to the existing spatial patterns of sediment sources. The increase of water yield would be larger for the removal of range brush on a soil that is adjacent to the stream channels. For a given soil, the predicted water yield increase was greater for the wetter hydrologic condition than that for the drier one. A reasonable generalization of this study was that the development of best management practices for watershed health and sustainability may need to take into account land use–soil interactive effects on an individual soil basis.

Nitrogen and water requirements of fertigated cabbage in Ontario

Increasing nutrient and water regulations have necessitated development of best management practices for application of nitrogen (N) and water. This study was conducted to determine if there was an optimal balance of N and water applied for late storage cabbage (Brassica oleracea L. var. capitata). Five rates of N and five irrigation rates arranged in a response surface design replicated three times were supplied to Huron cabbage grown on sandy loam soil to study the interaction of N and water applied. Plots were located at the University of Guelph, Simcoe Research Station, Ontario, Canada from 2003 to 2005. Total and marketable yields were maximized from a low of 278 kg ha-1 N in 2005 to above the highest rate tested (400 kg ha-1 N) in the other 2 yr. In 2005, there were 29 d above 30 °C and marketable yield was 49% lower than 2004, which had only 1 d above 30 °C. A target soil water value of 100% of field capacity was required to maximize yield in all 3 yr. More N is required as the water supply increases. The main influence of irrigation and N application was on head volume. Head density based on fresh weight was not influenced by irrigation or N application, but head density based on dry weight decreased with increased N application. Irrigation and N application should be managed concurrently to maximize yield and quality and N and irrigation efficiency for late storage cabbage. However, N and water will not prevent lost yield due to hot days, which suggests that late-cabbage yields are very sensitive to high air temperatures. Key words: Brassica oleracea var. capitata, cabbage, irrigation, fertigation, quality, nutrient management, air temperature