scholarly journals Outputs: Potassium Losses from Agricultural Systems

2020 ◽  
pp. 75-97
Author(s):  
Keith Goulding ◽  
T. Scott Murrell ◽  
Robert L. Mikkelsen ◽  
Ciro Rosolem ◽  
Johnny Johnston ◽  
...  
Keyword(s):  
Crop Residues ◽  
Economic Cost ◽  
Particulate Material ◽  
Relative Importance ◽  
Agricultural Ecosystem ◽  
Runoff Water ◽  
Factors Affecting ◽  
Fine Soil ◽  
Strong Winds ◽  
Soil K Status

AbstractPotassium (K) outputs comprise removals in harvested crops and losses via a number of pathways. No specific environmental issues arise from K losses to the wider environment, and so they have received little attention. Nevertheless, K is very soluble and so can be leached to depth or to surface waters. Also, because K is bound to clays and organic materials, and adsorbed K is mostly associated with fine soil particles, it can be eroded with particulate material in runoff water and by strong winds. It can also be lost when crop residues are burned in the open. Losses represent a potential economic cost to farmers and reduce soil nutritional status for plant growth. The pathways of loss and their relative importance can be related to: (a) the general characteristics of the agricultural ecosystem (tropical or temperate regions, cropping or grazing, tillage management, interactions with other nutrients such as nitrogen); (b) the specific characteristics of the agricultural ecosystem such as soil mineralogy, texture, initial soil K status, sources of K applied (organic, inorganic), and rates and timing of fertilizer applications. This chapter provides an overview of the main factors affecting K removals in crops and losses through runoff, leaching, erosion, and open burning.

scholarly journals Socioeconomic Risks and Their Impacts on Ecological River Health in South Korea: An Application of the Analytic Hierarchy Process

2021 ◽  
Vol 13 (11) ◽  
pp. 6287
Author(s):  
Suyeon Kim ◽  
Sang-Woo Lee ◽  
Se-Rin Park ◽  
Yeeun Shin ◽  
Kyungjin An
Keyword(s):  
South Korea ◽  
Socioeconomic Factors ◽  
Ecosystem Health ◽  
Relative Importance ◽  
River Ecosystem ◽  
River Health ◽  
Analytic Hierarchy ◽  
Factors Affecting ◽  
Factors Influencing ◽  
Hierarchy Process

It is imperative to develop a methodology to identify river impairment sources, particularly the relative impact of socioeconomic sources, to enhance the efficiency of various river restoration schemes and policies and to have an internal diagnosis system in place. This study, therefore, aims to identify and analyze the relative importance of the socioeconomic factors affecting river ecosystem impairment in South Korea. To achieve this goal, we applied the Analytical Hierarchy Process (AHP) to evaluate expert judgement of the relative importance of different socioeconomic factors influencing river ecosystem impairment. Based on a list of socioeconomic factors influencing stream health, an AHP questionnaire was prepared and administered to experts in aquatic ecology. Our analysis reveals that secondary industries form the most significant source of stream ecosystem impairment. Moreover, the most critical socioeconomic factors affecting stream impairment are direct inflow pollution, policy implementation, and industrial wastewater. The results also suggest that the AHP is a rapid and robust approach to assessing the relative importance of different socioeconomic factors that affect river ecosystem health. The results can be used to assist decision makers in focusing on actions to improve river ecosystem health.

scholarly journals Factors Contributing to Heat Resistance of Clostridium perfringens Endospores

2008 ◽  
Vol 74 (11) ◽  
pp. 3328-3335 ◽  
Author(s):  
Benjamin Orsburn ◽  
Stephen B. Melville ◽  
David L. Popham
Keyword(s):  
Cell Wall ◽  
Heat Resistance ◽  
Clostridium Perfringens ◽  
Food Poisoning ◽  
High Heat ◽  
Relative Importance ◽  
High Heat Resistance ◽  
Factors Affecting ◽  
Cooking Process ◽  
Determining Factors

ABSTRACT The endospores formed by strains of type A Clostridium perfringens that produce the C. perfringens enterotoxin (CPE) are known to be more resistant to heat and cold than strains that do not produce this toxin. The high heat resistance of these spores allows them to survive the cooking process, leading to a large number of food-poisoning cases each year. The relative importance of factors contributing to the establishment of heat resistance in this species is currently unknown. The present study examines the spores formed by both CPE+ and CPE− strains for factors known to affect heat resistance in other species. We have found that the concentrations of DPA and metal ions, the size of the spore core, and the protoplast-to-sporoplast ratio are determining factors affecting heat resistance in these strains. While the overall thickness of the spore peptidoglycan was found to be consistent in all strains, the relative amounts of cortex and germ cell wall peptidoglycan also appear to play a role in the heat resistance of these strains.

scholarly journals THE FACTORS AFFECTING MILK YIELD IN DIARY FARMING IN GREATER GUWAHATI REGION OF ASSAM

2021 ◽  
Vol 9 (08) ◽  
pp. 723-728
Author(s):  
Heman Sarmah ◽  
◽  
Jnanashree Borah ◽  
Tirthankar Sarma ◽  
◽  
...  
Keyword(s):  
Regression Analysis ◽  
Dairy Cattle ◽  
Milk Production ◽  
Milk Yield ◽  
Policy Maker ◽  
Production Cost ◽  
Relative Importance ◽  
Factors Affecting ◽  
Micro Level ◽  
Farming Households

The production of milk is conceived of several factors and a very multifarious process. The knowledge of relative importance of the resource inputs influencing in milk production is essential for the dairy farmer for introducing desirable change in his operation at micro level and for the policy maker for formulating plans for improvements in dairy cattle productivity based on sound economic principles at the macro level (Rao, 1985).The income level of the dairy household is determined by the production of milk they produce at their farms. Generally, the income of the dairy household increases when the milk production cost decreases or when the milk production increases .For this it is essential to study the factors which directly or indirectly effect the milk production. Household samples have been selected both from the municipal wards of Guwahati Municipal Corporation area. Out of 672 dairy farming households, 201 household have been selected for the survey. Regression analysis has been used for the study of factors affecting milk production in greater Guwahati region of Assam.

Relative Importance of Factors Affecting Corneal Hysteresis Measurement

2012 ◽  
Vol 89 (5) ◽  
pp. E803-E811 ◽  
Author(s):  
Michael Sullivan-Mee ◽  
Suchitra Katiyar ◽  
Denise Pensyl ◽  
Kathy D. Halverson ◽  
Clifford Qualls
Keyword(s):  
Corneal Hysteresis ◽  
Relative Importance ◽  
Factors Affecting

scholarly journals Residues of sweet sorghum promotes suppression of weeds in sugarcane rotation

2020 ◽  
pp. 565-573
Author(s):  
Paulo Roberto Fidelis Giancotti ◽  
Mariluce Pascoína Nepomuceno ◽  
Juliana de Souza Rodrigues ◽  
Micheli Yamauti ◽  
José Valcir Fidelis Martins ◽  
...  
Keyword(s):  
Seed Bank ◽  
Vegetation Cover ◽  
Sweet Sorghum ◽  
Crop Residues ◽  
Soil Seed Bank ◽  
Cyperus Rotundus ◽  
Relative Importance ◽  
Raphanus Raphanistrum ◽  
Velvet Bean ◽  
Allelopathic Potential

Sorghum is an important crop to plant in rotation with sugarcane. This is mainly because both are inputs for the ethanol industry. Crop residues of sweet sorghum promote suppression of weed re-infestation, avoiding weed interference to the sugarcane crop due to the strong allelopathic potential of sorghum. In order to determine the suppressive effects of sorghum crop residues on weeds, a field experiment was carried out. Seven vegetation covers were used as options for crop rotation with sugarcane. The treatments were sweet sorghum, velvet bean, sunflower, soybean, sugar cane, fallow, and an area without cover. The experiment was randomized blocks with four replications of 27 m2 plots. The weed community of each plot was evaluated by phytosociological indexes at 60 and 120 days after the formation of vegetation cover. The composition of soil seed bank was also evaluated. The weeds with the highest indexes of relative importance during the evaluations were Cyperus rotundus, Raphanus raphanistrum and Parthenium hysterophorus. The diversity of the weed community, estimated by relative importance indexes, was lower in the area with velvet bean as soil cover. Sorghum, velvet bean and sunn hemp covers reduced the soil seed bank compared to the fallow treatment and the treatment without vegetation cover. Crop residues of sweet sorghum and velvet bean provide a decrease in weed infestation in field, and the weed suppression period can last up to 120 days during the dry season.

Factors affecting the operation of the weed-sensing Detectspray system

Weed Science ◽  
1998 ◽  
Vol 46 (1) ◽  
pp. 127-131 ◽  
Author(s):  
Robert E. Blackshaw ◽  
Louis J. Molnar ◽  
Duane F. Chevalier ◽  
C. Wayne Lindwall
Keyword(s):  
Near Infrared ◽  
Field Experiments ◽  
Crop Residues ◽  
Soil Surface ◽  
Physical Factors ◽  
Weed Detection ◽  
Factors Affecting ◽  
Green Foxtail ◽  
Infrared Wavelengths ◽  
Herbicide Use

Field experiments were conducted for 3 yr to determine the effect of various biological and physical factors on the operation of the weed-sensing Detectspray system. Plant detection is achieved by sensors measuring differential reflectance of red and near-infrared wavelengths of light from green plants, crop residues, and soil. Weed detection was greatly reduced 70 to 80 min after sunrise and before sunset when operated at lat 50°N because of reduced solar irradiance. Tall, dense-standing crop stubble limited detection of small weeds at the soil surface. Weed detection varied with plant species. Canola with three to four leaves consistently was detected, but wheat or green foxtail usually required five to six leaves to be detected. Small weeds were detected if present at densities greater than 70 plants m−2. Growers and commercial applicators need to be aware of the limitations of the Detectspray system to use it effectively to control weeds with concurrent reductions in herbicide use.

Soil erosion processes. I. The relative importance of rainfall detachment and dunoff entrainment

Soil Research ◽  
1991 ◽  
Vol 29 (5) ◽  
pp. 671 ◽  
Author(s):  
APB Proffitt ◽  
CW Rose
Keyword(s):  
Soil Erosion ◽  
Overland Flow ◽  
Water Flux ◽  
Equilibrium Concentration ◽  
Sediment Concentration ◽  
Soil Types ◽  
Relative Importance ◽  
Runoff Water ◽  
Erosion Processes ◽  
Volumetric Flux

Experiments carried out in a simulated-rainfall tilting-flume facility are reported in which sediment concentrations (c) in runoff water resulting from overland flow only, or from a combination of rainfall and overland flow, were measured under controlled conditions using a series of slopes (0.1, 05, 1, 3 and 5%). The mixture of rainfall (of rate 100 mm h-1) and runon of water at the top of the flume were arranged to provide a constant volumetric flux (1.0x10-3 m3 m-l s-1) at exit from the 5.8 m long flume. Two contrasting soil types were studied: a cracking clay (black earth or vertisol), and a slightly dispersive sandy clay loam (solonchak or aridisol). Two major processes which can contribute to soil erosion under rainfall are rainfall detachment and runoff entrainment. For both soil types, c was generally highest for the steepest slope and decreased with slope. For constant rainfall and/or runoff conditions, c generally decreased with time until an equilibrium concentration was reached. At this equilibrium, the relative importance of rainfall detachment and entrainment in terms of soil loss was dependent on soil type and streampower which incorporates effects of slope and water flux. For streampowers <0.1 W m-2 for the black earth, and <0.3 W m-2 for the solonchak, the greatest contribution to c was by rainfall detachment, whilst at greater streampowers entrainment was the dominant contributor to c. At any streampower, the contribution by rainfall detachment was greater for the weakly structured solonchak than for the well aggregated black earth. At lower strearnpowers, the interaction between erosion processes was found to give higher c than the sum of both sediment concentrations resulting from the separately occurring processes. At streampowers greater than approximately 0.5 W m-2, rainfall reduced eroded sediment concentration by suppressing rill development. The findings in this study suggest that both runoff entrainment and rainfall detachment can contribute to sediment concentration from 'interrill' areas.

Prominent demotivational factors influencing the productivity of construction project managers in Qatar

2014 ◽  
Vol 63 (8) ◽  
pp. 1070-1090 ◽  
Author(s):  
Abdulaziz M. Jarkas ◽  
Milan Radosavljevic ◽  
Liu Wuyi
Keyword(s):  
Construction Project ◽  
Project Managers ◽  
The State ◽  
Relative Importance ◽  
Productivity Level ◽  
Content Type ◽  
Factors Affecting ◽  
Factors Influencing ◽  
Technical Specifications ◽  
The Impact

Purpose – An extensive search of the literature revealed a dearth of research on the demotivational factors affecting the performance and productivity level of site-based construction project managers. Following the announcement of awarding the FIFA 2022 World Cup hosting rights to the State of Qatar, the State is pledging to spend tens of Billions of Dollars on hundreds of new construction projects. Therefore, the purpose of this paper is to identify, explore, and rank the relative importance of the demotivational factors influencing the productivity of the State's construction management force. Design/methodology/approach – A structured questionnaire survey comprising 38 potential demotivational factors, which were shortlisted based on relevant previous studies on the impact of motivation on construction productivity, and numerous interviews with local industry professionals, was distributed to a relatively large sample of site-resident project managers. Using the “Relative Importance Index” technique, the influence ranks of the factors explored were determined. Findings – The results obtained reveal the following as the prominent demotivational factors influencing the productivity of construction project managers: lack of financial incentive schemes; slow decision-making process by owners; remuneration scale; delay in responding to Requests For Information (RFI); shortage of skilled labour force; shortage of materials; clarity and completeness of technical specifications; frequent changing orders during execution; drawings quality level; and rework. Research limitations/implications – It is clear, based on the outcomes, that the cultural background of individuals, and the prevalent practices within the environment in which they operate, are two critical factors in determining their motivation drivers. Hence, it is prudent to explore the dominant culture and values of the management workforce, in addition to the characteristics of the working environment, before trying to apply relevant motivational theories, or even implement new management strategies. Practical implications – The results demonstrate that, within the geographical setting and cultural aspects of the sample surveyed, “tributes” and “pecuniary” may be interpreted to have the largest effect on the productivity of construction project managers. Originality/value – The findings not only contribute to the overall body of knowledge related to the effect of the motivation phenomenon on the productivity of the construction operation, but can also be used to provide industry practitioners with guidance for focusing, acting upon, and controlling the significant demotivational factors affecting the efficiency of the construction project management force practicing in State.

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