Compost amendments in agricultural ecosystems: confirmatory path analysis to clarify the effects on soil chemical and biological properties

2014 ◽  
Vol 153 (2) ◽  
pp. 282-295 ◽  
Author(s):  
A. BELLINO ◽  
D. BALDANTONI ◽  
F. DE NICOLA ◽  
P. IOVIENO ◽  
M. ZACCARDELLI ◽  
...  

SUMMARYCompost use is increasingly proposed as a sustainable strategy to restore the fertility of degraded agricultural soils and to reduce landfill disposal or incineration of organic wastes. The effects of compost application on many soil physico-chemical and biological properties, as well as on soil contamination, have been investigated widely, but a model for the ecological interactions among them has never been developed. The aim of the present paper was to provide an integrated view of the causal processes induced by repeated compost amendments on agricultural soil properties. For this purpose, a confirmatory path analysis was performed to enable inferences to be drawn about the causal processes involving compost amendment, soil organic matter content, nutrient concentrations, microbial activity and soil contamination. The path analysis was performed on a dataset derived from a 3-year field trial carried out by the current authors in a Mediterranean intensive agricultural system, where 0, 15, 30 or 45 t/ha of certified compost from municipal solid wastes were annually applied. A script (‘cpa’) was developed using the R programming language and used to test 13 hypothetical models, expressed as directed acyclic graphs, against the observed data. Within the above-mentioned dataset, potassium and zinc available concentrations, microbial respiration and total polycyclic aromatic hydrocarbon (PAH) concentrations were selected as indicative of soil nutrient availability, microbial activity and organic contamination. The applied approach highlights that compost amendment directly influences all the other variables considered in the study and is the main determinant of the observed trends. Other important relationships are those among organic matter, nutrient availabilities, respiration and PAHs, as well as their temporal dynamics.

Agronomy ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 795
Author(s):  
Robert P. Larkin

The potential benefits of different types of soil amendments and mulch ground covers on soil chemical and biological properties, crop development and yield, and disease and pest issues in organic vegetable production, as represented by legume (green snap bean), cucurbit (green zucchini squash), and brassicaceous (turnip) vegetable crops, were evaluated in a two-year field trial in Maine, USA. Soil amendments evaluated (following an initial fertilizer base) included a commercial organic fertilizer alone, composted dairy manure, compost plus fish meal, and compost plus Wollastonite, a natural source of silicon (Si). A paper mulch was also compared with a woven polypropylene fabric mulch for their performance and effects as weed barriers within these systems. Mulch type significantly affected soil properties, with the fabric mulch associated with increases in soil moisture, organic matter, and other soil chemical and biological properties relative to the paper mulch. The fabric mulch also resulted in earlier emergence and earlier harvests for bean and zucchini. Soil amendments affected soil properties and crop growth and yield of bean and zucchini, with compost amendments increasing soil pH, organic matter, and several nutrient concentrations, as well as crop emergence and yield relative to a fertilizer-only treatment. Compost treatment also reduced the infestation and damage caused by mites on beans in 2018. Addition of fish meal increased most nutrient element concentrations and microbial respiration, and Si amendment increased emergence of beans, and reduced powdery mildew on squash and late season browning of beans. These results help define specific management practices to improve organic vegetable production and provide useful information and options for growers.


1989 ◽  
Vol 69 (1) ◽  
pp. 39-47 ◽  
Author(s):  
A. NDAYEGAMIYE ◽  
D. CÔTÉ

Chemical and biological properties were evaluated in 1987 on an acidic silty loam soil following a long-term field study established in 1978 and cultivated with silage corn. Treatments included a control, solid cattle manure (20, 40 and 60 Mg ha−1 FYM) and pig slurry (60, 120 m3 ha−1 SLU) applied every 2 yr and annually, respectively. No fertilizer was applied. The results of this study have shown that neither treatment significantly affected soil pH values, total-N contents and C:N ratios compared to the control. The cation exchange capacity (CEC) of the soil was significantly higher with FYM treatment than with control or SLU application. The highest rates of FYM and SLU have also increased (P < 0.05) soil organic carbon, microbial activity and potentially mineralizable nitrogen. The soil microflora populations (bacteria, fungi, actinomycetes, ammonifiers and nitrifiers) were greatly improved by both treatments. There were no significant differences in organic matter content or the relative amount of humic and fulvic acids between FYM and SLU plots. In spite of these results, FYM application (40 and 60 Mg ha−1) did affect more significantly the distribution of organic carbon in HA and the E4/E6 quotients than SLU additions. Humic acids extracted from SLU amended soils had a lower C content and lower E4/E6 ratios than humic acids from FYM soils. Long-term SLU application did not contribute to decreased organic matter content, CEC and humic acids yield, probably because of optimal organic residues returned to the soil by the corn crops. The FYM application generally improved soil chemical and biological properties. For a sustainable soil productivity, long-term SLU application should then be avoided in rotation in which small amounts of plant residues are returned, especially on soils with low organic matter contents. Key words: Organic matter, microbial activity, nitrogen mineralization potential, CEC, solid cattle manure, pig slurry


2012 ◽  
Vol 28 (1) ◽  
pp. 17-31 ◽  
Author(s):  
Carmen M. Ugarte ◽  
Michelle M. Wander

AbstractSoil testing strategies that include biologically based indicators in organic and alternative farming systems are needed in order to improve recommendations that balance production and environmental goals. In this study, soil samples were collected before and after soils were transitioned from conventional row crop production to organic management using rotations that varied in both their inputs and tillage intensity. Ley-, row crop- and vegetable-based farming systems were implemented using locally specific production practices. Subplots were imposed within each system to allow comparison of farming systems without amendment and with dairy manure- and compost-amendment. Soil analyses included standard chemical tests (0–15 cm) for available phosphorus, exchangeable potassium, calcium, magnesium, pH, total organic carbon (SOC) and total nitrogen (TN). Biological assays (0–15 and 15–30 cm) included particulate organic matter-C and -N (POM-C, POM-N), soil and POM C:N ratios, fluorescein diacetate (FDA) hydrolysis, potentially mineralizable N (PMN) and hydrolysable amino-N + NH4(IL-N). Even though cropping and tillage intensity varied among systems (ley < row crop < vegetable), organic matter and nutrient reserves were not statistically different. Nutrient concentrations tested medium to high, even without compost or manure application. Labile fractions of soil organic matter were more enriched in the deeper sampling depth; whereby, POM stocks within the 15–30 cm depth increased by 20% on average compared to roughly 6% in the surface depth. This and observed changes in other properties demonstrate the multiple benefits derived from use of winter annual or perennial crops. Results from our analyses suggested PMN and POM have particular promise as metrics of change in commercial soil testing facilities to assist recommendations for amendments to balance production and environmental goals.


1989 ◽  
Vol 69 (4) ◽  
pp. 739-749 ◽  
Author(s):  
T. L. ROBERTS ◽  
J. R. BETTANY ◽  
J. W. B. STEWART

Organic C, N, P, and S contents in soil are thought to be the result of interactions among soil-forming processes, which occur in all soils but to different degrees. To test this hypothesis, the effect of climate, vegetation and topography on the organic matter composition in cultivated soil profiles was examined along an environmental gradient, from semiarid to subhumid regions in Saskatchewan. This transect encompasses a narrow environmental gradient of decreasing evapotranspiration and increasing precipitation (350–450 mm). Representative catenas selected from Brown, Dark Brown, Black and Gray Luvisol soil zones showed changes in the quantity and composition of organic matter. Concentrations of organic C, N, P and S progressively increased from the Brown to the Black soils and then decreased substantially in the Gray soils. Nutrient concentrations also increased from the upper to the lower slope positions of the catenas and decreased with depth in the soil profile. However, the distribution of organic elements across the soil zones, relative to each other (i.e. C:N, C:P, or C:N:P:S ratios), did not follow the same trends as concentration of the individual elements. The most consistent trends were observed in the lower slope soils, where organic C:N (9.8 to 12.5:1), C:P (48 to 78:1) and C:N:P:S (68:6.9:1.4:1 to 145:11.6:1.8:1) ratios widened from the Brown to the Gray soils. Within any one catena, organic C:N:P:S ratios narrowed with depth in the soil profile, often showing a several-fold decrease relative to the C:N:P:S ratios of the surface horizons. This study demonstrates the value of recognizing integrative relationships among soil processes. It provides a mechanism for better understanding and explaining the patterns of distribution and behavior of various soil chemical, physical and biological properties. Key words: Catenary sequence, Chernozem, Luvisol, hierarchical relationships


2008 ◽  
Vol 5 (2) ◽  
pp. 281-298 ◽  
Author(s):  
P. Raimbault ◽  
N. Garcia ◽  
F. Cerutti

Abstract. During the BIOSOPE cruise the RV Atalante was dedicated to study the biogeochemical properties in the South Pacific between the Marquesas Islands (141° W–8° S) and the Chilean upwelling (73° W–34° S). Over the 8000 km covered by the cruise, several different trophic situations were encountered, in particular strong oligotrophic conditions in the South Pacific Gyre (SPG, between 123° W and 101° W). In this isolated region, nitrate was undetectable between the surface and 160–180 m and only trace quantities (<20 nmoles l−1) of regenerated nitrogen (nitrite and ammonium) were detected, even in the subsurface maximum. Integrated nitrate over the photic layer, which reached 165 m, was close to zero. Despite this severe nitrogen-depletion, phosphate was always present in significant concentrations (≈0.1 μmoles l−1), while silicic acid was maintained at low but classical oceanic levels (≈1 μmoles l−1). In contrast, the Marquesas region (MAR) to the west and Chilean upwelling (UPW) to the east were characterized by high nutrient concentrations, one hundred to one thousand fold higher than in the SPG. The distribution of surface chlorophyll reflected the nitrate gradient, the lowest concentrations (0.023 nmoles l−1) being measured at the centre of the SPG, where integrated value throughout the photic layer was very low (≈ 10 mg m−2). However, due to the relatively high concentrations of chlorophyll-a encountered in the DCM (0.2 μg l−1), chlorophyll-a concentrations throughout the photic layer were less variable than nitrate concentrations (by a factor 2 to 5). In contrast to chlorophyll-a, integrated particulate organic matter (POM) remained more or less constant along the study area (500 mmoles m−2, 60 mmoles m−2 and 3.5 mmoles m−2 for particulate organic carbon, particulate organic nitrogen and particulate organic phosphorus, respectively), with the exception of the upwelling, where values were two fold higher. The residence time of particulate carbon in the surface water was only 4–5 days in the upwelling, but up to 30 days in the SPG, where light isotopic δ15N signal noted in the suspended POM suggests that N2-fixation provides a dominant supply of nitrogen to phytoplankton. The most striking feature was the large accumulation of dissolved organic matter (DOM) in the SPG compared to the surrounding waters, in particular dissolved organic carbon (DOC) where concentrations were at levels rarely measured in oceanic waters (>100 μmoles l−1). Due to this large pool of DOM in the SPG photic layer, integrated values followed a converse geographical pattern to that of inorganic nutrients with a large accumulation in the centre of the SPG. Whereas suspended particulate matter in the mixed layer had a C/N ratio largely conforming to the Redfield stochiometry (C/N≈6.6), marked deviations were observed in this excess DOM (C/N≈16 to 23). The marked geographical trend suggests that a net in situ source exists, mainly due to biological processes. Thus, in spite of strong nitrate-depletion leading to low chlorophyll biomass, the closed ecosystem of the SPG can accumulate large amounts of C-rich dissolved organic matter. The implications of this finding are examined, the conclusion being that, due to weak lateral advection, the biologically produced dissolved organic carbon can be accumulated and stored in the photic layer for very long periods. In spite of the lack of seasonal vertical mixing, a significant part of new production (up to 34%), which was mainly supported by dinitrogen fixation, can be exported to deep waters by turbulent diffusion in terms of DOC. The diffusive rate estimated in the SPG (134 μmolesC m−2 d−1), was quite equivalent to the particles flux measured by sediments traps.


2016 ◽  
Vol 28 (0) ◽  
Author(s):  
Nilva Brandini ◽  
◽  
Ana Paula de Castro Rodrigues ◽  
Ilene Matanó Abreu ◽  
Luiz Carlos Cotovicz Junior ◽  
...  

Abstract Aim: There are few studies dealing with the biogeochemical processes occurring in small estuaries receiving high sewage loading in tropical regions. The aim of this investigation was to characterize the biogeochemical behavior of nutrients in superficial waters collected at the Iguaçu estuarine system, during specific conditions (neap tide), located at the inner sector of a heavily eutrophicated embayment (Guanabara Bay, SE Brazil). Methods Physical and chemical variables were measured in situ (pH, temperature, conductivity, salinity, total dissolved solids, transparency, dissolved oxygen), whereas suspended particulate matter, chlorophyll a, phaepigments and nutrients (carbon, nitrogen and phosphorus forms) were measured in laboratory across the mesohaline estuarine gradient. Results The Iguaçu River mouth is in a high stage of eutrophication, considering nutrient concentrations, chlorophyll a and transparency of water column. Results indicate a transition from heterotrophic conditions to autotrophic conditions, since the nutrients concentrations showed a decreasing pattern along the saline gradient, while the chlorophyll an increased over the transects. The pH values and chlorophyll : phaeopigments ratios are significantly related to the amount and quality of organic matter contents, especially at transects under strong marine influence. More than 95% of the dissolved and total nitrogen concentrations are represented by NH4+ contributions, which are related to the ammonification of organic matter contents in this region, indicating the existence of untreated sewage loads in this area. Conclusion In this study, the Iguaçu River seemed to contribute with high inputs of nutrients that support important phytoplankton production at the inner regions of the bay related to the CO2 sink and autotrophic metabolism, showing the importance of verifying the biogeochemical behaviors of nutrients in estuarine areas, even in small scale.


2010 ◽  
Vol 44 (11) ◽  
pp. 4076-4082 ◽  
Author(s):  
Brent G. Pautler ◽  
André J. Simpson ◽  
David J. Mcnally ◽  
Scott F. Lamoureux ◽  
Myrna J. Simpson

2016 ◽  
Vol 29 (1) ◽  
pp. 94-100 ◽  
Author(s):  
ADERVAN FERNANDES SOUSA ◽  
LINDBERGUE ARAÚJO CRISOSTOMO ◽  
OLMAR BALLER WEBER ◽  
MARIA EUGENIA ORTIZ ESCOBAR ◽  
TEÓGENES SENNA DE OLIVEIRA

ABSTRACT: Irrigation using produced water, which is generated during crude oil and gas recovery and treated by the exploration industry, could be an option for irrigated agriculture in semiarid regions. To determine the viability of this option, the effects of this treated water on the nutritional status of plants should be assessed. For this purpose, we examined the nutritional changes in sunflowers after they were irrigated with oil-produced water and the effects of this water on plant biomass and seed production. The sunflower cultivar BRS 321 was grown for three crop cycles in areas irrigated with filtered produced water (FPW), reverse osmosis-treated produced water (OPW), or ground water (GW). At the end of each cycle, roots, shoots, and seeds were collected to examine their nutrient concentrations. Produced water irrigation affected nutrient accumulation in the sunflower plants. OPW irrigation promoted the accumulation of Ca, Na, N, P, and Mg. FPW irrigation favored the accumulation of Na in both roots and shoots, and biomass and seed production were negatively affected. The Na in the shoots of plants irrigated with FPW increased throughout the three crop cycles. Under controlled conditions, it is possible to reuse reverse osmosis-treated produced water in agriculture. However, more long-term research is needed to understand its cumulative effects on the chemical and biological properties of the soil and crop production.


1970 ◽  
pp. 14-18
Author(s):  
Tufail Shah ◽  
Zahir Shah ◽  
Syed Atizaz Ali Shah ◽  
Nazir Ahmad

A study was performed to check the effects of various sources of sulfur on microbial activity, microbial population, N mineralization and organic matter content in an alkaline calcareous soil by using soil samples collected from Malakandher Farm at 0-20 cm depth, and analyzed for microbial activity, total mineral nitrogen, bacterial and fungal population and organic matter content. The results showed that the rate of CO2 evolution and cumulative CO2 production were higher in soils amended with elemental sulfur followed by sulfuric acid and gypsum treated soils. The microbial activity decreased with incubation period in all treatments, and the microbial population was greatly affected by sulfur sources. Generally, the bacterial population decreased in soils amended with elemental sulfur, but the population was higher in soils amended with gypsum. Bacterial population was suppressed in soils treated with sulfuric acid. However, the fungal population was higher in soils amended with sulfuric acids was less in soil amended with elemental sulfur. The sulfur amendments promoted immobilization of N. The net N immobilized was higher in soil amended with gypsum followed by soils amended with sulfuric acid and elemental sulfur. The percent organic matter was higher in soils amended with gypsum and was decreased compared with that amended with elemental sulfur or sulfuric acid. These results suggested that soil microbiological properties changed with sulfur amendments during laboratory incubation.


2012 ◽  
Vol 25 (1) ◽  
pp. 11-18 ◽  
Author(s):  
Juliana Vanir De Souza Carvalho ◽  
Eduardo De Sá Mendonça ◽  
Newton La Scala ◽  
César Reis ◽  
Efrain Lázaro Reis ◽  
...  

AbstractPolar Regions are the most important soil carbon reservoirs on Earth. Monitoring soil carbon storage in a changing global climate context may indicate possible effects of climate change on terrestrial environments. In this regard, we need to understand the dynamics of soil organic matter in relation to its chemical characteristics. We evaluated the influence of chemical characteristics of humic substances on the process of soil organic matter mineralization in selected Maritime Antarctic soils. A laboratory assay was carried out with soils from five locations from King George Island. We determined the contents of total organic carbon, oxidizable carbon fractions of soil organic matter, and humic substances. Two in situ field experiments were carried out during two summers, in order to evaluate the CO2-C emissions in relation to soil temperature variations. The overall low amounts of soil organic matter in Maritime Antarctic soils have a low humification degree and reduced microbial activity. CO2-C emissions showed significant exponential relationship with temperature, suggesting a sharp increase in CO2-C emissions with a warming scenario, and Q10 values (the percentage increase in emission for a 10°C increase in soil temperature) were higher than values reported from elsewhere. The sensitivity of the CO2-C emission in relation to temperature was significantly correlated with the humification degree of soil organic matter and microbial activity for Antarctic soils.


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