scholarly journals Decomposition Rates and Residue-Colonizing Microbial Communities ofBacillus thuringiensisInsecticidal Protein Cry3Bb-Expressing (Bt) and Non-Bt Corn Hybrids in the Field

2010 ◽  
Vol 77 (3) ◽  
pp. 839-846 ◽  
Author(s):  
Kai Xue ◽  
Raquel C. Serohijos ◽  
Medha Devare ◽  
Janice E. Thies
Keyword(s):  
Environmental Factors ◽  
Crop Residues ◽  
Rflp Analysis ◽  
Soil Surface ◽  
Protein S ◽  
Bt Corn ◽  
Decomposition Rates ◽  
Cry Protein ◽  
Corn Hybrids ◽  
Effect Of Treatment

ABSTRACTDespite the rapid adoption of crops expressing the insecticidal Cry protein(s) fromBacillus thuringiensis(Bt), public concern continues to mount over the potential environmental impacts. Reduced residue decomposition rates and increased tissue lignin concentrations reported for some Bt corn hybrids have been highlighted recently as they may influence soil carbon dynamics. We assessed the effects of MON863 Bt corn, producing the Cry3Bb protein against the corn rootworm complex, on these aspects and associated decomposer communities by terminal restriction fragment length polymorphism (T-RFLP) analysis. Litterbags containing cobs, roots, or stalks plus leaves from Bt and unmodified corn with (non-Bt+I) or without (non-Bt) insecticide applied were placed on the soil surface and at a 10-cm depth in field plots planted with these crop treatments. The litterbags were recovered and analyzed after 3.5, 15.5, and 25 months. No significant effect of treatment (Bt, non-Bt, and non-Bt+I) was observed on initial tissue lignin concentrations, litter decomposition rate, or bacterial decomposer communities. The effect of treatment on fungal decomposer communities was minor, with only 1 of 16 comparisons yielding separation by treatment. Environmental factors (litterbag recovery year, litterbag placement, and plot history) led to significant differences for most measured variables. Combined, these results indicate that the differences detected were driven primarily by environmental factors rather than by any differences between the corn hybrids or the use of tefluthrin. We conclude that the Cry3Bb corn tested in this study is unlikely to affect carbon residence time or turnover in soils receiving these crop residues.

Decomposition rate of cereal straw as affected by soil placement

Soil Research ◽  
2008 ◽  
Vol 46 (2) ◽  
pp. 152 ◽  
Author(s):  
D. Curtin ◽  
G. S. Francis ◽  
F. M. McCallum
Keyword(s):  
Crop Residues ◽  
Soil Layer ◽  
Soil Surface ◽  
Decomposition Rates ◽  
Straw Decomposition ◽  
Litter Bags ◽  
Litter Bag ◽  
Residue Contact ◽  
Co2 Output ◽  
Soil Residue

Decomposition rates for crop residues have generally been estimated based on data obtained using buried litter bags. Because of limited soil–residue contact, the litter bag technique may not adequately simulate decomposition when residues are mixed through the soil. In field microplots, decomposition of wheat (Triticum aestivum) and barley (Hordeum vulgare) straw (autumn-incorporated at a rate of 7 t/ha) mixed through the 0–0.20 m soil layer was compared with straw decomposition in fibreglass bags (4-mm mesh) buried at a depth of 0.20 m. A surface-placed straw treatment and a no-straw control were included for comparison. Emissions of CO2 were monitored from the incorporated straw treatments and undecomposed straw was recovered after 158 days (mean soil temperature during the trial period was 8°C at 0.10 m). Emissions of CO2 from the soil‐mixed straw treatment were generally greater than from the buried bag treatment in the 2 months following incorporation. Output of CO2-C over the first 73 days averaged 83 g/m2 for the soil-mixed straw treatment compared with 61 g/m2 for the litter bag treatment and 34 g/m2 for the no-straw control. Over the entire trial, CO2-C attributable to straw (CO2-C output from straw-treated plots minus CO2-C emitted from the control) was 66% greater for soil‐mixed straw than for litter bag straw, indicating that within soil placement can have a strong and persistent effect on straw decomposition. Straw type had a small but significant (P < 0.05) effect on CO2 output (barley > wheat). Straw mass loss during the trial averaged 66% for soil-mixed straw, 32% for litter bag straw, and 13% for straw placed on the soil surface. The low recovery of soil‐mixed straw is partly due to difficulty of extracting small (<2 mm) residue fragments from the soil; however, such fragments could legitimately be considered part of the soil organic matter. The results confirm that straw that is well distributed through the soil may decompose more rapidly than would be anticipated from litter bag measurements.

scholarly journals Crop residues on short-term CO2 emissions in sugarcane production areas

2013 ◽  
Vol 33 (4) ◽  
pp. 699-708 ◽  
Author(s):  
Mariana M. Corradi ◽  
Alan R. Panosso ◽  
Marcílio V. Martins Filho ◽  
Newton La Scala Junior
Keyword(s):  
Co2 Emissions ◽  
Field Experiments ◽  
Crop Residues ◽  
Soil Surface ◽  
Dry Mass ◽  
Agricultural Crop ◽  
Short Term ◽  
Sugarcane Production ◽  
Soil Temperatures ◽  
Production Areas

The proper management of agricultural crop residues could produce benefits in a warmer, more drought-prone world. Field experiments were conducted in sugarcane production areas in the Southern Brazil to assess the influence of crop residues on the soil surface in short-term CO2 emissions. The study was carried out over a period of 50 days after establishing 6 plots with and without crop residues applied to the soil surface. The effects of sugarcane residues on CO2 emissions were immediate; the emissions from residue-covered plots with equivalent densities of 3 (D50) and 6 (D100) t ha-1 (dry mass) were less than those from non-covered plots (D0). Additionally, the covered fields had lower soil temperatures and higher soil moisture for most of the studied days, especially during the periods of drought. Total emissions were as high as 553.62 ± 47.20 g CO2 m-2, and as low as 384.69 ± 31.69 g CO2 m-2 in non-covered (D0) and covered plot with an equivalent density of 3 t ha-1 (D50), respectively. Our results indicate a significant reduction in CO2 emissions, indicating conservation of soil carbon over the short-term period following the application of sugarcane residues to the soil surface.

scholarly journals Soil preparation and nutrient losses by erosion in the culture cucumber

2005 ◽  
Vol 62 (6) ◽  
pp. 572-577 ◽  
Author(s):  
Nelson Moura Brasil do Amaral Sobrinho ◽  
Nelson Mazur
Keyword(s):  
Crop Residues ◽  
Total Concentration ◽  
Organic Matter Content ◽  
Soil Surface ◽  
Crop Productivity ◽  
Matter Content ◽  
Nutrient Losses ◽  
Cucumis Sativus L ◽  
Minimum Tillage ◽  
Fine Sediments

Minimum tillage reportedly reduce erosion, avoid soil degradation and improve crop productivity. This study aimed to determine how tillage operations may affect either nutrient accumulation or nutrient losses by erosion. The study was, carried out from December, 2000 to March, 2001, in the watershed of the Caetés River, in Rio de Janeiro State, Brazil (22º25'43"S, 43º25'07"W). The experiment was set up in sandy clay Kandiudult soil, 60% slope, under cucumber (Cucumis sativus L.) crop. Soil samples were collected before planting and after harvest, on 22.0 X 4.0 m Greeoff plots. After each rainfall, fine sediments carried by runoff were deposited into two collecting tanks in a row, installed at the end of each plot, and were later dried, weighed and stored for analyses. Treatments (n = 4) were characterized by different tillage systems: (i) downhill plowing followed by the burning of crop residues (DPB); (ii) downhill plowing with no burning of the crop residues (DPNB); (iii) animal traction contour plowing, with strips of guinea grass planted at a spacing of 7.0 m (AT); and (iv) minimum tillage (MT). Samples of the soil-plowed layer were collected before planting and after harvest, between the rows and from the plants. Total concentration of Ca, Mg, K and P were determined after extraction with nitric perchloride digestion. Labile P and exchangeable K were extracted with the Mehlich 1 extractant solution. The MT system reduced losses of both exchangeable bases (15%) and P (8%), and affected the distribution of labile and organic P. Crop residues left on soil surface in the MT system, resulted in increased organic matter content. Downhill plowing, the most used tillage operation in the region, resulted in the greatest losses of Ca, Mg, K, and P.

scholarly journals Impact of Environmental Factors on Seed Germination and Seedling Emergence of White Clover (Trifolium repens L.)

Agronomy ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 190
Author(s):  
Lei Chu ◽  
Yiping Gao ◽  
Lingling Chen ◽  
Patrick E. McCullough ◽  
David Jespersen ◽  
...  
Keyword(s):  
Seed Germination ◽  
Environmental Factors ◽  
White Clover ◽  
Trifolium Repens ◽  
Germination Rate ◽  
Seedling Emergence ◽  
Soil Surface ◽  
High Sensitivity ◽  
Series Of Experiments ◽  
Trifolium Repens L

White clover (Trifolium repens L.) is cultivated as a forage crop and planted in various landscapes for soil conservation. There are numerous reports of failed white clover stands each year. A good understanding of the seed germination biology of white clover in relation to environmental factors is essential to achieve successful stand establishment. A series of experiments were conducted to investigate the impacts of light, temperature, planting depth, drought, and salt stress on seed germination and the emergence of white clover. White clover is negatively photoblastic, and seed germination averaged 63 and 66% under light and complete dark conditions 4 weeks after planting (WAP), respectively. Temperature affected the seed germination speed and rate. At 1 WAP, seeds incubated at 15 to 25 °C demonstrated a significantly higher germination rate than the low temperatures at 5 and 10 °C; however, the germination rate did not differ among the temperature treatments at 4 WAP. The results suggest that white clover germination decreases with increasing sowing depths, and the seeds should be sown on the soil surface or shallowly buried at a depth ≤1 cm to achieve an optimal emergence. White clover seeds exhibited high sensitivity to drought and salinity stress. The osmotic potential and NaCl concentration required to inhibit 50% seed germination were −0.19 MPa and 62.4 mM, respectively. Overall, these findings provide quantifiable explanations for inconsistent establishment observed in field conditions. The results obtained in this research can be used to develop effective planting strategies and support the successful establishment of white clover stands.

scholarly journals Crop Residue Management for Sustenance of Natural Resources and Agriculture Productivity

2019 ◽  
Vol 40 (03) ◽  
Author(s):  
Maninder Singh ◽  
Anita Jaswal ◽  
Arshdeep Singh
Keyword(s):  
Organic Matter ◽  
Environmental Impacts ◽  
Crop Production ◽  
Crop Residue ◽  
Crop Residues ◽  
Crop Yields ◽  
Soil Surface ◽  
Residue Management ◽  
Soil Productivity ◽  
Crop Residue Management

Crop residue management (CRM) through conservation agriculture can improve soil productivity and crop production by preserving soil organic matter (SOM) levels. Two major benefits of surface-residue management are improved organic matter (OM) near the soil surface and boosted nutrient cycling and preservation. Larger microbial biomass and activity near the soil surface act as a pool for nutrients desirable in crop production and enhance structural stability for increased infiltration. In addition to the altered nutrient distribution within the soil profile, changes also occur in the chemical and physical properties of the soil. Improved soil C sequestration through enhanced CRM is a cost-effective option for reducing agriculture's impact on the environment. Ideally, CRM practices should be selected to optimize crop yields with negligible adverse effects on the environment. Crop residues of common agricultural crops are chief resources, not only as sources of nutrients for subsequent crops but also for amended soil, water and air quality. Maintaining and managing crop residues in agriculture can be economically beneficial to many producers and more importantly to society. Improved residue management and reduced tillage practices should be encouraged because of their beneficial role in reducing soil degradation and increasing soil productivity. Thus, farmers have a responsibility in making management decisions that will enable them to optimize crop yields and minimize environmental impacts. Multi-disciplinary and integrated efforts by a wide variety of scientists are required to design the best site-specific systems for CRM practices to enhance agricultural productivity and sustainability while minimizing environmental impacts.

scholarly journals Crop residue decomposition in Minnesota biochar-amended plots

Solid Earth ◽  
2014 ◽  
Vol 5 (1) ◽  
pp. 499-507 ◽  
Author(s):  
S. L. Weyers ◽  
K. A. Spokas
Keyword(s):  
Microbial Biomass ◽  
Crop Residue ◽  
Crop Residues ◽  
Soil Surface ◽  
Microbial Dynamics ◽  
Wood Pellet ◽  
First Order ◽  
Residue Decomposition ◽  
Continuous Corn ◽  
Crop Residue Decomposition

Abstract. Impacts of biochar application at laboratory scales are routinely studied, but impacts of biochar application on decomposition of crop residues at field scales have not been widely addressed. The priming or hindrance of crop residue decomposition could have a cascading impact on soil processes, particularly those influencing nutrient availability. Our objectives were to evaluate biochar effects on field decomposition of crop residue, using plots that were amended with biochars made from different plant-based feedstocks and pyrolysis platforms in the fall of 2008. Litterbags containing wheat straw material were buried in July of 2011 below the soil surface in a continuous-corn cropped field in plots that had received one of seven different biochar amendments or a uncharred wood-pellet amendment 2.5 yr prior to start of this study. Litterbags were collected over the course of 14 weeks. Microbial biomass was assessed in treatment plots the previous fall. Though first-order decomposition rate constants were positively correlated to microbial biomass, neither parameter was statistically affected by biochar or wood-pellet treatments. The findings indicated only a residual of potentially positive and negative initial impacts of biochars on residue decomposition, which fit in line with established feedstock and pyrolysis influences. Overall, these findings indicate that no significant alteration in the microbial dynamics of the soil decomposer communities occurred as a consequence of the application of plant-based biochars evaluated here.

scholarly journals CORN BORER RESISTANCE AND GRAIN YIELD FOR BT AND NON-BT CORN HYBRIDS, 1998

1999 ◽  
Vol 24 (1) ◽  
Author(s):  
R. Higgins ◽  
L. Buschman ◽  
P. Sloderbeck ◽  
V. Martin
Keyword(s):  
Grain Yield ◽  
Bt Corn ◽  
Corn Hybrids ◽  
Corn Borer

Factors affecting the operation of the weed-sensing Detectspray system

Weed Science ◽  
1998 ◽  
Vol 46 (1) ◽  
pp. 127-131 ◽  
Author(s):  
Robert E. Blackshaw ◽  
Louis J. Molnar ◽  
Duane F. Chevalier ◽  
C. Wayne Lindwall
Keyword(s):  
Near Infrared ◽  
Field Experiments ◽  
Crop Residues ◽  
Soil Surface ◽  
Physical Factors ◽  
Weed Detection ◽  
Factors Affecting ◽  
Green Foxtail ◽  
Infrared Wavelengths ◽  
Herbicide Use

Field experiments were conducted for 3 yr to determine the effect of various biological and physical factors on the operation of the weed-sensing Detectspray system. Plant detection is achieved by sensors measuring differential reflectance of red and near-infrared wavelengths of light from green plants, crop residues, and soil. Weed detection was greatly reduced 70 to 80 min after sunrise and before sunset when operated at lat 50°N because of reduced solar irradiance. Tall, dense-standing crop stubble limited detection of small weeds at the soil surface. Weed detection varied with plant species. Canola with three to four leaves consistently was detected, but wheat or green foxtail usually required five to six leaves to be detected. Small weeds were detected if present at densities greater than 70 plants m−2. Growers and commercial applicators need to be aware of the limitations of the Detectspray system to use it effectively to control weeds with concurrent reductions in herbicide use.

Performance of Bt Corn Hybrids, their Near Isolines, and Leading Corn Hybrids in Pennsylvania and Maryland

2004 ◽  
Vol 96 (3) ◽  
pp. 1 ◽  
Author(s):  
Bryan L. Dillehay ◽  
Gregory W. Roth ◽  
Dennis D. Calvin ◽  
Robert J. Kratochvil ◽  
Gretchen A. Kuldau ◽  
...  
Keyword(s):  
Bt Corn ◽  
Corn Hybrids
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