scholarly journals Short-Term Effects of Maize Rhizosphere and N-Fertilization on Stable Organic Matter in a Tropical Soil

2018 ◽  
Vol 11 (1) ◽  
pp. 418
Author(s):  
Rafael da Silva Teixeira ◽  
Rafael Silva Santos ◽  
Rodrigo Nogueira de Sousa ◽  
Ivan Francisco de Souza ◽  
Thalles Guimarães Reis ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Surface ◽  
N Fertilization ◽  
N Availability ◽  
N Addition ◽  
Short Term ◽  
Maize Rhizosphere ◽  
Stable Organic Matter ◽  
C Assimilation ◽  
Mass Balance Approach

The objective of this study was to investigate the effect of maize rhizosphere in the dynamics of soil organic matter (SOM) fractions (particulate organic matter—POM and mineral associated organic matter—MAOM) under different soil nitrogen (N) availability. The experiment was laid out as a factorial scheme 2 × 2: (i) without (-Plant) and with maize plant (+Plant); (ii) without (-N) and with N fertilization (+N) throughout 56 d under greenhouse conditions. Soil surface CO2-C efflux was monitored by static PVC chambers, and soil- and root-derived CO2-C efflux was determined using the mass-balance approach. In the absence of plants, N addition reduced total soil CO2-C efflux over the 56-d experiment and increased MAOM-C. This was followed by an increase of 366% in microbial biomass (MB-C), indicating a high C assimilation by soil microbes. In the presence of plants, there was evidence of positive rhizosphere priming effect (RPE) at 42-d after planting when N was applied. The new C input by rhizodeposition promoted an increase of 495% and 50% in MB-C under -N and +N addition, respectively. The short-term effect of maize rhizosphere appeared to preserve native SOM and allowed higher incorporation of microbial residues-derived C into the MAOM.

scholarly journals Nitrogen fertilization modifies organic transformations and coatings on soil biogeochemical interfaces through microbial polysaccharides synthesis

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Xizhi Huang ◽  
Georg Guggenberger ◽  
Yakov Kuzyakov ◽  
Olga Shibistova ◽  
Tida Ge ◽  
...  
Keyword(s):  
Organic Matter ◽  
Photoelectron Spectroscopy ◽  
Chemical Structure ◽  
N Fertilization ◽  
N Availability ◽  
Organic Transformations ◽  
X Ray ◽  
Mineral Associations ◽  
Soil Pores ◽  
Insight Into

AbstractThe soil-water interfaces (SWI) in soil pores are hotspots for organic matter (OM) transformation. However, due to the heterogeneous and opaque nature of soil microenvironment, direct and continuous tracing of interfacial reactions, such as OM transformations and formation of organo-mineral associations, are rare. To investigate these processes, a new soil microarray technology (SoilChips) was developed and used. Homogeneous 800-μm-diameter SoilChips were constructed by depositing a dispersed Oxisol A horizon suspension on a patterned glass. Dissolved organic matter from the original soil was added on the SoilChips to mimic SWI processes. The effects of ammonium fertilization (90 mg N kg−1 soil) on chemical composition of SWIs were evaluated via X-ray photoelectron spectroscopy. Over 21 days, ammonium addition increased OM coatings at SWIs and modified the OM chemical structure with more alcoholic- and carboxylic-C compared to the unfertilized control. Molecular modeling of OM composition at SWIs showed that N fertilization mainly facilitated the microbial production of glucans. We demonstrated that N availability modifies the specific OM molecular processing and its immobilization on SWIs, thereby providing a direct insight into biogeochemical transformation of OM at micro-scale.

scholarly journals How Soil Ecological Intensification by Means of Cover Crops Affects Nitrogen Use Efficiency in Pepper Cultivation

Agriculture ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 145 ◽  
Author(s):  
Roberto Mancinelli ◽  
Rosario Muleo ◽  
Sara Marinari ◽  
Emanuele Radicetti
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Cover Crops ◽  
N Uptake ◽  
N Fertilization ◽  
Fruit Yield ◽  
Soil Tillage ◽  
N Availability ◽  
Common Vetch ◽  
Ecological Intensification

Ecological intensification, based on agricultural practices that promote ecosystem services, has been recently proposed to match crop yield and environmental concerns. Two-year experiments were conducted in a Mediterranean environment. The treatments were: (i) four intensification levels (common vetch (CV), ryegrass (RG), bare soil without Nitrogen (N) fertilization (Control-N0) and with 100 kg ha−1 of N fertilization (Control-N100) applied during pepper cultivation), and(ii) two soil tillage [soil tillage at 15 cm and 30 cm of soil depth (ST-15 and ST-30, respectively)]. The field experiment was disposed in a randomized block design with three replications. Cover crop, soil samples, and pepper samples were collected for analysis. Soil available nitrogen increased after soil tillage, especially in CV, which showed the highest fruit yield. The reduced soil N availability in RG decreased fruit yield and N uptake. The agro-physiological efficiency of pepper was similar in common vetch and Control-N100, while it was low in ryegrass. However, the adoption of RG increased the soil organic matter more than both control treatments, which, in turn, caused a depletion of soil organic matter. Moreover, reduced tillage practices for green manuring that both cover crops arepreferable to reduce external inputs in terms of fuel saving and farming operations.

scholarly journals In-season Soil Nitrate Testing as a Guide to Nitrogen Management for Annual Crops

2002 ◽  
Vol 12 (4) ◽  
pp. 706-710 ◽  
Author(s):  
J.R. Heckman
Keyword(s):  
Organic Matter ◽  
Organic Matter Content ◽  
N Fertilization ◽  
Matter Content ◽  
N Fertilizer ◽  
Growth Stages ◽  
N Availability ◽  
Soil Nitrate ◽  
Annual Crops ◽  
Crop Growth Stages

In-season soil nitrate testing is most useful when there is reason to believe, based on field history, that N availability may be adequate. These reasons may include soil organic matter content, applied manure, compost, legumes in the rotation, or residual N fertilizer. Soil nitrate testing is not helpful when crops are grown on sandy, low organic matter content soils that are known from experience to be N deficient. Soil nitrate testing is useful for annual crops such as vegetables or corn for which supplemental N fertilization is a concern. Soil nitrate tests must be performed at critical crop growth stages, and the results must be obtained rapidly to make important decisions about the need for N fertilization. Soil nitrate-N (NO3-N) concentrations in the range of 25 to 30 mg·kg-1 (ppm) indicate sufficiency for most crops, but N fertilizer practice should be adjusted based on local extension recommendations.

scholarly journals Fungi Outcompete Bacteria for Straw and Soil Organic Matter Mineralization

2020 ◽  
Author(s):  
Dan Xiao ◽  
Xunyang He ◽  
Guihong Wang ◽  
Xuechi Xu ◽  
Yajun Hu ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Compounds ◽  
Priming Effect ◽  
N Fertilization ◽  
N Addition ◽  
Straw Decomposition ◽  
Organic Matter Mineralization ◽  
Fungal Abundance ◽  
N Additions

Abstract Background: Understanding the effects of straw return and nitrogen (N) fertilization on soil organic matter (SOM) transformations will help to mitigate climate change and maintain crop production and soil function. A 100-day soil incubation experiment was conducted using a two-factorial design with three fertilization levels and four 13C-labeled maize straw and N addition treatments. The competition and contributions of the bacterial and fungal communities were assessed with relation to straw mineralization.Results: Mineral fertilizer alone and with straw increased straw decomposition by 59% and 55% and SOM mineralization by 27% and 37%, respectively, compared with the unfertilized soil, due to raised β-N-acetylglucosaminidase and cellobiohyrolase activities. Conversely, priming effect was decreased by 59% and 39%, respectively. Priming effect increased with higher N additions and decreased with lower N additions because an improved C:N ratio for microorganisms. Straw additions increased bacterial and fungal abundance by 1.4 and 4.9 times. Fungal diversity decreased with N fertilization because lower C:N ratios increased the bacterial competition. Bacterial abundance decreased but diversity increased with the duration of incubation as bacteria preferred to utilize labile organic compounds abundant in the initial stages. Along with labile organic compounds depletion, fungal abundance was increased. Firmicutes, Actinobacteria, and Proteobacteria bacterial as well as Ascomycota, Basidiomycota, and Mucoromycota fungi dominated straw and SOM decomposition. Firmicutes were mostly involved in straw and SOM mineralization on day one because of their capacity for labile compound decomposition. Integrated co-occurrence networks revealed that fungal taxa had a stronger correlation with straw decomposition than bacterial groups. Straw and N addition increased the number of negative edges among bacterial taxa but these decreased within fungal groups when compared to trials without straw and N. The ratio for pairwise correlations between abundant fungal taxa, straw, and SOM mineralization (29.9%) was greater than with bacteria (1.2%).Conclusions: Straw with low N additions increased soil C sequestration by decreasing priming effect. Straw alone and with N addition decreased competition for C and N among fungal groups, but increased competition within bacterial taxa. Fungi outcompete bacteria for straw and soil organic matter mineralization in long-term fertilized soils.

scholarly journals Influence of summer crop residues on 15N present in organic matter fractions under two lowland soils

2019 ◽  
Vol 49 (4) ◽  
Author(s):  
Carolina Schultz Pollet ◽  
Leandro Souza da Silva ◽  
Bruno Chaves ◽  
Lethícia Rosa Neto ◽  
Mariana Ferneda Dossin ◽  
...  
Keyword(s):  
Organic Matter ◽  
Crop Residues ◽  
Aerobic Condition ◽  
N Fertilization ◽  
Plant Residues ◽  
N Availability ◽  
N Losses ◽  
New Crops ◽  
Flooded Rice ◽  
Organic Matter Fractions

ABSTRACT: The state of Rio Grande do Sul has about 20% of the total area as lowland soils, suitable for flooded rice (Oryza sativa). In order to mitigate damage caused by rice monoculture, new crops such as sorghum (Sorghum bicolor) and soybean (Glycine max) have been cultivated in these areas. With different qualities of crop residues, it is expected a change in soil organic matter (SOM) dynamics and consequently, nitrogen (N) availability. The objective of this study was to evaluate the influence of rice, soybean and sorghum crop residues on the N present in physical fractions of SOM of two lowland soils, using labeled 15N technique, under incubation for 180 days in aerobic condition and more 180 days in anaerobic condition. At 30, 180 and 360 days of incubation the remaining N of the plant residues and N destination from the residues in both soils were quantified in the physical fractions of SOM >250 μm, 250-53 μm and <53 μm. The soil with higher amount of clay+silt received a larger quantity of 15N from residues, while flooding of the soil after 180 days caused a loss of N added to the soil by the soybean and sorghum residues. In general, larger amounts of 15N were reported in the fraction <53 μm, associated with clay minerals, throughout the incubation period. These N losses should be considered in N fertilization for the following crops in rotation with flooded rice.

Photosynthetic responses of Coffea arabica leaves to a short-term high light exposure in relation to N availability

1997 ◽  
Vol 101 (1) ◽  
pp. 229-239 ◽  
Author(s):  
Jose C. Ramalho ◽  
Thos L. Pons ◽  
Henri W. Groeneveld ◽  
M. Antonieta Nunes
Keyword(s):  
Coffea Arabica ◽  
Light Exposure ◽  
High Light ◽  
N Availability ◽  
Short Term ◽  
Photosynthetic Responses

scholarly journals Effect of Digestate and Straw Combined Application on Maintaining Rice Production and Paddy Environment

2021 ◽  
Vol 18 (11) ◽  
pp. 5714
Author(s):  
Xue Hu ◽  
Hongyi Liu ◽  
Chengyu Xu ◽  
Xiaomin Huang ◽  
Min Jiang ◽  
...  
Keyword(s):  
Organic Matter ◽  
Surface Water ◽  
Soil Organic Matter ◽  
Paddy Soil ◽  
Rice Yield ◽  
Soil Surface ◽  
Rice Production ◽  
Straw Decomposition ◽  
Rice Grains ◽  
Combined Application

Few studies have focused on the combined application of digestate and straw and its feasibility in rice production. Therefore, we conducted a two-year field experiment, including six treatments: without nutrients and straw (Control), digestate (D), digestate + fertilizer (DF), digestate + straw (DS), digestate + fertilizer + straw (DFS) and conventional fertilizer + straw (CS), to clarify the responses of rice growth and paddy soil nutrients to different straw and fertilizer combinations. Our results showed that digestate and straw combined application (i.e., treatment DFS) increased rice yield by 2.71 t ha−1 compared with the Control, and digestate combined with straw addition could distribute more nitrogen (N) to rice grains. Our results also showed that the straw decomposition rate at 0 cm depth under DS was 5% to 102% higher than that under CS. Activities of catalase, urease, sucrase and phosphatase at maturity under DS were all higher than that under both Control and CS. In addition, soil organic matter (SOM) and total nitrogen (TN) under DS and DFS were 20~26% and 11~12% higher than that under B and DF respectively, suggesting straw addition could benefit paddy soil quality. Moreover, coupling straw and digestate would contribute to decrease the N content in soil surface water. Overall, our results demonstrated that digestate and straw combined application could maintain rice production and have potential positive paddy environmental effects.

scholarly journals Some Peculiarities of Arable Soil Organic Matter Detection Using Optical Remote Sensing Data

2021 ◽  
Vol 13 (12) ◽  
pp. 2313
Author(s):  
Elena Prudnikova ◽  
Igor Savin
Keyword(s):  
Remote Sensing ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Spectral Reflectance ◽  
Remote Sensing Data ◽  
Soil Surface ◽  
Optical Remote Sensing ◽  
Test Field ◽  
Sensing Data ◽  
Sentinel 2

Optical remote sensing only provides information about the very thin surface layer of soil. Rainfall splash alters soil surface properties and its spectral reflectance. We analyzed the impact of rainfall on the success of soil organic matter (SOM) content (% by mass) detection and mapping based on optical remote sensing data. The subject of the study was the arable soils of a test field located in the Tula region (Russia), their spectral reflectance, and Sentinel-2 data. Our research demonstrated that rainfall negatively affects the accuracy of SOM predictions based on Sentinel-2 data. Depending on the average precipitation per day, the R2cv of models varied from 0.67 to 0.72, RMSEcv from 0.64 to 1.1% and RPIQ from 1.4 to 2.3. The incorporation of information on the soil surface state in the model resulted in an increase in accuracy of SOM content detection based on Sentinel-2 data: the R2cv of the models increased up to 0.78 to 0.84, the RMSEcv decreased to 0.61 to 0.71%, and the RPIQ increased to 2.1 to 2.4. Further studies are necessary to identify how the SOM content and composition of the soil surface change under the influence of rainfall for other soils, and to determine the relationships between rainfall-induced SOM changes and soil surface spectral reflectance.

scholarly journals Short-Term N-Fertilization Differently Affects the Leaf and Leaf Litter Chemistry of the Dominant Species in a Mediterranean Forest under Drought Conditions

Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 605
Author(s):  
Helena Vallicrosa ◽  
Jordi Sardans ◽  
Romà Ogaya ◽  
Pere Roc Fernández ◽  
Josep Peñuelas
Keyword(s):  
Leaf Litter ◽  
Dominant Species ◽  
Isotope Analysis ◽  
Mediterranean Ecosystems ◽  
N Fertilization ◽  
N Deposition ◽  
Mediterranean Forest ◽  
Short Term ◽  
Species Response ◽  
Drought Conditions

Nitrogen (N) deposition is a key driver of global change with significant effects on carbon (C) cycling, species fitness, and diversity; however, its effects on Mediterranean ecosystems are unclear. Here, we simulated N deposition in an N-fertilization experiment with 15N-labeled fertilizer in a montane evergreen Mediterranean holm oak forest, in central Catalonia, to quantify short-term impacts on leaf, leaf litter elemental composition, and resorption efficiency in three dominant species (Quercus ilex, Phillyrea latifolia, and Arbutus unedo). We found that even under drought conditions, 15N isotope analysis of leaf and leaf litter showed a rapid uptake of the added N, suggesting an N deficient ecosystem. Species responses to N fertilization varied, where A. unedo was unaffected and the responses in P. latifolia and Q. ilex were similar, albeit with contrasting magnitude. P. latifolia benefited the most from N fertilization under drought conditions of the experimental year. These differences in species response could indicate impacts on species fitness, competition, and abundance under increased N loads in Mediterranean forest ecosystems. Further research is needed to disentangle interactions between long-term N deposition and the drought predicted under future climate scenarios in Mediterranean ecosystems.

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