Winter Wheat Production Systems Research Articles

Environmental Assessment of Dryland and Irrigated Winter Wheat Cultivation under Compost Fertilization Strategies.

Wheat (Triticum aestivum L.) is a strategic agricultural crop that plays a significant role in maintaining national food security and sustainable economic development. Increasing technical performance considering lowering costs, energy, and environmental consequences are significant aims for wheat cultivation. For drylands, which cover approximately 41% of the world's land surface, water stress has a considerable negative impact on crop output. The current study aimed to assess the environmental aspects of chemical fertilizer in combination with compost in dryland and irrigated winter wheat production systems through life cycle assessment (LCA). The cradle-to-farm gate was considered as the system boundary based on one tone of wheat yield and four strategies: D-C (dryland with compost), D (dryland without compost), I-C (irrigated with compost), and I (irrigated without compost). Based on the results, the highest and lowest amounts of wheat yield were related to the I-C and D strategies with 12.2 and 6.7 ton ha-1, respectively. The LCA result showed that the I strategy in comparison with other strategies had the highest negative impact on human health (49%), resources (59%), ecosystem quality (44%), and climate change (43%). However, the D-C strategy resulted in the lowest adverse effect of 6% on human health, 1% on resources, 10% on ecosystem quality, and 11% on climate change. Utilizing a combination of fertilizer and compost in dryland areas could ensure a higher yield of crops in addition to alleviating negative environmental indicators.

Winter Wheat Response to Winter Pea Cover Crop Under Dryland Cropping

AbstractCover cropping with legumes such as winter peas under dryland winter wheat production systems has several benefits that could improve the resiliency of production systems and agroecosystem services. This article demonstrates the use of winter pea cover crops to increase winter wheat yields in the intermediate (12–16 inch) rainfall zone and to improve drought resiliency. Earn 0.5 CEUs in Crop Management by reading the article and taking the quiz at https://web.sciencesocieties.org/Learning‐Center/Courses.

Dynamic Analysis of the Carbon Footprint in Winter Wheat Production Based on Lifecycle Assessment and the LMDI Model: A Case Study of Jiangsu Province in China

This study applies the lifecycle assessment (LCA) to quantify the carbon footprint within the winter wheat production system in Jiangsu Province during 2011–2020. Additionally, the study employs the Logarithmic Mean Division Index (LMDI) to analyze the driving factors behind its changes. The results show that (1) the greenhouse gas emissions from wheat production in the region increased from 4837.8 kgCO2-eq/hm2 to 5701.1 kgCO2-eq/hm2 with an annual average increase of 95.9 kgCO2-eq/hm2; (2) the primary carbon sequestration method for wheat production in Jiangsu Province is straw returning; (3) the carbon footprint of wheat at yield scale and value scale generally increased during the period, whereas the carbon footprint at cost scale decreased over the years; (4) the driving factors effects’ cumulative contribution rates are as follows: economic level > population size > employment structure > production structure > production efficiency. This research explores the dynamic changes and driving factors influencing the carbon footprint associated with winter wheat production in Jiangsu Province, which could provide theoretical references for the future clean production of winter wheat.

Integrated impacts of irrigation and nitrogen management for balancing winter wheat yield and greenhouse gas emissions

Irrigation and nitrogen (N) input are effective methods of balancing crop yields and greenhouse gas (GHG) emissions. However, the effects of irrigation and N management on the GHG emission of winter wheat production systems have not yet been well documented. Therefore, we conducted 2-year field experiments on winter wheat and studied the effects of irrigation and N reduction/replacement on GHG emissions, grain yield, global warming potential (GWP), and GHG emission intensity (GHGI). The winter wheat was irrigated once or twice with 60 or 90 ​mm each time. Five N reduction/replacement treatments were no N application (CK), 25% traditional urea (U) reduction (75%U), traditional U (U), 25% reduction in polymer-coated U (PCU), and 25% reduction in traditional U combined with organic fertilizers (U ​+ ​OM). The results indicated that N reduction/replacement significantly reduced N2O emissions, but had no significant effect on CH4 emissions. Soil water-filled pore space was the same key factor affecting the emission fluxes of N2O and CH4. Soil temperature significantly affected the fluxes of CH4 (P ​< ​0.001). Irrigation treatment did not exhibit a significant effect on grain yield, but high irrigation input increased the GWP and GHGI. Compared with U, the grain yield of CK, 75%U, PCU, and U ​+ ​OM increased by −46%, −9.2%, −1.8%, and 5.4%, respectively; GWP decreased by 35.9%, 11.6%, 7.3%, and 2.7%, respectively; and GHGI decreased by −22.1%, 3.1%, 6.0%, and 8.0%, respectively. Therefore, sustainable production goals of increasing grain yield and reducing GHG emissions were achieved with N reduction/replacement using U + OM and low irrigation input of 60 ​mm.

Effect of Tillage and Sowing Technologies Nexus on Winter Wheat Production in Terms of Yield, Energy, and Environment Impact

Crop production is considered one of the most important agricultural areas in the world, supplying humanity with raw food materials. However, intensive farming very often has a detrimental effect on the environment. The aim of this study was to investigate and assess the efficiency of strip tillage and a sowing machine as well as a direct sowing machine in differently prepared soils in terms of yield, energy, and environmental impact. The experiments were performed with winter wheat (Triticum aestivum L.) grown using three different tillage techniques and two sowing machines. The results show that the inputs of diesel fuel, energy, and time are directly affected by the number and complexity of technological operations throughout the production chain. The highest inputs of diesel fuel, working time, and energy consumption were needed using conventional tillage technology with strip tillage and a sowing machine (CT–STS), amounting to 130.2 l ha−1, 6.65 h ha−1, and 18,349 MJ ha−1, respectively. The best yields were obtained using no tillage–direct sowing technology (NT–DS), where were reached 7.54 t ha−1. The lowest environmental impact was achieved in the winter wheat production system using NT–DS, where the CO2 emissions were as high as 15%, lower than those under conventional tillage–direct sowing (CT–DS) and CT–STS. The costs of winter wheat production can be reduced by up to 23.6%. The main conclusion regarding the use of strip tillage and sowing and direct sowing machines in traditional tillage technology is that energy and environmental indicators have deteriorated compared to no tillage, but no significant difference in winter wheat yields has been identified.

Modelling soil emissions and precision agriculture in fertilization life cycle assessment - A case study of wheat production in Austria

The environmental assessment of using optical crop sensors for variable rate nitrogen application (VRNA) has been limited by the lack of a robust method to quantify site- and technology-specific impacts. This study aimed to (1) present a comparative life cycle assessment (LCA) of a conventional winter wheat production system with and without using a crop sensor for VRNA applied to an Austrian case study. Special emphasis was placed on simulating site-specific field emissions with the DeNitrification-DeComposition (DNDC) biogeochemical soil model; (2) assess the environmental impacts of only the fertilization process; and (3) compare soil emissions simulated by the DNDC with soil emissions coming from a benchmark ecoinvent wheat production process. Three nitrogen fertilization schemes – one conventional and two VRNA – were modeled. Two functional units were used – 1 ha of cultivated winter wheat and 1 kg of winter wheat produced. The system boundary includes tillage, seeding, plant protection, nitrogen fertilization, and harvesting processes. Information communication technologies (ICT) – manufacturing of the sensor, internet and computer manufacturing and usage – were also included within the boundary. Local and global environmental impacts attributed to nitrogen emissions due to fertilization were evaluated in this LCA, including climate change (CC), fine particulate matter formation (FPMF), freshwater eutrophication (FE), freshwater ecotoxicity (FET), terrestrial acidification (TA), marine eutrophication (ME), and human noncarcinogenic toxicity (HTnc). The CC of the fertilization process was 1,662.8 kg CO2 eq./ha with conventional nitrogen application versus 1,518.8 kg CO2 eq./ha as the lower of the two VRNA results, an 8.6% reduction due to less fertilizer applied. Fertilization was found to be responsible for more than 80% of the total emissions that impact CC, 55% of the FET, 44% of the HTnc, 96% of the FE and 96% of the TA. The largest greenhouse gas (GHG) emitters were soil N emissions as simulated by the DNDC, followed by the fertilizer manufacturing process in all of the impacts, except for FET and HTnc, where fertilizer production was the highest contributor. ICT components contributed less than 1% to all of the impacts assessed. The amount of applied N fertilizer has a greater influence on NH3 and NO3 indirect soil emissions than on direct N2O emissions. This study demonstrates that using optical crop sensors for VRNA could have a limited but positive environmental impact and highlights the importance of applying site-specific soil models to estimate field emissions.

Herbicide Resistance Status of Italian Ryegrass (Lolium multiflorum Lam.) and Alternative Herbicide Options for Its Effective Control in the Huang-Huai-Hai Plain of China

Italian ryegrass (Lolium multiflorum Lam.) was introduced into China as a kind of turfgrass and has invaded wheat fields of the Huang-Huai-Hai Plain, causing great losses to grain yield. The acetyl–CoA carboxylase (ACCase) inhibitor clodinafop-propargyl and the acetolactate synthase (ALS) inhibitor mesosulfuron-methyl are highly efficient herbicides that have been widely used for control of this species, which has also resulted in its resistance evolution. However, the resistance status of L. multiflorum in the Huang-Huai-Hai Plain of China remains unclear, which hinders the integrated management of this weed in winter wheat production systems. In the current study, a total of 37 L. multiflorum populations were collected from the wheat fields across the region, and their susceptibility to clodinafop-propargyl and mesosulfuron-methyl was assessed. Of these, 13 populations were resistant or evolving resistance to clodinafop-propargyl (R?, RR, and RRR) with resistance index (RI) ranging from 2.62 to 830.05, and 8 populations were resistant or evolving resistance to mesosulfuron-methyl (R? and RR) with RI ranging from 3.89 to 16.68. Seven populations showed multiple-resistance to both clodinafop-propargyl and mesosulfuron-methyl. Three ACCase (I1781L, I2041N, and D2078G) and four ALS (P197T, P197S, P197A, and W574L) resistance mutations were identified in the herbicide-resistant populations, and I1781L and P197T were predominant ACCase and ALS mutations, respectively. Real-time quantitative PCR assays showed that compared with the susceptible population, the ACCase expression was slightly upregulated in some of the clodinafop-propargyl-resistant populations (AH-01 and AH-05) following clodinafop-propargyl treatment, while the ALS expression in the mesosulfuron-methyl-resistant populations showed no significant change following mesosulfuron-methyl treatment. Whole-plant dose-response testing showed that the AH-01 population carrying an ACCase gene I2041N mutation exhibited cross-resistance to all the ACCase inhibitors tested and multiple-resistance to the ALS inhibitor bispyribac-sodium, the AH-05 population carrying an ACCase gene I1781L mutation and an ALS gene P197T mutation showed cross-resistance to all the ACCase and ALS inhibitors tested, and the HN-07 population carrying an ACCase gene D2078G mutation showed cross-resistance to all the ACCase inhibitors tested and multiple-resistance to some ALS inhibitors. All the resistant populations remained susceptible to the 5-enolpyruvylshikimate-3-phosphate inhibitor glyphosate and the photosystem II inhibitor isoproturon. This study has clarified the distributions of clodinafop-propargyl- and/or mesosulfuron-methyl-resistant L. multiflorum in the Huang-Huai-Hai Plain of China, and target gene mutation was one of the most common mechanisms responsible for the resistance.

Optimizing irrigation for winter wheat to maximize yield and maintain high-efficient water use in a semi-arid environment

Optimizing irrigation scheduling is vital in maintaining high crop yield and sustainable water use in water-limited regions worldwide. In this study, a 4-year field experiment (2016–2020) was conducted to evaluate the effect of six irrigation schedules on the grain yield performance, soil water content, plant evapotranspiration, and irrigation water use efficiency of typical winter wheat production system in the North China Plain. The six irrigation schedules involved irrigation at different growth stages, including one critical growth stage (60 mm per stage, I60), two stages (I120), three stages (I180), four stages (I240), and five stages (I300). No irrigation was performed in the control field (I0). The results showed that the plant height and yield components of winter wheat (spike number per hectare, kernels per spike, thousand-kernel weight) increased with the increase in annual irrigation amount. The grain yield in each study year increased quadratically (P < 0.05) with the annual irrigation amount. The soil water content in the 0–90 cm soil layer (where the wheat roots are mainly distributed) increased significantly during the growing season with the increase in annual irrigation amount. In I240, the mean soil water content (0–90 cm) during the growing seasons (17.3–22.6 %) was 61.7–80.8 % of the field water holding capacity, sufficiently favoring wheat growth. The average soil water storage (0–90 cm) during the wheat growing season ranged from 241.1 to 283.2 mm in the irrigation applied treatments, which were 21.7–63.8 mm (9.9–29.1 %) higher than in no irrigation treatment (I0, 219.4 mm). The 4-year averages of wheat grain yield did not differ significantly between I240 (7909.1 kg ha-1) and I300 (7868.6 kg ha-1); however, the average irrigation water use efficiency decreased from 33.0 kg ha-1 mm-1 in I240 to 26.2 kg ha-1 mm-1 in I300. Therefore, we recommend an irrigation scheduling at the regreening, jointing, flowering, and filling stages (I240, 60 mm per stage, 240 mm in total) to maintain high grain yield and sustainable soil water use for winter wheat production in the North China Plain and similar semi-arid regions.

Carbon dioxide and water vapor fluxes of multi-purpose winter wheat production systems in the U.S. Southern Great Plains

• We synthesized CO 2 fluxes and ET from differently managed eight winter wheat fields. • Wheat fields, including graze-out, were large sinks of CO 2 during growing seasons. • Wheat fields were from near CO 2 neutral to large sinks of CO 2 at annual scales. • In general, evapotranspiration (ET) was smaller under no-till than tilled fields. • CO 2 fluxes and ET were poorly correlated with biometric variables in grazed fields. Eddy fluxes collected during 2016 to 2019 from eight production-scale multi-purpose winter wheat fields (grain only, graze-grain, and graze-out), managed under conventional till (CT) and no-till (NT), were synthesized to determine seasonality, daily magnitudes, seasonal, and annual budgets of carbon dioxide (CO 2 ) fluxes and evapotranspiration (ET), and to investigate spatio-temporal variability of the fluxes. Maximum daily net ecosystem CO 2 exchange (NEE), gross primary production (GPP), and ecosystem respiration (ER) approximated -11, 19, and 12 g C m −2 , respectively, and daily ET approximated 7 mm. Wheat fields, including graze-out, were large sinks of CO 2 (ranged from -149 ± 8 to -564 ± 9 g C m −2 ) during growing seasons (October–May). Wheat fields, left fallow during summer, were from near neutral to large sinks of CO 2 at annual (calendar year) scales. Cumulative annual NEE was up to -242 ± 12 g C m −2 in a NT and -183 ± 12 g C m −2 in a CT field, which had grain-only wheat in spring followed by graze-grain wheat in fall. Cumulative seasonal ET ranged from 260 mm to 521 mm, and maximum annual ET approximated 800 mm. In general, ET was smaller under NT than CT. Eddy fluxes showed stronger relationships with remotely-sensed enhanced vegetation index and in-situ biometric variables in grain-only fields than grazed fields. Across-site analysis for grain-only wheat showed biomass and leaf area index alone explained >80% of variations in NEE, GPP, and ET, and ∼70% of variations in ER. Similarly, Canopy coverage explained >80% of variations in NEE and GPP, and ∼60% of variations in ER and ET. Strong relationships of biometric observations with the fluxes demonstrated their potential to model and explain spatio-temporal variability of CO 2 fluxes and ET. Results also indicated huge implications of management practices on carbon and water budgets by altering vegetative properties.

Feral rye control in quizalofop‐resistant wheat in central Great Plains

AbstractFeral rye (Secale cereale L.) is one of the most troublesome winter annual grass weed species in semi‐arid winter wheat (Triticum aestivum L.) production systems across the central Great Plains (CGP). Lack of effective herbicide options further complicates the selective control of feral rye in winter wheat. The main objectives of this research were: (a) determine the sensitivity response of 10 feral rye populations collected from Kansas wheat fields to quizalofop‐p‐ethyl in a dose‐response assay, and (b) to determine the effectiveness of various rates and application timings (fall or spring) of quizalofop‐p‐ethyl for feral rye control in quizalofop‐resistant winter wheat in the CGP. Dose‐response assays indicated that all tested feral rye populations were highly sensitive to quizalofop‐p‐ethyl with GR90 values (doses of quizalofop‐p‐ethyl needed for 90% reductions in shoot biomass at 3 wk after treatment) ranging from 33 to 72 g a.i. ha−1. A field study conducted in Colorado, Kansas, and Oklahoma for a total of 5 site‐years indicated that quizalofop‐p‐ethyl applied at ≥77 g a.i. ha−1 in the fall or spring provided season‐long feral rye control at 92–100% in quizalofop‐resistant winter wheat. Irrespective of tested rates and application timings, a quizalofop‐p‐ethyl treatment protected winter wheat yield loss of 17–27% due to reduced feral rye competition compared to the nontreated weedy check in Colorado and Oklahoma. Results suggested that quizalofop‐p‐ethyl at labelled use rates (77–92 g a.i. ha−1) applied in fall or spring can provide effective feral rye control in quizalofop‐resistant winter wheat.

Florasulam resistance status of flixweed (Descurainia sophia L.) and alternative herbicides for its chemical control in the North China plain

Flixweed (Descurainia sophia L.) is widely distributed in winter wheat (Triticum aestivum L.) fields in the North China Plain and has evolved resistance to herbicides, including the acetolactate synthase (ALS) inhibitor florasulam. However, the florasulam resistance status of flixweed in the North China Plain is poorly understood, which hinders the integrated management of this weed in winter wheat production systems. Thus, 45 flixweed populations were collected in wheat fields in these areas, and their sensitivity to florasulam and ALS-inhibitor-resistant mutation diversity were assessed. Meanwhile, alternative herbicides/herbicide mixtures for the control of florasulam-resistant flixweed were screened and evaluated under greenhouse and field conditions. Of the populations, 30 showed florasulam resistance (RRR and RR), 9 had a high risk of evolving florasulam resistance (R?) and 6 were susceptible. These populations had 5.3 to 345.1-fold resistance to florasulam, and 4 ALS resistance mutations (P197H, P197S, P197T and W574L) were observed. The subsequent herbicide sensitivity assay showed that the SD-06 population (with ALS1 P197T and ALS2 W574L mutations) exhibited cross-resistance to all ALS inhibitors tested, but was sensitive to MCPA-Na, fluroxypyr, carfentrazone-ethyl and bipyrazone. Meanwhile, the other HN-07 population with non-target-site resistance (NTSR) also showed resistance to all tested ALS inhibitors, and it was “R?” to MCPA-Na while sensitive to fluroxypyr, carfentrazone-ethyl and bipyrazone. The field experiments were conducted at the research farm where the SD-06 population was collected, and the results suggested that florasulam at 3.75–4.5 g ai ha−1 had little efficacy (0.6–12.1%), whereas MCPA-Na + carfentrazone-ethyl (87.1–91.2%) and bipyrazone+fluroxypyr (90.1–97.8%) controlled the resistant flixweed.

Estimation of nitrogen supply for winter wheat production through a long-term field trial in China

Excessive synthetic nitrogen (N) applications, high mineral N accumulation and low N use efficiency (NUE) are current issues in intensively cultivated winter wheat production system impeding the sustainable development of agriculture in China. To solve these problems, soil accumulated N in the top 1 m of the soil profile before sowing (Nsoil), returned straw-N from the previous maize crop (Nstraw) and fertilizer N application (Nfertilizer) should be comprehensively considered N supply sources in N management. As such, the objective of this research was to determine the optimal total N supply (TNsupply) level needed to meet crop requirements while minimizing environmental impacts. A 9-year on-farm experiment was conducted in accordance with a split-plot design involving two different fertilizer management systems (main treatments) and three N application strategies (sub treatments). Extensive TNsupply levels (ranging from 61 kg ha−1 to 813 kg ha−1) were detected, and relative yield (RY), N input and N output in response to the TNsupply were measured. The relationships between TNsupply and RY, N input, and N output strongly fit linear-plateau, linear, and linear-plateau models, respectively. The minimum TNsupply levels needed to achieve the maximum RY and N output were 325 and 392 kg ha−1, respectively. On the basis of N supply capacity, the TNsupply was removed from the growing system by 61% (N input). As the N input increased past 209 kg ha−1, the NUE declined, at which point the TNsupply reached 433 kg ha−1. Therefore, the suitable TNsupply should range from 325 kg ha−1 (ensuring a total N supply for high yield and N uptake) to 433 kg ha−1 (obtaining a relatively higher NUE and less N loss to the environment). The TNsupply was highlighted to be an indicator for use in N management recommendations. Considering the average high N accumulation in winter wheat production systems, N management should essentially take into account the consumption of Nsoil, the levels of Nstraw and the minimum application of Nfertilizer to obtain high yields while minimizing environmental impacts under suitable TNsupply levels.

Efficiency under different methods for incorporating undesirable outputs in an LCA+DEA framework: A case study of winter wheat production in Poland

Incorporating undesirable outputs in the operational assessments through the integration of Life Cycle Assessment (LCA) and Data Envelopment Analysis (DEA) has received great attention recently. There are many studies throughout literature that apply various methods to integrate LCA and DEA. In this case study, the six most common approaches were employed to assess the winter wheat cropping system in Poland. These six methods were: a) ignoring undesirable outputs, b) treating undesirables as inputs to the DEA model, c) data transformation, d) impact rate, e) ratio model, and f) slack based measurement DEA with undesirable outputs. The environmental impact of wheat production was assessed by determining its carbon footprint (CF). The mean CF equalled 0.45 kg CO2eq per kg wheat grain (ranging from 0.25 to 0.67). According to the model comparison results, a slack based measurement DEA with undesirable outputs could better reflect the performance of undesirable outputs, and was selected as the most appropriate method to maximize the efficiency of winter wheat production while minimizing undesirable outputs. The advantage of applying the slack based model with undesirable outputs was that the targets presented by this model were based on existing efficient farms, as opposed to theoretical results; thus achieving these targets are feasible. The average efficiency score equalled 0.43, whereby few farms were classified as efficient farms. The results of the proposed integrated model showed a high reduction potential for mineral fertilizers (up to 595 kg ha−1 y−1), seed (up to 37 kg ha−1 y−1), and fuel (up to 75 L ha−1 y−1) in winter wheat farms. These results help farmers to obtain a realistic and reliable usage pattern for inputs in a winter wheat production system, whereby the greatest production can be achieved in conjunction with the lowest possible environmental impact.

Jointed Goatgrass Biomass and Spikelet Production Increases in No‐till Winter Wheat

Core Ideas Initial spikelet density affects jointed goatgrass populations in subsequent years. Jointed goatgrass density can quickly increase in consecutive no‐till winter wheat crops. Maintaining low spikelet densities is critical for jointed goatgrass management. Jointed goatgrass (Aegilops cylindrica Host) remains a troublesome winter annual grass weed in winter wheat (Triticum aestivum L.) production systems in the western US. A study involving two field experiments (1992–1994 and 1993–1995) was conducted near Pullman, WA to quantify the effect of initial jointed goatgrass spikelet density on jointed goatgrass biomass and spikelet production in the first and second year of consecutive no‐till winter wheat crops. Initial jointed goatgrass densities were established by placing jointed goatgrass spikelets on the soil surface in 10.8 sq ft (1 sq m) quadrats at target densities of 2, 4, 8, 16, 32, 64, and 128 spikelets/10.8 sq ft. Precipitation varied greatly between the three winter wheat growing seasons and influenced the increase of jointed goatgrass biomass and spikelet production between the first and second year of both field experiments. Despite seasonal precipitation differences, the increase in jointed goatgrass biomass and spikelet production from Year 1 to Year 2 was directly related to initial spikelet density in both experiments. Although keeping jointed goatgrass densities low may slow the rate of increase in jointed goatgrass density from year‐to‐year compared to greater jointed goatgrass densities, even at low densities, jointed goatgrass has the potential to quickly increase population density in consecutive no‐till winter wheat crops.

Microbial communities in soil profile are more responsive to legacy effects of wheat-cover crop rotations than tillage systems

Declining trends in soil health under continuous monoculture systems of winter wheat are a concern for sustainable production in the Southern Great Plains of the US. This study was conducted to evaluate the long-term implementation of conservation tillage in combination with nitrogen treatments and summer cover crop (cowpeas) rotations with winter wheat, for their legacy effects on soil health attributes of microbial communities and soil organic carbon (SOC). Microbial biomass and composition were estimated, along with soil physico-chemical parameters in the soil profile during the annual rotation cycle of wheat and cover crops. Positive legacy effects of cover crop rotations were evident, as arbuscular mycorrhizal fungi (AMF) biomass during the wheat-growing season was significantly higher in cover crop treatments (by around 30-70%) compared to summer fallow treatment. Some dominant taxons such as Acidobacteria, Actinobacteria, Proteobacteria (>70% of prokaryotic relative abundance) and Ascomycota (>50% of fungal relative abundance) were detected in all experimental treatments. Microbial composition did not significantly change at phylum level, although some reorganization at OTU level was evident throughout the soil profile, mostly because of nitrogen treatments. Several Glomeromycota OTUs were significantly altered by soil depth and by nitrogen fertilization suggest distinct mycorhizosphere interactions in subsurface soil than the surface soil. Tillage treatment did not significantly alter the microbial abundance and their diversity. Differences in microbial biomass-C concentration among experimental treatments did not result in a change in SOC concentrations within the soil profile. Results of this study demonstrated that summer cowpea appeared to be an effective cover crop for enhancing beneficial microbial biomass and expansion of the mycorrhizosphere to deeper soil layers. Cover crop rotations appeared to be a suitable option for rapidly enhancing soil health in winter wheat production systems.

Tillage and crop straw methods affect energy use efficiency, economics and greenhouse gas emissions in rainfed winter wheat field of Loess Plateau in China

ABSTRACTData from a field experiment conducted in China's Loess Plateau (2013–2015) were used to determine the energy balance of winter wheat (Triticum aestivum L.) as affected by tillage and straw treatments. Tillage treatments included chisel plow, no tillage, and mouldboard plow. Crop straw levels included straw returning and straw removed. The energy balance was evaluated by comparing the following parameters: net energy, energy profitability, energy use efficiency, and energy intensity. The yield parameters were significantly influenced by the tillage treatments and revealed that the chisel plow entailed fewer field operations and lower energy requirements with a higher yield than mouldboard plowing tillage. The highest proportion of energy input came from a nitrogen fertiliser, followed by diesel fuel. The total energy input applied per hectare increased with an increase in the tillage intensity, and the lowest energy input was required for the no tillage case with the straw returning treatment, and the highest for the case of mouldboard plow with the straw returning treatment. The lowest average energy intensity was recorded for the no tillage case, followed by the case of chisel plow tillage in both cropping seasons. Moreover, in the case of mouldboard plough tillage, the maximum energy intensity was recorded in both cropping seasons. In the cases of the chisel plow tillage and the no tillage, we observed the maximum energy gain, while in the no tillage case, we observed the maximum energy use efficiency. The net return and the benefit/cost ratio were higher in the case of straw returning than those in the case of no straw treatment. We concluded that no tillage and chisel plow tillage with straw returning could improve the energy use efficiency and the benefit/cost ratio of winter wheat production systems.

Assessing the utility of the growth regulator trinexapac-ethyl and fungicides in mid-Atlantic soft red winter wheat production systems

Soft red winter wheat (SRWW) is an important crop in the mid-Atlantic. The use of growth regulators such as trinexapac-ethyl (TE) applied with nitrogen applications at pseudo-stem erection [Zadocks (ZGS) 30] has gained more interest in the region as a means to reduce lodging and potentially improve yields. Fungicide use has also increased, with many growers applying fungicides at ZGS 30 and again at ZGS 37 or ZGS 60. The safety and utility of TE in SRWW production systems, used alone or in combination with fungicides, is unknown. We evaluated the utility and safety of TE, applied alone, tank mixed with a fungicide at ZGS 30, and in combination with a foliar fungicide at ZGS 37 or ZGS 60 for utility and safety in mid-Atlantic SRWW. Three replicated field experiments were conducted over two growing seasons in Delaware, and yield, test weight, and disease severity on the flag leaf, were assessed. No phytotoxicity was noted in any of the TE or TE x fungicide treatments tested. TE applied alone reduced plant height by nearly 7 cm, but the application of fungicide at ZGS 37 or 60 slightly negated this effect. No lodging was observed. The addition of a fungicide at ZGS 30 followed by Prosaro (prothioconazole + tebuconazole) at ZGS 60 resulted in the greatest yields and test weights. All fungicide programs significantly reduced leaf blotch complex on the flag leaves relative to untreated controls; however, no difference was detected between ZGS 37 and ZGS 60 treatments. These results indicate that TE can be used safely in SRWW production when applied alone or when tank mixed with a fungicide; however, the effect on plant height reduction and potential impact on lodging may be reduced in situations where fungicides are used.

Evaluation of foliar fungicide programs in mid-Atlantic winter wheat production systems

Foliar fungicides are commonly used to manage foliar fungal diseases of soft-red winter wheat (SRWW) grown in the mid-Atlantic region, but data on the overall performance and utility of various products and application timings on yield and quality is lacking. Eight replicated experiments were conducted in Delaware and Maryland in 2015 and 2016 to evaluate the effects of 13 fungicide programs, consisting of five commercially-available fungicides applied at flag leaf emergence ([Zadoks growth stage (ZGS) 37], anthesis (ZGS 60), or in two-pass programs with the first application at green-up (ZGS 30) followed by applications at either ZGS 37 or ZGS 60, for utility on naturally occurring foliar diseases on the flag leaf and head, yield, and test weight compared to an untreated check. All fungicide programs reduced disease severity on the flag leaf and resulted in higher test weight and yield compared to the untreated check. Foliar disease on the flag leaf and glume blotch were best managed with ZGS 60 applications. Two-pass programs (ZGS 30 + ZGS 37 or ZGS 30 + ZGS 60) did not result in significantly lower disease severity compared to single applications at ZGS 37 or ZGS 60. Yield was highest within the ZGS 30 + ZGS 60 timing, and while significant, increases were small, ranging from 111 to 198 kg ha−1. Within a given application timing, Priaxor® (ZGS 37), Quilt Xcel® (ZGS 30 + ZGS 37), and Quilt Xcel® (ZGS 30) + Prosaro® (ZGS 60) provided the greatest yields. This information will help guide Integrated Disease Management (IDM) systems in the mid-Atlantic region and assist growers in avoiding unnecessary fungicide applications in SRWW.

COMPARATIVE LIFE CYCLE ASSESSMENT STUDY OF THREE WINTER WHEAT PRODUCTION SYSTEMS IN THE EUROPEAN UNION

Three different winter wheat production systems for three European countries (United Kingdom, France and Italy), all with different climatic conditions, soil management and input levels (e.g. tillage, fertilizers, herbicides and pesticides) were analysed from an environmental perspective. The intended applications were the analysis and comparison from a Life Cycle Assessment (LCA) perspective and the identification of the key parameters which have the greatest influence on final results. The analysis considered the entire production system, including the extraction of raw materials, production of farming inputs and all agricultural operations. The adoption of LCA was considered the most appropriate methodology to define the environmental impact. The functional unit considered was 1 hectare of winter wheat production. The results showed that the impact due to machinery use was mostly dependent on the number of interventions related to the application of fertilizers, herbicides and plant protection. Emissions due to on-field fertilizer application and their production also showed a significant contribution for each impact category showing percentages reaching 90% of the total, whereas the impact due to fungicides and herbicides were negligible, since their contribution never exceeded 4% of the total emissions. Emissions to soil, air and water were affected by factors such as local weather conditions and soil characteristics, which can vary on a local scale, the time of farming activities, N, P and K uptake by the plants, amount and typology of fertilizers adopted. Nitrate losses from arable cropping may be reduced by limiting N-based fertilizer inputs.

A Comparison between Conventional Tilled and Bicropped Winter Wheat Grown in Monoculture over Four Years

&lt;p&gt;A four year experiment was conducted at a site in the south-east of Ireland in which medium and high input conventional winter wheat production systems were compared to no input and low input systems in which winter wheat was direct drilled into an understory of white clover. Whole crop and grain yields from all systems were strongly related to external input levels, yields from bicropped treatments were poor. Nitrogen uptake and grain yields from the conventional treatments declined during the course of the study whereas nitrogen uptake and yields from bicropped treatments were more stable. Fertiliser N application significantly depressed biological production efficiency and altered biomass partitioning. The proportion of biomass partitioned to the stem decreased with fertiliser N, differences between treatments persisted until final harvest. Although the clover sward was still present in the fourth year, this component of the bicrop was gradually replaced by weeds as the experiment progressed in spite of several attempts to control weeds. It is suggested that further research is needed to identify a clover management strategy which ensures the persistence of the white clover sward and allows it to enrich soil fertility in such a way as to be of benefit to the accompanying wheat crop.&lt;/p&gt;