Amendments with organic and industrial wastes stimulate soil formation in mine tailings as revealed by micromorphology

Mine tailings are inhospitable to plants and soil organisms, because of low pH and poor soil organic matter contents. Vegetation establishment requires a soil system capable of supporting the nutrient and water requirements of plants and associated organisms. The objective of this study was to understand the influence of added organic and industrial wastes to the formation of soils in degraded landscapes left behind by past mining activities. Specifically, we stimulated the build up of soil organic matter (SOM) and the accumulation of calcite in mine tailing deposits. We amended field experimental plots with pig manure (PM), sewage sludge (SS) in combination with blanket application of marble wastes (MW). Soil samples were collected for physical and chemical analyses, two years after the addition of industrial wastes. Three years after amendments, we took undisturbed samples for micromorphological analysis. Soil pH increased from 2.7 to 7.4 due to dissolution of calcite from MW amendment. The acidity in tailings and low rainfall in the study area precipitated the secondary calcite as infillings within the 0-4 cm layer. Total organic carbon (TOC) increased from 0.86 to 2.5 g TOC kg − 1 soil after 24 months since the application of amendments. The build up of SOM resulted to stable SOM-calcite complex as dense incomplete infillings mixed with secondary calcite, and cappings on calcite particles from MW addition. These SOM cappings provide water and nutrient to support initial seedling establishment in mine tailings. We attribute the granular structure of amended materials to soil organisms (e.g., earthworm activity) involved in the decomposition of plant materials. We suggest that any organic matter amendments to acidic mine tailing deposits must be combined with calcium carbonate-rich materials to accelerate the build up of SOM to accelerate the establishment of functional ecosystem characterized by, among others, the presence of healthy soils with granular microstructure

El impacto de la ganadería y la agricultura en los ecosistemas terrestres.-Utilización sostenible de purines de cerdo, con y sin tratamiento, como enmienda orgánica en cultivos de almendro.

RESUMEN This study consists in the use of different forms of slurry, as an organic fertilizer, on almond trees located in La Aljorra (Cartagena, Murcia). The slurry used comes from a farm near the area of study, which has a treatment system composed by tree parts: a phase separator, a bioreactor and 5 constructed wetlands of vertical flow. Different phases of slurry are obtained from each part of the system. The results show the reduction of most of the parameters like salinity, BOD5, QOD, nitrates, etc. The use of these effluents as an organic amend in different doses, supposes a sustainable way of management of these residues; at the same time it improves the soil properties and the agronomic quality of the almond tree crop

Granular soil structure indicates reclamation of degraded to productive soils: a case study in southeast Spain

Accelerated conversion of degraded landscapes in mining areas to productive ecosystems requires stimulation of soil formation. The evolution in microstructure and changes to chemical properties in metal mine wastes 5 yr after amendments with pig manure, sewage sludge and marble waste is reported. Mine wastes had <1% organic carbon, <0.05% total nitrogen, pH2.0, electrical conductivity up to 20 dS m−1 and high concentrations of metals such as 22000 mg zinc kg−1 and 7000 mg lead kg−1. After 5 yr, one time amendment increased total carbon (g kg−1) from 1.4 (control) to 5.6 (marble waste +sewage sludge) to 8.3 (marble waste+pig manure). Soil pH in amended plots was 6.0 compared with 2.8 in controls. Micromorphological characteristics clearly showed that primary and secondary calcite serve as active sorption sites for organic matter. These calcitic zones were areas conducive to root growth. Soil microstructure in amended mine wastes was dominantly granular, resulting from activities of soil organisms such as fungi and enchytraeds. Results suggest organic matter can be effectively enriched in mine waste deposits through simultaneous additions of pig manure, sewage sludge and calcite. Soil amendments promoting formation of granular structure can accelerate establishment of productive landscapes in degraded mine sites

El impacto de la ganadería y la agricultura en los ecosistemas terrestres.-Programa de valorización de restos de pimiento y melón en producción hortícola en el campo de Cartagena, Murcia

ABSTRACT In the last decades, the irrigated agricultural areas have increased in Murcia, S.E. Spain, especially in the agrarian District “Comarca del Campo de Cartagena”. A consequence of this increase is the high use of fertilizers resulting to an excess of nutrients such as nitrogen. Another problem associated with the agriculture is the disposal of the increasing amount of organic agricultural residues from post-harvest practices. In this research we will study the effects of recycling crop residues as an organic fertilizer in vegetable production as a disposal management technique to reduce the amount of post-harvest residues

Erosión y desertificación.-Contenido en carbono orgánico como indicador del proceso de desertificación en suelos desarrollados de material parental volcánico en la Región de Murcia

RESUMEN Soil Organic Carbon (SOC) is an essential component of the global carbon cycle, especially in soils developed from volcanic rocks, due to these soils does not have inorganic carbon. In arid and semiarid areas mineralization of organic carbon is very intense due to climatic conditions, causing soils depletion and therefore desertification. The objective of this study is to determine the content of OC, as a first step in the assessment of desertification processes affecting this area of the southeast of Spain. In this study we selected 14 volcanic outcrops where 10-14 samples were taken and total organic carbon content determined. In some of them, samples from sedimentary parent material were taken for comparing the SOC contents. The results indicated that most of the outcrops show percentages of organic carbon moderately high; this is because of high plant colonization in this outcrop generating a significant content of SOC. Soils developed on volcanic rock showed percentages of SOC higher than the adjacent soils developed on sedimentary material. This could be due to several factors, firstly, the vegetation that colonizes volcanic soil is higher than in sedimentary soils; secondly, the erosion of the sedimentary material produce a loss of topsoil and therefore a decrease in organic carbon content. A third factor could be the stabilizing action exerted by the amorphous materials released during alteration of volcanic rocks

El impacto de la ganadería y la agricultura en los ecosistemas terrestres.-Efecto de la actividad agrícola en los contenidos de sales en suelos de Murcia: comparación con otros usos de suelo

ABSTRACT Salinization is one of the main problems of soil degradation in arid and semiarid areas, causing a reduction of soil quality, declining yield and productivity, and even land abandonment. The aim of this study was to evaluate the effect of different land uses, particularly agricultural use in the salt content in soil. The study area is located in the surroundings of Murcia city (SE Spain), with an surface of 100 km2, with high agricultural productivity. In order to determine salt content in soil, E.C. was measured in the 1:5 ratio. The results showed that the study area is saline, being the salinity higher when anthropogenic activity is more severe. Agricultural lands present the widest range of data, probably due to the application of poor quality irrigation water, fertilizers and livestock waste. Supporting this hypothesis, spatial distribution showed that the salinity is clearly located in the agricultural area. Detailed studies will be useful to understand the salinization process in order to implement measures to control and reduce salinity

Effect of different lignocellulosic wastes on Hericium americanum yield and nutritional characteristics

WOS: 000390708500029PubMed ID: 27100377BACKGROUNDThe aim of this study was to investigate the possibility of using cottonseed hulls (CSH) and olive press cake (OPC) as new supplement materials for substrate preparation in Hericium americanum cultivation. Some chemical properties of the substrates prepared by mixtures of oak sawdust (OS) with wheat bran (WB), CSH and OPC in different ratios were determined. In addition, the effect of mixtures of OS:CSH and OS:OPC on spawn run time, yield and biological efficiency (BE), average mushroom weight and nutrition content of the fruiting body were compared with the control substrate (8OS:2WB). RESULTSThe yield, BE and average mushroom weight of substrates containing CSH and OPC were higher than the control substrate and increased with an increase in the rate of CSH and OPC in the mixtures. Hericium americanum showed (on a dry weight basis) 8.5-23.7% protein, 9.9-21.2 g kg(-1) P, 26.6-35.8 g kg(-1) K, 0.63 - 1.33 g kg(-1) Mg, 0.19 - 0.23 g kg(-1) Ca, 1.34-1.78 g kg(-1) Na, 49.5-72.2 mg kg(-1) Fe, 6.22-10.11 mg kg(-1) Mn, 32.8-82.8 mg kg(-1) Zn and 8.6-11.2 mg kg(-1) Cu on different growing substrates. The nutritional value of mushrooms was greatly affected by the growing media. CONCLUSIONThe results revealed that CSH and OPC could be used as new supplement materials for substrate preparation in H. americanum cultivation. (c) 2016 Society of Chemical Industr