scholarly journals Nematodos del suelo en el sistema maíz–soya y en hábitats naturales adyacentes de la Altillanura colombiana (Meta)

2008 ◽  
Vol 9 (1) ◽  
pp. 61
Author(s):  
María Claudia Leguízamo ◽  
Julio C. Parada

<p>Se describe la estructura de la comunidad de nematodos en muestras de suelos de la Altillanura colombiana procedentes de hábitats cultivados con arroz y el sistema maíz-soya, y hábitats naturales de bosque nativo adyacentes a los agroecosistemas mencionados. A tal fin, se colectaron 240 muestras de suelo, 86% de áreas cultivadas y 14% en áreas naturales; para la extracción de los nematodos se utilizó el elutridador Oostenbrink y para su identificación, claves morfológicas que incluyeron caracteres morfométricos y diagnósticos. Los taxa identificados se asignaron a grupos tróficos a nivel de Familia. A partir de las poblaciones obtenidas, se calcularon los índices de diversidad de Shanon, de riqueza de Simpson, de madurez total (mMI), de madurez (IM), de parásitos de plantas, la relación fungívoros/bacterióvoros, y los porcentajes de dorylaimidos y criconematidos, los cuales muestran diferencias entre hábitats naturales y cultivados. Los resultados permiten determinar posibles condiciones de pérdida de estructura en la cadena trófica del cultivo de arroz, ligera inestabilidad en suelos de parches de hábitat naturales, y una posible recuperación de la cadena trófica en el sistema maíz–soya. Este trabajo constituye el primer registro de nematodos de vida libre en suelos de la Orinoquía colombiana y propone la caracterización de poblaciones de nematodos en los estudios de calidad de hábitat como fundamento de procesos de recuperación de suelos. </p><p> </p><p><strong>Soil nematodes of the corn-soy rotation system and adjacent natural habitats of the Colombian well drained savannahs (Meta department) </strong></p><p>The structure of the soil nematode community in the Colombian well drained upland savannas cropped with rice, a corn soy bean rotation system, and natural adjacent habitats of native forest is described. In all, 240 soil samples were collected, 86% from cultivated areas and 14% from natural areas. Extractions were performed using an Oostenbrink elutriator and identifications with the help of key morphological, taking into account morphometry and diagnostic characters. Taxa identified, were assigned to trophic groups at the family level. Shannon diversity, richness Simpson, maturity index (MI), total maturity index (mIM), plant parasitic index, fungi/bacteria eaters relationship and % of dorylaimid and criconematid were calculated, which show the differences between cultivated and natural habitat. The results, allow for inferences of possible conditions of structure loss in the rice cropping system; some instability in soil patches of natural habitat, and possible recovery within the system corn – soybeans rotation system trophic chains. This work is the first record of free-living nematodes in the soils of the Colombian well drained savannas as a tool for the recovery of degraded soils. </p><p> </p>

2016 ◽  
Vol 7 ◽  
pp. 417-424
Author(s):  
Andrei Giurginca ◽  
Ştefan Cătălin Baba

Our study is a brief biodiversity evaluation of a less investigated community of Oniscidea, Diplopoda and Chilopoda from a plains location situated in South-Eastern Romania (Bărăganului Plain). The study targeted three types of habitat (two natural habitats and one semi-natural habitat) from Pădurea Călugărească: we can record the presence of 7 families of Oniscidea, 4 families of Diplopoda and 6 families of Chilopoda. Our study confirms the presence in Romania of Propolyxenus trivittatus and Lophoproctus lucidus, also, we can record new distribution data for Schendyla mediterranea (second location from Romania), Lithobius burzenlandicus euxinicus and Lithobius aeruginosus luciae (first record in the Romanian Plain). Although using only qualitative collecting methods, our data underline the significance of forest plains in one of the most arid regions in Romania in supporting the biodiversity of soil-dwelling arthropods and, also, show the potential of this region of Romania for subsequent, more complex studies.


2020 ◽  
Vol 13 (11) ◽  
pp. 1
Author(s):  
A. R. B. Zanco ◽  
A. Ferreira ◽  
G. C. M. Berber ◽  
E. N. Gonzaga ◽  
D. C. C. Sabino

The different integrated production systems can directly interfere with its bacterial community. The present study aimed to assess density, bacterial diversity and the influence of dry and rainy season in different integrated and an exclusive production system. The fallow and a native forest area was assessed to. Samples were collected in 2012 March and September. The isolation were carried out into Petri dishes containing DYGS medium. The number of colony forming units (CFU) was counted after 48 hours and. The bacterial density ranged between 106 and 107 CFU g-1 soil. The crop system affected the dynamics of the bacterial community only in the rainy season. The rainy season showed greater density of total bacteria when compared to the dry period regardless of the cropping system. The dendrograms with 80 % similarity showed thirteen and fourteen groups in the rainy and dry seasons. Isolates with the capacity to solubilize phosphate in vitro were obtained from all areas in the two seasons, but this feature has been prevalent in bacteria isolated during the rainy season


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Cheng Gong ◽  
Liangtao Li ◽  
Jan C. Axmarcher ◽  
Zhenrong Yu ◽  
Yunhui Liu

AbstractIn the intensively farmed, homogenous agricultural landscape of the North China Plain, family graveyards form distinct cultural landscape features. In addition to their cultural value, these graveyards represent semi-natural habitat islands whose potential roles in biodiversity conservation and ecological functioning has remained poorly understood. In this study, we investigated plant species richness on 199 family graveyards of different ages and sizes. In accordance with biogeography theory, both overall and insect-pollinated plant species richness increased with area and age of graveyards. Even small graveyards show a strong potential for conserving local plant richness, and a mosaic of both large and small family graveyards could play an important role in the conservation of farmland biodiversity and related ecosystem functions. The launch of agri-environmental measures that conserve and create semi-natural habitats, in turn benefitting agricultural biodiversity and ecological functioning, has proven difficult in China due to the shortage of dispensable arable land. Given the great value of family graveyards as semi-natural habitats reflected in our study, we propose to focus preliminary efforts on conserving these landscape features as existing, widespread and culturally important semi-natural habitat islands. This would represent an effective, complementary policy to a subsequent re-establishment of other semi-natural habitats for the conservation of biodiversity and ecological functioning in agricultural landscapes.


1983 ◽  
Vol 31 (5) ◽  
pp. 695 ◽  
Author(s):  
IJ Rooke ◽  
SD Bradshaw ◽  
RA Langworthy

Total body water content (TBW) and TBW turnover were measured by means of tritiated water (HTO) in free-ranging populations of silvereyes, Zosterops lateralis, near Margaret River, W.A. Birds were studied in their natural habitats during spring and summer, and compared with a vineyard population in summer. In the natural habitat TBW content was found to be 77.6% in spring, which was not significantly different from that measured in summer (78.3%). Birds in vineyards in summer, however, were dehydrated, with a TBW content of 69.4%. Calculated rates of water influx for spring, summer and summer vineyards birds were 1.44,2.20 and 0.65 ml g.day-' respectively. These water turnover rates are much higher than those of any other bird yet studied. Dehydration was marked in the vineyard birds, with a significantly lower TBW content and an average net water loss of 0.63 ml day-'. Laboratory studies showed that silvereyes have a low tolerance to sodium loading. Their tolerance is, however, quite adequate for them to drink the most concentrated free water available to them in the field. Ingestion of concentrated sugar solutions of up to 25% did not provoke an osmotic diuresis and thus cannot account for the dehydration and negative water balance of vineyard birds.


2004 ◽  
Vol 31 (2) ◽  
pp. 86-91 ◽  
Author(s):  
D. T. Gooden ◽  
H. D. Skipper ◽  
J. H. Kim ◽  
K. Xiong

Abstract Rhizobacteria play an important role in sustainable agriculture via plant growth and biological control of pests in a number of ecosystems. Understanding the interactions of crop rotation and rhizobacteria on peanut production is a critical research need. Development of a database on the rhizobacteria obtained from continuous and rotational fields of peanut was initiated in 1997 and terminated in 2000. Peanut was planted in monoculture for 4 yr. In rotational plots, peanut, cotton, corn, and peanut were planted in sequence. Rhizobacteria were isolated from the roots of crop plants grown in a Norfolk soil near Florence, SC. These isolates were identified by composition of fatty acids from gas chromatography analysis (GC/FAME). Arthrobacter and Bacillus were the major genera from non-rhizosphere soils. At initiation of this study in July 1997, the plots selected for continuous peanut had more diversity in rhizobacteria than those plots selected for rotation. In July 2000, rhizobacteria diversity was greater from peanut roots in the rotation cropping system than continuous peanut. Even though rhizobacteria diversity was greater in the rotation system, higher peanut yields were recorded in the continuous peanut system in 2000. Burkholderia spp. were always isolated from the peanut and other crop rhizospheres at each sampling date.


2011 ◽  
Vol 48 (2) ◽  
pp. 116-123 ◽  
Author(s):  
W. Zhang ◽  
Y. Xiao ◽  
X. Wang ◽  
Y. Lv

AbstractDiversity and nematode abundance were investigated in soils collected around the Gangue hill of Fushun West open-pit mine to evaluate soil pollution, due to heavy metals contents, using nematodes as bioindicators. Nematodes were collected from soil samples using elutriate-sievingflotation and centrifugation methods. The species richness and ecological indices were analyzed. On the base of chemical and nematological analysis, the results indicated that the area around the Gangue hill of Fushun West Openpit mine was polluted by heavy metal, but the degree of pollution was not very serious. According to the results obtained from single-factor analysis, cadmium soil content was ten times higher than the background; 29 genera of nematodes were identified and Acrobeloides, Cervidellus and Mesorhabtidis were the dominant genera in almost all sampling sites. The dominant genera were different as the distances to the Gangue hill changed. In particular, in the investigated areas bacterivores and plant-parasites nematodes were more diffuse than fungivores and omnivorepredators. Copper soil content was significantly correlated with plant parasitic trophic group and with total number of nematodes, thus suggesting that nematode communities studies are important scientific basis for understanding the healthy development of soil ecosystem.


2019 ◽  
Vol 77 ◽  
pp. 1-18
Author(s):  
Julien Carlier ◽  
James Moran

Across Europe, Greenways upcycle disused railway infrastructure into non-motorised public infrastructure, often with limited consideration to potential ecological synergies. Pre-development, disused transport corridors become relatively undisturbed and potentially host diverse semi-natural habitats. The study objectives were 1) to produce a highly detailed and accurate dataset using remote sensing with rapid assessment techniques for ground truthing and 2) subsequently examine habitat diversity existing along a proposed Greenway. A 7000 ha study corridor was based on a disused railway proposed as a transfrontier Greenway connecting the Republic of Ireland and the United Kingdom. The study applied a rapid-assessment virtual validation techniquealongside remote sensing and accuracy assessment. Inter-relationship between seminatural habitat diversity and land-use intensification was examined. Remote sensing accuracies of 89% and 99% for a real and linear habitat classification were obtained. Degrees of land-use intensification were observed throughout the corridor, highlighting the importance of maintaining and enhancing remaining semi-natural habitat that exists along the proposed Greenway route. Through understanding the landscape matrix composition and semi-natural habitat diversity, European Greenwayscan achieve multi-functionality for ecosystem conservation, forming integral components of Green Infrastructure.


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