scholarly journals Assessment of soil microbial and enzyme activity in the rhizosphere zone under different land use/cover of a semi-arid ecosystem, India

2020 ◽  
Author(s):  
Archana Meena ◽  
K.S. Rao

Abstract Background Land use/cover changes and management practices are widely known to influence SOM quality and quantity. The present study investigated the effect of different land uses i.e. forests viz. mixed forest cover (MFC), Prosopis juliflora (Sw.) DC dominated forest cover (PFC), and cultivated viz. agriculture field (AF), vegetable filed (VF), respectively, on soil parameter, microbial activity, and enzymes involved in soil nutrient cycle in a semi-arid ecosystem.Results The results showed a significant reduction (P < 0.05) in soil carbon (SC), soil nitrogen (SN) content (~ 30–80%) and consequently the soil microbial biomass carbon (SMBC) (~ 70–80%), soil basal respiration (SBR), soil substrate induced-respiration (SSIR), and soil enzyme activities (β-glucosidase, acid phosphatase, and dehydrogenase) under cultivated sites in comparison to forest analogs due to land use management practices. Pearson’s correlation showed a positive correlation of SC with SMBC, SBR, and SSIR (P < 0.01) and enzymatic activities i.e. β-glucosidase, dehydrogenase (P < 0.05) suggesting the critical role of SC in regulating microbial and enzymatic activity. Also, a positive correlation of SM with urease (P < 0.01) was observed indicating the importance of soil abiotic factors in controlling enzymatic activities. Additionally, based on the PCA analysis, we observed the clustering of SMBC/SC ratio and qCO2 nearby AF.Conclusion Our study suggested that degraded sites are more sensitive to the land management practices and land use changes and needed immediate attention in future studies related to SC dynamics in semi-arid ecosystems.

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Archana Meena ◽  
K. S. Rao

Abstract Background Land use/cover and management practices are widely known to influence soil organic matter (SOM) quality and quantity. The present study investigated the effect of different land use, i.e., forests viz. mixed forest cover (MFC), Prosopis juliflora (Sw.) DC-dominated forest cover (PFC), and cultivated sites viz. agriculture field (AF), vegetable field (VF), respectively, on soil parameter, microbial activity, and enzymes involved in soil nutrient cycle in a semiarid region of India. Results The results showed a significant reduction (P < 0.05) in soil carbon (SC), soil nitrogen (SN) content (~ 30–80%) and consequently the soil microbial biomass carbon (SMBC) (~ 70–80%), soil basal respiration (SBR), soil substrate-induced respiration (SSIR), and soil enzyme activities (β-glucosidase, acid phosphatase, and dehydrogenase) under cultivated sites in comparison with forest sites. Pearson’s correlation showed that a positive correlation of SC with SMBC, SBR, SSIR (P < 0.01), and enzymatic activities (i.e., β-glucosidase, dehydrogenase) (P < 0.05) may imply the critical role of SC in regulating microbial and enzymatic activity. Also, a positive correlation of soil moisture with urease activity (P < 0.01) was found suggesting it as a significant abiotic factor for soil biological functions. Additionally, based on the PCA analysis, we observed the clustering of SMBC/SC ratio and qCO2 nearby AF. Conclusion Our study suggests that soil microbial parameters (SMBC, SBR, SSIR, SMBC/SC, qCO2) and enzyme activity are key indicators of soil health and fertility. Land use/cover alters the SOM content and soil microbial functions. The management strategies focusing on the conservation of natural forest and minimizing the land disturbances will be effective in preventing soil carbon flux as CO2 and maintaining the SC stock.


2013 ◽  
Vol 368 (1619) ◽  
pp. 20120153 ◽  
Author(s):  
Marcia N. Macedo ◽  
Michael T. Coe ◽  
Ruth DeFries ◽  
Maria Uriarte ◽  
Paulo M. Brando ◽  
...  

Large-scale cattle and crop production are the primary drivers of deforestation in the Amazon today. Such land-use changes can degrade stream ecosystems by reducing connectivity, changing light and nutrient inputs, and altering the quantity and quality of streamwater. This study integrates field data from 12 catchments with satellite-derived information for the 176 000 km 2 upper Xingu watershed (Mato Grosso, Brazil). We quantify recent land-use transitions and evaluate the influence of land management on streamwater temperature, an important determinant of habitat quality in small streams. By 2010, over 40 per cent of catchments outside protected areas were dominated (greater than 60% of area) by agriculture, with an estimated 10 000 impoundments in the upper Xingu. Streams in pasture and soya bean watersheds were significantly warmer than those in forested watersheds, with average daily maxima over 4°C higher in pasture and 3°C higher in soya bean. The upstream density of impoundments and riparian forest cover accounted for 43 per cent of the variation in temperature. Scaling up, our model suggests that management practices associated with recent agricultural expansion may have already increased headwater stream temperatures across the Xingu. Although increased temperatures could negatively impact stream biota, conserving or restoring riparian buffers could reduce predicted warming by as much as fivefold.


2008 ◽  
Vol 19 (5) ◽  
pp. 516-529 ◽  
Author(s):  
R. E. Masto ◽  
P. K. Chhonkar ◽  
T. J. Purakayastha ◽  
A. K. Patra ◽  
D. Singh

2015 ◽  
Vol 37 (5) ◽  
pp. 497 ◽  
Author(s):  
Sofia Marinaro ◽  
Ricardo H. Grau

Increasing global food demand requires the exploration of agricultural production systems that minimise the conflict between food production and biodiversity conservation. Cattle ranching is a main land-use in tropical and sub-tropical South American semi-arid ecosystems, such as the Chaco eco-region of sub-tropical Argentina, one of the most active frontiers of land-use change. Despite open habits being a key component of the Chaco landscape, conservation studies and policies have focussed on forests. In this study, bird and mammal communities of three different open-canopy livestock-producing systems in the semi-arid Argentinian Chaco: natural grasslands, sown non-native pastures and silvopastoral systems are discussed. Diversity (Inverse Simpson index) and species composition (multivariate ordinations) were measured and species identified that characterise each system (indicator species). The three livestock systems did not significantly differ in terms of diversity but showed differences in the composition of bird communities. Natural grasslands had the highest number of bird and mammal indicator species (including Myrmecophaga tridactyla, a high conservation-value species). These results highlight natural grasslands as a landscape unit with a high conservation value and indicate that they should be explicitly targeted by conservation and land-use policies, particularly because they represent a small and rapidly decreasing proportion of the semi-arid Argentinian Chaco.


Author(s):  
S. A. Rahaman ◽  
S. Aruchamy ◽  
K. Balasubramani ◽  
R. Jegankumar

Nowadays land use/ land cover in mountain landscape is in critical condition; it leads to high risky and uncertain environments. These areas are facing multiple stresses including degradation of land resources; vagaries of climate and depletion of water resources continuously affect land use practices and livelihoods. To understand the Land use/Land cover (Lu/Lc) changes in a semi-arid mountain landscape, Kallar watershed of Bhavani basin, in southern India has been chosen. Most of the hilly part in the study area covers with forest, plantation, orchards and vegetables and which are highly affected by severe soil erosion, landslide, frequent rainfall failures and associated drought. The foothill regions are mainly utilized for agriculture practices; due to water scarcity and meagre income, the productive agriculture lands are converted into settlement plots and wasteland. Hence, land use/land cover change deduction; a stochastic processed based method is indispensable for future prediction. For identification of land use/land cover, and vegetation changes, Landsat TM, ETM (1995, 2005) and IRS P6- LISS IV (2015) images were used. Through CAMarkov chain analysis, Lu/Lc changes in past three decades (1995, 2005, and 2015) were identified and projected for (2020 and 2025); Normalized Difference Vegetation Index (NDVI) were used to find the vegetation changes. The result shows that, maximum changes occur in the plantation and slight changes found in forest cover in the hilly terrain. In foothill areas, agriculture lands were decreased while wastelands and settlement plots were increased. The outcome of the results helps to farmer and policy makers to draw optimal lands use planning and better management strategies for sustainable development of natural resources.


2021 ◽  
Vol 2 ◽  
Author(s):  
Nayani Ilangakoon ◽  
Nancy F. Glenn ◽  
Fabian D. Schneider ◽  
Hamid Dashti ◽  
Steven Hancock ◽  
...  

Assessing functional diversity and its abiotic controls at continuous spatial scales are crucial to understanding changes in ecosystem processes and services. Semi-arid ecosystems cover large portions of the global terrestrial surface and provide carbon cycling, habitat, and biodiversity, among other important ecosystem processes and services. Yet, the spatial trends and patterns of functional diversity in semi-arid ecosystems and their abiotic controls are unclear. The objectives of this study are two-fold. We evaluated the spatial pattern of functional diversity as estimated from small footprint airborne lidar (ALS) with respect to abiotic controls and fire in a semi-arid ecosystem. Secondly, we used our results to understand the capabilities of large footprint spaceborne lidar (GEDI) for future applications to semi-arid ecosystems. Overall, our findings revealed that functional diversity in this ecosystem is mainly governed by elevation, soil, and water availability. In burned areas, the ALS data show a trend of functional recovery with time since fire. With 16 months of data (April 2019-August 2020), GEDI predicted functional traits showed a moderate correlation (r = 41–61%) with the ALS predicted traits except for the plant area index (PAI) (r = 11%) of low height vegetation (&lt;5 m). We found that the number of GEDI footprints relative to the size of the fire-disturbed areas (=&lt; 2 km2) limited the ability to estimate the full effects of fire disturbance. However, the consistency of diversity trends between ALS and GEDI across our study area demonstrates GEDI’s potential of capturing functional diversity in similar semi-arid ecosystems. The capability of spaceborne lidar to map trends and patterns of functional diversity in this semi-arid ecosystem demonstrates its exciting potential to identify critical biophysical and ecological shifts. Furthermore, opportunities to fuse GEDI with complementary spaceborne data such as ICESat-2 or the upcoming NASA-ISRO Synthetic Aperture Radar (NISAR), and fine scale airborne data will allow us to fill gaps across space and time. For the first time, we have the potential to monitor carbon cycle dynamics, habitats and biodiversity across the globe in semi-arid ecosystems at fine vertical scales.


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