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Background: Achieving a net zero greenhouse gas United States (US) economy is likely to require both deep sectoral mitigation and additional carbon dioxide removals to offset hard-to-abate emissions. Enhancing the terrestrial carbon sink, through practices such as the adoption of no-till and cover cropping agricultural management, could provide a portion of these required offsets. Changing domestic agricultural practices to optimize carbon content, however, might reduce or shift US agricultural commodity outputs and exports, with potential implications on respective global markets and land use patterns. Here, we use an integrated energy-economy-land-climate model to comprehensively assess the global land, trade, and emissions impacts of an adoption of domestic no-till farming and cover cropping practices based on carbon pricing. Results: We find that the adoption of these practices varies depending on which aspects of terrestrial carbon are valued. Valuation of all terrestrial carbon resulted in afforestation at the expense of domestic agricultural production. In contrast, a policy valuing soil carbon in agricultural systems specifically indicates strong adoption of no-till and cover cropping for key crops. Conclusions: We conclude that under targeted terrestrial carbon incentives, adoption of no-till and cover cropping practices in the US could increase the terrestrial carbon sink with limited effects on crop availability for food and fodder markets. Future work should consider integrated assessment modeling of non-CO2 greenhouse gas impacts, above ground carbon storage changes, and capital and operating cost considerations. [ABSTRACT FROM AUTHOR]

Aims: No tillage (No-till, NT), a form of conservation agricultural management, can improve food security and alleviate world climate change by influencing crop yield and soil organic carbon (SOC), but the effects of NT on crop yields and SOC and the major factors which influence these effects remain poorly understood. Methods: We conducted a global meta-analysis using 5230 paired observations from 446 studies to evaluate the effects of NT on upland crop yield and SOC and to explore the associated influencing factors. Results: Generally, NT decreased upland crop yields by 5% (P < 0.05) and increased SOC sequestration by 9.9% (P < 0.05). Specifically, wheat and maize yields decreased by 7.7% and 2.3%, respectively. Our analyses indicate that NT combined with crop residue return and crop rotation reduced the negative effect of NT on crop yield from 5% to 2.44% and increased SOC up to 12.77%. The effects of NT on yield and SOC varied depending on the regulating factors. No-till increased yields in relatively arid areas, but reduced yields in more humid areas, whereas SOC is more likely to increase in humid regions. Soil organic carbon sequestration increased with temperature, but yield losses also increased in warmer regions. Conclusions: Our study suggests that NT combined with crop residue return and crop rotation could enhance SOC sequestration under moist and warm conditions without compromising crop yield. It may also improve soil quality and help alleviate global food security and climate change. [ABSTRACT FROM AUTHOR]

Sustainable agricultural management practices aimed at improving soil health can alter the soil microbiome, which can influence plant health and defenses against insects. The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, is a major belowground pest of corn. Pest management relies heavily on the planting of transgenic crops expressing Bacillus thuringiensis (Bt) toxins. In this study, we ask how corn-WCR interactions via the soil microbiome are affected by a conservation management system (extended corn-soybean-wheat rotation with cover crops under no-till) compared with a conventional management system (corn-soybean rotation under mulch tillage and no cover crops) when combined with transgenic Bt corn. To do this, we applied soil microbes from the conservation and conventional management systems to two corn lines, one producing Bt and one non-Bt. We then reared Bt-resistant and Bt-susceptible WCR on inoculated seedlings to examine plant and insect changes in fitness. We found that Bt was effective against susceptible larvae in both soil treatments. Bt-resistant larvae were ~ 20% smaller when reared in the presence of soil microbes from the conservation management system. Thus, control of Bt-resistant WCR may be improved in a conservation system without sacrificing Bt effectiveness in susceptible insects. Comparing the microbial communities using 16S rRNA sequencing revealed that management practices influenced the microbiomes associated with the soil and the plant rhizosphere, but not WCR. Our findings suggest value for growers in utilizing conservation management practices, such as no-till and cover crops, in agricultural systems through bottom-up changes to plant–insect interactions via the soil microbiome. [ABSTRACT FROM AUTHOR]

The agriculture sector is responsible for approximately one-quarter of Brazilian greenhouse gas (GHG) emissions. In the present study, we aimed to quantify the CO2 equivalent (CO2eq) balance on annual basis of three farms with soybean‒maize crop systems in the state of Mato Grosso. Each farm had an areas with native vegetation and two other areas cultivated with soybean under no-till practices with different conversion times [2–5 years (S1) and more than 10 years (S2)]. Soil samples were taken to determine soil C stocks. GHG emissions were estimated for the 2020/2021 crop season according to the scope, GHG type, and source. The results showed that, on average, the soil total carbon (C) stocks under S1 and S2 underwent a 12% reduction relative to native vegetation (< 15 Mg ha−1), but they increased by 30% (> 22 Mg ha−1) with increasing time since conversion (S2 vs. S1). The scope 1 (direct emissions from the use of fuels in mobile and stationary implements when applying lime and nitrogen fertilizers, and from decomposition of crop residues) represented 67% of the total emissions, whereas the scope 3 (indirect emissions associated with the production of synthetic fertilizers, lime, fuels and seeds) were responsible 33% of the total GHG emissions on the three farms. On average, for the soybean‒maize farms, the observed GHG emissions (losses) were approximately 2.1 Mg CO2eq ha−1 yr−1, while soil C sequestration amounted to 4 Mg CO2eq ha−1 yr−1, resulting in a mean CO2eq balance of approximately -1.9 Mg CO2eq ha−1 yr−1. Our study showed that the sequestration of C in soil can be adopted in initiatives as a carbon dioxide removal strategy in agriculture systems. [ABSTRACT FROM AUTHOR]

U.S. agricultural producers are increasingly able to participate in private voluntary carbon initiatives that compensate their efforts to sequester CO2, reduce GHG emissions, and provide ecosystem services through eligible conservation practices. This study examines the potential effects of alternative private payment regimes (per practice vs. per output), prices paid to farmers relative to out-of-pocket costs (low vs. high), and the availability of information on CO2 sequestration (limited vs. full), on the adoption of cover crops and no-till in the United States, the resulting CO2 sequestration, and changes in farmers' net returns. The analysis relies on a highly stylized model of heterogeneous farms calibrated with county-level agronomic data, and simulated for current estimates of GHG impacts of cover crop planting and no-till under different scenarios. Our results indicate that agricultural carbon markets can be profitable for U.S. farmers, although with substantial geographic variability, and that annual carbon sequestration could range between 17 and 75 million mtCO2e. Payments per output would incentivize higher carbon sequestration than payments per practice, but the former regime would be less favored by farmers as a unified group than the latter (due to lower aggregate net returns). However, if operators of farms with high carbon sequestration potential could decide the payment regime to be implemented, they would choose the payment per output regime (due to higher net returns per enrolled hectare). Total projected net changes in GHGs under payments per practice, based solely on county-average net GHG effects of cover crops and no-till, over-estimate actual total GHG sequestration (based on the entire distribution of net effects by county) by 2.1 and 14.2 million mtCO2e, or 18% and 21%, respectively. [ABSTRACT FROM AUTHOR]

The research aimed to study the effect of the No-till technology on the content of plant-available nitrogen, phosphorus, and potassium in ordinary chernozem of the Central Ciscaucasia. The work was carried out in 2013–2020 in a four-field crop rotation. Soil samples were taken after the first and second rotations. A two-factor experiment was performed to study soil cultivation options (recommended for the region and No-till) on different agricultural backgrounds (unfertilized and fertilized). During the entire observation period, despite the cultivation option used, the content of nitrate nitrogen in the 0–30-cm soil layer was low and ranged from 3.8–5.8 to 9.7–10.7 mg/kg. Such low nitrogen content indicates the need of application of nitrogen fertilizers. During two crop rotations, no significant changes in the content of available phosphorus have been determined on an unfertilized arable soil for the both variants of the used cultivation technologies. In all soil layers, the values of this indicator correspond to the average level of availability (from 15.2 to 17.2 mg/kg). The application of fertilizers led to an increase in the content of available phosphorus by the end of the second rotation of crop rotation in the soil layer of 0–30 cm. The content of available phosphorus increased up to 24.8 and 33.4 mg/kg with the recommended technology and the No-till option, respectively. The content of mobile potassium after the first crop rotation was similar for the variants with both studied technologies and natural soil fertility (261–266 mg/kg). However, on the fertilized soil, the difference associated with the application of the cultivation technique is significant: the No-till technology is associated with higher content of mobile phosphorus. In the 0–10 cm layer this difference amounted to 18 mg/kg, or 6.3%. The second rotation was characterized by a decrease in the K2O content in the 0–30 cm layer, which was more pronounced for the variant with the recommended technology (by 39–48 mg/kg (13.8–20.2%) and 28–39 mg/kg (9.8–16.5%) on an unfertilized and fertilized backgrounds, respectively). The use of No‑till technology on the unfertilized soil results in a decrease of this indicator by 22–34 mg/kg. In the 0‒10-cm layer, in the option with this technology, K2O content tends to increase on the unfertilized background by 9 mg/kg (3.1%) and significantly increases on the fertilized background (by 30 mg/kg or 9.9%). [ABSTRACT FROM AUTHOR]

Conservation agriculture is often assumed to reduce soil N2O emissions. Yet, studies analyzing the specific effect of conservation agriculture practices on N2O emissions give contradictory results. Herein, we synthesized a comprehensive database on the three main conservation agriculture practices (cover crops, diversified crop rotations, and no-till and/or reduced tillage (NT/RT)) to elucidate the role of conservation practices on N2O emissions. Further, we used a random meta-forest approach to identify the most important predictors of the effects of these practices on soil N2O emissions. Averaged across all comparisons, NT/RT significantly decreased soil N2O emissions by 11% (95% CI: –19 to –1%) compared to conventional tillage. The reductions due to NT/RT were more commonly observed in humid climates and in soils with an initial carbon content < 20 g kg–1. The implementation of cover crops and diversified crop rotations led to variable effects on soil N2O emissions. Cover crops were more likely to reduce soil N2O emissions at neutral soil pH, and in soils with intermediate carbon (~20 g kg–1) and nitrogen (~3 g kg–1) contents. Diversified crop rotations tended to increase soil N2O emissions in temperate regions and neutral to alkaline soils. Our results provide a comprehensive predictive framework to understand the conditions in which the adoption of various conservation agriculture practices can contribute to climate change mitigation. Combining these results with a similar mechanistic understanding of conservation agriculture impacts on ecosystem services and crop production will pave the way for a wider adoption globally of these management practices. [ABSTRACT FROM AUTHOR]

The methodological possibilities of micromorphological soil research to analyze digital images of soil thin sections at a quantitative level are presented in this study. A new software Thixomet Pro has been tested for quantitative micromorphological study of soil thin sections from the surface horizons of a Haplic Chernozem. Soil samples for preparing thin sections were collected on the territory of a field experiment for assessing the impact of agricultural technologies in grain crop rotation on soil properties in Kursk oblast, Russia. In the field experiment, conventional tillage and no-till (direct seeding) technologies were compared. Soil sampling was carried out in two replicates from a depth of 10–15 cm. The analysis of thin sections revealed the variability of microstructure of Haplic Chernozem in the size, shape, and orientation of aggregates associated with used agricultural technologies in grain crop rotation. Soil aggregates under no-till are generally larger compared to the aggregates under conventional tillage. This is noted for all levels of aggregate diameters: minimum, medium, and maximum. In trials with direct seeding, agronomically valuable aggregates typical of the structure of virgin soils predominate. The aggregates formed in the no-till soil are less rounded and isometric than those in the soil under conventional tillage, and the proportion of subhorizontal aggregates is higher (54.3 and 34.1%, respectively), which favors water retention in the surface horizon. [ABSTRACT FROM AUTHOR]

The influence of agricultural tillage technologies on the accumulation and distribution of trace elements in the soil is poorly studied. At the same time, intensive agriculture requires large amounts of fertilizers, growth stimulators, pesticides, and other substances, which can effect the ecological safety of the plant products and soil. This paper represents studying the effect of various agricultural techniques (including resource-saving technologies) on the mobility and profile distribution of Pb, Zn, and Cu in Haplic Chernozem. No significant influence of resource-saving tillage technologies was found on the total Pb content. Contrary, the resource-saving tillage technologies was observed to promote the growth of the total Zn and Cu content depending on the cultivation method (by 26% Zn, 34% Cu at minimal tillage, and 28% for both elements using No-till in Ap horizon). Amongst different applied agrotechnologies, there was no influence found on the profile distribution of total elements content. Only two horizons showed the total Pb content accumulation: biogenic (Ap-A) and carbonate (BC-C) horizon. In contrast, the only biogenic accumulation for Zn was determined. Copper characterizes by even distribution over the soil profile. The use of resource-saving agricultural technologies increases exchangeable fraction of Zn, Pb and Cu in soil almost by 1.5–2.0 times in the Ap horizon compared to moldboard ploughing. Despite the increase in the exchangeable fraction of Zn and Cu, this amount of micronutrients is not enough for adequate plant nutrition. The use of various agricultural technologies at Haplic Chernozem led to changes in the distribution of studied elements' exchangeable fraction over the soil profile. The study results suggested a need to increase the amount of Cu and Zn fertilizers applied to the soil with resource-saving cultivation technologies. [ABSTRACT FROM AUTHOR]

This review suggests that most of the management practices associated with regenerative agriculture are not likely to lead to a large net sequestration of organic carbon in soils. Some improved management practices, such as increased fertilizer use, manuring, and applications of biochar, are constrained by biogeochemical stoichiometry and the availability of organic inputs. Other management practices, such as fertilizer applications, irrigation, and applications of ground silicate minerals, entail ancillary and off-site emissions of carbon dioxide that reduce the net sequestration of carbon in soils. Carbon sequestration in agricultural soils, even with best management practices, is only likely to offer a small net storage of carbon that can be marketed as a credit to emissions from other sectors of the economy. [ABSTRACT FROM AUTHOR]

The advent of 'conservation agriculture' (CA) farming using zero- or no-tillage practices and an accompanying change in crop rotations in the last 10–15 years has potentially led to less disturbance of mouse burrows and increased cover and food supply. Given the irregular outbreaks of mice in grain cropping regions in Australia and the damage they cause, it is important to understand when and where mouse populations increase so that management strategies can be improved. We utilised a 20-year long-term mouse population data set collected prior to the introduction of CA farming practices and a more recent 8-year data set after CA to compare changes in mouse population abundance in a typical dryland grain cropping system in north-western Victoria, Australia. Mouse trapping data were used to compare abundance in crop and margin habitats during crop growth and non-crop (fallow) periods before ('conventional') and after introduction of CA. Mice are now resident year-round within crops and stubble and appear to only spill over into margin habitats. Previously developed recommendations for mouse management that include their control while in margin habitats may no longer be valid. [ABSTRACT FROM AUTHOR]

This study investigates the adsorption and dissipation of glyphosate and the formation/dissipation of AMPA in non-tilled (NT) and conventionally tilled (CT) soil at 0–5 and 5–20 cm depth. Glyphosate adsorption was mainly related to the different NT and CT soil properties (clay and amorphous Al oxides), whereas an effect of the soil management could not be identified. Glyphosate dissipation was initially fast, and it slowed down later. The initial glyphosate concentration in NT soil at 0–5 cm was significantly lower than the dose applied due to the interception by the weeds and crop residues. AMPA began to form early after treatment and persisted longer than glyphosate. The DT50 range was 8–18 days for glyphosate and 99–250 days for AMPA. Longer glyphosate and AMPA DT50 were observed in NT soil compared to CT soil but, for glyphosate, the difference was significant only at 5–20 cm. Higher glyphosate and AMPA concentrations were detected in NT than in CT soil at the end of the study at 0–5 cm. The differences in glyphosate and AMPA DT50 and persistence were mainly attributable to the influence of different NT and CT soil characteristics. However, other factors could have contributed to the different glyphosate and AMPA dynamics between the soils, like glyphosate wash-off from crop residues on NT soil with the rainfall, the delayed glyphosate return to the soil by weed root exudation or weeds decomposition, and the NT soil compaction which may have reduced the microbial degradation of glyphosate at low concentrations. Article Highlights: Glyphosate adsorption and dissipation were studied in non-tilled and tilled soils at two depths. Glyphosate adsorption was higher in non-tilled soil compared to the tilled soil at both depths. Glyphosate and AMPA DT50 were longer in non-tilled than in tilled soil at 5–20 cm depth. Differences in adsorption and DT50 were mainly attributable to the influence of soil characteristics. After 6 months, glyphosate and AMPA concentrations were higher in non-tilled than tilled soil at 0–5 cm depth. [ABSTRACT FROM AUTHOR]

Knowledge of the persistence of Cry proteins in transgenic corn residue after harvest is necessary to assess the ecological risk to nontarget organisms. The amount of protein remaining in crop residue declines over time by a combination of microbial decomposition and leaching, both influenced by temperature, precipitation, and the amount of residue-soil contact. Here, we investigated how long biologically active Cry proteins persist in SmartStax corn residue expressing Cry1A.105, Cry1F, Cry2Ab2, Cry3Bb1, and Cry34/35Ab1, when subjected to four post-harvest practices (chisel plow tillage, flail mowing, cover crop planting, and undisturbed residue). Protein activity in residue samples collected up to 25 weeks after harvest was measured by Ostrinia nubilalis feeding bioassays and cross validated with detection frequencies determined by ELISA. All corn residue remained above ground in the flail-mowed and undisturbed treatments, while the cover crop and chisel plow treatments left 88.3 and 39.6% of the residue remaining above ground, respectively. Cry proteins retained biological activity for as long as 24 weeks after harvest when residue was left above ground with less soil contact, typical of no-till corn systems. ELISA detections were positively correlated with results of the feeding bioassays, which revealed the presence of active proteins beyond the point of ELISA detection. [ABSTRACT FROM AUTHOR]

Our objective was to evaluate the impact of land use change, from natural forest to tillage-based systems, on the distribution of P pools and their stratification in soils under both no-till (NT) and conventionally tilled (CT) corn (Zea mays)-soybean (Glycine max) with and without cover crops, CT alfalfa (Medicago sativa), chicken and dairy manure, organic, and adjacent natural deciduous forest ecosystems (control). Results showed that residual P (RP) accounted for 68.7% followed by 13.3% calcium- and magnesium-bound P (CaMgP), 9.6% particulate organic P (POP), 8% iron- and aluminum-bound P (FeAlP), 0.3% soluble reactive P (SRP), and 0.1% exchangeable P (EP) of the total P. While the concentration of all P pools increased, the POP decreased at 0–10 cm depth under both CT and NT compared to the forest. The SRP increased threefold under NT, 2.6-fold under CT, sevenfold under alfalfa, and more than fourfold under organic, chicken and dairy manure systems. In contrast, the POP decreased by 63 to 73% under CT and 41 to 58% under NT. Likewise, the POP decreased under CT dairy and chicken manure, alfalfa, and organic systems. A similar tillage and cover crop impact on SRP and POP was observed at 10–20 cm depth. All P pools except POP have shown various degrees of stratification. An integration of cover crops under NT reduced the SRP stratification (by 41%), when compared to NT alone. Our results suggested that the SRP concentration and stratification in all agricultural systems are prone to edge-of-field loss either by drainage under NT or surface runoff under CT. [ABSTRACT FROM AUTHOR]

This article presents the results of research on the impact of no-till technology on the natural bulk density and macro- and microaggregate composition of the topsoil (0–20 cm) in different subtypes of chernozems before sowing and during the growing season. Haplic Chernozems (Loamic, Aric, Pachic) and Haplic Chernozems (Loamic, Aric) were studied. For all chernozems, improvement of physical properties was recorded when no-till was introduced in comparison with the control. Four and six years of crop growing without tillage did not cause any compaction of Haplic Chernozems (typical and ordinary subtypes). On the plots with direct sowing, the microaggregate composition of typical chernozems was characterized by a higher proportion of coarse fractions (>50 µm) in comparison with the control. Probably, this indicates the development of microaggregation similar to that under natural cenoses, which are characterized by a relatively high content of the fraction 50–250 µm, upon the transition to no-till. In all subtypes of chernozems under no-till, the water stability of aggregates increased. The share of agronomically valuable aggregates in typical chernozem also increased, which may be associated with an increase in the input of water-soluble organic matter into the soil during no-till, because this technology excludes translocation of plant residues into the soil. In southern chernozems, this effect was manifested only for fractions >7 mm, while water stability of finer aggregates was mainly due to the calcium content regardless of the type of tillage. [ABSTRACT FROM AUTHOR]

The potential of tillage systems for generating environmental pollution and the economic risks of the systems are influential factors for farmers to adopt conservation tillage practices. This study was carried out between 2000 and 2008 in order to evaluate the economic and risk of different tillage and planting systems in the province of Erzurum, Turkey. Tillage treatments consist of conventional tillage [moldboard plow + disk harrow + combined harrows + precision seeder, (CT)], reduced tillage 1 [cultivator + combined harrows + precision seeder, (RT1)], reduced tillage 2 [rotary power harrow + precision seeder, (RT2)] and no-till seeding [no-till seeder, (NT)] systems which were studied. A trial field has been tilled with four different tillage systems with a crop rotation of common vetch–winter wheat–sunflower. The economic evaluation of the tillage and planting systems was made by calculating the gross margin and the risk appraisal and the standard deviation of the yield and gross margins. The conventional tillage system required the most labor, fuel, oil and variable costs. According to conventional tillage and planting system, the most cost-saving system is direct planting by NT. The highest pollutant in terms of environment was the CT system with the highest carbon dioxide release, while the NT system was the most environmentally friendly system. The order of systems from high to low, in terms of obtained gross margin, ranked a CT, RT1, RT2 and NT. The lowest variation in terms of productivity was in the NT system for all products, and the highest variation was in the RT1 system. In terms of gross margin, the lowest variation was again in the NT system. A farmer who decides on the basis of gross margin should choose the CT system with the highest average gross margin. A producer considering gross margin should decide on the NT system based on risk assessment. [ABSTRACT FROM AUTHOR]

Background: Nutrient balance in rice paddy fields can change under different tillage management practices; however, the extent of the change may differ for various rice varieties. A field experiment was conducted over 2 successive years to clarify the effects of no-till and rice varieties on the apparent balance of nitrogen (N) and phosphorus (P). Four treatments: no-till/japonica rice (NTJ), no-till/glutinous rice (NTG), conventional tillage/japonica rice (CTJ), and conventional tillage/glutinous rice (CTG) with three replicates of each were established to test the hypothesis that no-till and japonica rice can improve the apparent balance of nutrients. Results: The tillage method and rice variety had interactive effects on the apparent balance of N and P. After the 2-year experiment, total N and P pools in the 20 cm surface soil layer were highest under the NTJ treatment (4757.0 kg N ha−1, 2428.5 kg P ha−1) and lowest under the CTG treatments (4726.3 kg N ha−1, 2412.0 kg P ha−1). Under no-till conditions, japonica rice had higher grain yield but lower straw biomass than that of glutinous rice. NTG treatment significantly increased the N and P content in rice grains and straw. The environmental losses of N and P in the rice fields mainly occurred during the rice season. Based on nutrient balance estimation, N losses in the NTJ, NTG, and CTJ treatments were reduced by 15.03 kg N ha−1, 11.55 kg N ha−1, 6.72 kg N ha−1, respectively, as compared with that of the CTG treatment. The corresponding P losses were reduced by 8.02 kg P ha−1, 7.84 kg P ha−1, and 3.96 kg P ha−1. In terms of economic benefits, NTJ also resulted in the highest actual income (2724.25 US dollars) and the highest ratio of production investment (6.40). Conclusion: No-till was more likely to maintain soil N and P nutrients than conventional tillage, and this advantage was most significant when planting japonica rice. In addition, no-till was conducive to N and P uptake by rice, but only japonica rice exhibited increased grain yield. Consequently, the NTJ treatment was recommended to improve the N and P balance. [ABSTRACT FROM AUTHOR]

To evaluate the combined effect of different agricultural practices on photosynthetic nitrogen and water-use efficiency, winter wheat was grown in the field under tillage and no-till conditions, with and without cover crops under low and high nitrogen fertilization inputs. Leaf physiological traits, such as the rate of photosynthesis, stomatal conductance, the rate of transpiration, the chlorophyll content index, the leaf area ratio, and specific leaf area were used as indicators representative of nitrogen and water-use efficiency. Six years after conversion to no-till, in the presence and in the absence of cover crops, significant increases in photosynthetic water-use efficiency and soil water content were observed both under low and high nitrogen fertilization input. Moreover, we observed that photosynthetic nitrogen-use efficiency, the rate of photosynthesis and specific leaf area were higher in the absence of tilling than in the presence of tilling. Thus, agronomic practices based on continuous no-till appear to be promising for increasing both photosynthetic nitrogen- and water-use efficiency in winter wheat. [ABSTRACT FROM AUTHOR]

The evolution of agricultural technologies in the development of human civilization is considered. Based on this example, it is shown that a new stage in soil cultivation technology began in the 20th century. It is associated with the transition from extensive "gray" technologies for the management of natural resources, which are strictly oriented only by momentary economic feasibility, to nontraditional ("nature-based") "green" farming technologies. A natural transition has taken place from the strategy of its development based on Ziegler's principle of maximum entropy production to Prigogine's strategy of minimum entropy production, which is based on the rationalization of the use of available resources for a dissipative structure on the planet, such as the human population. The foundation for the rationalization is nature-based technology for human use of natural resources. The theoretical justification of the inevitability of "green farming" is confirmed by the example of a long-term biosphere experiment on the development of agricultural technologies. This type of farming is characterized by a more economical method of tillage: partial or complete rejection of soil-turn plowing, the absence of vertical mixing of the arable layer, minimal disturbance of the soil cover by agricultural machines, and mandatory soil mulching ("no-till" or "mulch tillage") in order to preserve the soil moisture and reduce soil erosion. The no-till soil processing system, i.e., the absence of interference in the natural processes of soil formation, is a modern farming system in which the soil is not processed and its surface is covered with specially crushed plant residues (mulch). It is illustrated that the no-till technology of direct sowing and mulching is currently being introduced in various regions of the planet with shallow, surface loosening or even complete rejecting tillage. It is shown that the application of the green farming technologies leads to rationalization of the use of not only energy and soil resources but also water resources, for which the situation is becoming increasingly tense for human civilization. [ABSTRACT FROM AUTHOR]

After two decades of availability of grain yield-mapping technology, long-term trends in field-scale profitability for precision agriculture (PA) systems and conservation practices can now be assessed. Field-scale profitability of a conventional or 'business-as-usual' system with an annual corn (Zea mays L.)-soybean (Glycine max [L.]) rotation and annual tillage was assessed for 11 years on a 36 ha field in central Missouri during 1993 to 2003. Following this, a 'precision agriculture system' (PAS) with conservation practices was implemented for the next 11 years to address production, profit and environmental concerns. The PAS was multifaceted and temporally dynamic. It included no-till, cover crops, crop rotation changes, site-specific N and variable-rate or zonal P, K and lime. Following a recent evaluation of differences in yield and yield variability, this research compared profitability of the two systems. Results indicated that PAS sustained profits in the majority (97%) of the field without subsidies for cover crops or payments for enhanced environmental protection. Profit was only lower with PAS in a drainage channel where no-till sometimes hindered soybean stands and wet soils caused wheat (Triticum aestivum L.) disease. Although profit gains were not realized after 11 years of PA and conservation practices, this system sustained profits. These results should help growers gain confidence that PA and conservation practices will be successful. [ABSTRACT FROM AUTHOR]

Proposal: A 12-year field experiment was conducted to assess straw mulch effects on soil organic carbon fractions, the carbon pool management index (CPMI) at different depths, and crop yield under a no-till rice-wheat rotation system on the Chengdu Plain, southwestern China. Materials and methods: There were two treatments in the experiment: no-till without straw mulch (CK) and no-till with straw mulch (SM). The soil was sampled at 0–5, 5–10, 10–20, and 20–30-cm depths. Soil total organic carbon (TOC), the labile organic carbon fractions, including particulate organic carbon (POC), dissolved organic carbon (DOC), microbial biomass carbon (MBC), and permanganate-oxidizable carbon (KMnO4-C), and the CPMI were analyzed. The crop grains were measured between September 2013 and May 2018. Results and discussion: Between 2013 and 2018, rice and wheat grain yields under SM were comparable to CK, except there were higher rice yields in 2016 and higher wheat yields in 2017 under SM. The soil organic carbon decreased as soil depth increased in both treatments. Soil TOC, POC, and KMnO4-C concentrations at 0–5 and 5–10 cm, CPMI at 0–5 and 5–10 cm, and DOC at 0–5, 5–10, and 10–20-cm soil depths were significantly greater under SM than under CK, whereas the MBC at 0–5 and 5–10 cm under SM was lower than CK. The POC/TOC, KMnO4-C/TOC, and DOC/TOC ratios were greater under SM in the 0–5 and 5–10 cm, 0–5 cm, and 5–10 and 10–20-cm layers than CK, respectively, whereas the MBC/TOC ratio decreased under SM at 0–5, 5–10, and 10–20-cm depths. Conclusions: The results showed that straw mulching should be adopted when a no-till rice-wheat cropping system is used in southwestern China because it leads to effective improvements in SOC sequestration while still maintaining normal crop yields. [ABSTRACT FROM AUTHOR]

Ruzigrass (Urochloa ruziziensis) is a cover crop that is commonly used in Brazil and exudes high concentrations of organic acids from its roots, and is therefore expected to mobilize soil organic P such as inositol phosphates. However, it is not known if this can occur only under P deficient conditions. Specifically, we aimed to test the hypothesis that the degradation of inositol phosphates is increased by growing ruzigrass at two different P levels. To investigate this, we studied soil organic P in a 9-year-old field experiment, with treatments consisting of ruzigrass or fallow during the soybean (Glycine max) off-season, with or without P addition. Organic P was extracted in NaOH-EDTA, followed by colorimetric quantification of organic P hydrolysable by phytase, and myo-inositol hexakisphosphate by hypobromite oxidation and HPLC separation. Ruzigrass dry matter yield increased by about 80% with P application. Ruzigrass reduced the concentration of phytase labile P and myo-inositol hexakisphosphate, but only in soil receiving P. A corresponding increase in unidentified inositol phosphates, presumably representing lower-order esters, was also observed after ruzigrass in soil with P application. We deduce that the degradation of inositol phosphates under ruzigrass with P application is due to greater ruzigrass productivity in the more fertile treatment, increasing the release of root exudates that solubilize inositol phosphates and promote their decomposition by phytase. We conclude that ruzigrass cover cropping can promote the cycling of recalcitrant soil organic P, but only when fertility is raised to a sufficient level to ensure a productive crop. [ABSTRACT FROM AUTHOR]

Strategic tillage (ST), an occasional tillage in a continuous no-till (NT) farming system, is already being utilized by many landholders in the Northern Grains Region (NGR) of Australia to control weeds. But the impact on productivity (yield), both short- and long-term, has been largely under investigated. This study focused on yield data from 14 on-farm ST in NT experiments from 2012 to 2014 (3 years/4 seasons) and the comparison of the re-interpreted results of a long-term (27 years) tillage experiment. This study explored production impacts of tillage on long-term NT systems over the short and longer term. Results from tillage-frequency studies across the NGR demonstrated that overall grain yield was not significantly impacted. A long-term tillage trial at Biloela showed wheat (Triticum aestivum) and sorghum (Sorghum bicolor) grain yields were similar across no till, stubble mulch and reduced tillage treatments, these in turn were all significantly higher than aggressive tillage without stubble retention treatments. Dealing with increased herbicide resistance often associated with reduced tillage and no-till systems poses a real time issue with landholders in the NGR. This analysis of historical yield data together with the more recent strategic tillage data can aid in selecting the appropriate soil management option by providing tillage impacts on yield. [ABSTRACT FROM AUTHOR]

Background: Nitrate leaching is a primary pathway of nitrogen loss from agricultural systems, and is affected by both tillage and cropped species. However, there is little information on conservation systems without nitrogen fertilization.Methods: Nitrate leaching was assessed in soybean (Glycine max) cropped in rotation with the following cover crops under no-till and chiseling: ruzigrass (Brachiaria ruziziensis), grain sorghum (Sorghum bicolor), pearl millet (Pennisetum glaucum), forage sorghum (Sorghum bicolor), Sunn hemp (Crotalaria juncea), triticale (X Triticosecale) and sunflower (Helianthus annuus).Results: Ruzigrass and grain sorghum cropped in the fall/winter resulted in similar NO3− leaching, which was greater under sunflower than under triticale, likely due to high N uptake and immobilization in plant residues. Sunn hemp as a spring crop resulted in higher NO3− leaching than pearl millet at two locations and forage sorghum at one location likely due to a higher N input by biological fixation. Millet resulted in the lowest N leaching by depleting the soil solution. Chiseling/fallow resulted in higher nitrogen leaching as compared with non-fixing N cover crops.Conclusions: Even when N is not applied, it is important to intensify cropping systems in tropical environments using cover crops with vigorous root systems and high N demand, which prevent N leaching, as well as provides N to the following crop as the straw is mineralized. [ABSTRACT FROM AUTHOR]

Research is lacking on the long-term impacts of field-scale precision agriculture practices on grain production. Following more than a decade (1993-2003) of yield and soil mapping and water quality assessment, a multi-faceted, 'precision agriculture system' (PAS) was implemented from 2004 to 2014 on a 36-ha field in central Missouri. The PAS targeted management practices that address crop production and environmental issues. It included no-till, cover crops, growing winter wheat ( Triticum aestivum L.) instead of corn ( Zea mays L.) for field areas where corn was not profitable, site-specific N for wheat and corn using canopy reflectance sensing, variable-rate P, K and lime using intensively grid-sampled data, and targeting of herbicides based on weed pressure. The PAS assessment was accomplished by comparing it to the previous decade of conventional, whole-field corn-soybean ( Glycine max L.) mulch-tillage management. In the northern part of the field and compared to pre-PAS corn, relative grain yield of wheat in PAS was greatly improved and temporal yield variation was reduced on shallow topsoil, but relative grain yield was reduced on deep soil in the drainage channel. In the southern part of the field where corn remained in production, PAS did not lead to increased yield, but temporal yield variation was reduced. Across the whole field, soybean yield and temporal yield variation were only marginally influenced by PAS. Spatial yield variation of all three crops was not altered by PAS. Therefore, the greatest production advantage of a decade of precision agriculture was reduced temporal yield variation, which leads to greater yield stability and resilience to changing climate. [ABSTRACT FROM AUTHOR]

Use of reduced and no-tillage systems has increased in recent years due to concerns for ecological and economic sustainability of agricultural production. Effective weed control is a serious concern in reduced tillage production. This study was conducted to investigate weed control practices in reduced and no-till maize production. The most effective timing of glyphosate application, either before or after sowing, was investigated in combination with pre-emergence application of acetochlor (840 g a.i/L), post-emergence application of foramsulfuron (22.5 g a.i/L), and two hoeing treatments. The treatments were maintained on the same plots during 2011 and 2012 to evaluate the cumulative effects of the treatments. Main plot treatments consisted of four timings of glyphosate application: 20 or 10 days before sowing, day of sowing, 5 days after sowing, and an untreated control. Sub-plot treatments were: pre- plus post-emergence herbicides, pre-emergence herbicide plus rotary hoeing, post-emergence herbicide plus rotary hoeing, and post-emergence herbicide plus two hoeing treatments (rotary and lister hoe). In the main plots, the lowest weed biomass was produced in glyphosate treatments at sowing and 5 days after sowing; the highest biomass was produced in control plots and in the plots with glyphosate treatments 20 days before sowing. In the sub-plots, the greatest weed biomass was produced in plots with two hoeing treatments (rotary and lister hoe). Glyphosate treatments at sowing and post-emergence herbicide treatment combinations produced the best weed control. Economic analysis revealed that pre-sowing, non-selective herbicide treatments provided a slight increase in net profit. Mechanical hoeing decreased net income due to increased production costs. The highest income was obtained from the pre-emergence plus post-emergence herbicide treatment combinations with no glyphosate. [ABSTRACT FROM AUTHOR]

Background and aims: Relevant soil properties and nutrient distributions influencing crop root growth might be different under no-till (NT) and mouldboard plough (MP) management. The possible different root systems within different managements might have key impact on crop nutrient uptake and consequently crop production. Our objective was to assess the long-term combined effects of tillage and phosphorus (P) fertilization on corn ( Zea mays L.) root distribution and morphology. Methods: Corn root and soil samples were collected during the silking stage at five depths (0-5, 5-10, 10-20, 20-30 and 30-40 cm) and three horizontal distances perpendicular to the corn row (5, 15 and 25 cm) under MP and NT with three P fertilizations (0, 17.5, and 35 kg P ha) for a long-term (22 years) experiment in eastern Canada. Root morphology and soil properties were determined. Results: NT practice decreased corn root biomass by −26 % compared to MP, mainly by decreasing the primary and secondary roots. Additionally, corn roots in NT tend to be more expansive on the surface layer with higher root length and surface densities for the depth of 0-5 cm at two sampling distances of 15 and 25 cm. The 35 kg P ha rate increased the root biomass by 26 and 41 % compared to the 0 and 17.5 kg P ha rates. Conclusions: No-tillage practice and low rates of P fertilization reduce corn roots. This is probably caused by the weed competition in NT and the continued downward P status with low P rates over 22 years. [ABSTRACT FROM AUTHOR]

A field experiment was conducted to compare the effects of long-term tillage and crop residue management on some physical properties and nitrate leaching of a Typic Haploxerert soil under winter wheat (Triticum vulgare L.)-soybean (Glycine max L.) double-cropping system. The tillage systems consisted of conventional tillage with stubble (CT1), conventional tillage with stubbles burned (CT2), heavy disc harrow reduced tillage (RT1), rototiller reduced tillage (RT2), reduced tillage with heavy tandem disc harrow fallowed by no-tillage (RNT) and no-till (NT). Each tillage method applied at 480 m² plot and replicated three times in randomly distributed plots. In the experiment, organic matter content (OM), aggregate stability (AS), penetration resistance (PR), porosity, bulk density (BD) in 0-15 cm and 15-30 cm depth and nitrate concentrations at 90 cm depth were determined. Tillage practices significantly affected the measured properties at both soil depths. The BD and PR within the conservational managed plots were higher than under conventional managed plot. Whereas, OM content and AS were significantly greater under conservational managed plots, indicating improved soil quality. Soybean yield was not affected by tillage practices. The concentrations of NO3-N leached had strong variation within sampling dates and significantly different among treatments after the first and the third irrigation (P<0.01). The highest average NO3-N (1440.8b±74.9 mg L-1) in leachate was measured in the CT2 plot while the lowest value (774.8a±56.5 mg L-1) was obtained in the RT1 plot. The results of this study revealed that reduced tillage and no-till treatments could significantly improve soil physical quality and reduce NO3-N leaching of Typic Haploxerert soil in the Çukurova Region. [ABSTRACT FROM AUTHOR]

Background and aims: Tillage system and crop rotation influences soil organic carbon (SOC) and total N (TN), but there remains considerable uncertainty in the response of C and N dynamics to fertilizer N inputs. A long-term (11-yr) experiment on a clay loam Orthic Humic Gleysol at Ridgetown, Ontario, Canada was used to evaluate the impact of fertilizer N applications (in-season zero N (−N) compared to (+N) 100 and 80 kg N ha yr. to corn ( Zea mays L.) and wheat ( Triticum aestivum L.), respectively) on soil attributes. Methods: The cropping systems consisted of continuous corn (CC), corn-soybean ( Glycine max L.) (C-S) and corn-soybean-wheat (C-S-W) rotations using conventional moldboard plough and no-till systems. Soil was collected from the 0-120 cm profile in 5, 10, and 20 cm increments and analyzed for SOC and TN. Results: The effect and interaction of N fertilization on soil attributes was highly dependent on crop rotation and tillage system. The gain in SOC and TN contents due to +N fertilizer was greatest (up to 31 and 57 % relative to the -N control, respectively) in the 0-20 cm depth with the C-S-W rotation, and lowest under CC, which showed no N fertilizer effect. However, differences in SOC and TN were not confined to the surface 20 cm, as N fertilizer treatments significantly influenced the contents at 20-60 and 60-120 cm in certain rotation and tillage systems; C-S-W was the most responsive to N fertilizer-induced SOC and TN gains. Conclusions: Using regression analysis, we found that higher SOC contents corresponded to lower variability in the 5-yr. mean corn yield, which suggests that the inclusion of winter wheat in a C-S rotation may have important implications for sustainable and resilient agroecosystems in humid, temperate climates. [ABSTRACT FROM AUTHOR]

Aim: Conservation agriculture is increasingly adopted to improve soil fertility and reduce the depressive effects of intensive farming on soil functions and associated services. However, conservation agriculture systems may vary greatly regarding time since conversion to this system and the quality and biomass production of cover crops. In addition, the effects of these variables on soil fauna are still poorly known. Here, we aim to gain insight into the impact of conservation agriculture on soil mesofauna and macrofauna communities at the cropping system level.Collembola and earthworm communities were compared in seven neighbouring pairs of fields (same topography, spring crop and soil type) being either under conventional systems or under conservation agriculture systems with cover crops.Conservation agriculture systems influenced soil mesofauna and macrofauna communities compared to conventional systems. The beneficial effects of conservation agriculture on earthworm communities may predominantly be related to the lower soil physical disturbance (no-tillage) while Collembola may also be positively affected by cover crops characteristics and time since conversion to conservation agriculture.The adoption of conservation agriculture systems may improve earthworm and Collembola abundance and represents thus an innovative opportunity for sustainable crop production through the preservation of soil fauna. Finally, we suggest the use of a trait-based approach to draw functional consequences of soil faunal community changes operating in conservation agriculture.Method: Conservation agriculture is increasingly adopted to improve soil fertility and reduce the depressive effects of intensive farming on soil functions and associated services. However, conservation agriculture systems may vary greatly regarding time since conversion to this system and the quality and biomass production of cover crops. In addition, the effects of these variables on soil fauna are still poorly known. Here, we aim to gain insight into the impact of conservation agriculture on soil mesofauna and macrofauna communities at the cropping system level.Collembola and earthworm communities were compared in seven neighbouring pairs of fields (same topography, spring crop and soil type) being either under conventional systems or under conservation agriculture systems with cover crops.Conservation agriculture systems influenced soil mesofauna and macrofauna communities compared to conventional systems. The beneficial effects of conservation agriculture on earthworm communities may predominantly be related to the lower soil physical disturbance (no-tillage) while Collembola may also be positively affected by cover crops characteristics and time since conversion to conservation agriculture.The adoption of conservation agriculture systems may improve earthworm and Collembola abundance and represents thus an innovative opportunity for sustainable crop production through the preservation of soil fauna. Finally, we suggest the use of a trait-based approach to draw functional consequences of soil faunal community changes operating in conservation agriculture.Results: Conservation agriculture is increasingly adopted to improve soil fertility and reduce the depressive effects of intensive farming on soil functions and associated services. However, conservation agriculture systems may vary greatly regarding time since conversion to this system and the quality and biomass production of cover crops. In addition, the effects of these variables on soil fauna are still poorly known. Here, we aim to gain insight into the impact of conservation agriculture on soil mesofauna and macrofauna communities at the cropping system level.Collembola and earthworm communities were compared in seven neighbouring pairs of fields (same topography, spring crop and soil type) being either under conventional systems or under conservation agriculture systems with cover crops.Conservation agriculture systems influenced soil mesofauna and macrofauna communities compared to conventional systems. The beneficial effects of conservation agriculture on earthworm communities may predominantly be related to the lower soil physical disturbance (no-tillage) while Collembola may also be positively affected by cover crops characteristics and time since conversion to conservation agriculture.The adoption of conservation agriculture systems may improve earthworm and Collembola abundance and represents thus an innovative opportunity for sustainable crop production through the preservation of soil fauna. Finally, we suggest the use of a trait-based approach to draw functional consequences of soil faunal community changes operating in conservation agriculture.Conclusions: Conservation agriculture is increasingly adopted to improve soil fertility and reduce the depressive effects of intensive farming on soil functions and associated services. However, conservation agriculture systems may vary greatly regarding time since conversion to this system and the quality and biomass production of cover crops. In addition, the effects of these variables on soil fauna are still poorly known. Here, we aim to gain insight into the impact of conservation agriculture on soil mesofauna and macrofauna communities at the cropping system level.Collembola and earthworm communities were compared in seven neighbouring pairs of fields (same topography, spring crop and soil type) being either under conventional systems or under conservation agriculture systems with cover crops.Conservation agriculture systems influenced soil mesofauna and macrofauna communities compared to conventional systems. The beneficial effects of conservation agriculture on earthworm communities may predominantly be related to the lower soil physical disturbance (no-tillage) while Collembola may also be positively affected by cover crops characteristics and time since conversion to conservation agriculture.The adoption of conservation agriculture systems may improve earthworm and Collembola abundance and represents thus an innovative opportunity for sustainable crop production through the preservation of soil fauna. Finally, we suggest the use of a trait-based approach to draw functional consequences of soil faunal community changes operating in conservation agriculture. [ABSTRACT FROM AUTHOR]

Crop residues like corn ( Zea mays L.) stover perform important functions that promote soil health and provide ecosystem services that influence agricultural sustainability and global biogeochemical cycles. We evaluated the effect of corn stover removal from a no-till, corn-soybean ( Glycine max (L.) Merr) rotation on soil greenhouse gas (GHG; CO, NO, CH) fluxes, crop yields, and soil organic carbon (SOC) dynamics. We conducted a 4-year study using replicated field plots managed with two levels of corn stover removal (none; 55 % stover removal) for four complete crop cycles prior to initiation of ground surface gas flux measurements. Corn and soybean yields were not affected by stover removal with yields averaging 7.28 Mg ha for corn and 2.64 Mg ha for soybean. Corn stover removal treatment did not affect soil GHG fluxes from the corn phase; however, the treatment did significantly increase (107 %, P = 0.037) NO fluxes during the soybean phase. The plots were a net source of CH (∼0.5 kg CH-C ha year average of all treatments and crops) during the generally wet study duration. Soil organic carbon stocks increased in both treatments during the 4-year study (initiated following 8 years of stover removal), with significantly higher SOC accumulation in the control plots compared to plots with corn stover removal (0-15 cm, P = 0.048). Non-CO greenhouse gas emissions (945 kg CO-eq ha year) were roughly half of SOC (0-30 cm) gains with corn stover removal (1.841 Mg CO-eq ha year) indicating that no-till practices greatly improve the viability of biennial corn stover harvesting under local soil-climatic conditions. Our results also show that repeated corn stover harvesting may increase N loss (as NO) from fields and thereby contribute to GHG production and loss of potential plant nutrients. [ABSTRACT FROM AUTHOR]

Better understanding of soil C dynamics under actual agricultural conditions is important for predicting impacts of land use and climate change on soil C sequestration. Few field studies have compared simultaneous decomposition of intact roots and surface shoot residues under no-till (NT) field conditions. Therefore, we estimated the actual decomposition of intact roots and shoot residues simultaneously under NT field conditions. Wheat ( Triticum aestivum L.), pea ( Pisum sativum L.), and vetch ( Vicia sativa L.) plants were grown inside polyvinyl chloride (PVC) cylinders hydraulically forced into a field of sandy loam-textured Typic Paleudalf. After 20 days of emergence, the crops were pulse labeled weekly with CO until flowering. At harvest, the treatments were designed by combining C-labeled shoots with unlabeled roots and unlabeled shoots with C-labeled roots, resulting in six treatments (two combinations × three species), plus a non-amended control treatment. Soil CO emissions were measured continuously by the alkaline trap method during 180 days. Apparent C mineralization was similar for the three species in paired treatments: 54 ± 8.8 % added C for wheat, 54 ± 3.4 % for pea and 51 ± 3.4 % for vetch. However, actual mineralization of the roots C was higher than that of the C shoots, for the three species (73 vs. 45 % initial C for wheat, 76 vs. 48 % for pea, and 73 vs. 51 % for vetch). These findings emphasize that the environmental drivers of decomposition, i.e., the crop residue location, their contact with soil, and the soil moisture and temperature, are important factors that significantly promote root decomposition in situ compared to shoots, negating the consequences of their different initial chemical composition on their kinetics of decomposition. [ABSTRACT FROM AUTHOR]

It was shown that the agrochernozems of trans-Ural steppe (Bashkortostan) used under conditions of the No-Till system (NT) from 4 to 19 years are marked by favorable hydrophysical properties for the growth and development of plants and medium and high humus content, but, on the other hand, by the lack of nitrogen and, especially, phosphorus. Slightly eroded agrochernozems occupied by eastern galega for 19 years are similar in their properties to noneroded ones; noneroded chernozems treated with the use of NT technique are similar to the virgin analogues. [ABSTRACT FROM AUTHOR]

Poorly drained claypan soils can increase the importance of tillage and N management for corn (Zea mays L.) production. Field research in 2008, 2009 and 2010 (high rainfall years) near Novelty, MO (40° 1' N, 92° 11' W) sought to determine the effect of polymer-coated urea (PCU) placement [strip-tillage (ST) deep banded and no-till (NT) broadcast] and application timing (fall, early preplant and preplant) on red clover (Trifolium pratense L.) biomass and corn response compared to non-coated urea (NCU) and anhydrous ammonia (AA) in the presence and absence of nitrapyrin a nitrification inhibitor. Strip-tillage reduced clover dry weights 20% in 2008 and 2009 and early preplant ST reduced dry weights 40 to 45% in 2010 compared to NT. Corn plant population was 8,100 to 8,400 plants ha-1 greater with ST compared to NT. Preplant applications of AA plus nitrapyrin, AA, ST placement of PCU and NCU increased grain yields 1 to 1.2 Mg ha-1 compared to fall applications of these fertilizer sources. Fall and preplant ST placement of PCU increased grain yields 1.2 Mg ha-1 compared to NCU. Strip-till placement of PCU and NCU increased yields 2.1 to 3.2 Mg ha-1 over broadcast applications of these fertilizer sources. Strip-till placement of PCU synergistically increased yield over NCU and broadcast applications of PCU or NCU due to increased stands and possibly due to better plant utilization of the banded N fertilizer utility. [ABSTRACT FROM AUTHOR]

This article discusses the role of knowledge governance arrangements in the mainstreaming of sustainable practices, in particular, in the creation, sharing and use of integrated and contextualized knowledge. That is, knowledge which accounts for the social, economic, institutional, and ecological dimensions of potentially sustainable practices, and which considers the need to adapt generic practices to the sustainability requirements of specific places. An actor-centered approach is proposed for the study of the historical evolution of knowledge governance arrangements in order to understand their role in the adoption of sustainable practices. The approach is applied to explain the rapid adoption of no-till agriculture in the Argentine Pampas. A radical knowledge governance transformation occurring in this region during the 1990s led to increasing knowledge exchange and pushing sustainability practices to the top of key actors' agendas. This embracing of no-till agriculture illustrates the crucial role played by farmers' associations as boundary organizations: linking farmers with actors specialized in the generation of scientific knowledge and technology. This case reveals that sustainability transitions can be fostered through knowledge governance arenas characterized by: (a) promoting public-private collaboration through boundary organizations, (b) assigning private actors a leading role in the adoption of sustainability practices at the production unit scale, (c) fostering the public sector competence in regional and socio-ecological research, and (d) addressing the heterogeneous needs of knowledge users. However, the case also shows that the success of no-till agriculture in the Pampas is pushing the agriculturization of surrounding areas where this practice is largely unsustainable. This finding suggests that present knowledge governance arrangements fail to contextualize practices that are potentially sustainable. [ABSTRACT FROM AUTHOR]

The present study evaluated the changes of soil microbial communities that were subjected to no-till and compared the results to those subject to tillage for organic farming in a controlled horticultural field by fatty acid methyl ester. Fungi ( P < 0.001), gram-positive bacteria ( P < 0.001), arbuscular mycorrhizal fungi ( P < 0.01), and actinomycetes ( P < 0.01) in the no-till soils were significantly larger than those in the tillage soils. The no-till in the subsoil had a significantly lower ratio of cy17:0 to 16:1ω7c compared to that of tillage, indicating that microbial stress decreased because the soils were not disturbed ( P < 0.05). Fungi should be considered as a potential factor responsible for the obvious microbial community differentiation that was observed between the no-till and tillage areas in a controlled horticultural field. [ABSTRACT FROM AUTHOR]

Incorporation of manure slurry under reduced tillage conditions remains a challenge in the northeastern US. New technologies to directly incorporate slurry are available but their agronomic and environmental benefits have generally not been quantified. This study evaluated the effects of five manure slurry application methods on phosphorus (P) loss in runoff (broadcasting with and without incorporation by tillage, shallow disk injection, banded application and aeration, and pressurized injection) and a control (no manure). Research was conducted over a 2 year period in central Pennsylvania on a well-drained Hagerstown silt loam (fine, mixed, semiactive, mesic Typic Hapludalf) under corn ( Zea mays L.) production. Approximately 72 h after dairy ( Bos Taurus) slurry application (56,000 l ha) to 10 × 13 m plots, a single rainfall simulation (68 mm h) was conducted in triplicate on 10 × 2 m areas within the plots. Trends in total P losses in runoff (kg ha) from plots varied between years and treatments. Aeration yielded lower losses than all other treatments in 2006 and was amongst the lowest in 2007 with losses statistically similar to shallow disk and pressure injection. Remarkably, few differences were apparent in losses of dissolved reactive P between treatments, reflecting high variability in runoff depths. Indeed, variability in runoff depths resulted in some unexpected trends, including high loads from the unamended control and modest loads from the tillage treatment. Results highlight tradeoffs in alternative manure slurry application practices but point to the potential to significantly lower runoff P losses from reduced tillage systems receiving manure slurry. [ABSTRACT FROM AUTHOR]

Even in a country with a large population and rapid population growth, there can be labor shortages in the agricultural sector, because of outmigration of the able-bodied work force. The System of Rice Intensification (SRI) is not necessarily more labor-intensive once the methods have been learned, but the initial labor requirements can be a barrier to adoption, and farmers with large land areas cannot find the labor needed to use these more productive methods. Recognizing this problem, a set of agricultural implements have been designed for mechanizing the operations of SRI, with a view to reducing water requirements as well as labor requirements because the current conditions for agricultural production in the Punjab region of Pakistan include water scarcity and poor water quality as well as labor shortages. This article reports on the process of mechanizing SRI production in Punjab, which has been quite successful so far. Average yield is considerably increased with a 70% reduction in water requirements and a similar reduction in labor needs. The machinery and methods have been further adapted to other crops, being grown on permanent-raised beds, so that SRI with organic fertilization is combined with Conservation Agriculture. This combination is referred to as 'paradoxical agriculture' because it enables farmers to achieve higher outputs with reduced inputs. [ABSTRACT FROM AUTHOR]

Conservation tillage and judicious use of animal manures as fertilizers can make significant contributions for sustainable food production in the twenty-first century. Identifying and understanding the many interactions occurring within agricultural systems is fundamental for accomplishing this feat. This paper synthesizes 14 years of research results from a study that began in the early 1990s in which researchers from USDA-ARS and the University of Georgia investigated cropping system influences on nutrient management under natural rainfall. Increases in C and N with no-till resulted in improved soil structure that increased infiltration rate and soil water availability. Biological activity as indicated by earthworms was greater with no-till and poultry litter (PL). In all but the very driest year, yields of cotton and corn increased on average 10-27% with no-till and 32-42% with combination of no-till and PL. On the other hand soil nutrient accumulation, particularly P and Zn from long-term use of poultry litter in corn production, reached excessive levels and could present environmental risks. Drainage increased in no-till raising the risk of leaching of nutrients into the soil profile. However, runoff decreased in no-till and the presence of a rye cover crop during the winter reduced the leaching losses of N compared to no cover crop. During cotton production under relative drought, no-till and poultry litter led to somewhat elevated dissolved phosphorus concentration in runoff, and fluometuron was detected in runoff and drainage while pendimethalin was not. Fecal indicator bacteria ( Escherichia coli and fecal enterococci), and the hormones estradiol and testosterone were observed in drainage and runoff but concentrations were similar across all treatments. By conducting the study for an extended period under natural environmental conditions, we were able to highlight real risks and potentials of the contrasting cropping systems. While 6 out of 14 years of relative drought might have limited the water quality response of treatments, such droughts are common features of the weather pattern in the region. Even then, use of no-till as the predominant tillage system was supported by improved yields. Fertilizer management, especially crop N need-based use of PL, requires closer monitoring to insure that production advantages of no-till and poultry litter are not offset by concerns with environmental risks. Long-term research requires sustained resource inputs to answer critical questions of environmental risk and emerging unknown issues. [ABSTRACT FROM AUTHOR]

Scientists have theorized that weed management would be more efficient if prevention tactics were integrated with control tactics. The goals of prevention are to reduce weed community density and improve crop tolerance to weeds. Here we describe the impact of this approach in the semiarid steppe of the United States. As a result, producers have reduced herbicide inputs and costs by 50% compared to conventional practices. Critical factors for success with this approach are rotation design and no-till practices. Rotations comprised of two cool-season crops followed by two warm-season crops are the most disruptive of weed population growth. The impact of rotation design on weed community density is enhanced by no-till. Crop tolerance to weeds is improved by systems of cultural tactics. The tolerance is greatest when three tactics are combined together. This dualistic approach of prevention and control effectively controls weeds with four-crop rotations such that herbicides are not needed in some crops of the rotation. Weed density is so low that crop yield is not affected by weed interference. With this approach, herbicides are a choice rather than a requirement for cropping success in the semiarid steppe of the United States. [ABSTRACT FROM AUTHOR]

To evaluate the impact of N placement depth and no-till (NT) practice on the emissions of NO, N2O, CH4 and CO2 from soils, we conducted two N placement experiments in a long-term tillage experiment site in northeastern Colorado in 2004. Trace gas flux measurements were made 2–3 times per week, in zero-N fertilizer plots that were cropped continuously to corn ( Zea mays L.) under conventional-till (CT) and NT. Three N placement depths, replicated four times (5, 10 and 15 cm in Exp. 1 and 0, 5 and 10 cm in Exp. 2, respectively) were used. Liquid urea–ammonium nitrate (UAN, 224 kg N ha−1) was injected to the desired depth in the CT- or NT-soils in each experiment. Mean flux rates of NO, N2O, CH4 and CO2 ranged from 3.9 to 5.2 μg N m−2 h−1, 60.5 to 92.4 μg N m−2 h−1, −0.8 to 0.5 μg C m−2 h−1, and 42.1 to 81.7 mg C m−2 h−1 in both experiments, respectively. Deep N placement (10 and 15 cm) resulted in lower NO and N2O emissions compared with shallow N placement (0 and 5 cm) while CH4 and CO2 emissions were not affected by N placement in either experiment. Compared with N placement at 5 cm, for instance, averaged N2O emissions from N placement at 10 cm were reduced by more than 50% in both experiments. Generally, NT decreased NO emission and CH4 oxidation but increased N2O emissions compared with CT irrespective of N placement depths. Total net global warming potential (GWP) for N2O, CH4 and CO2 was reduced by deep N placement only in Exp. 1 but was increased by NT in both experiments. The study results suggest that deep N placement (e.g., 10 cm) will be an effective option for reducing N oxide emissions and GWP from both fertilized CT- and NT-soils. [ABSTRACT FROM AUTHOR]

A 2-year study was conducted to investigate the potential of no-till cropping systems to reduce N2O and NO emissions under different N application rates in an irrigated corn field in northeastern Colorado. Flux measurements were begun in the spring of 2003, using vented (N2O) and dynamic (NO) chambers, one to three times per week, year round, within plots that were cropped continuously to corn ( Zea mays L.) under conventional-till (CT) and no-till (NT). Plots were fertilized at planting in late April with rates of 0, 134 and 224 kg N ha−1 and corn was harvested in late October or early November each year. N2O and NO fluxes increased linearly with N application rate in both years. Compared with CT, NT did not significantly affect the emission of N2O but resulted in much lower emission of NO. In 2003 and 2004 corn growing seasons, the increase in N2O-N emitted per kg ha−1 of fertilizer N added was 14.5 and 4.1 g ha−1 for CT, and 11.2 and 5.5 g ha−1 for NT, respectively. However, the increase in NO-N emitted per kg ha−1 of fertilizer N added was only 3.6 and 7.4 g ha−1 for CT and 1.6 and 2.0 g ha−1 for NT in 2003 and 2004, respectively. In the fallow season (November 2003 to April 2004), much greater N2O (2.0–3.1 times) and NO (13.1–16.8 times) were emitted from CT than from NT although previous N application did not show obvious carry-over effect on both gas emissions. Results from this study reveal that NT has potential to reduce NO emission without an obvious change in N2O emission under continuous irrigated corn cropping compared to CT. [ABSTRACT FROM AUTHOR]

The objectives of this study are to develop and test a framework to estimate the cost of enhancing agriculture’s potential as a carbon sink through the implementation of reduced tillage productive systems. A major factor inhibiting the adoption of reduced tillage practices is the additional risk perceived by farmers and its effect on net revenues. The expected utility model provides a useful means for evaluating risk–return tradeoffs of agricultural production systems. Incentive levels required to induce implementation of reduced tillage practices are calculated using estimated certainty equivalents. The framework developed is applied to eight case studies across the United States. Results indicate that in the Corn Belt, the required incentive payment for corn/soybeans would have to be $10.20 and $8.30 per acre for poorly drained and well-drained soils, respectively. Continuous corn incentive payments for poorly drained soils were found to be $40.40 and $26.70 for well-drained soils. In the central Great Plains, an incentive level of $14.60 per acre was required for continuous sorghum. Although the mean yields for conventional and reduced tillage practices are fairly close in this case, the higher costs associated with no-till sorghum result in the high incentive level. In the wheat/fallow and wheat/sorghum/fallow rotations of the western Great Plains, the yields associated with no-till were higher than intensive till. Thus, incentive levels near $6.00 per acre are the result of higher costs of no-till in these rotations. In the Mississippi River Corridor region, results show that the switch from corn/soybean to the same no-till rotation would require an incentive level of $7.90 per acre. [ABSTRACT FROM AUTHOR]