Fungi Associated with Caryopses ofSetariaSpecies from Field-Harvested Seeds and from Soil Under Two Tillage Systems

Seeds of green foxtail [Setaria viridis(L.) P. Beauv. # SETVI] and giant foxtail (S. faberiHerrm. # SETFA) were collected from mature plants in the field and recovered from three soil depths under two types of tillage. Fungi colonizing the caryopses were isolated to determine the effect of tillage and soil depth on fungal colonization and the field flora.Alternaria alternata(Fr.) Keissler andEpicoccum purpurascensEhrenb. ex Schlecht. were the two fungi most frequently isolated from the hand-harvested seeds. Percentages of fungal colonization were directly related to size of the caryopses. The most frequently isolated fungus species recovered from seeds from soil wereA. alternata, Cladosporium cladosporioides(Fresen.) de Vries,E. purpurascens, and two unidentified fungi with sterile mycelium. One sterile fungus had white rough mycelium, and the other had dark mycelium. These two sterile fungi had a detrimental effect on foxtail seed germination in the laboratory. Caryopsis colonization seems to be related to the placement of the crop residues in the soil. In reduced-tillage plots, more caryopses were colonized in the top soil layer (0 to 7.5 cm) than in the 7.5- to 15-cm layer. In plowed soils, greater colonization occurred at the lower depth.

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Weed seed bank emergence across the Corn Belt

Weed Science ◽

10.1017/s0043174500092493 ◽

1997 ◽

Vol 45 (1) ◽

pp. 67-76 ◽

Cited By ~ 72

Author(s):

Frank Forcella ◽

Robert G. Wilson ◽

Jack Dekker ◽

Robert J. Kremer ◽

John Cardina ◽

...

Keyword(s):

Soil Temperature ◽

Field Experiments ◽

Soil Depth ◽

Early Spring ◽

Temperature And Precipitation ◽

Secondary Dormancy ◽

Giant Foxtail ◽

Green Foxtail ◽

Viable Seeds ◽

Common Purslane

Field experiments, conducted from 1991 to 1994, generated information on weed seedbank emergence for 22 site-years from Ohio to Colorado and Minnesota to Missouri. Early spring seedbank densities were estimated through direct extraction of viable seeds from soil cores. Emerged seedlings were recorded periodically, as were daily values for air and soil temperature, and precipitation. Percentages of weed seedbanks that emerged as seedlings were calculated from seedbank and seedling data for each species, and relationships between seedbank emergence and microclimatic variables were sought. Fifteen species were found in 3 or more site-years. Average emergence percentages (and coefficients of variation) of these species were as follows: giant foxtail, 31.2 (84%); velvetleaf, 28.2 (66); kochia, 25.7 (79); Pennsylvania smartweed, 25.1 (65); common purslane, 15.4 (135); common ragweed, 15.0 (110); green foxtail, 8.5 (72); wild proso millet, 6.6 (104); hairy nightshade, 5.2 (62); common sunflower, 5.0 (26); yellow foxtail, 3.4 (67); pigweed species, 3.3 (103); common lambsquarters, 2.7 (111); wild buckwheat, 2.5 (63), and prostrate knotweed, 0.6 (79). Variation among site-years, for some species, could be attributed to microclimate variables thought to induce secondary dormancy in spring. For example, total seasonal emergence percentage of giant foxtail was related positively to the 1st date at which average daily soil temperature at 5 to 10 cm soil depth reached 16 C. Thus, if soil warmed before mid April, secondary dormancy was induced and few seedlings emerged, whereas many seedlings emerged if soil remained cool until June.

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CHANGES IN MINERAL N AND NUMBERS OF BACTERIA AND ACTINOMYCETES DURING TWO YEARS UNDER WHEAT-FALLOW IN SOUTHWESTERN SASKATCHEWAN

Canadian Journal of Soil Science ◽

10.4141/cjss82-014 ◽

1982 ◽

Vol 62 (1) ◽

pp. 125-137 ◽

Cited By ~ 25

Author(s):

C. A. CAMPBELL ◽

V. O. BIEDERBECK

Keyword(s):

Environmental Conditions ◽

Microbial Growth ◽

Crop Residues ◽

Soil Depth ◽

Soil Layer ◽

Soil Microbial Activity ◽

Plate Count ◽

Upward Movement ◽

Mineral N ◽

Soil Microbial

The aim of this study was to identify, in situ, some of the microbial responses to environmental conditions previously noted in experiments in the laboratory and field. Soil samples were taken from a Brown Chernozem under a wheat-fallow rotation at 2-wk intervals during spring and autumn and at 4-wk intervals in winter and summer for a 2-yr period. Nitrate-N and exchangeable NH4-N, and numbers of bacteria and actinomycetes by plate count, were measured in 0- to 2.5-cm, 2.5- to 15-cm and 15- to 30-cm soil layers. Changes in microbial numbers and mineral N were correlated with soil depth, available carbon and environmental conditions. Bacterial numbers ranged between 14 and 119 million per gram of soil in the 0- to 2.5-cm layer, between 9 and 47 million in the 2.5-to 15-cm layer and were 4 million in the 15- to 30-cm soil layer. Bacteria:actinomycetes ratios were 3:1 in the 0- to 2.5-cm layer, 2:1 in the 2.5- to 15-cm layer and 1:1 in the 15- to 30-cm layer. Exchangeable NH4- and NO3-N as high as 20 and 280 ppm, respectively, were found in the top 2.5 cm. Different processes with similar or opposing effects often occurred simultaneously, thus making interpretation difficult. However, we identified (i) the stepwise nature of the ammonification-nitrification process; (ii) the importance of crop residues in microbial growth, and denitrification; (iii) the flush in microbial growth when a dry soil is moistened; (iv) the importance of the tilled layer as the prime site of soil microbial activity; and (v) the rapid decrease in microbial population and activity below the tilled soil layer. There was also evidence of possible upward movement of NO3 due to temperature gradient (as soil froze), and due to evaporation.

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Different Cropping System Effects of Depth-Wise Distribution of Available NPKS in an Inceptisol of Southern Telangana Zone

International Research Journal of Pure and Applied Chemistry ◽

10.9734/irjpac/2020/v21i1730263 ◽

2020 ◽

pp. 32-39

Author(s):

Knight Nthebere ◽

S. H. K. Sharma ◽

Ch. Pragathi Kumari ◽

A. Aziz Qureshi

Keyword(s):

Soil Depth ◽

Cropping Systems ◽

Soil Layer ◽

Cropping System ◽

Nutrient Status ◽

Pigeon Pea ◽

Positive Influence ◽

Bt Cotton ◽

Available N ◽

Lower Depth

The present study was undertaken in the ongoing long-term experiment initiated during 2017 at the experimental farm of College of Agriculture, Rajendranagar, Hyderabad. Soil samples were collected from two depths (0–15 and 15–30 cm) and analysed for soil fertility parameters namely: available N, P, K and S. The results indicated that the different cropping systems had positive influence on improving the nutrient status (i.e., available N, P and K) significantly over the initial soil values (N: 112.20, P: 23.40 and K: 170.30 kg ha-1, respectively). Interestingly, it was noticed that improved availability of nutrients (N, P, K and S) was more profound in the upper soil layer (0–15 cm) compared to lower depth (15–30 cm) in all the cropping systems (CS). The CS: Bt cotton + Greengram – Groundnut had recorded high nitrogen (N=221.60 kg-1), CS: Fodder maize – Lucerne recorded high in available P (P=49.13 kg-1) and CS: Fodder sorghum + Fodder cowpea – Horsegram – Sunhemp recorded high in K and S (K=208.10 kg-1, S= 172.0 kg S ha-1) after kharif season. While, CS: Pigeon pea + Greengram – Sesame showed high for N (N=228.57 kg-1), CS: Fodder maize – Lucerne for high P (P=48.27 kg-1) and Rice – Maize recorded high for K and S (K=207.63 kg-1 and S= 95.40 kg S ha-1) in top soil layer (0–15 cm) after harvest of rabi compared to lower soil depth (15–30 cm).

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Microbial and biochemical changes induced by rotation and tillage in a soil under barley production

Canadian Journal of Soil Science ◽

10.4141/cjss93-004 ◽

1993 ◽

Vol 73 (1) ◽

pp. 39-50 ◽

Cited By ~ 94

Author(s):

D. A. Angers ◽

N. Bissonnette ◽

A. Légère ◽

N. Samson

Keyword(s):

Alkaline Phosphatase ◽

Organic Matter ◽

Microbial Biomass ◽

Phosphatase Activity ◽

Alkaline Phosphatase Activity ◽

Soil Layer ◽

Red Clover ◽

Organic C ◽

Top Soil ◽

Total Organic C

Crop rotations and tillage practices can modify not only the total amount of organic matter (OM) in soils but also its composition. The objective of this study was to determine the changes in total organic C, microbial biomass C (MBC), carbohydrates and alkaline phosphatase activity induced by 4 yr of different rotation and tillage combinations on a Kamouraska clay in La Pocatière, Quebec. Two rotations (continuous barley (Hordeum vulgare L.) versus a 2-yr barley–red clover (Trifolium pratense L.) rotation) and three tillage treatments (moldboard plowing (MP), chisel plowing (CP) and no-tillage (NT)) were compared in a split-plot design. Total organic C was affected by the tillage treatments but not by the rotations. In the top soil layer (0–7.5 cm), NT and CP treatments had C contents 20% higher than the MP treatment. In the same soil layer, MBC averaged 300 mg C kg−1 in the MP treatment and up to 600 mg C kg−1 in the NT soil. Hot-water-extractable and acid-hydrolyzable carbohydrates were on average 40% greater under reduced tillage than under MP. Both carbohydrate fractions were also slightly larger in the rotation than in the soil under continuous barley. The ratios of MBC and carbohydrate C to total organic C suggested that there was a significant enrichment of the OM in labile forms as tillage intensity was reduced. Alkaline phosphatase activity was 50% higher under NT and 20% higher under CP treatments than under MP treatment and, on average, 15% larger in the rotation than in the continuous barley treatment. Overall, the management-induced differences were slightly greater in the top layer (0–7.5 cm) than in the lower layer of the Ap horizon (7.5–15 cm). All the properties measured were highly correlated with one another. They also showed significant temporal variations that were, in most cases, independent of the treatments. Four years of conservation tillage and, to a lesser extent, rotation with red clover resulted in greater OM in the top soil layer compared with the more intensive systems. This organic matter was enriched in labile forms. Key words: Soil management, soil quality, organic matter, carbohydrates, microbial biomass, phosphatase

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Variation in Salinity through the Soil Profile in South Coastal Region of Bangladesh

Journal of Bangladesh Academy of Sciences ◽

10.3329/jbas.v42i1.37829 ◽

2018 ◽

Vol 42 (1) ◽

pp. 11-23

Author(s):

Mohammad Asadul Haque

Keyword(s):

Electrical Conductivity ◽

Salt Stress ◽

Soil Profile ◽

Ph Value ◽

Soil Depth ◽

Coastal Region ◽

Soil Samples ◽

Salt Accumulation ◽

Top Soil ◽

Academy Of Sciences

The spatial variability of salt accumulation through the soil profile was studied at Latachapali union of Kalapara upazila, Patuakhali district, Bangladesh. The soil samples were collected from 30 locations covering six villages of the union: Kuakata, Malapara, Fashipara, Khajura, Mothaopara and Tajepara. Five locations were randomly selected from each village. From each location soil samples were collected from three soil depths at 0-2 cm, 2.1-4 cm and 4.1-6 cm. Electrical conductivity of top 0-2 cm soil depth was 20.49 dS/m, in 2.1-4 cm soil depth was 7.14 dS/m and in 4.1-6 cm soil depth 4.15 dS/m. The study soils were strongly acidic having pH value 4.73, 4.99 and 5.20 in 0-2, 2.1-4 and 4.1-6 cm soil depth, respectively. The highest of 8.8 Na:K ratio was found in 0-2 cm soil depth. The Na:K ratio gradually decreased with the increase of soil depth, having 6.59 in 2.1-4 cm and 5.42. in 4.1-6 cm soil depth. The results clearly reveal that the top soil is very much sensitive to salt stress. Based on the electrical conductivity and Na:K ratio the Fashipara, Kuakata and Tajepara village were found seriously affected by salinity.Journal of Bangladesh Academy of Sciences, Vol. 42, No. 1, 11-23, 2018

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The Impact of Error Accounting in a Bayesian Approach to Calibrating Modeled Turbulent Fluxes in an Open-Canopy Forest

Journal of Hydrometeorology ◽

10.1175/jhm-d-17-0030.1 ◽

2017 ◽

Vol 18 (7) ◽

pp. 2029-2042

Author(s):

Tony E. Wong ◽

William Kleiber ◽

David C. Noone

Keyword(s):

Markov Chain ◽

Land Surface ◽

Hydrological Modeling ◽

Soil Layer ◽

Turbulent Fluxes ◽

Surface Model ◽

Model Parameters ◽

Top Soil ◽

The Impact ◽

Calibration Approach

Abstract Land surface models are notorious for containing many parameters that control the exchange of heat and moisture between land and atmosphere. Properly modeling the partitioning of total evapotranspiration (ET) between transpiration and evaporation is critical for accurate hydrological modeling, but depends heavily on the treatment of turbulence within and above canopies. Previous work has constrained estimates of evapotranspiration and its partitioning using statistical approaches that calibrate land surface model parameters by assimilating in situ measurements. These studies, however, are silent on the impacts of the accounting of uncertainty within the statistical calibration framework. The present study calibrates the aerodynamic, leaf boundary layer, and stomatal resistance parameters, which partially control canopy turbulent exchange and thus the evapotranspiration flux partitioning. Using an adaptive Metropolis–Hastings algorithm to construct a Markov chain of draws from the joint posterior distribution of these resistance parameters, an ensemble of model realizations is generated, in which latent and sensible heat fluxes and top soil layer temperature are optimized. A set of five calibration experiments demonstrate that model performance is sensitive to the accounting of various sources of uncertainty in the field observations and model output and that it is critical to account for model structural uncertainty. After calibration, the modeled fluxes and top soil layer temperature are largely free from bias, and this calibration approach successfully informs and characterizes uncertainty in these parameters, which is essential for model improvement and development. The key points of this paper are 1) a Markov chain Monte Carlo calibration approach successfully improves modeled turbulent fluxes; 2) ET partitioning estimates hinge on the representation of uncertainties in the model and data; and 3) despite these inherent uncertainties, constrained posterior estimates of ET partitioning emerge.

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Qualitative and quantitative response of soil organic carbon to 40 years of crop residue incorporation under contrasting nitrogen fertilisation regimes

Soil Research ◽

10.1071/sr15377 ◽

2017 ◽

Vol 55 (1) ◽

pp. 1 ◽

Cited By ~ 19

Author(s):

Christopher Poeplau ◽

Lisa Reiter ◽

Antonio Berti ◽

Thomas Kätterer

Keyword(s):

Organic Carbon ◽

Soil Organic Carbon ◽

Crop Residue ◽

Crop Residues ◽

Management Practice ◽

Soil Layer ◽

Clay Fraction ◽

Residue Incorporation ◽

Crop Residue Incorporation ◽

Soc Stocks

Crop residue incorporation (RI) is recommended to increase soil organic carbon (SOC) stocks. However, the positive effect on SOC is often reported to be relatively low and alternative use of crop residues, e.g. as a bioenergy source, may be more climate smart. In this context, it is important to understand: (i) the response of SOC stocks to long-term crop residue incorporation; and (ii) the qualitative SOC change, in order to judge the sustainability of this measure. We investigated the effect of 40 years of RI combined with five different nitrogen (N) fertilisation levels on SOC stocks and five SOC fractions differing in turnover times on a clay loam soil in Padua, Italy. The average increase in SOC stock in the 0–30cm soil layer was 3.1Mgha–1 or 6.8%, with no difference between N fertilisation rates. Retention coefficients of residues did not exceed 4% and decreased significantly with increasing N rate (R2=0.49). The effect of RI was higher after 20 years (4.6Mgha–1) than after 40 years, indicating that a new equilibrium has been reached and no further gains in SOC can be expected. Most (92%) of the total SOC was stored in the silt and clay fraction and 93% of the accumulated carbon was also found in this fraction, showing the importance of fine mineral particles for SOC storage, stabilisation and sequestration in arable soils. No change was detected in more labile fractions, indicating complete turnover of the annual residue-derived C in these fractions under a warm humid climate and in a highly base-saturated soil. The applied fractionation was thus useful to elucidate drivers and mechanisms of SOC formation and stabilisation. We conclude that residue incorporation is not a significant management practice affecting soil C storage in warm temperate climatic regions.

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Depth-Dependent C-N-P Stocks and Stoichiometry in Ultisols Resulting from Conversion of Secondary Forests to Plantations and Driving Forces

Forests ◽

10.3390/f12101300 ◽

2021 ◽

Vol 12 (10) ◽

pp. 1300

Author(s):

Xiaogang Ding ◽

Xiaochuan Li ◽

Ye Qi ◽

Zhengyong Zhao ◽

Dongxiao Sun ◽

...

Keyword(s):

Soil Depth ◽

Soil Layer ◽

Pinus Elliottii ◽

Slash Pine ◽

Pine Plantations ◽

Secondary Forests ◽

Masson Pine ◽

Soil Layers ◽

Soil C ◽

Significant Difference

Stocks and stoichiometry of carbon (C), nitrogen (N), and phosphorus (P) in ultisols are not well documented for converted forests. In this study, Ultisols were sampled in 175 plots from one type of secondary forest and four plantations of Masson pine (Pinus massoniana Lamb.), Slash pine (Pinus elliottii Engelm.), Eucalypt (Eucalyptus obliqua L’Hér.), and Litchi (Litchi chinensis Sonn., 1782) in Yunfu, Guangdong province, South China. Five layers of soil were sampled with a distance of 20 cm between two adjacent layers up to a depth of 100 cm. We did not find interactive effects between forest type and soil layer depth on soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP) concentrations and storages. Storage of SOC was not different between secondary forests and Eucalypt plantations, but SOC of these two forest types were lower than that in Litchi, Masson pine, and Slash pine plantations. Soil C:P was higher in Slash pine plantations than in secondary forests. Soil CNP showed a decreasing trend with the increase of soil depth. Soil TP did not show any significant difference among soil layers. Soil bulk density had a negative contribution to soil C and P stocks, and longitude and elevation were positive drivers for soil C, N, and P stocks. Overall, Litchi plantations are the only type of plantation that obtained enhanced C storage in 0–100 cm soils and diverse N concentrations among soil layers during the conversion from secondary forests to plantations over ultisols.

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Effects of different biomass materials as a salt-isolation layer on water and salt migration in coastal saline soil

PeerJ ◽

10.7717/peerj.11766 ◽

2021 ◽

Vol 9 ◽

pp. e11766

Author(s):

Mao Yang ◽

Runya Yang ◽

Yanni Li ◽

Yinghua Pan ◽

Junna Sun ◽

...

Keyword(s):

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Salt Concentration ◽

Saline Soil ◽

Soil Depth ◽

Soil Layer ◽

Thick Layer ◽

Peat Layer ◽

Salt Accumulation

The aim of this study was to find a material suited for the prevention of evaporative water loss and salt accumulation in coastal saline soils. One-dimensional vertical water infiltration and phreatic evaporation experiments were conducted using a silty loam saline soil. A 3-cm-thick layer of corn straw, biochar, and peat was buried at the soil depth of 20 cm, and a 6-cm-thick layer of peat was also buried at the same soil depth for comparison. The presence of the biochar layer increased the upper soil water content, but its ability to inhibit salt accumulation was poor, leading to a high salt concentration in the surface soil. The 3-cm-thick straw and 6-cm-thick peat layers were most effective to inhibit salt accumulation, which reduced the upper soil salt concentration by 96% and 93%, respectively. However, the straw layer strongly inhibited phreatic evaporation and resulted in low water content in the upper soil layer. Compared with the straw layer, the peat layer increased the upper soil water content. Thus, burying a 6-cm-thick peat layer in the coastal saline soil is the optimal strategy to retain water in the upper soil layer and intercept salt in the deeper soil layer.

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Depth distribution of belowground net primary production across global biomes

10.21203/rs.3.rs-65178/v2 ◽

2021 ◽

Author(s):

Zhongkui Luo ◽

Guocheng Wang ◽

Liujun Xiao ◽

Xiali Mao ◽

Xiaowei Guo ◽

...

Keyword(s):

Primary Production ◽

Depth Distribution ◽

Net Primary Production ◽

Soil Depth ◽

Soil Layer ◽

Soil Nutrient ◽

Data Sets ◽

Large Variability ◽

Belowground Carbon ◽

Belowground Net Primary Production

Abstract The depth distribution of belowground net primary production (BNPP) has been unquantified globally, hindering our understanding of belowground carbon dynamics. We synthesize global observational data sets to infer the depth allocation of BNPP down to 2 m, and map depth-specific BNPP globally at 1 km resolution. We estimate that global average BNPP in the 0–20 soil layer is 1.1 Mg C ha–1 yr–1, accounting for >50% of total BNPP. Across the globe, the depth distribution of BNPP shows large variability, and more BNPP is allocated to deeper layers in hotter and drier regions. Edaphic, climatic and topographic properties (in the order of importance) can explain >80% of such variability in different soil depths; and the direction and magnitude of the influence of individual properties (e.g., precipitation and soil nutrient) are soil depth- and biome-dependent. Our results provide global benchmarks for predictions of whole-soil carbon profiles across global biomes.

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