scholarly journals Multiple factors drive the abundance and diversity of the diazotrophic community in typical farmland soils of China

2019 ◽  
Vol 95 (8) ◽  
Author(s):  
Li-Li Han ◽  
Qing Wang ◽  
Ju-Pei Shen ◽  
Hong J Di ◽  
Jun-Tao Wang ◽  
...  

ABSTRACT Biological nitrogen fixation plays an important role in nitrogen cycling by transferring atmospheric N2 to plant-available N in the soil. However, the diazotrophic activity and distribution in different types of soils remain to be further explored. In this study, 152 upland soils were sampled to examine the diazotrophic abundance, nitrogenase activity, diversity and community composition by quantitative polymerase chain reaction, acetylene reduction assay and the MiSeq sequencing of nifH genes, respectively. The results showed that diazotrophic abundance and nitrogenase activity varied among the three soil types. The diazotrophic community was mainly dominated by Bradyrhizobium, Azospirillum, Myxobacter, Desulfovibrio and Methylobacterium. The symbiotic diazotroph Bradyrhizobium was widely distributed among soils, while the distribution of free-living diazotrophs showed large variation and was greatly affected by multiple factors. Crop type and soil properties directly affected the diazotrophic ɑ-diversity, while soil properties, climatic factors and spatial distance together influenced the diazotrophic community. Network structures were completely different among all three types of soils, with most complex interactions observed in the Red soil. These findings suggest that diazotrophs have various activities and distributions in the three soil types, which played different roles in nitrogen input in agricultural soil in China, being driven by multiple environmental factors.

2021 ◽  
Author(s):  
Sneha Gowda ◽  
Karivaradharajan Swarnalakshmi ◽  
Meenakshi Sharma ◽  
Kedharnath Reddy ◽  
Arpan Bhoumik ◽  
...  

Abstract Rhizosphere microbial communities are dynamic and play a crucial role in diverse biochemical processes and nutrient cycling. Soil type and cultivar modulate the compositionof rhizosphere microbial communities. Changes in the community composition significantly alter microbial function and ecological process. We examined the influence of soil type on eubacterial and diazotrophic community abundance and microbial metabolic potential in chickpea (cv. BG 372 and cv. BG 256) rhizosphere. The total eubacterial and diazotrophic community as estimated through 16S rDNA and nifH gene copy numbers using qPCR showed the soil type influence with clear rhizosphere effect on gene abundance. PLFA study has shown the variation in microbial community structure with different soil types. Differential influence of soil types and cultivar on the ratio of Gram positive to Gram negative bacteria was observed with most rhizosphere soils corresponding to higher ratios than bulk soil. The rhizosphere microbial activities (urease, dehydrogenase, alkaline phosphatase and beta-glucosidase) were also assessed as an indicator of microbial metabolic diversity. Principal component analysis and K-means non-hierarchical cluster mapping grouped soils into three categories, each having different soil enzyme activity or edaphic drivers. Soil type and cultivar influence on average substrate utilization pattern analyzed through community level physiological profiling (CLPP) was found to be higher for rhizosphere soils than bulk soils. The soil nutrient studies revealed that both soil type and cultivar influenced the available N, P, K and organic carbon content of rhizosphere soil. Our study signifies that soil type and cultivarjointly influenced soil microbial community abundance and their metabolic potential.


2018 ◽  
Vol 10 (10) ◽  
pp. 3825 ◽  
Author(s):  
Jianli Liao ◽  
Yun Liang ◽  
Danfeng Huang

Agricultural practices have significant impacts on soil properties and microbial communities; however, little is known about their responses to open field and plastic tunnels under organic and conventional farming. We therefore investigated the responses of soil chemical variables and microbial communities to different agricultural management and cultivation types, including organic management in open field (OF), organic management in plastic tunnels (OP), conventional management in open field (CF) and conventional management in plastic tunnels (CP), by using a pyrosequencing approach of 16S rRNA gene amplicon. Both factors had significant influences on the soil properties and microbial communities. Organic farming increased the nutrient-related soil variables compared to conventional farming regardless of cultivation type, especially for the available N and P, which were increased by 137% and 711%, respectively, in OP compared to CP. Additionally, OP had the highest microbial abundance and diversity among treatments, whereas no difference was found between OF, CF and CP. Furthermore, OP possessed diverse differential bacteria which were mainly related to the organic material turnover (e.g., Roseiflexus, Planctomyces and Butyrivibrio) and plant growth promotion (e.g., Nostoc, Glycomyces and Bacillus). Redundancy analysis (RDA) showed that pH, electrical conductivity (EC), nutrient levels (e.g., available N and available P) and total Zn content were significantly correlated to the structure of the microbial community. Overall, our results showed that the long-term organic farming with high fertilizer input increased soil nutrient levels and microbial abundance and diversity under plastic-tunnel condition compared to other cultivation systems.


HortScience ◽  
2013 ◽  
Vol 48 (5) ◽  
pp. 625-632 ◽  
Author(s):  
Bryant C. Scharenbroch

Aerated compost teas (ACTs) are applied to soils with the intent of improving microbial properties and nutrient availability and stimulating plant growth. Anecdotal accounts of ACT for these purposes far outnumber controlled, replicated, and peer-viewed experiments that have examined the impacts of ACT on soil properties and plant growth responses. This research assessed the impacts of four rates of ACT compared with water on containerized Acer saccharum and Quercus macrocarpa saplings growing in loam, compacted loam, and sandy soils. No significant differences were found comparing water with ACT applied at rates of 2, 4, and 40 kL ACT/ha for any of the six tree responses and 21 soil responses. Microbial biomass nitrogen (N) and potassium (K) increased, and available N decreased, in soils treated with ACT at 400 kL·ha−1 compared with water. Shoot, root, total biomass, and the root/shoot ratio were significantly greater for Quercus macrocarpa trees growing in compact loam with the 400 kL ACT/ha treatment compared with water, but significant differences were not detected for this application rate compared with water in the other soil types and in no instances with Acer saccharum saplings. These results provide some support for claims of ACT being able to increase soil microbial biomass and K, but provide minimal support for ACT being able to increase tree growth across multiple species in a variety of soil types. An application rate of 400 kL ACT/ha may be attainable for trees in containers with limited soil volumes, but this application rate is likely cost-prohibitive, and not practical, in the landscape. At this application rate, ≈1000 L of ACT would be required to treat a typical, and relatively small, critical root zone of 25 m2.


Agriculture ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 171
Author(s):  
Gaurav Mishra ◽  
Rosa Francaviglia

Northeast (NE) India is a typical tropical ecosystem with a luxuriant forest vegetation cover, but nowadays forests are under stress due to exploitation and land use changes, which are known to affect soil health and productivity. However, due to a scarcity of data, the influence of land uses and altitude on soil properties of this peculiar ecosystem is poorly quantified. This study presents the changes in soil properties in two districts of Nagaland (Mon and Zunheboto) in relation to land uses (forest, plantation, jhum and fallow jhum), altitude (<500 m, 500–1000 m, >1000 m) and soil texture (coarse, medium, fine). For this, a random soil sampling was performed in both the districts. Results indicated that soil organic carbon (SOC) stocks and available potassium (K) were significantly influenced by land uses in the Mon district, while in Zunheboto a significant difference was observed in available phosphorus (P) content. SOC stocks showed an increasing trend with elevation in both districts. The influence of altitude on P was significant and the maximum concentration was at lower elevations (<500 m). In Mon, soil texture significantly affected SOC stocks and the available N and P content. The variability in soil properties due to land uses, altitudinal gradients and textural classes can be better managed with the help of management options, which are still needed for this ecosystem.


2019 ◽  
pp. 1-12
Author(s):  
Mohamed I. Mohaseb ◽  
Mona H. M. Kenawy ◽  
Khaled A. H. Shaban

A field experiment (randomized complete blocks with three replicates) was conducted during two successive summer seasons of 2016 and 2017 at Sahl El-Houssinia Agriculture Research Station in El-Shakia Governorate, Egypt. Its lies between 32˚00/00 to 32˚15/00/ N latitude and 30˚50 / 00// to 31˚15 00// E longitude. The combined effect of bio-fertilizers inoculated with Rhizobium radiobacter sp strain (salt tolerant PGPR); Bacillus megatherium (dissolving phosphate) and Bacillus circulans (enhancing potassium availability) and yeast strains (Saccharomyces cerevisiae) combined with different rates of N, P and K fertilizers (50, 75 and 100%) was evaluated on some soil properties, nutrient content in rice plants, and rice productivity in a reclaimed saline soil. From the crop field of the Agricultural Research Institute (ARC), Egypt, 101 grain kernels from rice (Oryza sativa) var. Sakha were selected.   The results indicated that soil pH and EC were decreased in soil treated with bio-fertilizers combined with different rates of mineral fertilizers in comparison with soil treated with yeast and control. Available N, P, K, Fe, Mn and Zn in the soil increased with the use of bio-fertilizers. Application of mineral fertilizers (N, P and K) alone or combined with bio-fertilizers (bacteria and yeast) resulted in increased yield grains and straw of rice plant. Macro- and micronutrients concentrations and uptake in grain and straw of rice plants increased in soil treated with bacteria + 75% N+P+K fertilizers compared with other treatments.                          


Soil Research ◽  
2019 ◽  
Vol 57 (7) ◽  
pp. 738 ◽  
Author(s):  
D. E. Allen ◽  
P. M. Bloesch ◽  
T. G. Orton ◽  
B. L. Schroeder ◽  
D. M. Skocaj ◽  
...  

We explored soil properties as indices of mineralisable nitrogen (N) in sugarcane soils and whether we could increase the accuracy of predicting N mineralisation during laboratory incubations. Utilising historical data in combination with samples collected during 2016, we: (i) measured mineralised N over the course of short-term (14 days) and long-term (301 days) laboratory incubations; (ii) compared models representing mineralisation; then (iii) related model parameters to measured soil properties. We found measures representing the labile organic N pool (Hydrolysable NaOH organic N; amino sugar Illinois soil N test) best related to short-term mineralised N (R2 of 0.50–0.57, P &lt; 0.001), while measures of CO2 production (3, 7, 10 and 14 days) best related to longer-term mineralised N (R2 of 0.75–0.84, P &lt; 0.001). Indices were brought together to model the active and slow pools of a two-pool mineralisation model in the statistical framework of a mixed-effects model. Of the models that relied on measurement of one soil property, cumulative CO2 production (7 days) performed the best when considering all soil types; in a cross-validation test, this model gave an external R2 of 0.77 for prediction of the 301-day mineralised N. Since the mixed-effects model accounts for the various sources of uncertainty, we suggest this approach as a framework for prediction of in-field available N, with further measurement of long-term mineralised N in other soils to strengthen predictive certainty of these soil indices.


2004 ◽  
Vol 5 (5) ◽  
pp. 521-536 ◽  
Author(s):  
H. Bourennane ◽  
B. Nicoullaud ◽  
A. Couturier ◽  
D. King

2010 ◽  
Vol 14 (6) ◽  
pp. 979-990 ◽  
Author(s):  
Y. Y. Liu ◽  
J. P. Evans ◽  
M. F. McCabe ◽  
R. A. M. de Jeu ◽  
A. I. J. M. van Dijk ◽  
...  

Abstract. Vertisols are clay soils that are common in the monsoonal and dry warm regions of the world. One of the characteristics of these soil types is to form deep cracks during periods of extended dry, resulting in significant variation of the soil and hydrologic properties. Understanding the influence of these varying soil properties on the hydrological behavior of the system is of considerable interest, particularly in the retrieval or simulation of soil moisture. In this study we compare surface soil moisture (θ in m3 m−3) retrievals from AMSR-E using the VUA-NASA (Vrije Universiteit Amsterdam in collaboration with NASA) algorithm with simulations from the Community Land Model (CLM) over vertisol regions of mainland Australia. For the three-year period examined here (2003–2005), both products display reasonable agreement during wet periods. During dry periods however, AMSR-E retrieved near surface soil moisture falls below values for surrounding non-clay soils, while CLM simulations are higher. CLM θ are also higher than AMSR-E and their difference keeps increasing throughout these dry periods. To identify the possible causes for these discrepancies, the impacts of land use, topography, soil properties and surface temperature used in the AMSR-E algorithm, together with vegetation density and rainfall patterns, were investigated. However these do not explain the observed θ responses. Qualitative analysis of the retrieval model suggests that the most likely reason for the low AMSR-E θ is the increase in soil porosity and surface roughness resulting from cracking of the soil. To quantitatively identify the role of each factor, more in situ measurements of soil properties that can represent different stages of cracking need to be collected. CLM does not simulate the behavior of cracking soils, including the additional loss of moisture from the soil continuum during drying and the infiltration into cracks during rainfall events, which results in overestimated θ when cracks are present. The hydrological influence of soil physical changes are expected to propagate through the modeled system, such that modeled infiltration, evaporation, surface temperature, surface runoff and groundwater recharge should be interpreted with caution over these soil types when cracks might be present. Introducing temporally dynamic roughness and soil porosity into retrieval algorithms and adding a "cracking clay" module into models are expected to improve the representation of vertisol hydrology.


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