scholarly journals Evaluation of Infiltration Models in Soils of Two Land Use Systems in Calabar, Nigeria

2018 ◽  
pp. 81-94
Author(s):  
Isong I.A ◽  
Ogban P.I. ◽  
Antigha N.R.B. ◽  
Okon P.B.
Keyword(s):  
Land Use ◽  
Oil Palm ◽  
Coefficient Of Determination ◽  
Or Efficiency ◽  
Infiltration Process ◽  
Teaching And Research ◽  
Land Use Systems ◽  
Cumulative Infiltration ◽  
Infiltration Models ◽  
The University

Recently, the importance of the infiltration process in agriculture and the environ- ment has resulted in an upsurge of interest by soil and water scientists to model the process for quantitative application. A study was conducted on the University of Cal- abar Teaching and Research Farm, Calabar to evaluate the effect of oil palm (OP) and arable farm (AF) land use systems on the Green-Ampt (GA), Philip (P), Kostiakov (K), Horton (H) and Mezencev (MZ) infiltration models, as well as the applicability or efficiency of the models to predict infiltration into the soils. Infiltration data were obtained with double-ring infiltrometer, and the parameters of the models were obtained through curve-fitting. Model accuracy was evaluated with the Willmott’s index of agreement (W), chi-square (X2), coefficient of determination (R2), root mean square error (RMSE) and mean error (ME) test statistics. The results showed that soil under oil palm had measured cumulative infiltration and infiltration rate of 72.81 cm and 14.10cm/hr while arable farm had 74.76 cm and 12.92 cm/hr, respectively. The cumulative infiltration predicted by Philip and Kostiakov models were very close to the field data for OP and AF. Horton and Mezencev models underestimated the infiltration process because their ME values were negative while Green–Ampt, Kostia- kov, and Philip overestimated the infiltration process as they had positive ME values. In terms of accuracy and applicability, the order of performance was P>K>MZ>GA>H. Therefore, the Philip and Kostiakov models could be used to pre- dict infiltration into the soils, but that the Philip model was superior to the Kostiakov model for the University of Calabar Teaching and Research Farm and similar soils in other ecologies.

scholarly journals Frequência, diversidade e composição da fauna de cupins (Blattodea: Isoptera) em diferentes sistemas de uso do solo no sudoeste do Amazonas, Brasil

2018 ◽  
Vol 11 (2) ◽  
pp. 78-84 ◽  
Author(s):  
Agno Nonato Serrão Acioli
Keyword(s):  
Land Use ◽  
Species Richness ◽  
Oil Palm ◽  
Elaeis Guineensis ◽  
Taxonomic Composition ◽  
Primary Forest ◽  
Agricultural Crops ◽  
Termite Species ◽  
Land Use Systems ◽  
Elaeis Guineensis Jacq

Resumo. Os cupins são importantes decompositores da matéria de origem vegetal. Este estudo teve como objetivo analisar e comparar a diversidade e composição das espécies de cupins em três diferentes sistemas de uso do solo na região do Alto Solimões, Amazonas, Brasil. Os cupins foram coletados na floresta primária, em cultivos de dendê (Elaeis guineensis Jacq.) e mandioca (Manihot sculenta Crantz). Em cada área selecionada as coletas foram realizadas dentro de um transecto retangular medindo 100 m x 2 m, subdivididos em 20 parcelas de 5 m x 2 m. Foram encontradas 24 espécies de cupins, pertencentes a 14 gêneros e duas famílias, nos três sistemas de uso do solo. As espécies mais frequentes foram Nasutitermes cf. dendrophilus (Desneux) (28,43%), seguida de Heterotermes tenuis (Hagen) (14,37%) e Anoplotermes sp. 2 (9,58%). A riqueza de espécies foi maior na floresta primária (16 espécies), seguida dos cultivos de dendê (14 espécies) e mandioca (seis espécies). A composição taxonômica e os grupos funcionais também sofreram modificações, sendo mais diversificados e equilibrados na floresta primária quando comparados com os dois tipos de cultivos. A comunidade de cupins é fortemente afetada quando ocorre a substituição da floresta primária pelos cultivos agrícolas. Neste estudo, as espécies N. cf. dendrophilus e H. tenuis merecem atenção, pois se constata o aumento de sua frequência nos cultivos de dendê e mandioca.Frequency, Diversity and Composition of Termite Fauna (Blattodea: Isoptera) in Land Use Systems in the Southwest of Amazonas, Brazil Abstract. Termites are important decomposers of matter of vegetable origin. This study aims to analyze and compare the diversity and composition of termite species in three different land use systems in Alto Solimões, Amazonas, Brazil. Termites were collected in the primary forest, oil palm (Elaeis guineensis Jacq.) and cassava (Manihot sculenta Crantz) crops. In each area the collections were made within a rectangular transect measuring 100 m x 2 m, subdivided into 20 plots of 5 m x 2 m. Twenty four species of termites were found, belonging to 14 genera and two families. The most frequent species were Nasutitermes cf. dendrophilus (Desneux) (28.43%), Heterotermes tenuis (Hagen) (14.37%) and Anoplotermes sp. 2 (9.58%). The species richness was higher in the primary forest (16 species), followed by oil palm (14 species) and cassava (six species) crops. The taxonomic composition and the functional groups were also modified, being more diversified and balanced in the primary forest than in the crops. The termite community was strongly affected when the primary forest was replaced by agricultural crops. The species N. cf. dendrophilus and H. tenuis deserve attention, it was verified the increase of their frequency in the crops.

scholarly journals Trophic niche differentiation and utilisation of food resources in Collembola is altered by rainforest conversion to plantation systems

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10971
Author(s):  
Winda Ika Susanti ◽  
Rahayu Widyastuti ◽  
Stefan Scheu ◽  
Anton Potapov
Keyword(s):  
Land Use ◽  
Oil Palm ◽  
Ecosystem Functioning ◽  
Trophic Structure ◽  
Niche Differentiation ◽  
Food Resources ◽  
Soil Conditions ◽  
Isotopic Niche ◽  
Land Use Systems ◽  
Trophic Niches

Intensively managed monoculture plantations are increasingly replacing natural forests across the tropics resulting in changes in ecological niches of species and communities, and in ecosystem functioning. Collembola are among the most abundant arthropods inhabiting the belowground system sensitively responding to changes in vegetation and soil conditions. However, most studies on the response of Collembola to land-use change were conducted in temperate ecosystems and focused on shifts in community composition or morphological traits, while parameters more closely linked to ecosystem functioning, such as trophic niches, received little attention. Here, we used stable isotope analysis (13C and 15N) to investigate changes in the trophic structure and use of food resources by Collembola in Jambi province (Sumatra, Indonesia), a region that experienced strong deforestation in the last decades. Isotopic values of Collembola from 32 sites representing four land-use systems were analyzed (rainforest, rubber agroforest, rubber (Hevea brasiliansis) and oil palm (Elaeis guineensis) monoculture plantations). Across Collembola species Δ13C values were highest in rainforest suggesting more pronounced processing of litter resources by microorganisms and consumption of these microorganisms by Collembola in this system. Lower Δ13C values, but high Δ13C variation in Collembola in oil palm plantations indicated that Collembola shifted towards herbivory and used more variable resources in this system. Small range in Δ15N values in Collembola species in monoculture plantations in comparison to rainforest indicated that conversion of rainforest into plantations is associated with simplification in the trophic structure of Collembola communities. This was further confirmed by generally lower isotopic niche differentiation among species in plantations. Across the studied ecosystems, atmobiotic species (Symphypleona and Paronellidae) occupied the lowest, whereas euedaphic Collembola species occupied the highest trophic position, resembling patterns in temperate forests. Some species of Paronellidae in rainforest and jungle rubber had Δ15N values below those of leaf litter suggesting algivory (Salina sp.1, Callyntrura sp.1 and Lepidonella sp.1), while a dominant species, Pseudosinella sp.1, had the highest Δ15N values in most of the land-use systems suggesting that this species at least in part lives as predator or scavenger. Overall, the results suggest that rainforest conversion into plantation systems is associated with marked shifts in the structure of trophic niches in soil and litter Collembola with potential consequences for ecosystem functioning and food-web stability.

scholarly journals Diversity and Seasonal Dynamics of Arthropods in Okomu Forest Reserve

2021 ◽  
pp. 23-36
Author(s):  
Adeduntan S. A. ◽  
Akinbi O. J. ◽  
Osabiya O. S. ◽  
Olusola J. A.
Keyword(s):  
Land Use ◽  
Oil Palm ◽  
Seasonal Dynamics ◽  
National Park ◽  
Species Abundance ◽  
Insect Species ◽  
Rubber Plantation ◽  
Forest Reserve ◽  
Land Use Systems ◽  
Oil Palm Plantation

A field survey was conducted in Okomu Forest Reserve Edo State, to assess the diversity and seasonal dynamics of arthropod species in selected land use systems (Okomu national park, Okomu rubber plantation and Okomu oil palm plantation). Samplings of arthropods were carried out between February and September 2020, arthropods were collected by hand picking and sweep net in each sampled plots at 25 m x 25 m in the study area. Insects encountered were killed and preserved by chloroform. Arthropods samples were taken to the laboratory for oven dry and identification. A total of 382 arthropods spread across 15 orders, 34 families and 81 species were recorded. The most dominant orders were Hymenoptera (Ants) followed by Odonta (dragonfly) and Lepidoptera (butterfly and Moth) during dry season while highest abundance of orders were Spirostreptida (millepde) followed by Hymenoptera (Ants) and Araneae (spider) during rainy season. Okomu National Park has the highest (220) insect species abundance follow by Okomu Rubber Plantation (136) while the least was Okomu Oil Palm Plantation (72) in the study area. Study revealed that Okomu Rubber Plantation has no record of Scolopendromorphra (centipede) andHemiptera (bug) while in Okomu Oil Palm Plantation no record of Scolopendromorphra (centipede), lepidoptera (butterfly), also there were norecord of blattodea (crockroach) order of insect species in Okomu National Park. The highest species diversity and evenness was observed in Okomu National Park (H’ = 3.03 and E’= 0.83) follow by Okomu Oil Palm Plantation (H’=1.89 and E’=0.86) while Okomu Rubber Plantation was the least (H’ = 1.53 and E’= 0.60). ANOVA showed significant (P≤0.05) different on diversity and abundance between land use systems while there is nosignificant (P≥0.05) different seasons in the study area. Observation was made on seasonal variation of arthropods species in different land use systems and dominant species as bio-indicators in the study area.

scholarly journals Spatial and temporal dynamic of land-cover/land-use and carbon stocks in Eastern Cameroon: a case study of the teaching and research forest of the University of Dschang

2018 ◽  
Vol 14 (4) ◽  
pp. 181-191 ◽  
Author(s):  
Lucie Félicité Temgoua ◽  
Marie Caroline Momo Solefack ◽  
Vianny Nguimdo Voufo ◽  
Chrétien Tagne Belibi ◽  
Armand Tanougong
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Carbon Stocks ◽  
Temporal Dynamic ◽  
Teaching And Research ◽  
The University ◽  
Eastern Cameroon

scholarly journals Predicting the infiltration characteristics for semi-arid regions using regression trees

2021 ◽  
Author(s):  
Parveen Sihag ◽  
Munish Kumar ◽  
Saad Sh. Sammen
Keyword(s):  
Input Parameter ◽  
Regression Tree ◽  
Soil Surface ◽  
Infiltration Rate ◽  
Absolute Error ◽  
Coefficient Of Determination ◽  
Infiltration Process ◽  
Data Set ◽  
Cumulative Infiltration ◽  
Tree Methods

Abstract The study of infiltration process is considered as essential and necessary for all hydrology studies. Therefore, accurate predictions of infiltration characteristics are required to understand the behavior of subsurface flow of water through the soil surface. The aim of the current study is to simulate and improve the prediction accuracy of infiltration rate and cumulative infiltration of soil using regression tree methods. Experimental data recorded with a double ring infiltrometer for 17 different sites are used in this study. Three regression tree methods: Random tree, Random forest (RF) and M5 tree are employed to modelling the infiltration characteristics using the basic soil characteristics. The performance of the modelling approaches is compared in predicting the infiltration rate as well as cumulative infiltration, obtained results suggest that performance of RF model is better than other applied models with coefficient of determination (R2) = 0.97 & 0.97, root mean square error (RMSE) = 8.10 & 6.96 and mean absolute error (MAE) = 5.74 & 4.44 for infiltration rate and cumulative infiltration respectively. RF model is used to represent the infiltration characteristics of the study area. Moreover, parametric sensitivity is adopted to study the significance of each input parameter in estimating the infiltration process. Results suggest that time (t) is the most influencing parameter in predicting the infiltration process using this data set.

scholarly journals Ecological and socio-economic functions across tropical land use systems after rainforest conversion

2016 ◽  
Vol 371 (1694) ◽  
pp. 20150275 ◽  
Author(s):  
Jochen Drescher ◽  
Katja Rembold ◽  
Kara Allen ◽  
Philip Beckschäfer ◽  
Damayanti Buchori ◽  
...  
Keyword(s):  
Land Use ◽  
Oil Palm ◽  
Labour Productivity ◽  
Agricultural Landscapes ◽  
Ecosystem Functions ◽  
Economic Interests ◽  
Land Use Systems ◽  
Crop Choice ◽  
Below Ground ◽  
Jungle Rubber

Tropical lowland rainforests are increasingly threatened by the expansion of agriculture and the extraction of natural resources. In Jambi Province, Indonesia, the interdisciplinary EFForTS project focuses on the ecological and socio-economic dimensions of rainforest conversion to jungle rubber agroforests and monoculture plantations of rubber and oil palm. Our data confirm that rainforest transformation and land use intensification lead to substantial losses in biodiversity and related ecosystem functions, such as decreased above- and below-ground carbon stocks. Owing to rapid step-wise transformation from forests to agroforests to monoculture plantations and renewal of each plantation type every few decades, the converted land use systems are continuously dynamic, thus hampering the adaptation of animal and plant communities. On the other hand, agricultural rainforest transformation systems provide increased income and access to education, especially for migrant smallholders. Jungle rubber and rubber monocultures are associated with higher financial land productivity but lower financial labour productivity compared to oil palm, which influences crop choice: smallholders that are labour-scarce would prefer oil palm while land-scarce smallholders would prefer rubber. Collecting long-term data in an interdisciplinary context enables us to provide decision-makers and stakeholders with scientific insights to facilitate the reconciliation between economic interests and ecological sustainability in tropical agricultural landscapes.

scholarly journals Effects of Residue Cover on Infiltration Process of the Black Soil Under Rainfall Simulations

Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2593
Author(s):  
Yan Xin ◽  
Yun Xie ◽  
Yuxin Liu
Keyword(s):  
Soil Conservation ◽  
Bare Soil ◽  
Black Soil ◽  
Northeastern China ◽  
Rainfall Simulation ◽  
Simulation Experiments ◽  
Infiltration Process ◽  
Black Soil Region ◽  
Cumulative Infiltration ◽  
Infiltration Models

Residue cover is widely used for soil conservation after crop harvesting in the black soil region of the Northeastern China, which influences infiltration. It is necessary to optimize infiltration models for accurate predictions under bare and residue cover slope conditions. Rainfall simulation experiments were conducted to quantify the infiltration for the black soil under four rainfall intensities (30, 60, 90, and 120 mm/h), five residue coverage controls (15%, 35%, 55%, 75%, and bare slope), and two soil moisture (8% and approximately 30%) conditions. The observed data were used to fit and compare four infiltration models by Kostiakov, Mein and Larson (short for GAML, a modification of GreenAmpt model made by Mein and Larson), Horton, and Philip under the bare slope conditions. The residue cover infiltration factor (RCFi) was derived to predict the infiltration under the residue cover slopes, which was defined as the ratio of infiltration from residue-covered soil to that from bare soil. The results showed that the newly derived equation coupling the Philip model with the RCFi was the most accurate way of predicting the cumulative infiltration of black soil under various residue covers, and could be applied to the black soil region for residue cover infiltration predictions.

scholarly journals Changes in diversity and community assembly of jumping spiders (Araneae: Salticidae) after rainforest conversion to rubber and oil palm plantations

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11012
Author(s):  
André Junggebauer ◽  
Tamara R. Hartke ◽  
Daniel Ramos ◽  
Ina Schaefer ◽  
Damayanti Buchori ◽  
...  
Keyword(s):  
Land Use ◽  
Community Assembly ◽  
Oil Palm ◽  
Phylogenetic Diversity ◽  
Plant Biomass ◽  
Canopy Openness ◽  
Tropical Asia ◽  
Land Use Systems ◽  
Top Predators ◽  
Jungle Rubber

Rainforest conversion into monoculture plantations results in species loss and community shifts across animal taxa. The effect of such conversion on the role of ecophysiological properties influencing communities, and conversion effects on phylogenetic diversity and community assembly mechanisms, however, are rarely studied in the same context. Here, we compare salticid spider (Araneae: Salticidae) communities between canopies of lowland rainforest, rubber agroforest (“jungle rubber”) and monoculture plantations of rubber or oil palm, sampled in a replicated plot design in Jambi Province, Sumatra, Indonesia. Overall, we collected 912 salticid spider individuals and sorted them to 70 morphospecies from 21 genera. Salticid richness was highest in jungle rubber, followed by rainforest, oil palm and rubber, but abundance of salticids did not differ between land-use systems. Community composition was similar in jungle rubber and rainforest but different from oil palm and rubber, which in turn were different from each other. The four investigated land-use systems differed in aboveground plant biomass, canopy openness and land use intensity, which explained 12% of the observed variation in canopy salticid communities. Phylogenetic diversity based on ~850 bp 28S rDNA fragments showed similar patterns as richness, that is, highest in jungle rubber, intermediate in rainforest, and lowest in the two monoculture plantations. Additionally, we found evidence for phylogenetic clustering of salticids in oil palm, suggesting that habitat filtering is an important factor shaping salticid spider communities in monoculture plantations. Overall, our study offers a comprehensive insight into the mechanisms shaping communities of arthropod top predators in canopies of tropical forest ecosystems and plantations, combining community ecology, environmental variables and phylogenetics across a land-use gradient in tropical Asia.

Evaluation of the Academic Setting in Spain 1This study was financed by the University of Oviedo.

1995 ◽  
Vol 11 (2) ◽  
pp. 133-137 ◽  
Author(s):  
Juan Fernández ◽  
Miguel A. Mateo ◽  
José Muñiz
Keyword(s):  
Higher Education ◽  
Decision Making ◽  
Social Climate ◽  
Three Dimensions ◽  
Academic Setting ◽  
Teaching And Research ◽  
Evaluation Questionnaire ◽  
University Teachers ◽  
The University

The conditions are investigated in which Spanish university teachers carry out their teaching and research functions. 655 teachers from the University of Oviedo took part in this study by completing the Academic Setting Evaluation Questionnaire (ASEQ). Of the three dimensions assessed in the ASEQ, Satisfaction received the lowest ratings, Social Climate was rated higher, and Relations with students was rated the highest. These results are similar to those found in two studies carried out in the academic years 1986/87 and 1989/90. Their relevance for higher education is twofold because these data can be used as a complement of those obtained by means of students' opinions, and the crossing of both types of data can facilitate decision making in order to improve the quality of the work (teaching and research) of the university institutions.

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