scholarly journals Abundance and Diversity of Soybean-Nodulating Rhizobia in Black Soil Are Impacted by Land Use and Crop Management

2014 ◽  
Vol 80 (17) ◽  
pp. 5394-5402 ◽  
Author(s):  
Jun Yan ◽  
Xiao Zeng Han ◽  
Zhao Jun Ji ◽  
Yan Li ◽  
En Tao Wang ◽  
...  

ABSTRACTTo investigate the effects of land use and crop management on soybean rhizobial communities, 280 nodule isolates were trapped from 7 fields with different land use and culture histories. Besides the knownBradyrhizobium japonicum, three novel genospecies were isolated from these fields. Grassland (GL) maintained a higher diversity of soybean bradyrhizobia than the other cultivation systems. Two genospecies (Bradyrhizobiumspp. I and III) were distributed widely in all treatments, whileBradyrhizobiumsp. II was found only in GL treatment. Cultivation with soybeans increased the rhizobial abundance and diversity, except for the soybean monoculture (S-S) treatment. In monoculture systems, soybeans favoredBradyrhizobiumsp. I, while maize and wheat favoredBradyrhizobiumsp. III. Fertilization decreased the rhizobial diversity indexes but did not change the species composition. The organic carbon (OC) and available phosphorus (AP) contents and pH were the main soil parameters positively correlated with the distribution ofBradyrhizobiumspp. I and II andBradyrhizobium japonicumand negatively correlated withBradyrhizobiumsp. III. These results revealed that different land uses and crop management could not only alter the diversity and abundance of soybean rhizobia, but also change interactions between rhizobia and legume or nonlegume plants, which offered novel information about the biogeography of rhizobia.

Insects ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 306
Author(s):  
Vinicio Carrión-Paladines ◽  
Andreas Fries ◽  
Andrés Muñoz ◽  
Eddy Castillo ◽  
Roberto García-Ruiz ◽  
...  

This study evaluated the effects of land-use change (L-UCH) on dung beetle community structure (Scarabaeinae) in a disturbed dry ecosystem in southern Ecuador. Five different L-UCH classes were analyzed by capturing the dung beetle species at each site using 120 pitfall traps in total. To determine dung beetle abundance and diversity at each L-UCH, a general linear model (GLM) and a redundancy analysis (RDA) were applied, which correlated environmental and edaphic conditions to the community structure. Furthermore, changes in dung-producing vertebrate fauna were examined, which varied significantly between the different L-UCH classes due to the specific anthropogenic use or level of ecosystem disturbance. The results indicated that soil organic matter, pH, potassium, and phosphorus (RDA: component 1), as well as temperature and altitude (RDA: component 2) significantly affect the abundance of beetles (GLM: p value < 0.001), besides the food availability (dung). The highest abundance and diversity (Simpson’s index > 0.4, Shannon-Wiener index > 1.10) was found in highly disturbed sites, where soils were generally more compacted, but with a greater food supply due to the introduced farm animals. At highly disturbed sites, the species Canthon balteatus, Dichotomius problematicus, and Onthphagus confuses were found specifically, which makes them useful as bio-indicators for disturbed dry forest ecosystems in southern Ecuador.


2016 ◽  
Vol 5 (2) ◽  
pp. 57 ◽  
Author(s):  
Nahusenay Abate ◽  
Kibebew Kibret

The study was conducted to investigate the effects of land use, depth and topography on soil physicochemical properties at the Wadla Delanta Massif, northcentral Ethiopia. Four land uses (natural forest, shrub, grazing and cultivated land), three soil depths (0-20, 20-40, 40-60 cm) and three topographic positions (upper, middle and lower) in three replications were considered for this study. A total of 108 composite samples were collected for laboratory analysis. The results show that particle size distribution was affected by the main effects of land use and soil depth; bulk and particle densities, total porosity, organic matter and total nitrogen contents, C:N ratio and available phosphorus were significantly affected by the interaction of land use by soil depth only, whereas, soil pH, electrical conductivity, exchangeable bases, cation exchange capacity, percent base saturation and extractable micronutrients were affected by the interaction effects of the three factors. Highest clay and bulk density were recorded at the bottom layer of the cultivated land soils, while the utmost porosity, organic matter and nitrogen contents, and available phosphorus were recorded at the surface layers of the natural forest land soils. Highest pH was at the bottom layer of the cultivated land at the three topographic positions. Highest exchangeable bases and cation exchange capacity were observed in the bottom layers of soils under the four land use types at the lower topographic position, whilst extractable micronutrients were recorded at the surface layers of the forest land soils at the upper topographic position. In general, most of the measured soil properties were measured better in forest than in other land use soils and the lower topographic positions than the upper and middle ones. Interaction of land use with topography showed negative effects especially on cultivated and grazing land soils in all topographic positions. Therefore, integrated soil fertility management and soil conservation measures are required in all topographic positions to maintain soil physicochemical properties.


Soil Research ◽  
2011 ◽  
Vol 49 (7) ◽  
pp. 606 ◽  
Author(s):  
Peng-Tao Guo ◽  
Wei Wu ◽  
Hong-Bin Liu ◽  
Mao-Fen Li

Knowledge about soil properties associated with land use and topographical attributes is vital for modelling soil–landscape relationships and establishing sustainable on-field management practices. Our study focuses on an arable area in south-western China, where paddy fields and vegetable growing are dominant land uses. These are representative of millions of hectares of farmland in south-western China. Samples from 120 sites were collected according to a gridded sampling scheme and analysed. Land-use map units were delineated at a scale of 1 : 2000 from field survey. Topographical indicators (elevation, aspect, slope) were extracted from a digital elevation model with a resolution of 2 m. One-way and two-way analyses of variance and Pearson correlations were adopted to investigate the effects of land use and topographical variables on the selected soil properties: pH, organic matter (OM), ammonium-nitrogen (N), available phosphorus (P), available potassium (K), exchangeable calcium (Ca), and exchangeable magnesium (Mg). Statistically significant differences were found for OM, P, Ca, Mg, and pH between the land-use types and elevation gradient as well as slope classes. Mean contents of OM and P in paddy fields (lower and flat locations) were lower than in vegetable lands (higher and steep places) (P < 0.05). Mean values of Ca, Mg, and pH in paddy fields were higher than in vegetable lands (P < 0.05). Further analysis combining with management practice demonstrated that the redistribution of pH, OM, N, P, Ca, and Mg was mainly controlled by the interactive effects of topography and land use. Therefore, interactions between topography and land-use types need to be considered in regional soil properties inventory assessments.


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