Residue Removal Research Articles

Response of soil respiration to thinning is altered by thinning residue treatment in Cunninghamia lanceolata plantations

Forest thinning is a widely used practice in traditional and multiple function forest management. However, the effects of thinning residue treatment on soil respiration in forest are not fully understood. Here, a two-year field experiment quantified the effects of thinning intensity (medium and heavy thinning, 45% and 70% of volume removed, respectively) and the resulting residue treatment (retention and removal) on soil respiration in a subtropical Cunninghamia lanceolata plantation on a thin soil. Both thinning intensity and residue treatment significantly impacted on soil respiration. The control had a relative low mean soil respiration rate of 158 mg CO2 m−2 h−1 or 13.9 t ha−1 yr−1. Compared with the control, medium thinning with residue retained (MTR1) increased annual cumulative soil respiration by 13% only in the first year, while medium thinning with residue removal (MTR0) did not affect it in the two years. Heavy thinning with residue retention (HTR1) and removal (HTR0) elevated the mean annual cumulative respiration by 32% and 20%, respectively. Besides, there was no difference between MTR1 and HTR0. Soil respiration rate was correlated positively with soil temperature, moisture, and the concentrations of permanganate-oxidizable C and microbial biomass C, and inversely with the concentration of water-soluble organic C. Furthermore, heavy thinning with residue retention decreased the temperature sensitivity of soil respiration. Our findings highlight that the response of soil respiration to forest thinning was associated with thinning residue treatment.

Process Considerations for selective doping of poly-Si thin films with spin-on dopants and nickel silicide formation for planar thermoelectric devices

The formation of highly doped p-type (boron-doped) and n-type (phosphorus-doped) poly-Si thin films with spin-on dopants on the same wafer poses unique challenges. This work evaluates the pros and cons of different approaches to dopant diffusion, residue removal, and diffusion mask selection when working with spin-on dopants. The experiments have been carried out to optimize the formation of highly doped poly-Si thin films that will form the active layers of a micro-thermoelectric generator (μ-TEG). Building upon previous work on residue removal methods, we report that the residue formation is also dependent on the oxide-silicon surface with a PECVD oxide-Si interface not requiring a post-dopant diffusion nitric acid treatment to achieve a hydrophobic surface. Furthermore, comparing the direct dispense and proximity diffusion methods verifies the existing reports of enhanced diffusion in the latter case. Besides, we observe that doping first with Boron is more conducive than doping first with phosphorus to reduce sheet resistance. We also optimize the contact formation with Ti/Ni thin films and report the mean contact resistivity. Notably, contact annealing precludes the nitric acid treatment requirement even if the surface is hydrophilic after removing dopant residue. Additionally, the sequence of silicidation is observed to be dependent on the doping of the underlying areas.

Crop residue return improved soil nitrogen availability by increasing amino acid and mineralization under appropriate N fertilization

AbstractSoil organic nitrogen (SON) and its mineralization are among the most critical factors that affect soil N availability. However, it is unclear how crop residue return and chemical N fertilization affect soil N availability by altering SON and its mineralization. Therefore, we studied the SON pools, SON mineralization, and related soil properties and enzymes activities in the lower reaches of the Yangtze River Valley in China with stand ages of 7‐year N (0, 75, 150, and 300 kg N ha−1) fertilization and 4‐year barley‐cotton residue return. Regardless of residue retention or removal, the contents of total SON and its fractions (ammonium N, amino acid N, amino sugar N, and unidentified N) increased consistently with the increasing of N input, while SON mineralization, microbial biomass N content, urease and protease activities showed a curvilinear response that was highest at N rate of 150 kg N ha−1. Crop residue returning significantly increased SON content under 75 and 150 kg N ha−1, mostly due to the increase of amino acids N. Other variables, such as SON mineralization, microorganism, and enzymes, were also enhanced by residue returning, and the largest increases were observed at 150 kg N ha−1. In addition, our result also show that excessive N input (300 kg N ha−1) would reduce soil N availability by mainly suppressing microbial N processes. We concluded that crop residue combined with appropriate N has a great potential to improve soil N availability by mainly improving amino acid N content and SON mineralization.

Climate warming causes changes in wheat phenological development that benefit yield in the Sichuan Basin of China

The effects of climate warming on wheat yields vary geographically under different warming scenarios. Such variations reflect real climatic differences and our insufficient understanding of how physiological processes respond to warming conditions. In this study, a 16-year trial comprising three crop production systems (CPSs) and a 5-year trial including seven cultivars were conducted in the Sichuan Basin of China to investigate the effects of climate warming on the phenological development, grain yield (GY), dry matter (DM) accumulation and translocation of wheat. The three CPSs included conventional rotary tillage with residue removal for both rice and wheat (CPS1), conventional rotary tillage with the wheat residue incorporated for the rice following zero tillage with residue-mulching for wheat (CPS2), and zero tillage and residue-mulching employed for both wheat and rice (CPS3). The wheat cultivars used in this study were all spring-type wheat, and the trials were planted from 26 to 30 October each year, irrigation was applied only at the seeding and topdressing stages and in amounts less than 20 mm. The results showed that mean of daily mean temperature from November to March (MTNov-Mar) and November to April (MTNov-Apr) significantly increased by 0.0964 °C yr-1 and 0.0947 °C yr-1 from 2004 to 2020, respectively. This warming caused earlier flowering and significantly decreased mean temperature from anthesis to maturity (PostATmean) by 0.091 °C yr-1. However, grain number m-2 was unaffected by this warming. Cooler and longer grain-gilling periods (GFP) lead to larger grain sinks and allow more preanthesis assimilates to be transported to the grain, resulting in increased individual grain weight and harvest index under all CPSs and all cultivars. There were no significant differences in sensitivities of GY and DM related trait responses to temperature change between CPSs or between cultivars. Averaged over all CPSs, GY increased 741.9 kg ha-1 with each 1 °C increases in MTNov-Apr. The increase in yield was mainly attributable to increase in grain weights while grain number m-2 was maintained. In addition, the MTNov-Apr values in the Sichuan Basin were predicted to reach 14.7 °C and 16.5 °C by the end of this century under the SSP245 and SSP585 climate change scenarios, respectively. When the CO2 concentration was fixed at 350 ppm, the Agricultural Production Systems SIMulator (APSIM) model showed that the increasing MTNov-Apr values significantly increased the GY under the SSP245 scenario, but the GY was initially positively and then negatively affected under the SSP585 scenario. These results lay the foundation for developing adaptation strategies to address future climate change in climates like that of Sichuan Basin and ensure wheat supplies.

Wet Cleaning of Molybdenum for Nano Interconnects

Copper (Cu) has been used as the metal for interconnects for many years. Along with the continued scaling of semiconductor devices, especially beyond 10 nm nodes, alternative metals such as ruthenium (Ru) and molybdenum (Mo) have emerged as interesting candidates to replace Cu [1] at certain levels of the interconnect.Despite having higher bulk resistivities with respect to that of Cu, these alternative barrierless metals have lower resistivity at dimensions below ~12 nm. For instance, the resistivity of Mo was found to be lower than that of TaN/Cu/TaN stack of a total thickness below 8 nm [2]. In addition, besides W which is considered as a prime candidate as a first-generation buried power rail (BPR) metal [3,4], Mo has also been introduced as a potential candidate to achieve even lower BPR resistance.For both dual damascene and semi-damascene structures, typically, a wet cleaning step needs to be carried out prior to the next processing step, aiming at a complete removal of the residues generated during the dielectric patterning (dual damascene) or the metal patterning (semi-damascene). Therefore, the compatibility and etching behavior of the metals in chemical solutions must be well understood. In this work, the effect of various chemical solutions on the removal of post-etch residues and the etch characteristics of Mo is investigated.For the cleaning study, we first compared the etching rate on blanket Mo of two commodity chemicals (diluted HF of 0.05% and SC1) and formulated mixtures. The etching characteristics of the as-deposited and 420 °C-annealed Mo were similar for most chemical solutions. 0.05% HF and semi-aqueous alkaline mixtures were found to be highly compatible with Mo, while SC1 mixture significantly etched Mo. The high etching rate of Mo can be explained by the presence of H2O2 in the SC1 mixture, even at low concentration. The surface chemistry of the as-deposited Mo was compared with the surface after different treatments. Figure 1(a) shows the normalized XPS Mo 3d core-level spectra recorded on blanket Mo films after deposition, after Cl2-based plasma treatment and with subsequent wet cleaning. The narrow peak recorded at ~228.0 and 231.1 eV can be assigned to the Mo 3d5/2 and 3d3/2 components, respectively, of the metallic Mo. While the shoulder and broader peak recorded at higher binding energies, ~232.6 and 235.4 eV, are attributed to Mo oxides (3d5/2 and 3d3/2 components, respectively). It is clear that the surface became less oxidized after the plasma treatment. While the clean using 0.05% HF for 1 min did not show any change in terms of surface oxidation, the semi-aqueous mixture (FOTOPUR R-2403 formulation from BASF) clearly dissolved most of the Mo oxides present at the Mo surface. Since the XPS measurement was carried out ex-situ, this result could also be further explained by the dissolution of the surface Mo oxides combined with a better surface passivation provided by the formulated chemical vs. HF solution. In addition, these results also indicate that Mo surface is readily oxidized [5], and it needs to be protected after a dry etching or wet cleaning process. Figure 1(b) displays the atomic ratio of O 1s/Metallic Mo (measured from the Mo 3d level) for the surface described above, giving additional evidence of the low oxygen content of the Mo surface after being cleaned in the formulated chemical solution FOTOPUR R-2403.The assessment of post-etch residue removal was done on a semi-damascene structure (metal pitch = 32 nm), where Mo lines were formed by a non-optimized Cl2-based plasma etch. Figure 2 shows the TEM images obtained after the plasma etch, with the residues formed in between the lines (Figure 2(a)), and with subsequent cleaning using the semi-aqueous formulation FOTOPUR R-2403 from BASF (Figure 2(b)), showing efficient removal of the residues and good compatibility behavior with the top hard mask and the metal lines. The latter thus confirmed the etching rate results on blanket Mo films.Quantification of surface roughness and a study of the oxide growth on Mo surface will also be presented and discussed.

Effect of Inclusion of Legumes in Cropping System and their Residue Incorporation on the Yield of Maize

Background: Maize (Zea mays L.) is one of the important cereal crops of world. Its multiple uses in food industry made it most demanded crop, but the productivity in India is still low. Inclusion of legumes in the cropping system can help in restoring soil fertility in incredible ways hence, enhancing the crop productivity. Methods: A field experiment was conducted at B. A. College of Agriculture, AAU, Anand during summer-kharif seasons of years 2017 and 2018 to examine the impact of legume crop residue and nitrogen levels on maize crop. Experiment comprised of three legume crops grown in summer season viz., green gram, groundnut and cluster bean, two residue management treatments viz., residue removal and incorporation and three nitrogen levels in kharif maize viz., 100%, 75% and 50% recommended dose of nitrogen. Result: Cluster bean-maize cropping system followed by groundnut-maize cropping system observed for the highest improvement in growth parameters, yield attribute and grain and straw yield. Residue incorporation of summer legumes and full dose of nitrogen in maize was found significant for increasing growth and yield parameters and grain yield of maize. Study indicate that residue incorporation had positive effects on maize growth and yield, however incorporation was not able to reduce the nitrogen requirement through chemical means.

Implications of crop residue removal on soil physical properties: A review

AbstractCrop residues are often removed for livestock and biofuel production, but how such removal impacts soil physical properties has not been widely discussed. The objectives of this paper were to discuss: (a) the impacts of crop residue removal on soil physical properties, (b) factors affecting residue removal effects on soils, (c) threshold level of residue removal, (d) strategies to offset the removal negative effects, and (e) research needs. We compiled 66 studies on crop residue removal and soil physical properties published prior to 17 Aug. 2021. Residue removal may not affect bulk density and water infiltration rate but increases penetration resistance by 55% and soil temperature by 1.8 °C in spring. However, it reduces wet aggregate stability by 31%, dry aggregate stability by 44%, and water retention at –33 kPa by 24% in most studies, indicating residue removal can increase erosion risks and reduce soil water storage. Residue removal rate is the leading factor that explains changes in soil physical properties. Residue removal at rates above 50%, in general, adversely affected soil physical properties, which correlates to retaining about 4 Mg ha–1 of residue. Cover crops and manure application may partially offset adverse effects of residue removal on soil physical properties, but studies are too few to make a strong conclusion. Consistency of soil sampling depths, accurate reporting of residue removal rates, and additional data from long‐term experiments are needed. Overall, high rates of residue removal can increase erosion potential and reduce soil water but have mixed impacts on other physical properties.

Crop residues in corn-wheat rotation in a semi-arid region increase CO2 efflux under conventional tillage but not in a no-tillage system

Appropriate management of crop residue plays a key role in mitigating greenhouse gas emissions. However, it has been inadequately implemented in general agricultural management practices. In a field investigation using static chambers, we evaluated the effects of crop residue at three different rates - 100 % (R100), 50 % (R50), and residue removal (R0) - on carbon dioxide (CO2) efflux. The field study was conducted in corn-wheat rotation under conventional (CT) and no-tillage (NT) systems in a semi-arid region. The main results showed that CO2 efflux was positively correlated with higher soil temperature (0.43–0.79) and microbial biomass carbon (0.66–0.89). The crop residue treatments affected these traits. A strong positive relationship between CO2 efflux and the crop residue (R2 = 0.96, CT and R2 = 0.9 for NT) was observed. In the CT system, significant increases were detected among residue rates on cumulative CO2 efflux, where R100 and R50 resulted in 36 % and 25 % higher cumulative CO2 efflux, respectively, than R0. In contrast, there was no significant difference in cumulative CO2 efflux among the crop residue retention (R100 and R50) and removal (R0) treatments under the NT system. Our study revealed that crop residue retention led to increased CO2 efflux under the CT system in semi-arid conditions during the first year of application, while under the NT system, CO2 efflux was not impacted by crop residue. Our results indicate that there is considerable potential for improving soil management practices in the context of soil degradation, climate change, increasing crop productivity, and carbon (C) sequestration.

Corn and Wheat Residue Management Effects on Greenhouse Gas Emissions in the Mid-Atlantic USA

Greenhouse gas (GHG) emissions from crop residue management have been studied extensively, yet the effects of harvesting more than one crop residue in a rotation have not been reported. Here, we measured the short-term changes in methane (CH4), nitrous oxide (N2O), and carbon dioxide (CO2) emissions in response to residue removal from continuous corn (Zea mays L.) (CC) and corn–wheat (Triticum aestivum L.)–soybean (Glycine max L. Merr.) (CWS) rotations in the Mid-Atlantic USA. A first experiment retained five corn stover rates (0, 3.33, 6.66, 10, and 20 Mg ha−1) in a continuous corn (CC) in Blacksburg, VA, in 2016 and 2017. Two other experiments, initiated during the wheat and corn phases of the CWS rotation in New Kent, VA, utilized a factorial combination of retained corn (0, 3.33, 6.66, and 10.0 Mg ha−1) and wheat residue (0, 1, 2, and 3 Mg ha−1). Soybean residue was not varied. Different crop retention rates did not affect CO2 fluxes in any of the field studies. In Blacksburg, retaining 5 Mg ha−1 stover or more increased CH4 and N2O emissions by ~25%. Maximum CH4 and N2O fluxes (4.16 and 5.94 mg m−2 day−1) occurred with 200% (20 Mg ha−1) retention. Two cycles of stover management in Blacksburg, and one cycle of corn or wheat residue management in New Kent did not affect GHG fluxes. This study is the first to investigate the effects of crop residue on GHG emissions in a multi-crop system in humid temperate zones. Longer-term studies are warranted to understand crop residue management effects on GHG emissions in these systems.

TEKNIK PERTANIAN KONSERVASI BERDASARKAN PENGOLAHAN TANPA OLAH TANAH

To support sustainable agriculture, technology and practices that have been proven relevant to increase production and environmental sustainability are needed. Conservation agriculture (CA) with three main principles, namely zero tillage (ZT), the use of cover crops and crop rotation has spread throughout the world, but by applying 1 or 2 of the three principles and on a very diverse land area, it has been proven to increase production yields in various places in the world (Fao, 2015a; Hobbs, 2012; FAO, 2014 in Hendrik et al, 2021). ZT with residue retention uses rainfall more efficiently and results in a more robust agronomic system than practices involving conventional tillage CT or ZT with residue removal. while conservation agriculture with zero tillage treatment and no residue retention gives lower yields than conventional farming practices (Verhulst et.al, 2011 in Romero-Perezgrovas, et al 2014). Conservation agriculture according to Derpsch et al, 2016, is based on diversification through crop rotation and cover crops and on fixed application without tillage. The results show that removing residues can reduce yields and reduce returns on ZT economic yields (Derpsch et al ,2014) . Planting without tillage (ZT) which is not combined with ground cover gives poor production performance (Ashburner, 1984 in Derpsch et al, 2014). In areas with low rainfall, the highest yields were obtained from ZT and the use of crop residue retention, in contrast to the conventional system (CT), and the lowest yields were obtained in the absence of ZT and did not use residues. Similar results were also found in rainfed land, wheat and maize yields were drastically reduced when the residue was removed from the no till system (ZT). This means that the residue produced in many small-scale farms is not only low but also has many competing uses (Magnan et al., 2012; Valbuena et al., 2012; Tittonel et al., 2007). The majority of farmers use crop residues as animal feed (Hendrik, et al, 2021). Or crop residues are only burned in corn fields. For successful farming with conservation farming techniques, at least a combination of no tillage (ZT) and the use of crop residues as ground cover or crop rotation is required.

Characterization of Soil Pores Through X-Ray Computed Microtomography and Carbon Mineralization Under Contrasting Tillage and Land Configurations in the Indo-Gangetic Plains of India

Contrasting tillage and land configuration have important roles in porosity and pore size distribution (PSD), which in turn affects the carbon mineralization in soil. Information on the effects of these treatments on PSD and subsequent carbon mineralization is very limited. Hence, an attempt was made to evaluate the long-term impact of soil tillage and land configurations on the distribution of soil pores and its relationship with soil carbon mineralization under a maize (Zea mays)-wheat (Triticum aestivum) rotation. There were five treatments, that is, conventional tillage, (CT); permanent broad bed, (PBB); PBB + residue (R); zero tillage, (ZT); and ZT + R. Soil pores were quantified by X-ray computed tomography (μ-CT). The conversion of CT to ZT and PBB with or without residue retention (+R) resulted in the reduction of pores >60 μm diameter and was mostly due to a reduction in the number of larger size macro-pores (>110 μm). This resulted in restricted drainage. However, under these practices, pores with larger diameters (60–110 μm) facilitated soil aeration. The total organic carbon (TOC) was 15–48% and 17–47% higher under PBB, PBB + R, ZT, and ZT + R than that under CT in the 0–5 and 5–15 cm layers. The highest MWD (1.01 mm) was in the plots under PBB + R, and the lowest was in the CT plots, and all residue-retained plots (ZT + R and PBB + R) had a higher MWD than residue removal plots (ZT and PBB). Relative to CT, soil C mineralization rates in 0–5 and 5–15 cm soil depths were 63 and 55% higher in the alternate tillage practices, respectively, and the highest value occurred in PPB + R treatments. Increased labile C concentrations were indicative of greater mineralization and were correlated with pores >60 μm, particularly in the size range 110–500 μm and TOC concentrations of 0–15 cm soil layer. Thus, the transition to alternate tillage from the conventional tillage enhanced soil organic carbon concentration (16–47.5%), improved soil structure, reduced the diameter of pores up to >60 μm, and facilitated C mineralization by altering the pore size distribution of soil under a maize-wheat system in the IGP.

Tillage Practices and Residue Management Manipulate Soil Bacterial and Fungal Communities and Networks in Maize Agroecosystems.

Tillage practices and residue management are highly important agricultural practices. However, very few studies have examined the influence of tillage practices and residue management on both bacterial and fungal communities and network patterns in consecutive years. We examined the effects of different tillage practices, including no tillage, rotary tillage, and deep tillage, on soil bacterial and fungal communities and co-occurrence networks following residue removal and residue retention in 2017 and 2018. This study showed that both bacterial and fungal communities were unaffected by tillage practices in 2017, but they were significantly impacted in 2018. Soil fungal operational taxonomic unit (OTU) richness was significantly enhanced by deep tillage compared with no tillage in 2018, while bacterial OTU richness was unaffected in either year. Tillage practices had differing effects on soil microbial co-occurrence networks, with rotary and deep tillage increasing the complexity of bacterial networks but simplifying fungal networks. However, residue retention only induced a shift in the fungal community and simplified soil bacterial and fungal networks in 2018. This study highlights the dissimilar responses of bacterial and fungal networks to tillage practices and emphasizes that tillage practice is more important than residue management in shaping soil microbial communities.

Wet Cleaning of Molybdenum for Nano Interconnects

The effect of various chemical solutions on the etch characteristics of molybdenum and on the removal of post-etch residues formed between Mo lines was investigated. In contrast to diluted SC1 mixtures, it was found that diluted HF solution (0.05%) and formulated semi-aqueous alkaline mixtures are highly compatible with Mo. The high etching rate measured for SC1 is attributed to the presence of the oxidizer in the mixture. Post-etch residue removal assessment performed on a semi-damascene structure with metal pitch of 32 nm showed that cleaning using diluted HF did not completely removal the residues. On the contrary, a clean using FOTOPUR R-2403, a semi-aqueous formulated mixture, resulted in efficient removal of the residues. The effect of oxygen in the plasma gas mixture and subsequent wet cleaning on the thickness of Mooxides was also performed on blanket Mo

Почвозащитное и ресурсосберегающее земледелие как система для улучшения качества почвы и устойчивости производственных процессов

Agriculture in Azerbaijan is mainly characterized by small farms. The average size of the farm is only 1.5 hectares. About 83% of farmers own land plots, and they cultivate almost 55% of arable land. On the other hand, only 1.6% of farmers have operational land plots. The pace of development of environmental agriculture and the resulting economic gain in turns depend on the environment, which is influenced by economic, social, environmental and other factors. However, land is an inelastic factor of production. Therefore, conservation agriculture becomes a separate, albeit integrated body of general agricultural production due to its peculiarities of distribution of inelastic factors among competing crop production variants. The transfer of conventional tillage to zero can lead to a loss of total pore space, as evidenced by an increase in bulk density. Infiltration is generally higher, and runoff decreases with zero tillage with residue retention compared to conventional tillage and zero tillage with residue removal. The necessary yield growth, production stability, risk reduction and environmental sustainability can be achieved only with the help of management methods that lead to improved soil quality. This article presents the results of a study devoted to the study of possible changes in the physical properties of the soil.

Impact of long-term residue burning versus retention on soil organic carbon sequestration under a rice-wheat cropping system

Despite rice residue burning is popularized against its retention under rice-wheat system in the Indo-Gangetic Plains (IGP), limited information is available on the impacts of long-term rice residue burning versus its retention on carbon stock, soil aggregation and aggregated-associated carbon in the region. Hence, a 18 (1998–2016) years old conservation agriculture (different combinations of tillage and residue management) experiment was selected to understand the impact of CA on soil aggregation, carbon pools and soil organic carbon (SOC) stock in a rice-wheat system. Experiment was laid down in a split-plot design with three replications having three tillage management viz. zero-tillage (ZT), conventional tillage (CT) and strip tillage (ST) as main plots and three residue management options namely residue retention (R), residue burning (RB) and no-residue (NR). The total SOC content was 20% higher (p < 0.05) under ZT and residues retention over CT and residue removal, in the 0–5 cm layer. The SOC stock increased with depth (from 0 to 5 cm to 5–15 cm). ZT with added residues had 25% higher (p < 0.05) SOC stock than CT without residues because of higher aggregation with lesser disturbance in ZT promoted SOC accumulation over time. Macro-aggregate fraction was higher in ZT by 18% (p < 0.05) than CT in the 0–5 cm soil depth. Whereas, CT without residues resulted in higher silt and clay size fraction than ZT. Labile carbon (very labile + labile fractions) was 7–25% increased (p < 0.05) under ZT+R than CT-R across depth. Recalcitrant carbon (less-labile + non-labile) followed the same trend. Notably, ZT with residues retention (conservation agriculture, CA) increased 32.6–41.7% potassium permanganate oxidizable carbon than CT without residues in the 0–5 cm and 5–15 cm, respectively. No mechanical tillage in ZT with added residues over the years promoted bridging between aggregates that brought about carbon accumulation. The study highlighted the importance of CA in enhancing SOC stock, soil aggregation and managing long-term SOC content.

Potential for the adoption of measures to reduce N2O emissions from crop residues in Denmark

Crop residues represent a climate change dilemma: they can promote carbon (C) sequestration, but they may also stimulate emissions of the powerful greenhouse gas nitrous oxide (N2O). Although there are crop residue management measures to reduce N2O emissions, N2O reductions achieved at national scale with these measures have been seldom studied, and how farmers' willingness to accept the measures constrains their potential remains largely unknown. Using Denmark as a case study, we combined a survey (completed by 592 farmers) and national data to assess the practical potential and obstacles for the successful implementation of management strategies to reduce N2O emissions from crop residues. Crop residue removal (particularly from vegetables and cover crops) and nitrification inhibitors were identified as effective in reducing N2O emissions from a biophysical perspective. If all aboveground crop residues from vegetables and cover crops were removed, N2O emissions could be reduced by 0.181 Gg N2ON, corresponding to 11% of the total N2O emissions from crop residues nationally. However, a low percentage of farmers would be willing to remove crop residues from the field, especially for vegetables and cover crops (25%), in connection to the possible short- to medium-term reduction in C sequestration. Similarly, use of nitrification inhibitors would reduce emissions by 0.247 Gg N2ON, corresponding to 15% of the total residue N2O emissions, and only 37% of all farmers would accept their use. Our results highlight that farmer’ preferences for the adoption of measures can constrain the use of the few available effective mitigation options. Better knowledge dissemination and advisory services are crucial to address this challenge; farmers may be motivated to remove aboveground crop residues by highlighting the proportionally more important contribution of belowground residues to C sequestration, and that aboveground residues may have commercial value (biorefining, biogas, biofuel), although these options need further development.

A New LC-MS Method for Evaluating the Efficacy of Pesticide Residue Removal from Fruit Surfaces by Washing Agents

Modern agriculture uses pesticides to improve the quality and quantity of crops. However, pesticide residues can remain on agricultural products, posing very serious risks to human health and life. It is recommended to wash fruits and vegetables before consumption. To assess the removal efficacy of pesticide residue, a sensitive and reliable method based on ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was developed and optimized for the simultaneous determination of four pesticide residues (acetamiprid, boscalid, pyraclostrobin, and pendimethalin). Isotope-labeled standards were used to validate the method in terms of recovery, linearity, matrix effects, precision, and sensitivity. The mean recovery values for both low-quality control (LQC) and high-quality control (HQC) transitions were in the range of 89–105%, and the intra-day precision was less than 13.7%. The limits of detection (LOD) and quantification (LOQ) were 0.003 mg/kg and 0.01 mg/kg, respectively. The proposed method is suitable for evaluating the quality of detergents for removing pesticide residues from fruit surfaces.

Double no-till and rice straw retention in terraced sloping lands improves water content, soil health and productivity of lentil in Himalayan foothills

Designing suitable conservation tillage and rice straw management practices are vital to conserve limited soil water in sloping terraced lands for growing a second crop like lentil (Lens esculentum L.) after rice (Oryza sativa L.). A field study was conducted to evaluate the effects of tillage, rice straw management and supplemental irrigation on soil physico-chemical properties and productivity of lentil grown in rice fallow land. The maximum soil water content in lentil was observed in plots under rice residue retention as mulch (@ 5 Mg ha−1) which was followed by 20 cm standing rice stubble and residue removal. Rice residue retention and 20 cm standing stubble also increased infiltration rate, cumulative infiltration and sorptivity. Adoption of double no-till (NT) for rice and subsequent lentil crop increased soil organic carbon (SOC) concentration by 2.8%, 3.4% and 7.4% at 0–5, 5–10 and 10–15 cm soil depth, respectively than those under conventional tillage (CT). Soil available nitrogen and phosphorus contents were higher under residue retention either as mulch or standing rice stubble as compared to residue removal. Double NT and added residues (mulch and 20 cm standing stubble) increased soil microbial biomass carbon and dehydrogenase activity than CT without rice residues. Application of one supplemental irrigation did not significantly influence the soil properties. The NT in both rice and lentil enhanced lentil yield by 10–18% than lentil grown after rice under CT. Rice residue retention as mulch @ 5 Mg ha−1 and 20 cm standing rice stubble gave 35–42% and 23–27% higher lentil yield against residue removal over the years, respectively. Therefore, NT in both rice and subsequent lentil along with rice residue retention @ 5 Mg ha−1 as mulch or 20 cm standing stubble would pay substantial dividends for improving the soil health, enhancing lentil productivity and ensuring double cropping in rice fallow areas of Himalayan foothills and in similar agro-ecologies elsewhere.

Resin Cement Residue Removal Techniques: In Vitro Analysis of Marginal Defects and Discoloration Intensity Using Micro-CT and Stereomicroscopy.

The objective was to compare marginal defects and evaluate discoloration for adhesively cemented veneers in vitro when using two cement removal techniques. Twenty premolars were prepared with chamfer and borders in enamel. IPS e.max CAD veneers were cemented using Panavia V5 and divided in two groups (n = 10): cement excess removed with a probe after tack-curing for 3–5 s, or cement excess removed with a brush, then completely polymerized. All teeth were stored in alginate gel until micro-CT examination. Scanning was performed twice: directly after cementation and after thermocycling (5000 cycles, between 5 and 55 °C). To analyze discoloration, teeth were colored using 0.5% basic fuchsine and examined under a stereomicroscope. Depth of dye infiltration was scored 0 (no discoloration) to 5 (discoloration along the entire margin). Statistically significant differences of cement defects before thermocycling were reported, where brushing showed more defects than probing (p = 0.0161). After thermocycling, the defects increased for both groups. Extensive discoloration was the most common (55.56%) when removing excess by probing; by brushing, 90% of the specimens exhibited slight discoloration (p = 0.008). Regression analysis showed no relationship between type of defect and degree of discoloration. Removing cement with a brush causes more marginal defects, however less discoloration after thermocycling.

Nitrogen Fertilization and Straw Management Economically Improve Wheat Yield and Energy Use Efficiency, Reduce Carbon Footprint

Fertilization is an effective agronomic management technique for increasing crop production. However, the overuse of chemical fertilizer stimulates energy consumption and greenhouse gas (GHG) emissions, which are antagonistic to sustainable wheat production. In this study, we estimated the energy and GHG performances of different fertilization regimes based on a 32−year fertilization experiment. In this long−term experiment, there are five treatments: CK (no fertilizer with wheat residue removal), NPK (chemical fertilizer with wheat residue removal), NPKPM (chemical fertilizer and pig manure with wheat residue removal), NPKCM (chemical fertilizer and cattle manure with wheat residue removal), and NPKWS (chemical fertilizer with wheat residue retention). The results indicated that NPKCM and NPKPM consumed higher total energy than NPK and NPKWS, which was attributed to the extra energy usage of farmyard manure. Although NPKCM and NPKPM increased energy output by 4.7 and 2.8%, NPKWS stood out by delivering the highest energy use efficiency (EUE) of 6.66, energy productivity of 0.26 kg MJ−1, energy profitability of 5.66, net return of 1799.82 US$ ha−1 and lower specific energy of 3.84 MJ kg−1. Moreover, the yield scale carbon footprint of NPKWS decreased by 66.7 and 52.3% compared with NPKCM and NPKPM, respectively. This study shows that the application of chemical fertilizer in combination with wheat residue retention is a good strategy to increase EUE and economic benefits while decreasing the carbon footprint of wheat production.