共查询到20条相似文献,搜索用时 46 毫秒
1.
Diammonium phosphate (DAP) and urea are commonly used fertilizers throughout the world. The effects of these fertilizers on
the freshwater flagellate Euglena gracilis was studied after 7 days of growth using morphological, physiological and biochemical parameters as end points. NOEC and
EC50 values for various parameters like cell density, motility, velocity, cell shape, gravitaxis, chlorophyll a, b and total carotenoids were calculated. NOEC and EC50 values of DAP varied from 0.5 to 2.5 g L−1 and 3.14 to 5.96 g L−1, respectively, for different parameters. NOEC and EC50 values for urea ranged from 5 to 25 g L−1 and 28 to 44.05 g L−1, respectively, for various parameters. Photosynthetic pigments were found to be more sensitive to both fertilizers as compared
to other measured end points. The NOEC and EC50 values obtained for DAP were much lower than those for urea; i.e., DAP showed a stronger inhibitory effect as compared to
urea. Application of DAP resulted in an increased concentration of ammonia in Euglena cultures but urea did not. The stronger inhibitory effect of DAP is attributed to release of free ammonia in the culture
due to DAP decompostion. No release of ammonia by urea occurred due to the absence of the enzyme urease in E. gracilis. 相似文献
2.
Laboratory incubation and field experiments were conducted to evaluate thiourea, ATC (4-amino-1, 2, 4 triazole hydrochloride)
and N-Serve 24 E (2-chloro-6-trichloromethyl-pyridine) as inhibitors of nitrification of fertilizer N. In the incubation experiment,
most of the added aqueous NH3 or urea was nitrified at 14 days on both soils, but addition of the inhibitors to fertilizer N decreased the conversion of
NH4−N to NO3−N markedly. There was less nitrification for ATC and thiourea but not for N-Serve 24 E when the fertilizers and the inhibitors
were placed at a point as opposed to when mixed into soil. After 28 days, ATC and N-Serve 24 E were more effective in inhibiting
nitrification than thiourea. ATC and N-Serve 24 E also inhibited release of mineral N (NH4−N+NO3−N) from native soil N. In the uncropped field experiment, which received N fertilizers in the fall, nitrification of fall-applied
N placed in the 15-cm bands was almost complete by early May in the Malmo soil, but not in the Breton soil. When ATC or thiourea
had been applied with urea, nitrification of fall-applied N was depressed by May and the recovery of applied N as NH4−N was greater with increasing band spacing to 60 cm or placing N fertilizer in nests (a method of application where urea
prills were placed at a point in the soil in the center of 60×60 cm area). In late June, the percentage recovery of fall-applied
N in soil as NH4−N or mineral N increased with wide band spacing, or nest placement, or by adding ATC to fertilizer N on both soils. These
results indicate that placing ammonium-based N fertilizers in widely-spaced bands or in nests with low rates of inhibitors
slows nitrification enough to prevent much of the losses from fall-applied N.
Scientific Paper No. 552, Lacombe Research Station, Research Branch, Agric, Can. 相似文献
3.
Inhibition of atrazine degradation by cyanazine and exogenous nitrogen in bacterial isolate M91-3 总被引:7,自引:0,他引:7
A variety of s-triazine herbicides and nitrogen fertilizers frequently occur as co-contaminants at pesticide manufacturing and distribution
facilities. The degradation of atrazine and cyanazine by the bacterial isolate M91-3 was investigated in washed-cell suspensions
and crude cellular extracts. Cyanazine competitively inhibited atrazine degradation. The maximum atrazine degradation rate
(V
max) was 41 times higher and the half-saturation constant for the inhibitor (K
i) was 1.3 times higher in the crude cellular extract than in the washed-cell suspension, suggesting that cellular uptake influenced
degradation of the s-triazines. Cultures that had received prior exposure to atrazine and simazine exhibited comparable atrazine degradation rates,
while cells exposed to cyanazine, propazine, ametryne, cyanuric acid, 2-hydroxyatrazine, biuret, and urea exhibited a lack
of atrazine-degradative activity. Growth in the presence of exogenous inorganic nitrogen inhibited subsequent atrazine-degradative
activity in washed-cell suspensions, suggesting that regulation of s-triazine and nitrogen metabolism are linked in this bacterial isolate. These findings have significant implications for the
environmental fate of s-triazines in agricultural settings since these herbicides are frequently applied to soils receiving N fertilizers. Furthermore,
these results suggest that bioremediation of s-triazine-contaminated sites (common at pesticide distribution facilities in the cornbelt) may be inhibited by the presence
of N fertilizers that occur as co-contaminants.
Received: 3 March 1998 / Received revision: 24 September 1998 / Accepted: 11 October 1998 相似文献
4.
Jugnia LB Mottiar Y Djuikom E Cabral AR Greer CW 《Applied microbiology and biotechnology》2012,93(6):2633-2643
The effects of compost, nitrogen salts, and nitrogen–phosphorous–potassium (NPK) fertilizers on the methane oxidation potential
(MOP) of landfill cover soil at various temperatures were assessed. For this, we used batch assays conducted at 5°C, 15°C,
and 25°C with microcosms containing landfill cover soil slurries amended with these elements. Results indicated variable impacts
dependent on the type of amendment and the incubation temperature. For a given incubation temperature, MOP varied from one
compost to another and with the amount of compost added, except for the shrimp/peat compost. With this latter compost, independent
of the amount, MOP values remained similar and were significantly higher than those obtained with other composts. Amendment
with most of the tested nitrogen salts led to similar improvements in methanotrophic activity, except for urea. MOP with NPK
fertilizer addition was amongst the highest in this study; the minimum value obtained with NPK (20–0–20) suggested the importance
of P for methanotrophs. MOP generally increased with temperature, and nutrient limitation became less important at higher
temperatures. Overall, at each of the three temperatures tested, MOP with NPK fertilizer amendments provided the best results
and was comparable to those observed with the addition of the shrimp/peat compost. The results of this study provide the first
evidence of the following: (1) compost addition to improve methanotrophic activity in a landfill cover soil should consider
the amount and type of compost used and (2) the importance of using NPK fertilizers rather than nitrogen salts, in enhancing
this activity, primarily at low temperatures. One can also consider the potential beneficial impact of adding these elements
to enhance plant growth, which is an advantage for MOP. 相似文献
5.
Evaluation and indirect estimation of nitrate losses from the agricultural microbasin Rybárik 总被引:1,自引:0,他引:1
The long-term trends of mean monthly nitrate concentrations in stream and drainage runoff were evaluated in the experimental
microbasin Rybárik (0.119 km2) at the Institute of Hydrology, Slovak Academy of Sciences, during the period 1987–2005. The results of analyses indicate
a decreasing trend of nitrate concentration after the year 1989, but with relatively high losses in some years and relatively
low losses in other years. This decreasing trend is mainly caused by a decrease in the use of nitrogen fertilizers. The nitrate
concentration in surface runoff strongly correlates with runoff and fertilization. Based on measured data, an empirical relation
was found describing the dependence of annual nitrate transport in the stream on annual runoff depth and on the annual amount
of applied nitrogen fertilizers.
Presented at the International Conference on Bioclimatology and Natural Hazards, Poľana nad Detvou, Slovakia, 17–20 September
2007. 相似文献
6.
Combined inoculation of Rhizobium and ‘Phosphate-solubilizing’Pseudomonas striata orBacillus polymyxa with and without added chemical fertilizer on chickpea yield and nutrient content was studied under greenhouse conditions.
While the single inoculation of Rhizobium increased the nodulation and nitrogenase activity, the ‘phosphate-solubilizers’
increased the available phosphorus content of the soil. Combined inoculation of Rhizobium andP. striata orB. polymyxa increased the above parameters and also the dry matter content, the grain yield and nitrogen and phosphorus uptake significantly
over the uninoculated control. The inoculation effects were more pronounced in the presence of added fertilizers. The possibilities
of saving half the dose of N and replacing superphosphate with rockphosphate and inoculation with ‘phosphate-solubilizers’
are discussed. 相似文献
7.
Quantification of methane emissions from Chinese rice fields (Zhejiang Province) as influenced by fertilizer treatment 总被引:7,自引:0,他引:7
Reiner Wassmann Helmut Schütz Hans Papen Heinz Rennenberg Wolfgang Seiler Dai Aiguo Shen Renxing Shangguan Xingjian Wang Mingxing 《Biogeochemistry》1993,20(2):83-101
Methane emissions from rice paddies were quantified by using an automatic field system stationed in Zhejiang Province, one
of the centres for rice cultivation in China. The data set showed pronouned interannual variations over 5 consecutive vegetation
periods; by computing average values of all experimental plots the annual emissions were 177 g CH4 m−2 yr−1 in 1987, 50 g CH4 m−2 yr−1 in 1988, and 187 g CH4 m−2 yr−1 in 1989.
The field preparations encompassed 4 different treatments: (1) no fertilizers, (2) mineral fertilizer (KCl, K2SO4), (3) organic manure (rape seeed cake, animal manure), (4) mineral fertilizer plus organic manure. The methane emission rates
of the different fertilizer treatments did not show significant differences. The mean emission rates, calculated over the
entire observation period of 5 seasons, were 30.4 mg CH4 m−2 h−1 (non-fertilized plot) and 28.3 mg CH4 m−2 h−1 (mineral fertilizers). These values indicate a high level of methane production even without additional input of organic
material into the rice-soils. In the other plots, the organic fertilizers were added once per vegetation period at app. 1
t fresh weight per ha, a relatively low application rate by agronomical standards. The mean emission rates were 35.1 mg CH4 m−2 h−1 when manure was applied as sole fertilizer and 27.5 mg CH4 m−2 h−1 when applied jointly with potassium fertilizers.
Based on the results of this study we estimate a range of 18–28 Tg CH4 yr−1 as the total methane emission from Chinese rice fields. However, more field data from representative sites in China are needed
to reduce the uncertainties in this estimate. 相似文献
8.
This study investigate the potential contribution of
nitrogen fixation by indigenous cyanobacteria to rice production in the rice fields of Valencia (Spain). N2-fixing cyanobacteria abundance and N2 fixation decreased with increasing amounts of fertilizers. Grain yield increased with increasing amounts of fertilizers up
to 70 kg N ha-1. No further increase was observed with 140 kg N ha-1. Soil N was the main source of N for rice, only 8–14% of the total N incorporated by plants derived from 15N fertilizer. Recovery of applied 15N-ammonium sulphate by the soil–plant system was lower than 50%. Losses were attributed to ammonia volatilization, since only
0.3–1% of applied N was lost by denitrification. Recovery of 15N from labeled cyanobacteria by the soil–plant system was higher than that from chemical fertilizers. Cyanobacterial N was
available to rice plant even at the tillering stage, 20 days after N application.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
9.
Summary The influence exerted by organic matter on the correction of iron chlorosis inLupinus albus L., grown in calcareous soil, was studied through a pot experiment by incorporating two rates (1.5 per cent and 3 per cent
on the soil) of three organic fertilizers obtained from poplar barks. The fertilizers differed in the length of humification
process and in the integration with different materials,i.e.:
H fertilizer: 8 months humified poplar barks without any addition,
HF fertilizer: 4 years humified poplar barks with 4 per cent of metallic iron,
HP fertilizer: 18 months humified poplar barks with 25 per cent of poultry manure.
The higher rate (3 per cent) of the H fertilizer was the most efficient in reducing chlorosis symptoms and gave the greatest
dry matter yield. Among the treatments with the lower rate (1.5 per cent), the HF fertilizer gave the best results; conversely,
the HP fertilizer failed to correct chlorosis and to enhance yield. Therefore the experiment suggested that organic fertilizers
are useful to correct iron chlorosis, provided their phosphorus content is low and they have undergone a prolonged humification
process; furthermore, integration with small amounts of iron leads to a considerable saving of organic fertilizer. 相似文献
10.
蚓粪和益生菌互作对土壤性状及番茄产量和品质的影响 总被引:1,自引:1,他引:0
本试验研究了两株益生细菌(巨大芽孢杆菌BM和解淀粉芽孢杆菌BA)与化肥和蚓粪配施对土壤性状、番茄产量和品质的影响.结果表明:与化肥相比,在等养分条件下蚓粪能够提高番茄产量、果实可溶性糖和蛋白质含量,并提高土壤pH和速效磷含量.与单施蚓粪相比,益生菌与蚓粪配施不仅能提高番茄产量、果实可溶性糖、蛋白质、维生素C含量和糖酸比,降低有机酸和硝态氮含量,而且增加了土壤pH和硝态氮含量,降低了土壤电导率;益生菌与化肥配施的效果不如益生菌与蚓粪配施.BA和BM与化肥或蚓粪配施时,番茄品质无显著差异,但BA配施蚓粪处理的番茄产量显著高于BM配施蚓粪处理;BM与化肥配施处理显著提高了土壤速效磷含量,而BA与蚓粪配施处理则显著提高了土壤速效钾含量.本研究表明,益生菌和蚓粪可替代化肥用于番茄生产和土壤肥力改良. 相似文献
11.
不同施肥模式对蔬菜生长、氮肥利用及菜地氮流失的影响 总被引:33,自引:0,他引:33
在天然降雨条件下,通过一年三茬蔬菜(小白菜、空心菜和苋菜)田间试验,研究了7种不同施肥模式(不施肥、化肥基施、化肥基追肥各半、化肥和双氰胺基施、化肥和双氰胺基追肥各半、化肥和有机肥基追肥各半、有机肥基施)对蔬菜株高、单株质量、产量、氮累积量、氮肥利用率及菜地硝态氮和铵态氮随地表径流流失的影响.结果表明:与不施肥对照相比,化肥和有机肥基追肥各半、化肥和双氰胺基施2种施肥模式可改善蔬菜农艺性状,分别使蔬菜产量提高103%~219%和93%~226%、植株氮累积量增加153%~216%和231%~320%、氮肥利用率较高,与化肥基施处理相比,还可减少蔬菜种植期间菜地土壤硝态氮和铵态氮随地表径流的流失量,减少幅度分别为48.1%和46.5%,从而减少了菜地土壤造成的农业面源污染.这两种施肥模式应在今后蔬菜生产中推广应用. 相似文献
12.
Marcel Viana Pires Dênis Ant?nio da Cunha Sabrina de Matos Carlos Marcos Heil Costa 《PloS one》2015,10(8)
The agriculture sector has historically been a major source of greenhouse gas (GHG) emissions into the atmosphere. Although the use of synthetic fertilizers is one of the most common widespread agricultural practices, over-fertilization can lead to negative economic and environmental consequences, such as high production costs, depletion of energy resources, and increased GHG emissions. Here, we provide an analysis to understand the evolution of cereal production and consumption of nitrogen (N) fertilizers in Brazil and to correlate N use efficiency (NUE) with economic and environmental losses as N2O emissions. Our results show that the increased consumption of N fertilizers is associated with a large decrease in NUE in recent years. The CO2 eq. of N2O emissions originating from N fertilization for cereal production were approximately 12 times higher in 2011 than in 1970, indicating that the inefficient use of N fertilizers is directly related to environmental losses. The projected N fertilizer forecasts are 2.09 and 2.37 million ton for 2015 and 2023, respectively. An increase of 0.02% per year in the projected NUE was predicted for the same time period. However, decreases in the projected CO2 eq. emissions for future years were not predicted. In a hypothetical scenario, a 2.39% increase in cereal NUE would lead to $ 21 million savings in N fertilizer costs. Thus, increases in NUE rates would lead not only to agronomic and environmental benefits but also to economic improvement. 相似文献
13.
A field experiment was conducted for two years in sandy loam acid lateritic soil to study the direct effect of fly ash, organic wastes and chemical fertilizers on rice (Oryza sativa) and their residual effect on mustard (Brassica napus var glauca) grown in sequence. Rice yields were higher when fly ash, organic wastes and chemical fertilizers were used in an integrated manner as compared to sole application of chemical fertilizers. Yields of mustard were also higher under the residual effect of the former rather than the latter. However, this beneficial residual effect under integrated nutrient sources was inadequate for the mustard crop in the low fertility test soil. Hence, direct application of fertilizers was needed, in addition to residual fertility. The effect of fly ash on mean rice equivalent yield of the rice–mustard cropping sequence was highest (up to 14%) when it was used in combination with organic wastes and chemical fertilizers. While the yield increase was 10% when it was used in combination with only chemical fertilizers. The minimum yield advantage, 3%, occurred when fly ash was applied alone. The equivalent yield of the rice–mustard cropping sequence was equally influenced by either of the organic wastes. Cadmium and Ni content in rice grain and straw were less under the direct effect of fly ash. The residual effect on mustard was similar for Ni content in seed and stover; however, Cd content was increased. Beneficial residual soil chemical properties in terms of pH, organic carbon and available N, P and K were noted for integrated nutrient treatments involved fly ash, organic wastes and chemical fertilizers as compared to continuous use of only chemical fertilizers. Application of fly ash alone was effective in raising soil available P. Thus, integrated use of fly ash, organic wastes and chemical fertilizers was beneficial in improving crop yield, soil pH, organic carbon and available N, P and K in sandy loam acid lateritic soil. 相似文献
14.
Energy and economic efficiencies were evaluated on young (6 year) and old (20 year) jhum fields in Mizoram, north-eastern
India during second year of cropping, and were compared with those in the first year. The effect of auxiliary measures such
as tilling the soil or application of fertilizers (chemical or farm-yard manure or both in combination) was also examined
on energy and economic efficiencies. The results indicated that traditional jhum cultivation is labour intensive and energy
efficient, producing almost 15–20 times of energy invested. Energy and economic efficiencies decline with shortening of jhum
cycle. These efficiencies decline further from first to second year of cropping. Tilling is not useful to improve either energy
or economic efficiency. Fertilizer application, which is though profitable from the point of view of economic efficiency,
is highly energy inefficient. Application of fertilizers during second year cropping can be encouraged. Organic manuring may
be a better option than others to alleviate energy efficiency. However, a combination of organic and inorgamic manuring could
be the best option to enhance economic efficiency. 相似文献
15.
Mathis BJ Marshall CW Milliken CE Makkar RS Creager SE May HD 《Applied microbiology and biotechnology》2008,79(1):147-155
Acquisition of nutrients by plants is primarily dependent on root growth and bioavailability of nutrients in the rooting medium.
Most of the beneficial bacteria enhance root growth, but their effectiveness could be influenced by the nutrient status around
the roots. In this study, two 1-aminocyclopropane-1-carboxylate (ACC)-deaminase containing plant-growth-promoting rhizobacteria
(PGPR), Pseudomonas fluorescens and P. fluorescens biotype F were tested for their effect on growth, yield, and nutrient use efficiency of wheat under simultaneously varying
levels of all the three major nutrients N, P, and K (at 0%, 25%, 50%, 75%, and 100% of recommended doses). Results of pot
and field trials revealed that the efficacy of these strains for improving growth and yield of wheat reduced with the increasing
rates of NPK added to the soil. In most of the cases, significant negative linear correlations were recorded between percentage
increases in growth and yield parameters of wheat caused by inoculation and increasing levels of applied NPK fertilizers.
It is highly likely that under low fertilizer application, the ACC-deaminase activity of PGPR might have caused reduction
in the synthesis of stress (nutrient)-induced inhibitory levels of ethylene in the roots through ACC hydrolysis into NH3 and α-ketobutyrate. The results of this study imply that these Pseudomonads could be employed in combination with appropriate
doses of fertilizers for better plant growth and savings of fertilizers. 相似文献
16.
中国氮磷钾肥制造温室气体排放系数的估算 总被引:17,自引:0,他引:17
通过收集、整合国内相关数据,推算了符合中国目前情况的各种氮肥、磷肥和钾肥的制造过程中的温室气体排放系数(从原料到工厂大门)。结果显示,我国平均水平的氮肥制造碳排放系数为:合成氨(液氨)1.672 t CE/t N,尿素2.041 t CE/t N,碳铵1.928 t CE/t N,硝酸铵4.202 t CE/t N,氯化铵2.220 t CE/t N,氮肥综合系数为2.116 t CE/t N。我国一般水平的磷肥制造碳排放系数为:重钙0.467 t CE/t P2O5,磷酸二铵1.109 t CE/t P2O5,磷酸一铵0.740 t CE/t P2O5,普钙0.195 t CE/t P2O5,钙镁磷肥2.105 t CE/t P2O5,磷肥综合系数为0.636 t CE/t P2O5。我国先进水平的钾肥制造碳排放系数为:氯化钾0.168 t CE/t K2O,硫酸钾0.409 t CE/t K2O(其中罗钾法硫酸钾0.443 t CE/t K2O、曼海姆法硫酸钾0.375 t CE/t K2O),钾肥综合系数为0.180 t CE/t K2O。我国大部分氮磷钾肥的温室气体排放系数普遍为欧美平均水平的2倍左右,因此利用国外系数来估算我国的农业温室气体排放量将严重低估化肥施用的影响。 相似文献
17.
O. D. Anderson F. C. Greene 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,95(1-2):59-65
The derived amino-acid sequences of all reported α-gliadin clones are compared and analyzed, and the patterns of sequence
change within the α-gliadin family are examined. The most variable sequences are two polyglutamine domains. These two domains
are characteristic features of the α-gliadin storage proteins and account for most of the variation in protein size of this
otherwise highly conserved protein family. In addition, their encoding DNA sequences form microsatellites. Single-base substitutions
in the α-gliadin genes show a preponderance of transitions, including the C to T substitution which contributes to the generation
of stop codons, and consequently to the observation that approximately 50% of the α-gliadin genes are pseudogenes. In one
unusual gene, a microsatellite has expanded to 321 bp as compared to the normal 36–72 bp, and may result from similar mechanisms
that produce polyglutamine-associated genetic diseases in humans. A comparison of the 27 reported sequences show several α-gliadin
gene subfamilies, at least some of which are genome specific.
Received: 1 October 1996/Accepted: 20 December 1996 相似文献
18.
Jeffrey Morris Jennifer Bagby 《The International Journal of Life Cycle Assessment》2008,13(3):226-234
Background, Aims and Scope
Measuring Environmental Value for Natural Lawn and Garden Care Practices provides a life cycle assessment and impacts valuation methodology to quantify environmental (public health and ecological)
and water conservation benefits from natural lawn and garden care practices in Seattle. Seattle Public Utilities (SPU) initiated
this study as part of a triple-bottom-line analysis of its Natural Lawn and Garden Care program.
Methods The study uses life cycle assessment (LCA) methods, including the Carnegie-Mellon Economic Input-Output Life Cycle Assessment
(EIOLCA) tool publicly available on the Internet, to inventory pollutant generation from a synthetic nutrients and pesticide
approach to lawn and garden care compared against a natural/organic care approach. The study applies US Environmental Protection
Agency’s TRACI (Tool for the Reduction and Assessment of Chemical and other environmental Impacts) climate change, acidification,
eutrophication, and human health-criteria air pollutant stressor factors, along with the Lawrence Berkeley National Laboratory’s
CalTOX risk assessment model’s human and ecosystem toxicity potentials to roll up the numerous pollutant quantities into six
environmental impact categories (global warming potential, human respiratory disease potential, human toxicity potential,
ecological toxicity potential, acidification potential and eutrophication potential). The study develops cost valuation estimates
for each impact category to produce a dollar estimate of the environmental cost of the two archetypical lawn and garden care
methods.
Results Lawns and gardens account for 25% of Seattle’s land area, so lawn and garden care methods potentially have substantial impacts
on the city’s land-and water-based ecosystems. LCA methods provide an informative methodology for comparing environmental
impacts from lawn and garden care practices. These methods reveal the importance of more natural lawn and garden care practices.
They also show that resource extraction and manufacturing impacts of pesticides and synthetic fertilizers dominate their on
site use impacts in the case of global warming, but that the reverse holds for human and ecological toxicity, and eutrophication.
In addition, releases of particulates, SOx and NOx associated with gasoline-powered lawn mowing are nearly an order of magnitude larger than releases of these pollutants as
a result of the production of pesticides and fertilizers.
Discussion The study proceeds by using available data and research to build a desktop model that characterizes and contrasts two archetypical
lawn and garden care practices: (1) Petroleum-based fertilizers and pesticides, a gasoline-powered lawn mower, and substantial
irrigation to maintain a traditional weed-free, always-green lawn and garden, versus (2) A backyard compost system to provide
lawn and garden nutrients, supplemented moderately by purchased non-synthetic soil amendments, an electricity-powered mower,
no pesticides, and drought tolerant lawn and garden species having little need for irrigation.
Conclusions The study concludes that each household converting from synthetic to natural practices produces nearly $75 in annual ongoing
public health, ecological, water conservation and hazardous waste management benefits — between $16 and $21 of environmental
benefits from reduced use of synthetic fertilizers and pesticides, $8 of environmental benefits for switching from gas to
electricity for lawn mowing, $42 in cost savings due to reduced irrigation, and $5 or $6 from lower hazardous waste management
costs. There also is a potential one time avoidance of $31 in construction costs resulting from reduced need for storm water
detention and diversion capacity.
Recommendations and Perspectives This study’s estimates of environmental value would benefit from comprehensive information on direct exposure to active ingredients
in insecticides during their application. Estimates of impacts are based only on volatilization and runoff of active ingredients
after application. Furthermore, the study would benefit from estimates of carbon sequestration in soils promoted by natural
lawn and garden care techniques, and on the upstream pollutant releases from production of synthetic versus organic fertilizers.
All three of these data gaps suggest that the estimated $75 per single family residence for environmental value is probably
a lower bound on benefits from natural lawn and garden care versus more traditional pesticide-and-synthetic-fertilizer-based
approaches.
ESS-Submission Editor: Mary Ann Curran (curran.maryann@epa.gov) 相似文献
19.
We investigated the influence of three factors—diesel oil concentration [2500, 5000, 10,000, 20,000 mg total petroleum hydrocarbons
(TPH) kg−1 soil], biostimulation (unfertilized, inorganic fertilization with NPK nutrients, or oleophilic fertilization with Inipol
EAP22), and incubation time—on hydrocarbon removal, enzyme activity (lipase), and microbial community structure [phospholipid
fatty acids (PLFA)] in a laboratory soil bioremediation treatment. Fertilization enhanced TPH removal and lipase activity
significantly (P ≤ 0.001). The higher the initial contamination, the more marked was the effect of fertilization. Differences between the
two fertilizers were not significant (P > 0.05). Microbial communities, as assessed by PLFA patterns, were primarily influenced by the TPH content, followed by fertilization,
and the interaction of these two factors, whereas incubation time was of minor importance. This was demonstrated by three-factorial
analysis of variance and multidimensional scaling analysis. Low TPH content had no significant effect on soil microbial community,
independent of the treatment. High TPH content generally resulted in increased PLFA concentrations, whereby a significant
increase in microbial biomass with time was only observed with inorganic fertilization, whereas oleophilic fertilization (Inipol
EAP22) tended to inhibit microbial activity and to reduce PLFA contents with time. Among bacteria, PLFA indicative of the
Gram-negative population were significantly (P ≤ 0.05) increased in soil samples containing high amounts of diesel oil and fertilized with NPK after 21–38 days of incubation
at 20°C. The Gram-positive population was not significantly influenced by TPH content or biostimulation treatment. 相似文献
20.
水肥耦合对橡胶树产胶量的影响 总被引:5,自引:0,他引:5
水分和养分是限制橡胶树生长和产胶量的重要因子.以17年生的7-33-97橡胶树为试验材料,采用施氮量、灌水量、施磷量和施钾量四因素五水平(1/2实施)的二次回归通用旋转设计,通过田间小区试验,研究了不同水肥耦合水平对橡胶树产量和干胶含量的影响,并建立了橡胶树干胶产量的水肥回归数学模型.结果表明:不同水肥耦合水平对橡胶树橡胶产量和干胶含量都有显著影响;各因素对橡胶产量的效应顺序为:施氮量>灌水量>施磷量>施钾量;各因素间耦合效应顺序为:氮、水>氮、磷>磷、水>钾、水,且施钾量和土壤水分呈负交互效应;水肥调控的最佳组合为:尿素用量为476.39 kg·hm-2,过磷酸钙用量为187.70 kg·hm-2,氯化钾用量为225.77 kg·hm-2,土壤相对含水量控制在82.78%左右. 相似文献