Corn Cropping System Research Articles

Nitrous oxide fluxes during a winter cover crop season in a Mississippi corn cropping system

Agroecosystems are the largest source of anthropogenic N2O fluxes. While cover crops (CC) offer benefits for soil health, their impacts on greenhouse gas fluxes are inconsistent. In the southeastern US, where intensive agriculture and low CC adoption are prevalent, few studies have investigated CC impact on soil N2O fluxes. Our study explored the effects of CC species and management practices on soil N2O fluxes during the winter CC growing season in Mississippi, which was conducted in a non-tilled corn cropping system with seven CC treatments. We measured in situ soil N2O fluxes, along with soil moisture and temperature, throughout the CC growing season from 2022 to 2023. Surface soil samples were also collected to analyze soil mineral nitrogen (N) content and enzyme activity. Over the study period (a total of 188 days), cumulative N2O fluxes were 0.50–1.03 ​kg N2O–N ha−1, with the lowest values from the annually-rotated Elbon rye treatment and the highest from the annually-rotated Austrian winter pea. Our results show that both CC treatments and sampling time significantly affected soil N2O fluxes. There was a strong positive correlation (r ​= ​0.34, p ​< ​0.05) between N2O fluxes and NO3–N content, which was lowest under continuous rye and rotated-rye treatments (0.31 and 0.34 ​mg ​kg−1 ). The results suggest that Elbon rye effectively reduced soil N2O fluxes during this period by lowering the soil NO3–N content, the primary substrate for denitrification. This study is one of the few studies to examine the impacts of cover crops on soil N2O fluxes in cropping systems in the southeastern US, offering insights into the cover crop effects on soil N2O fluxes during their growing season.

Irrigated corn yield and soil phosphorus response to long‐term phosphorus fertilization

AbstractLong‐term experiments can help to understand soil phosphorus (P) dynamics and improve nutrient management strategies. This research evaluated long‐term (2002–2021) soil P dynamics and yield response to a range of P fertilizer rates in a continuous high‐yielding irrigated corn (Zea mays L.) experiment with low initial soil phosphorus test (SPT, 10.5 mg kg−1). The experiment was established near Clay Center, NE, and five P rates (0, 10, 20, 39, and 59 kg P ha−1) were evaluated. Soil samples at 20‐cm depth were collected in eight cropping seasons. Yield response to P fertilizer increased after 20 years from 0.64 to 2.79 Mg ha−1. The application of 39 kg P ha−1 year−1 increased soil Bray‐1 P to 19.5 mg kg−1, outyielded all other P treatments, and resulted in a positive relative P balance. Over 20 years, 0 kg P ha−1 year−1 decreased Bray‐1 P from 10.5 to 5.5 mg kg−1. Annual P rates of 0, 10, and 20 kg P ha−1 produced a negative relative P balance and SPT below the critical soil test value (CSTV). The CSTV was 22.2 mg kg−1 for a continuous irrigated corn cropping system. A 53% increase in the P fertilizer rate (from 39 to 59 kg P ha−1 year−1) produced a threefold increment in the soil test P build‐up rate. High‐yielding irrigated continuous corn production systems (&gt;14 Mg ha−1) are required to apply at least 39 kg P ha−1 year−1 to maintain SPT and a positive relative P balance over years.

Optimizing molecular assays for glyphosate and ALS-inhibitor resistance diagnostics in four weed species

Herbicide-resistant weeds pose a threat to food production in modern agriculture, causing US$32 billion in crop production losses worldwide. In Michigan, highly troublesome and widespread weeds include waterhemp, Palmer amaranth, common ragweed, and horseweed, with accessions that are resistant to glyphosate (Group 9) and ALS-inhibitors (Group 2), major herbicide sites of action utilized in soybean and corn cropping systems. Molecular assays for rapid resistance diagnostics to confirm the in-field status of herbicide resistance can assist with more effective, timely, and proactive management. In this research, we developed and tested PCR-based assays to identify target site resistance mechanisms to both herbicide groups through Sanger sequencing and EPSPS copy number variation. Nine different SNPs were identified in five ALS positions known to confer herbicide resistance among all species surveyed. Pro197Ser was the most frequent in horseweed and common ragweed accessions, whereas Trp574Leu was the predominant mutation in Palmer amaranth and waterhemp. Four horseweed accessions contained the Pro106Ser mutation in the EPSPS gene, which confers resistance to glyphosate. Additionally, waterhemp and Palmer amaranth had 2–7 and 20–160 copies of EPSPS, respectively. The assays were validated by comparing genotyping of several field-collected accessions of unknown resistance status with known resistant and susceptible accessions. The efficacy of genotyping assays was &gt;98% and required only two days, confirming that molecular assays are a robust tool for rapid resistance diagnostics. These assays can help growers evaluate herbicide resistance status in weed populations within the same growing season, allowing them to adopt effective management practices.

Corn Cropping Systems in Agricultural Soils from the Bajio Region of Guanajuato: Soil Quality Indexes (SQIs)

Agriculture is a sector of great importance for Mexico’s economy, generating employment and contributing significantly to the country’s gross domestic product. The Bajio stands out as one of the most productive agricultural regions in Mexico. However, intensive agricultural practices in this area have caused a progressive deterioration and loss of soil fertility. This study focused on evaluating the quality of soils used for agriculture in the Bajio region of the State of Guanajuato, Mexico. This evaluation, utilised soil quality indexes (SQIs) based on a total of 27 physicochemical, biological and enzymatic indicators. These indicators were selected by means of a principal component analysis (PCA), which allowed for the identification of a minimum set of data. The SQIs developed in this study categorised soils into different quality levels, ranging from low to high, mainly based on the values observed in the biological indicators (SMR and qCO2), which comprised the established SQIs. The inclusion of these biological indicators provides the developed SQIs with greater sensitivity to detect minor disturbances in agricultural soils due to human activity, compared with SQIs consisting only of physicochemical indicators. The developed SQIs can be used to ensure high-quality food production in soils used for corn cultivation under similar conditions, both nationally and internationally.

Corn response to long‐term seasonal weather stressors: A review

AbstractLong‐term weather patterns (environmental conditions or stresses exceeding 10 days in length) have the potential to influence corn (Zea mays L.) growth, development, and yield. This review summarizes the current knowledge (with emphasis placed on the Midwestern U.S. production environment) on how long‐term weather conditions affect corn growth and yield, including (i) drought and heat stress, (ii) solar radiation, and (iii) distribution of heat unit accumulation during the season. Each section contains summaries of how these environmental factors influence corn growth and yield and provides context into past events experienced. The focus of the review is on dent corn grown for grain production, though relevant issues related to other types (i.e., silage corn) are included. This review also discusses agronomic recommendations or considerations to help alleviate the negative effects of stress conditions and identify areas where future research would be beneficial to continue improving the resiliency of corn cropping systems. Periods of high heat and water deficit as well as limited light availability challenge the ability to maximize yield production in corn. Temperature affects crop growth and development through the season, and accurately describing phenological progression using heat unit accumulation is a challenge. Advances in corn breeding and genetics, hybrid selection, and agronomic management practices will be key to ensuring long‐range productivity and fully leveraging possible benefits from the shifts in long‐range weather patterns.

Cover crops increase belowground N retention substantially in corn cropping systems: Results from a 15N residue swapping experiment

Cover crops increase belowground N retention substantially in corn cropping systems: Results from a 15N residue swapping experiment

Corn Cropping System and Nitrogen Fertilizers Technologies Affect Ammonia Volatilization in Brazilian Tropical Soils

The adoption of technologies for N fertilization has become essential for increasing the N use efficiency in no-till (NT) systems in Brazil. Thus, this study aimed to quantify ammonia losses, N removal in grains, and second crop season yield in no-till and conventional (T) areas that received the application of different N fertilizers and their technologies. Ammonia volatilization, N extraction in grains, and corn yield in response to the application of conventional fertilizers were compared to urea treated with urease inhibitors in NT and conventional systems. The treatments were: no-N (Control); Prilled urea (PU); urea + N-(n-Butyl) thiophosphoric triamide (UNBPT); urea + Cu + B (UCuB); ammonium nitrate (AN), and ammonium sulfate (AS). In the NT system, the N-NH3 losses were 49% higher than in the conventional; without differences in corn yield. The fertilizers AN and AS had the lowest N-NH3 losses, regardless of the tillage system. UNBPT reduced the mean N-NH3 loss by 33% compared to PU. UNBPT (1200 mg kg−1) and UNBPT (180 mg kg−1) reduced the N-NH3 losses by 72% and 22%, respectively, compared to PU in the NT system. We noticed that the NBPT concentration to be used in soils under NT should be adjusted, and a reduction of N-NH3 losses does not directly reflect an increase in yield and N extraction by corn.

Short-Term Crop Residue Management in No-Tillage Cultivation Effects on Soil Quality Indicators in Virginia

The use of crop residues for biofuel production has the potential to provide environmental and economic benefits to modern societies. Because of the profound impacts that crop residues have on agricultural productivity and soil health, a sustainable utilization of these residues is required. Thus, we determined crop yield and quality response for a range of biomass retention rates in grain cropping systems. Combinations of corn (Zea mays L.) stover (0, 3.33, 6.66 and 10 Mgha−1) and wheat (Triticum aestivum L.) straw (0, 1.0, 2.0, and 3.0 Mgha−1) were soil applied in a corn-wheat/soybean (Glycine max L. Merr.) rotation in Virginia’s Coastal Plain. Corn stover (0, 3.33, 6.66, 10 and 20 Mg ha−1) was applied in a continuous corn cropping system in the Ridge/Valley province. For each system, residues were applied following grain harvest over two production cycles. Each experiment was conducted as a randomized complete block design with four replications. Two cycles of crop residue management, with retention rates of up to 20 Mg ha−1 of corn stover retention in Blacksburg, and up to 13 Mg ha−1 of corn stover and wheat straw in New Kent, had no effect on total nitrogen (TN) and carbon (TC) concentrations, CN ratios, bulk density (BD), soil pH, field capacity, permanent wilting point, plant available water and water aggregate stability across soil depths and aggregate sizes in Virginia. In one situation when residue management slightly affected BD (0–2.5 cm depth, NK1), differences across the sixteen total retained residues treatments were less than 5%, thus rendering them not biologically or environmentally meaningful. Overall, results of this study did not show any clear short-term impact, resulting from various rates of crop residue retention in Virginia cropping systems. These incipient negative impacts resulting from very low rates of residue return warrant further studies to corroborate whether these results are to be found following long-term scenarios of crop residue management.

Effects of Cover Crops and Soil Amendments on Soil CO2 Flux in a Mississippi Corn Cropping System on Upland Soil

Agroecosystems, accounting for more than one-third of arable land worldwide, play an essential role in the terrestrial carbon (C) cycle. The development of agricultural practices, which maximize soil C sequestration from the atmosphere, is receiving growing attention due to the recognition of agroecosystems’ great potential to serve as sinks of atmospheric carbon dioxide (CO2). In particular, cover crop and soil amendment applications are generating much interest in mitigating climate change and enhancing agricultural ecosystem services. The objective of this study was to evaluate the effects of winter cover crop and soil amendments, including broiler litter (BL), flue gas desulfurization (FGD) gypsum and lignite, on soil CO2 flux from cropping systems in southeastern USA, where related studies were limited. A field study was conducted from 2019 to 2021 in a Mississippi upland corn cropping system with measurements of soil CO2 flux, moisture and temperature during cash crop growing seasons. We observed high temporal variability in soil CO2 flux with flux peaks between late June and early July, which is likely due to the temporal changes in soil moisture. A significant increase in soil CO2 flux was found with BL application (p &lt; 0.05). Co-application of FGD gypsum and lignite with BL-reduced soil CO2 flux by 15–23% but did not fully eliminate the rising effects. Significantly higher soil CO2 flux and lower soil temperature were observed from fields with cover crops than those without cover crops in the third year of this study (p &lt; 0.05), which is likely attributed to the higher organic C content accumulated in soil with cover crops. Future research should assess year-round soil greenhouse gas fluxes in both cash crop and cover crop growing seasons using a high temporal resolution measurement scheme.

Effect of mustard cover crops on corn growth, yield and soil water storage in southwest Texas

Mustard cover crops can provide multiple soil health benefits but may adversely affect cash crops by depleting soil water. This was tested in a center-pivot irrigated corn cropping system in southwest Texas from 2018 to 2020. Changes in biomass growth of both the cover crops and corn, and soil water content in the root zone were monitored multiple times during the main growth periods of the crops. Upon termination, biomass production of cover crops averaged 4271 kg/ha, with equivalent nitrogen and phosphorus inputs to the soil of 92 kg/ha and 12 kg/ha, respectively. Over 2 years, water use during the main growth period of the mustard cover crops and the fallow area averaged at 1.4 mm/day and 1.1 mm/day, respectively, and water use of corn following the mustard and fallow averaged at 4.0 mm/day and 3.7 mm/day, respectively, although the differences were only marginally significant. Our data suggest that water use of cover crops was affected by their growth patterns. The mustard cover crops depleted soil water in a dry year (2019–2020), but to a less extent in a wet year (2018–2019). In either year, however, corn yield was not reduced in association with cover crop use, although the improved shoot biomass growth in corn associated with mustard cover crops was observed in the wet year but not in the dry year. Mustard cover crops tended to reduce deep drainage during the corn seasons, which has implications in preventing the leaching loss of nitrogen in the crop root zone.

Rice (Oryza sativa L.)–Baby Corn (Zea mays L.) Cropping System Response to Different Summer Green Manuring and Nutrient Management

The nutrient and biomass supply capacity of green manure (GM) and its complimentary and synergistic relationship with chemical nutrients is needed for a sustainable rice–baby corn cropping system in the eastern part of North India. A two-year field study was performed to assess the effect of GM and nitrogen management (NM) on yield attributes (YA), the yield of rice, and their residual (R) effect with the half-recommended dose of fertilizers on the succeeding baby corn crop. The combination of GM and N levels had significant effects on rice yield, which also influenced the succeeding baby corn crop. A higher number of tillers/m2, panicle length (cm), number of grains/panicles, panicle weight (g), grain yield (Mg/ha), straw yield (Mg/ha), and biological yield (Mg/ha) were found with Sesbania aculeata incorporated at 45 DAS (SA), which was statistically on par with water hyacinth 5 t/ha dry weight basis (WH) during both years of the field study. Among the rates of nitrogen fertilizers, 100% RDN (50% N through FYM + 50% N through inorganic) (RDN100) was the best treatment with a corresponding increase in all YA and yields of rice. It has been proven that integrated nitrogen management (INM), or the use of organic material along with fertilizer, is an effective way of managing nitrogen. In the present investigation, green manuring and integrated nitrogen management on rice sustainably increased the yield attributes and yield of the succeeding baby corn. These results illustrated the complementary effects of summer green manuring in conjunction with INM in maximizing the yield attributes and yields of rice, its residual effect on succeeding baby corn, and the economics of the system.

Effects of cover crops on soil moisture dynamics of a corn cropping system

Climate change induced rainfall patterns have increased environmental extremities such as severe droughts and floods which can affect volumetric soil moisture content (θ), thus food security. Integrating cover crops (CC) with cropping systems can help mitigate these extreme conditions and improve soil water availability. The objective of this study was to evaluate the CC effects on the θ of a corn (Zea mays L.) cropping system. The study was conducted at the USDA Elsberry Plant Material Center, Missouri, USA, with three treatments: no-till cover crop (NC), conventional till no cover crop (CN), and no-till no cover crop (NN). Cereal rye (Secale cereale L.), crimson clover (Trifolium incarnatum L.), and daikon radish (Raphanus sativus L. var. Longipinnatus) CC mixture was established in the NC treatment in 2019 (first CC establishment). Spectrum Technologies Water Scout SM100 soil moisture sensors installed at 5-, 10-, 20- and 40-cm soil depths monitored θ in 15 min intervals throughout the study period. Numerically and significantly greater θ values were observed in the CN treatment than NC and NN at the first three depths during most of the study period. The NC treatment maintained higher θ than NN at all the studied depths during growing periods and were significantly different during some weeks. Results indicate that long-term use of CC can improve soil moisture dynamics of corn cropping systems through improved soil organic matter and would be a viable solution in soil moisture conservation and improving soil security.

Effects of cover crops on soil thermal properties of a corn cropping system

AbstractSoil thermal properties play many major roles in a soil as they influence the soil temperature and define the soil microclimate, which regulates many soil health parameters as well as life cycles of soil biota. Although cover crops (CC) can affect soil thermal properties, they are one of the least studied areas. This study compared the effects of CC on soil thermal properties in a corn (Zea mays L.) cropping system at the Elsberry Plant Material Center–USDA in Missouri (USA). The study design consisted of (a) no‐till CC (NC), (b) conventional till no CC (CN), (c) no‐till no CC (NN), and (d) grass (G) treatments. The first CC establishment in the NC treatment was done in October 2019. Soil cores were collected in April 2021 from 0‐to‐40‐cm depth at 10‐cm increments (96 samples) and analyzed for volumetric heat capacity (Cv), soil thermal conductivity (λ), soil thermal diffusivity (α), soil organic carbon (SOC), bulk density (BD), and volumetric water content (θ). As per the results, NC did not significantly improve SOC, BD, or soil thermal properties, because the biomass accumulation by CC was not enough due to the lack of CC establishment duration. The G treatment showed significantly higher Cv and lower λ in several soil depths. The study outcomes suggested that long‐term maintenance of CC with cropping systems are needed in quantifying the effects of CC on soil thermal properties.

Eddy covariance quantification of corn water use and yield responses to irrigations on farm‐scale fields

AbstractFurrow irrigations dominate row‐crop irrigation scenarios in many regions worldwide. In this study, corn (Zea mays L.) yield and evapotranspiration (ET) in an all‐furrow irrigation (FI) were compared against irrigations applied through alternate furrows irrigation (SFI, skip‐furrow irrigation) and rainfed (RF) systems on farm‐scale fields in 2017 and 2019 {corn phases of a soybean [Glycine max (L.) Merr.]–corn rotation} in clay soil in the Lower Mississippi Delta region, United States. Evapotranspiration was monitored using the eddy covariance (EC) method. The average corn yield in the SFI was significantly (12.1 Mg ha−1) higher (4.9%) than in the FI (11.7 Mg ha−1). Corn yield in RF (10.2 Mg ha−1) was significantly lower (10.7%) than in the FI. However, the leaf area index (LAI) in SFI was lower than in FI. Seasonal average ET was 556, 573, and 540 mm in FI, SFI, and RF, respectively. The average water use efficiencies (WUEs) were 0.021, 0.021, and 0.019 Mg ha−1 mm−1, respectively (10.5 % lower in RF than FI and SFI). This investigation revealed that adapting the SFI irrigation regime in the corn cropping system could produce grain yields equal to or higher than corn grown under the conventional FI, saving ∼40% of irrigation water. The farm‐scale studies conducted in this investigation gave better confidence to recommend SFI to replace conventional FI systems in the region for water conservation in corn cropping systems. Further investigations may be needed to evaluate the viability of SFI in other contrasting soils and climates and recommend the system for adoption by the farming community.

Comparisons of Corn Stover Silages after Fresh- or Ripe-Corn Harvested: Effects on Digestibility and Rumen Fermentation in Growing Beef Cattle.

Simple SummaryCorn stover is an important agricultural byproduct, and represents an animal feedstuff. Waxy corn is harvested at milk stage or dough stage (20 d difference in harvest time) to meet the market demand for fresh corn and ripe corn in China, resulting in plenty of byproducts of corn stover after fresh- (CF) or ripe-corn (CR) harvested. This study was conducted to investigate the digestibility and rumen fermentation of these two corn stover silages in growing beef cattle. We observed that CR silage had greater dry matter and fiber contents, but with similar substrate degradation through in vitro ruminal fermentation in comparison with the CF silage. Further feeding trials indicated that feeding a CR diet (i.e., replaced 50% forage of CF silage with CR silage on a dry matter basis) increased feed intake and decreased fiber digestibility with reduction in the abundance of ruminal fiber degraders, together with similar growth performance in beef cattle, when comparing with CF diet.Both waxy corn stover after fresh- (CF) and ripe-corn (CR) harvested are important byproducts of corn cropping system and have 20 d difference in harvest time. The study aimed to investigate the effects of prolonging harvest time on the nutritive value of corn stover silage by comparing CF with CR silages. In vitro ruminal experiment was firstly performed to investigate substrate degradation and fermentation of CF and CR silages. The CR diet was formulated by replacing 50% forage of CF silage with CR silage on a dry matter (DM) basis. Fourteen crossbred steers (Simmental × Limousin × local Chinese) aged 13 months with an average weight of 318.1 ± 37.1 kg were selected and randomly allocated into two dietary treatment groups. Although the CR silage had greater DM and fiber contents than CF silage, it did not alter in vitro degradation (p > 0.05), but with lower molar percentage of propionate and acetate to propionate ratio (p < 0.05). The cattle fed CR diet had a higher DM intake and lower fiber digestibility with reduction in 18S rRNA gene copies of protozoa and fungi and 16S rRNA gene copies of Fibrobacter succinogenes (p < 0.05). Further 16S rRNA gene amplicon analysis indicated a similar diversity of bacteria community between CR and CF treatments (p > 0.05). Few differences were observed in the abundance of genera larger than 1% (p > 0.05), except for the reduction in abundance of genera Ruminococcaceae_NK4A214_group in CR treatment (p < 0.05). In summary, prolonging 20 d harvest time of corn stover silage increases the forage fiber and DM content, which promotes feed intake with decreased fiber degradation, although rumen fermentation and growth performance are not changed in growing beef cattle.

Evaluation of Agrobiodiversity and Cover Crop Adoption in Southern Ontario Field Crops

Incorporating cover crops into corn and soybean operations across Southern Ontario is essential for maintaining yields under environmental stressors. Unfortunately, amongst the literature, there is a concern about the low adoption rate of cover crops in the northern Corn Belt due to a shift toward low agrobiodiversity and dominance of more profitable corn and soybean cropping systems, encouraged by extensive use of fertilizers, herbicides, and pesticides. This study examines whether Southern Ontario is following suit in decreasing agrobiodiversity trends, at the county level, and examines the adoption of cover crops within corn and soybean operations across Southern Ontario using digital imagery from 2013 to 2018. Results reveal that Southern Ontario is indeed shifting from systems characterized by higher agrobiodiversity to systems dominated with corn, soybean, and hay. Despite the benefits of cover crops, this study reveals that most of the current corn and soybean operations are not incorporating cover crops into the rotation. More significantly, the low adoption of cover crops is most apparent in southwestern Ontario, and increases in adoption occur toward the north.

Impact of short-term land-use change on soil organic carbon dynamics in transitional agro-ecosystems: a case study in the Brazilian Cerrado

Agricultural expansion directly impacts the dynamics of organic carbon (C) in the soil. After land use change, agricultural systems with greater resilience of soil C stocks could be preferentially adopted. The objective of the present study was to determine the impact of short-term conversion of grassland into different agricultural systems on soil organic C stocks and their resilience in a site-specific region of Brazilian Cerrado in the State of Goiás. The following systems were evaluated: pasture (PAST), no-tillage system (NT), four organic production systems (ORG) at different years of cultivation (2, 6, 8 and 10 years), and a continuous monoculture corn cropping system (CC). An area of native Cerrado (‘Savanna’, CE) was selected and sampled for use as a steady state reference point. Resilience of soil organic C was measured based on calculation of the C resilience index and C management index. Soil C stocks in the 0-0.40 m depth varied from 61 to 111 Mg ha−1 and were reduced by 33% when converting from CE to cultivation regardless of management system. The labile C contents varied from 425 to 900 mg kg−1, and increased when PAST soils were converted to ORG cultivation. The highest values of C resilience and management indexes occurred in the ORG-2 and ORG-6 soils, showing that organic systems can recover organic C levels in the soil faster than other agricultural systems. On the other hand, no-tillage system when converted from pasture presents the lowest potential of soil C resilience in short-term in the site-specific conditions of studied Cerrado of Goiás State.

Simulating no-tillage effects on crop yield and greenhouse gas emissions in Kentucky corn and soybean cropping systems: 1980–2018

CONTEXTNo-tillage (NT) is a conservation practice that aims to minimize soil disturbance and improve crop production. However, NT effects on crop production remain controversial due to the spatial heterogeneity of climate and soil conditions. Some studies argued that NT might offset its greenhouse gas (GHG) mitigation potential in agriculture by promoting soil N2O emissions. OBJECTIVEThis study used a process-based agroecosystem model (DLEM-Ag) along with spatially explicit environmental datasets to quantify the long-term effects of NT on crop yield and GHG emissions in corn and soybean cropping systems in the state of Kentucky (USA) from 1980 to 2018. METHODSThe DLEM-Ag was used to quantify the long-term effects of NT on crop yield and GHG emissions in corn and soybean cropping systems in the state of Kentucky. Three spatiotemporal tillage scenarios, i.e., historical varying tillage, consistent conventional tillage (CT), and consistent NT, were adopted to simulate changes in crop yield and GHG emissions. RESULTS AND CONCLUSIONSOverall, our results showed that NT could reduce soil CO2 (−1.6% for corn and −4.53% for soybean) and N2O emissions (−10.5% for corn and −19.6% for soybean) in Kentucky, as compared to CT, although corn and soybean yields with NT were not significantly different from those with CT. Our further analysis suggested that air temperature and soil clay content were the two main factors influencing NT advantages in reducing GHG emissions. The increased temperature decreased the benefits of mitigating GHG emissions, while high clay content soils had less N2O emission under NT. SIGNIFICANCEThis study represents one of few attempts to quantify the effects of NT on crop yield and soil GHG emissions at the regional scale using an agroecosystem modeling approach. The findings from this study provide insights into how NT can enhance agroecosystem production stability and support climate change mitigation. This information may be used by the scientific community and policymakers working on practical technologies to mitigate climate change from agriculture.

Stover harvest and tillage effects on corn seedling emergence

AbstractCorn (Zea mays L.) stover is an increasingly important feedstock for biofuel and bioproduct production; however, excessive harvest of corn stover from agricultural fields may affect corn seedling emergence and subsequent plant population which may reduce corn growth and yield. Field experiments were conducted over four consecutive growing seasons in southwestern Ontario to determine under continuous corn cropping system the effects of no‐tillage (NT), conventional tillage (CT), and five rates of stover harvest (0, 25, 50, 75, and 100 wt. %) on corn seedling emergence in a Harrow sandy loam and in a Brookston clay loam. Time to achieve 50% seedling emergence (t0.5), emergence rate constant (kG), and final seedling population (MG) were adequately simulated using the Gompertz function. Irrespective of stover removal rate and soil type, t0.5 was 2 d longer, and kG was 32% lower, under NT compared to CT. In Harrow sandy loam, stover removal from NT reduced t0.5 in 1 out of 4 yr. The 100% removal reduced t0.5 relative to 0, 25, 50, and 75% removal by 1.1–2.2 d in 2015. Averaged across both tillages and all removal rates, kG was greater in Harrow sandy loam than in Brookston clay loam. Stover removal rates had no effect on MG but averaged over all removal rates and soil types, MG was 9% lower for NT compared to CT in 2016. No‐tillage practice under corn production can impede seedlings emergence early in the growing season and stover removal from the field can help mitigate against this effect.

Energy use pattern of diversified cropping systems under different nutrient and crop residue management practices in Eastern Indo-Gangetic plain

Aim: Assessment of energy input output relationship, greenhouse gases emission and carbon footprint of diversified jute-rice cropping systems under different nutrients and crop residue management practices. Methodology: The inventory was prepared for all inputs required for crop cultivation and outputs of crops in cropping systems. These inputs and outputs were converted into energy by multiplying with energy equivalent coefficient and CO2 emission coefficient following standard procedure. Results: Jute-rice-baby corn cropping system recorded significantly higher net energy (324 GJ ha-1) and energy use efficiency (8.02). Among different nutrient and crop management (NCRM) practices, significantly higher energy output (336.9 GJ ha-1) and net energy (291.4 GJ ha-1) recorded 100% NPK with crop residue. The highest carbon footprint recorded with rice-rice (0.44 kg COe kg-1 economic yield) and the lowestwith jute-rice-pea (0.29 kg COe kg-1 economic yield) cropping system. Among different NCRM practices, higher carbon footprint was (0.38 kg COe kg-1 economic yield) recorded with 100% NPK with crop residue. Interpretation: The energy efficient and low input required cropping systems which include legume crops like garden pea and mungbean should be considered for cultivation for diversifying the existing rice-rice cropping system in Eastern India.