• Authors:
    • Benjamin, J. G.
    • Stahlman, P. W.
    • Mikha, M. M.
    • Geier, P. W.
  • Source: Agronomy Journal
  • Volume: 106
  • Issue: 1
  • Year: 2014
  • Summary: The response of manure applications on calcareous eroded soils in the western United States is unlike the responses observed on acid soils in the eastern United States. The objectives of this study were to restore the productivity and evaluate N loss of eroded land influenced by tillage practices, N sources, and N rates. The study was initiated in 2006 on an Armo silt loam (fine-loamy, mixed, mesic Entic Haplustolls) at the Agriculture Research Center, Hays, KS. Tillage practices were no-tillage (NT) and conventional tillage (CT). Nitrogen sources were beef manure (M); urea, as commercial fertilizer (F); and no-N control (C) at two rates, low (L) and high (H). The crop rotation was grain sorghum ( Sorghum bicolor L.), forage oat ( Avena sativa L.), winter wheat ( Triticum aestivum L.), grain sorghum, proso millet ( Panicum miliaceum L.), and winter wheat. Grain yield (2006-2011) and soil inorganic nitrogen (SIN) at 0- to 120-cm depth were evaluated. Grain yields were not influenced by tillage practices, except in 2006 when NT had greater yields than CT. Manure addition increased grain yields compared with F and C treatments. Excess amounts of N and low productivity lead to leaching of the SIN down the soil profile with HF and HM. The LM exhibited less productivity and less SIN loss than HM treatment. Overall, M could be the N source that can improve the productivity of the eroded site. The benefits of increasing the productivity and the risk of N loss with HM need to be further addressed.
  • Authors:
    • Kolling, D. F.
    • Sordi, A.
    • Nesi, C. N.
    • Wildner, L. do P.
    • Mattias, J. L.
    • Nicoloso Denardin, R. B.
    • Busnello, F. J.
    • Cerutti, T.
  • Source: Ciência Florestal
  • Volume: 24
  • Issue: 1
  • Year: 2014
  • Summary: The adoption of management practices that ensure the stability of soil organic matter also maintain the stability or quantitative increase of carbon (C) in the lithosphere, reducing the amount of CO2 in the atmosphere. You can also minimize the losses of C to the atmosphere by using conservation practices, or using cover crops to keep the soil C stocks, and the forest cover are considered great abduction and forest systems considered large reservoirs of C. This work was performed on a property located in Chapec, Santa Catarina state, where soils were sampled from different forest formations distributed in a homogeneous soil range. The local climate is mesothermal, rainy, and the soil was characterized as an association Cambissolo Haplico/Neossolo Litolico. The objectives were to estimate the C stocks in soils and estimate the C losses occurred due to the change of soil cover. It was evaluated soils under natural forest (FN), of secondary stage, with a high degree of preservation; planted forest of eucalyptus (Eucalyptus saligna) (PE), with eight years of cultivation, preceded by 17 years under crop conventional tillage; and a planted forest of herb mate (Ilex paraguariensis) (EM), with 25 years of cultivation under conventional system (cutting interval of 18 months, with removal of all waste produced and maintenance of the ground without cover, with periodic use of herbicide - glyphosate). In each area were opened four trenches with 50 cm deep, where soil samples were collected in depths of: 0-5 cm, 5-10 cm, 10-20 cm, 20-30 cm, 30-40 cm, and 40-50 cm, with kopeck rings. It was possible to determine the bulk density (Mg m(-3)), the soil volume per layer (depth) and per hectare, and the concentration of soil C in the different studied areas. To quantify the C stocks equal amounts of soil were used for each depth evaluated. It was observed higher densities of soils and under PE and EM, to FN the lowest density are explained by the large amount of organic material and the absence of anthropogenic effects. In FN, despite the lower bulk density, there was a greater soil content C, with 107.67 Mg C ha(-1). On the soil under PE, with stock 79.58 Mg C ha(-1), depending on previous use (17 years under crop conventional tillage), it is assumed that part of C has been recovered. Under EM, with stock of 47.29 Mg C ha(-1), C losses were evident, with about 221 Mg CO2 ha(-1) emitted from the soil. It was evident that the change in forest cover and management procedures can lead to large losses of C stored. Thus, the soil under forest, or the soil-plant a forest canopy, considered a major reservoir of C, can become a major source of C to the atmosphere, contributing to increased the greenhouse effect.
  • Authors:
    • Sainju, U. M.
  • Source: Agronomy Journal
  • Volume: 106
  • Issue: 4
  • Year: 2014
  • Summary: To determine farm C credit and reduce global warming potential, information is needed on the effect of management practices on soil C storage. The effects of tillage, cropping sequence, and N fertilization were evaluated on dryland crop biomass, surface residue C, and soil organic carbon (SOC) at the 0- to 120-cm depth in a Williams loam (fine-loamy, mixed, superactive, frigid, Typic Argiustolls) and their relationships with grain yields from 2006 to 2011 in eastern Montana. Treatments were no-till continuous malt barley ( Hordeum vulgare L.) (NTCB), no-till malt barley-pea ( Pisum sativum L.) (NTB-P), no-till malt barley-fallow (NTB-F), and conventional till malt barley-fallow (CTB-F), each with 0, 40, 80, and 120 kg N ha -1. Annualized crop grain and biomass yields, surface residue amount, and C contents were greater in NTB-P and NTCB than CTB-F and NTB-F and increased with increased N rates. At 0 to 5 and 5 to 10 cm, SOC was greater in NTB-P than CTB-F or NTCB with 40 kg N ha -1 and at 10 to 30 and 0 to 120 cm was greater in NTB-P than NTCB with 120 kg N ha -1. Surface residue C and SOC were related with grain yield and C content ( R2=0.21-0.55, P≤0.10, n=16). Greater amount of crop residue returned to the soil and turnover rate probably increased surface residue C, soil C storage, and crop yields in NTB-P with 40 and 120 kg N ha -1 than the other treatments. Soil organic matter and crop yields can be enhanced by using NTB-P with 40 kg N ha -1.
  • Authors:
    • Carvalho, P. C. de F.
    • Anghinoni, I.
    • Assmann, J. M.
    • Ferreira, A. O.
    • Amado, T. J. C.
    • Silva, F. D. da
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 190
  • Year: 2014
  • Summary: Brazil has the world's second-largest cattle herd and second-largest no-till grain crop area. However, these activities are not frequently integrated because there is a widespread perception that cattle have a negative effect on cropping, especially when high crop yields are a goal. This misunderstanding of the synergy between pastures, livestock and crops is linked to overgrazing at the pasture rotation phase, which causes a decline in soil quality. Few studies have investigated the effect of pasture grazing intensities on soil carbon (C) balance and soil quality in subtropical environments. This work assessed the effects of different grazing intensities (0.10, 0.20, 0.30 and 0.40 m sward height) on soil C indices and animal productivity in a clay Haplorthox. The crop-livestock system model was a soybean/ryegrass plus black oat annual rotation managed for 10 years, using a randomized complete block design with three replications. Grazing intensity affected the quantity and composition of soil C input. Under heavy grazing with limited soil C input, there was a decrease in pasture and an increase in soybean participation in total C input. Soil organic C (0-0.20 m) under different grazing intensities had a linear relationship with C stratification ratio, C management index (CMI) and C pool index. Our results suggest that integrated crop-livestock systems could act as atmospheric C sources or sinks, depending on the grazing intensity. Pastures managed at 0.20 and 0.40 m height had the best balance between CMI and animal daily gain. The best balance between CMI and live weight gain per unit area occurred in sward height of 0.20 m.
  • Authors:
    • Sperow, M.
  • Source: Agriculture Ecosystems and Environment
  • Volume: 193
  • Year: 2014
  • Summary: The Intergovernmental Panel on Climate Change (IPCC) provides a method to estimate soil organic carbon (SOC) stock changes relative to the SOC stock under native vegetation. This manuscript modifies the IPCC approach to use the ending SOC stock from the previous inventory as the SOC stock that is changed by land use and management activities during the next inventory and to track the crop rotation and tillage intensity through three inventories. The approach allows annual rates of change of carbon sequestration from different historic land uses and management to be estimated explicitly for each assessment point based on the effect of previous land use and management. The model generates 3524 unique annual SOC sequestration rates that vary by land use and management history on U.S. agricultural land based on the 30 SOC stock reference values provided by IPCC documentation. An average of 0.33 Mg C ha -1 yr -1 is stored when cropland that was conventionally tilled in two previous inventories is set-aside in the third inventory, but only 0.14 Mg C ha -1 yr -1 when it is conventionally tilled in the first inventory and no-till in the second inventory before it is set aside. Incorporating a winter cover on cropland that was conventionally tilled in the first inventory and no-till in the second and third inventories is estimated to store 0.49 Mg C ha -1 yr -1, but could store 0.81 Mg C ha -1 yr -1 if it was conventionally tilled in the first two inventories and under no-till in the final inventory. Cropland under conventional tillage in the first two inventories and no-till the final inventory could store an average of 0.34 Mg C ha -1 yr -1, but cropland under conventional tillage in the first, reduced tillage in the second, and no-till in the third inventory is estimated to store 0.19 Mg C ha -1 yr -1. The detailed annual rates of SOC stock change estimated using the approach is useful for economic or other analyses and for policymakers.
  • Authors:
    • Calegari, A.
    • Balota, E. L.
    • Nakatani, A. S.
    • Coyne, M. S.
  • Source: Agriculture Ecosystems and Environment
  • Volume: 197
  • Year: 2014
  • Summary: Soil degradation in Brazil is a concern due to intensive agricultural production. Combining conservation practice, such as no-tillage, with winter cover crops may increase microbial activity and enhance soil quality more than either practice alone. This research evaluated the benefits of long-term (23 years) winter cover crops and reduced tillage on soil microbial quality indicators in an Oxisol from Parana State, Southern Brazil. The winter cover treatments were: fallow, black oat, wheat, radish, blue lupin, and hairy vetch in conventional (plow) or no-tillage management; the summer crop was a soybean/maize rotation. Soil quality parameters included organic C, microbial biomass C and N, total and labile polysaccharide, easily extractable and total glomalin-related soil protein, and enzyme activity. Winter crops increased soil microbial quality parameters compared to fallow in both tillage systems, with greater relative increase in conventional than no-tillage. No-tillage had higher microbial biomass, polysaccharide, glomalin-related soil protein, and soil enzyme activity than conventional tillage. Including legumes in the crop rotation was important for N balance in the soil-plant system, increasing soil organic C content, and enhancing soil quality parameters to a greater extent than grasses or radish. The microbial parameters proved to be more sensitive indicators of soil change than soil organic C. Cultivating winter cover crop with either tillage is a beneficial practice enhancing soil microbial quality and also soil organic C stocks.
  • Authors:
    • Eisenhauer, D. E.
    • Gilley, J. E.
    • Blanco-Canqui, H.
    • Jasa, P. J.
    • Boldt, A.
  • Source: AGRONOMY JOURNAL
  • Volume: 106
  • Issue: 6
  • Year: 2014
  • Summary: The benefits of grass barriers or hedges for reducing offsite transport of non-point-source water pollutants from croplands are well recognized, but their ancillary benefits on soil properties have received less attention. We studied the 15-yr cumulative effects of narrow and perennial switchgrass ( Panicum virgatum L.) barriers on soil organic C (SOC), total N, particulate organic matter (POM), and associated soil structural properties as compared with the cropped area on an Aksarben silty clay loam (fine, smectitic, mesic Typic Argiudoll) with 5.4% slope in eastern Nebraska. Five switchgrass barriers were established in 1998 at ~38-m intervals parallel to the crop rows in a field under a conventional tillage and no-till grain sorghum [ Sorghum bicolor (L.) Moench]-soybean [ Glycine max (L.) Merr.]-corn ( Zea mays L.) rotation. Compared with the cropped area, switchgrass barriers accumulated about 0.85 Mg ha -1 yr -1 of SOC and 80 kg ha -1 yr -1 of total soil N at the 0 to 15 cm soil depth. Switchgrass barriers also increased coarse POM by 60%. Mean weight diameter of water-stable aggregates increased by 70% at 0 to 15 cm and by 40% at 15 to 60 cm, indicating that switchgrass barriers improved soil aggregation at deeper depths. Large (4.75-8 mm) macroaggregates under switchgrass barriers contained 30% more SOC than those under the cropped area. Switchgrass-induced changes in SOC concentration were positively associated with aggregate stability ( r=0.89***) and porosity ( r=0.47*). Overall, switchgrass barriers integrated with intensively managed agroecosystems can increase the SOC pool and improve soil structural properties.
  • Authors:
    • Dygert, C.
    • Chen, L.
    • Campbell, B.
    • Dick, W.
  • Source: JOURNAL OF SOIL AND WATER CONSERVATION
  • Volume: 69
  • Issue: 6
  • Year: 2014
  • Summary: Soils may be a source or sink of greenhouse gases (carbon dioxide [CO2], nitrous oxide [N2O], and methane [CH4]) that lead to global warming and climate change. While it is known that greenhouse gases are naturally cycled through soil and are part of the carbon (C) and nitrogen (N) cycles, it is not fully understood what effect crop production practices have on this cycling. Therefore, a study was conducted at the longest, continually maintained no-tillage plots in the world at Wooster (50 years no-till), near Wooster, Ohio, and Hoytville (49 years no-till), near Custar, Ohio, that represent two contrasting Ohio soils. Fluxes of greenhouse gases were measured by gas chromatography (GC) biweekly and following rainfall events greater than 1.2 cm (0.5 in) during the growing season of the corn (Zed mays L.), starting in July of 2011 until October of 2011, and then from May of 2012 to July of 2012. Samples were obtained at both sites in plots with rotations of corn after corn (CC) and corn after soybean (Glycine max L.) (CS), and when soils were managed using no-tillage (NT) and chisel or minimum conservation tillage (MT). Comparisons statistically significant at the p <0.10 level are as follows. For CO2 ' the CS rotation yielded lower emissions than the CC at both sites, due to less biomass cycling. For N2 O, the CS rotation yielded lower emissions than the CC at both sites due to less total N fertilizer input in the CS than the CC rotation. The NT system resulted in lower N2 O emissions than the MT system at Hoytville, but not at Wooster. For CH4, soil in the long-term plots often acted as sinks. Global warming potentials were lower for Hoytville than Wooster and lower for rotation of CS than CC at both Hoytville and Wooster. Overall, after about 50 years, it is evident that the use of no-tillage combined with crop rotations can lead to improved environmental (i.e., greenhouse gas emissions and global warming potential) benefits.
  • Authors:
    • Giurgiu, R. M.
    • Moraru, P. I.
    • Pop, A. I.
    • Bogdan, I.
    • Rusu, T.
    • Duda, B. M.
    • Coste, C. L.
  • Source: Research Journal of Agricultural Science
  • Volume: 46
  • Issue: 1
  • Year: 2014
  • Summary: This paper focuses on conservative agriculture, determined as minimal soil tillage, no tillage and enduring soil cover (mulch) together with rational rotations, as to achieve a more sustainable cultivation system for the future, in the context of the global warming and the permanent increase of population. Both farming and tillage play important roles in the agricultural systems. The conservative tillage systems in agriculture appeared in the U.S. and have developed in different ways, adapted to climatic zones and are considered unconventional or for soil conservation systems. Our research shows an improvement on conservative tillage, where no tillage, mulch and rotations significantly improve soil properties and other biotic factors also reducing the CO 2 emissions. Advantages of conservative tillage systems are represented by improving soil physics and excellent control of soil erosion, accumulation and water retention in the soil, reduced labor and fuel costs and in some cases even increased productivity. In the conservative tillage systems, land must be covered with plant debris at a rate of 15-30%, and in minimal tillage system with crop residue mulch, coverage exceeds 30%. In the no tillage system, sowing is done directly in the stubble or on a ground covered with plant debris from the preceding plant, using precision machinery. The paper concludes that a conservative tillage system is a more environmentally friendly and sustainable management system for cultivating crops. Case studies from all over the world show that when using conservative agriculture for most of the crops we get a raise production sustainably and profitably. Advantages in terms of greenhouse gas emissions and their effect on global warming are also taken into consideration. These systems also have a big disadvantage, high consumption of herbicides for weed control. An increased attention for direct seeding requires preventive plant protection characters. Seeds must be treated with insecticide-fungicide and soil requires more herbicide than for the classic systems with plough. The paper concludes that farming and agriculture in the next decade will have to produce more food from less or the same land through more efficient management of natural resources and with less impact on the environment in order to sustain the permanent growing population demands. Promoting and adopting conservative agriculture management systems can help meet this goal.
  • Authors:
    • Lal, R.
    • Kadono, A.
    • Nakajima, T.
    • Kumar, S.
    • Fausey, N.
  • Source: JOURNAL OF SOIL AND WATER CONSERVATION
  • Volume: 69
  • Issue: 6
  • Year: 2014
  • Summary: Intensive tillage practices and poorly drained soils of the Midwestern United States are one of the prime reasons for increased greenhouse gas (GHG) fluxes from agriculture. The naturally poorly drained soils prevalent in this region require subsurface drainage for improving aeration and reducing GHG fluxes from soils. However, very little research has been conducted on the combination of tillage and drainage impacts on GHG fluxes from poorly drained soils. Thus, the present study was conducted in central Ohio with specific objective to assess the influences of long-term (18-year) no-tillage (NT) and chisel-till (CT) impacts on carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4) fluxes from the soils in plots managed under drained (D) or nondrained (ND) conditions. The experimental site was established on a poorly drained Crosby silt loam soil in 1994 under corn (Zed mays L.)-corn rotation. Measurements of soil CO2, N2 O, and CH4 fluxes were conducted biweekly during 2011 and 2012 using the static chamber technique. In 2011, the annual CO2-C and N2 O-N from NT were 18% and 83%, respectively, lower compared to CT. Similar trends were observed for 2012. Methane fluxes were highly variable in both years.Tillage and drainage influenced seasonal soil GHG emissions; however, differences were not always significant. In general, plots under NT with subsurface drainage produced lower emissions compared to those under CT. Subsurface drainage lowered the emissions compared to those under ND. Results from this study concluded that subsurface drainage in poorly drained soils with long-term NT practice can be beneficial for the environment by emitting lower GHG fluxes compared to tilled soils with no drainage. However, long-term monitoring of these fluxes under diverse cropping systems under poorly drained soils is needed.