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Soil fertility

Jennifer E Schmidt, Dylan J Weese, Jennifer A Lau
Leguminous crops, like soybeans, often rely on biologically fixed nitrogen via their symbiosis with rhizobia rather than synthetic nitrogen inputs. However, agricultural management practices may influence the effectiveness of biological nitrogen fixation. While the ecological effects of agricultural management on rhizobia have received some attention, the evolutionary effects have been neglected in comparison. Resource mutualism theory predicts that evolutionary effects are likely, however. Both fertilization and tillage are predicted to cause the evolution of rhizobia that provide fewer growth benefits to plant hosts and fix less nitrogen...
September 16, 2017: Ecological Applications: a Publication of the Ecological Society of America
Karla Vilaça Martins, Durval Dourado-Neto, Klaus Reichardt, Quirijn de Jong van Lier, José Laércio Favarin, Felipe Fadel Sartori, Guilherme Felisberto, Simone da Costa Mello
The improvement of agronomic practices and the use of high technology in field crops contributes for significant increases in maize productivity, and may have altered the dynamics of nutrient uptake and partition by the plant. Official recommendations for fertilizer applications to the maize crop in Brazil and in many countries are based on critical soil nutrient contents and are relatively outdated. Since the factors that interact in an agricultural production system are dynamic, mathematical modeling of the growth process turns out to be an appropriate tool for these studies...
2017: Frontiers in Plant Science
Emmanuel Alepu Odey, Zifu Li, Xiaoqin Zhou, Loissi Kalakodio
The problems posed by fecal sludge (FS) are multidimensional because most cities rapidly urbanize, which results in the increase in population, urban settlement, and waste generation. Issues concerning health and waste treatment have continued to create alarming situations. These issues had indeed interfered with the proper steps in managing FS, which contaminates the environment. FS can be used in agriculture as fertilizer because it is an excellent source of nutrients. The recent decline in crop production due to loss of soil organic component, erosion, and nutrient runoff has generated interest in the recycling of FS into soil nutrients through stabilization and composting...
September 16, 2017: Environmental Science and Pollution Research International
Jianmin Qiao, Deyong Yu, Jianguo Wu
Agricultural ecosystem management needs to ensure food production and minimize soil erosion and nitrogen (N) leaching under climate change and increasingly intensive human activity. Thus, the mechanisms through which climatic and management factors affect crop production, soil erosion, and N leaching must be understood in order to ensure food security and sustainable agricultural development. In this study, we adopted the GIS-based Environmental Policy Integrated Climate (EPIC) model to simulate crop production, soil erosion, and N leaching, and used a partial least squares regression model to evaluate the contributions of climate variables (solar radiation, precipitation, wind speed, relative humidity, and maximum and minimum temperature) and management factors (irrigation, fertilization, and crop cultivation area) on agricultural ecosystem services (AES) in the agro-pastoral transitional zone (APTZ) of northern China...
September 13, 2017: Science of the Total Environment
Michael J Mitsch, George C diCenzo, Alison Cowie, Turlough M Finan
Symbiotic nitrogen fixation (SNF) is an energetically expensive process performed by bacteria during endosymbiotic relationships with plants. The bacteria require the plant to provide a carbon source for generation of reductant to power SNF. While C4-dicarboxylates (succinate, fumarate, malate) appear to be the primary, if not sole, carbon source provided to the bacteria, the contribution of each C4-dicarboxylate is not known. We address this issue using a genetic and systems-level analyses. Expression of a malate specific transporter (MaeP) in Sinorhizobium meliloti Rm1021 dct mutants unable to transport C4-dicarboxylates resulted in malate import rates up to 30% that of wild type...
September 15, 2017: Applied and Environmental Microbiology
Claudete G Chiochetta, Hela Toumi, Renata F S Böhm, Fernanda Engel, Gabriel Poyer-Radetski, Leonardo R Rörig, Fabrizio Adani, Claudemir M Radetski
Coal mining-related activities result in a degraded landscape and sites associated with large amounts of dumped waste material. The arid soil resulting from acid mine drainage affects terrestrial and aquatic ecosystems, and thus, site remediation programs must be implemented to mitigate this sequential deleterious processes. A low-cost alternative material to counterbalance the affected physico-chemical-microbiological aspects of the degraded soil is the amendment with low contaminated and stabilized industrial organic sludge...
September 14, 2017: Environmental Science and Pollution Research International
E D'Angelo
Tetracycline (TET) is commonly used to treat bacterial diseases in humans and chickens (Gallus gallus domesticus), is largely excreted, and is found at elevated concentrations in treated sewage sludge (biosolids) and poultry litter (excrement plus bedding materials). Routine application of these nutrient-and carbon-enriched materials to soils improves fertility and other characteristics, but the presence of antibiotics (and other pharmaceuticals) in amendments raises questions about potential adverse effects on biota and development of antibiotic resistance in the environment...
September 8, 2017: Chemosphere
Javier Calvo-Fernández, Ángela Taboada, Andreas Fichtner, Werner Härdtle, Leonor Calvo, Elena Marcos
Ecosystems adapted to low nitrogen (N) conditions such as Calluna-heathlands are especially sensitive to enhanced atmospheric N deposition that affects many aspects of ecosystem functioning like nutrient cycling, soil properties and plant-microbial-enzyme relationships. We investigated the effects of five levels of experimentally-simulated N deposition rates (i.e., N fertilization treatments: 0, 10, 20 and 50kgNha(-1)yr(-1) for 3years, and 56kgNha(-1)yr(-1) for 10years) on: plant, litter, microbial biomass and soil nutrient contents, soil extracellular enzymatic activities, and plant root ericoid mycorrhizal colonization...
September 11, 2017: Science of the Total Environment
Christian Dimkpa, Jason C White, Wade H Elmer, Jorge L Gardea-Torresdey
This study evaluated the effects of ZnO nanoparticles (NP) or Zn salt amendment on sorghum yield, macronutrient use efficiency, and grain Zn-enrichment. Amendments were through soil and foliar pathways, under ''low'' and ''high'' NPK. In soil and foliar amendments, grain yield was significantly (p≤0.05) increased by both Zn types, albeit insignificantly with soil-applied Zn at low NPK. Across NPK levels and Zn exposure pathways, both Zn types increased N and P accumulation relative to control plants. Compared to N and K, both Zn types had a mixed effect on P accumulation, depending on NPK level and Zn exposure pathway, and permitted greater soil P retention...
September 14, 2017: Journal of Agricultural and Food Chemistry
Santosh Kumar, Stephen Spiro
The genome of the denitrifying bacterium Paracoccus denitrificans predicts the expression of a small heme-containing nitric oxide (NO) binding protein, H-NOX. The genome organization and prior work in other bacteria suggest that H-NOX interacts with a diguanylate cyclase that cyclizes GTP to make cyclic di-GMP (cdGMP). Since cdGMP frequently regulates attached growth as a biofilm, we first established conditions for biofilm development by P. denitrificans. We found that adhesion to a polystyrene surface is strongly stimulated by the addition of 10 mM Ca(2+) to rich media...
September 2017: MSphere
Wentao Luo, Mai-He Li, Jordi Sardans, Xiao-Tao Lü, Chao Wang, Josep Peñuelas, Zhengwen Wang, Xing-Guo Han, Yong Jiang
Plant carbon (C) and nitrogen (N) stoichiometry play an important role in the maintenance of ecosystem structure and function. To decipher the influence of changing environment on plant C and N stoichiometry at the subcontinental scale, we studied the shoot and root C and N stoichiometry in two widely distributed and dominant genera along a 2,200-km climatic gradient in China's grasslands. Relationships between C and N concentrations and soil climatic variables factors were studied. In contrast to previous theory, plant C concentration and C:N ratios in both shoots and roots increased with increasing soil fertility and decreased with increasing aridity...
September 2017: Ecology and Evolution
Cong Xu, Xiao Han, Roland Bol, Pete Smith, Wenliang Wu, Fanqiao Meng
Requirements for mitigation of the continued increase in greenhouse gas (GHG) emissions are much needed for the North China Plain (NCP). We conducted a meta-analysis of 76 published studies of 24 sites in the NCP to examine the effects of natural conditions and farming practices on GHG emissions in that region. We found that N2O was the main component of the area-scaled total GHG balance, and the CH 4 contribution was <5%. Precipitation, temperature, soil pH, and texture had no significant impacts on annual GHG emissions, because of limited variation of these factors in the NCP...
September 2017: Ecology and Evolution
Lidia K Trocha, Bartosz Bulaj, Paulina Kutczynska, Joanna Mucha, Pawel Rutkowski, Marcin Zadworny
In general, respiration (RS) is highly correlated with nitrogen concentration (N) in plant organs, including roots, which exhibit a positive N-RS relationship. Less is known, however, about the relationship between N and RS in roots of different branch orders within an individual tree along a vertical soil profile; this is especially true in trees with contrasting life strategies, such as pioneer Scots pine (Pinus sylvestris L.) vs mid-successional sessile oak (Quercus petraea Liebl.). In the present research, the impact of root branch order, as represented by those with absorptive vs transporting ability, and soil genetic horizon on root N, RS and the N-RS relationship was examined...
August 1, 2017: Tree Physiology
Niloofar Paknezhad, Farbod Haji Mazdarani, Morteza Hessari, Iraj Mobedi, Faezeh Najafi, Negar Bizhani, Mahsasadat Makki, Gholamreza Hassanpour, Gholamreza Mowlavi
BACKGROUND: Paleoparasitology reveals the status of parasitic infections in humans and animals in ancient times based on parasitic particles found in biological remains from archaeological excavations. This line of research emerged in Iran in 2013. OBJECTIVE: The identification of parasites from Neolithic times is an attractive subject that shows the oldest origins of parasitic infections in a given geographical region. From an archaeological point of view, this archaeological site is well-known for animal domestication and agriculture in ancient Iran...
September 2017: Memórias do Instituto Oswaldo Cruz
Zhisheng Yao, Xunhua Zheng, Yanan Zhang, Chunyan Liu, Rui Wang, Shan Lin, Qiang Zuo, Klaus Butterbach-Bahl
Ground cover rice production system (GCRPS), i.e., paddy soils being covered by thin plastic films with soil moisture being maintained nearly saturated status, is a promising technology as increased yields are achieved with less irrigation water. However, increased soil aeration and temperature under GCRPS may cause pollution swapping in greenhouse gas (GHG) from CH4 to N2O emissions. A 2-year experiment was performed, taking traditional rice cultivation as a reference, to assess the impacts of N-fertilizer placement methods on CH4, N2O and NO emissions and rice yields under GCRPS...
September 12, 2017: Scientific Reports
Yulin Zhang, Gunasekhar Nachimuthu, Sean Mason, Michael J McLaughlin, Ann McNeill, Michael J Bell
The traditional soil potassium (K) testing methods fail to accurately predict K requirement by plants. The Diffusive Gradients in Thin-films (DGT) method is promising, but the relationship between the DGT-measured K pool and plant available K is not clear. Wheat (Triticum aestivum L., cv. Frame) was grown in 9 Australian broad acre agricultural soils in a glasshouse trial until the end of tillering growth stage (GS30) with different plant K demands generated by varying plant numbers and pot sizes. Different K concentrations in soils were varied by 4 rates of K fertilizer application...
September 12, 2017: Scientific Reports
Nan Xu, Xueying Cheng, Kairong Zhou, Xiaoting Xu, Zuling Li, Jianping Chen, Dongtian Wang, Duo Li
The widespread use of nanoparticles (NPs) has led to their inevitable introduction into environmental systems. How the existence of hydrochars in crop soils will affect the mobility of nanoparticle titanium dioxide (nTiO2), especially in the presence of ammonium (NH4(+)), remains unknown. Research is needed to study the effects of hydrochars on the transport and retention of nTiO2 and to uncover the mechanisms of these effects on nTiO2 transport. Column experiments with nTiO2 and hydrochars were performed in various electrolyte (NaCl, NH4Cl, and CaCl2) solutions under a controlled pH (6...
September 8, 2017: Science of the Total Environment
Min Gou, Hang-Wei Hu, Yu-Jing Zhang, Jun-Tao Wang, Helen Hayden, Yue-Qin Tang, Ji-Zheng He
Composting has been suggested as a potential strategy to eliminate antibiotic residues and pathogens in livestock manure before its application as an organic fertilizer in agro-ecosystems. However, the impacts of composting on antibiotic resistance genes (ARGs) in livestock manure and their temporal succession following the application of compost to land are not well understood. We examined how aerobic composting affected the resistome profiles of cattle manure, and by constructing laboratory microcosms we compared the effects of manure and compost application to agricultural soils on the temporal succession of a wide spectrum of ARGs...
September 8, 2017: Science of the Total Environment
Peng Liu, Shuyu Jia, Xiwei He, Xuxiang Zhang, Lin Ye
Both manure and chemical fertilizers are widely used in modern agriculture. However, the impacts of different fertilizers on bacterial community structure and antibiotic resistance genes (ARGs) in arable soils still remain unclear. In this study, high-throughput sequencing and quantitative PCR were employed to investigate the bacterial community structure, ARGs and mobile genetic elements (MGEs) influenced by the application of different fertilizers, including chemical fertilizers, piggery manure and straw ash...
September 4, 2017: Chemosphere
Haiyan Ren, Jian Hu, Yifei Hu, Gaowen Yang, Yingjun Zhang
AIM: Application of organic materials into agricultural systems enhances plant growth and yields, and improves soil fertility and structure. This study aimed to examine the effects of "compost extract (CE)", a soil conditioner, and bio-organic manure (BOM) on the growth of lucerne (Medicago sativa), and compare the efficiency between BOM (including numbers of microorganisms) and CE (including no added microorganisms). METHOD: A greenhouse experiment was conducted with four soil amendment treatments (control, BOM, CE and CEBOM), and was arranged in a completely randomized design with 10 replicates for each treatment...
2017: PeerJ
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