Subsurface Band Research Articles

Picosecond carrier dynamics in InAs and GaAs revealed by ultrafast electron microscopy.

Understanding the limits of spatiotemporal carrier dynamics, especially in III-V semiconductors, is key to designing ultrafast and ultrasmall optoelectronic components. However, identifying such limits and the properties controlling them has been elusive. Here, using scanning ultrafast electron microscopy, in bulk n-GaAs and p-InAs, we simultaneously measure picosecond carrier dynamics along with three related quantities: subsurface band bending, above-surface vacuum potentials, and surface trap densities. We make two unexpected observations. First, we uncover a negative-time contrast in secondary electrons resulting from an interplay among these quantities. Second, despite dopant concentrations and surface state densities differing by many orders of magnitude between the two materials, their carrier dynamics, measured by photoexcited band bending and filling of surface states, occur at a seemingly common timescale of about 100 ps. This observation may indicate fundamental kinetic limits tied to a multitude of material and surface properties of optoelectronic III-V semiconductors and highlights the need for techniques that simultaneously measure electro-optical kinetic properties.

Nutrient transformations based on sampling scheme and cropping system following subsurface‐banded poultry litter

AbstractPoultry litter (PL) is an excellent source of micro‐ and macronutrients. However, surface applications result in greater nutrient runoff and nitrogen loss via ammonia volatilization. Subsurface banding PL is a promising technology for combating these challenges, but scant information exists on proper soil sampling techniques and management recommendations for subsurface‐applied PL. Therefore, objectives were to quantify the nutrient status based on sampling depth (0–15 cm and 15–30 cm) and schema (systematic [0, 3, 7, and 10 cm from PL bands] and composite) to develop subsurface PL recommendations per system (annual cropping and perennial pasture). Soil samples were collected during PL application (subsurface and surface) and 1, 6, 12, 18, and 24 months thereafter. On average, total N, Mehlich‐3 extractable P, and Mehlich‐3 extractable K were 15%, 96%, and 72% greater, respectively, for subsurface compared to surface applications. Further, Mehlich‐3 and water‐soluble P at the 0‐ to 15‐cm depth were 4–5 and 2–3 times greater in soils receiving subsurface PL in perennial pasture and row crop systems, respectively, compared to surface applications, likely owing to lesser nutrient losses to the air, soil, and water under subsurface PL systems. Compared to surface applications, subsurface PL increased (p < 0.05) N, P, and K crop removal by 75%, 70%, and 72%, respectively, and resulted in 80% and 78% yield increases and N‐use efficiency, respectively. Consequently, subsurface PL conserved greater N, P, and K at the 0‐ to 15‐cm depth, thus increasing nutrient‐use efficiency in row crop systems and improving water quality in sensitive watersheds.

Deposition of high entropy alloy sub-surface films on metal substrates via DC magnetron sputtering with a CoCrFeMnNi target

High entropy alloys and high entropy alloy films (HEFs) are gaining increasing attention in the research community due to their superior mechanical properties. CoCrFeMnNi is one of the most investigated of these alloys in the literature; however, CoCrFeMnNi HEFs have not yet been extensively reported. To improve our understanding of the processes occurring during fabrication of CoCrFeMnNi HEFs, here, DC magnetron sputtering using a CoCrFeMnNi equimolar target is used to deposit HEFs on glass substrates, A5052 aluminum sheets, and S45C steel sheets. The resulting HEFs are observed to be embedded as sub-surface bands, less than a micrometer under the substrate surface. This is attributed to implantation of the HEF elements into the base material due to the high deposition energy of sputtering. Another possibility is that substrate elements migrate to the surface in an Ar plasma-assisted process. The HEF crystallite size on glass substrates was determined by x-ray diffraction to be several nanometers, meaning that high hardness is expected in HEFs produced by DC magnetron sputtering.

Residual Benefits of Poultry Litter Applied by Subsurface Band vs. Surface Broadcast to Cotton

Poultry litter (PL) is known to have residual effects on crop productivity long after applications cease. Whether this advantage is greater if applied by subsurface vs. surface broadcast is unknown. The objective of this study was to determine whether the residual benefit of PL to corn and cotton production is greater if applied in subsurface bands vs. surface broadcast and identify PL components contributing to this effect. The residual effect of PL applied by the two methods or synthetic nitrogen (sN) at seven plant available N rates (0–292 kg ha−1 yr−1) in 2014–2015 was tested on corn and cotton in 2016–2019. Corn was grown without applying PL or sN in 2016, and cotton was grown in 2017–2019 after applying 90 kg ha−1 yr−1 sN to all plots. Corn produced 40% greater grain and cotton produced 29% more lint yield due to residuals from PL than sN. Residuals from PL distinctly increased cotton leaf K over sN regardless of the method of application. Corn and cotton yield benefits from PL residual were greater if applied by subsurface banding vs. surface broadcast. This difference diminished with time. The overall results show PL components persist in the soil for up to 4 years and affect corn and cotton production, but this persistence is greater if the PL is applied by subsurface banding. This study identified K as the key PL nutrient that persisted in the soil and benefited cotton yield 4 years after the last application.

Spacing of subsurface poultry litter bands: Influence on maize performance and nitrogen use efficiency

AbstractPoultry litter (PL) is traditionally surface broadcast to no‐till maize (Zea mays L.). PL is nutrient‐dense, and surface‐applied PL nitrogen (N) is vulnerable to losses to the atmosphere and water systems. An application method was developed by USDA‐ARS scientists for shallow subsurface banding PL to reduce ammonia (NH3) volatilization and surface runoff. There is limited information on how this application method will affect conservation and nutrient accessibility in no‐till maize. The objectives were to determine if adjusting PL lateral subsurface band placement in relation to maize rows affects nutrient use and maize yields. Treatments were a nontreated control (NTC), urea ammonium nitrate surface banded (Fert), poultry litter surface broadcast (PLBr), and three subsurface banded PL treatments. The subsurface PL treatments were one (PLSub1), two (PLSub2), or three (PLSub3) bands between maize rows. Treatments receiving N were applied at 180 kg total N ha−1. Nitrogen concentration in V4 aboveground dry matter was higher in PLSub1 than PLSub2. Aboveground dry matter yields for all PLSub treatments were greater than PLBr and comparable to Fert. The PLSub1 and PLSub2 treatments resulted in maize grain yields equivalent to Fert and greater than PLBr and NTC when averaged across years. Few differences were observed in postharvest soil sample nutrient concentrations between PLSub treatments. These results suggest that subsurface banding PL can conserve N and increase no‐till maize yield over traditional surface broadcast PL; however, increasing the frequency of subsurface PL bands did not clearly affect nutrient conservation or accessibility to the maize.

Impact of manure injection on spatial variability in soil nitrate, carbon, and small grain growth

AbstractManure injection alters the spatial distribution of manure by concentrating it in a subsurface band which can lead to differential soil nutrient distribution and growth in small grains. This study assessed the effects of fall manure applications on soil NO3‐N, active carbon, and small grain growth compared to broadcasting and a no manure control. Soil samples were taken to represent whole plot soil means for all treatments, while in‐band (IB) and between‐band (BB) soil samples were taken in injected plots to assess nutrient spatial distribution after injection. Small grain forage samples were also taken IB and BB to assess the effects of manure injection on small grain growth. Soil samples were analyzed for NO3‐N, permanganate oxidizable carbon (POXC), and carbon mineralization (C‐min), while small grain dry matter (DM) yield and forage quality parameters were measured from plant samples. Manure injection did not result in any differences between whole plot injection and broadcast soil NO3‐N concentrations. However, injection resulted in initially elevated soil NO3‐N concentrations IB compared to BB. There were no differences in soil POXC or C‐min under manured versus unmanured soils, nor between IB and BB samples. Manure injection did not increase small grain DM yield or forage quality compared to broadcasting, nor were these measurements altered IB and BB. Even though manure injection altered the spatial distribution of soil NO3‐N, it did not affect soil C‐min, POXC, or small grain growth under the conditions seen in this study. Therefore, differential small grain growth and quality is likely not a concern under injection.

Nitrogen dose and placement in conservation agriculture for augmenting cropgrowth, productivity and profitability of Indian mustard (<i>Brassica juncea</i>)

Optimization of nitrogen (N) fertilization is vital for minimizing losses and realizing the yield potential of Indian mustard [Brassica juncea (L.) Czern.] under different tillage and residue management options. Hence, a field experiment was conducted during winter (rabi) seasons of 2021–22 and 2022–23 at research farm of ICAR-Indian Agricultural Research Institute, New Delhi to study the effect of nitrogen placement methods under conservation agriculture (CA) for augmenting crop growth, productivity and profitability of Indian mustard. Experiment consisted a split-plot design with three crop establishment practices (CEP) [ZT-R, Zero tillage without residue retention; ZT+R, Zero tillage with residue; CT, Conventional tillage] in main-plots and nitrogen placement methods (NPM) [control (no N); recommended dose of N (RDN)-conventional; RDN-SSB (subsurface band placement of second N split along the crop rows); 80% RDN-SSB] in sub-plots. The ZT+R enhanced crop growth rate by 6.0–36.1% over CT at various crop stages. The ZT+R reported higher soil moisture by 9–20.7% over CT and ZT-R. Significantly superior seed yield (14.3–28.5%), net return (20.5–53.9%) and benefit cost ratio (21.8–79.0%) was obtained with ZT+R over ZT-R and CT while RDN-SSB recorded 7.3–9.1% higher seed yield over other treatments. Statistically at par results were obtained under RDN-conventional and 80% RDN-SSB for yield attributing characters and seed yield delineating that a saving of 20% N in mustard production is possible without compromising yield and this can reduce environmental footprint as well. Therefore, this study concluded that the residue retention under ZT along with subsurface N placement in mustard crop gives better vegetative growth, yield attributes and yield with a potential to save 20% N and can be opted in semi-arid Indo-Gangetic plains and similar agro-ecologies.

Placement and nitrogen source effects on N2O emissions for canola production in Manitoba

AbstractThis study examined fertilizer nitrous oxide (N2O) emissions and canola (Brassica napus L.) grain yield for two granular urea sources (conventional and a dual urease and nitrification inhibitor [SuperU]) and three at‐planting placement methods (broadcast‐incorporated, shallow banded, and deep banded) on commercial fields in Manitoba. Nitrogen (N) rates were 100% and 70% of what was recommended based on soil test and target yield, with the 100% treatments having N2O emissions monitored. SuperU fertilizer consistently reduced N2O emissions (area‐, N‐applied‐, and yield‐based) compared to urea. Significant reductions in N2O emissions with SuperU occurred in four of six site‐years and coincided with delayed nitrification. Compared to broadcast‐incorporated, subsurface banding of conventional urea reduced N2O emissions in drier site‐years but increased emissions when rainfall was higher (especially in shallow banded urea). Across all six site‐years, shallow banding of urea resulted in significantly higher emission intensities than all other treatments. Nitrogen placement did not affect the emission reduction benefit of SuperU. N source or placement did not greatly affect canola yield within either 100% or 70% N rates. Fertilizer N recovery efficiency was also not greatly impacted by either N source or placement. The results demonstrate that dual inhibited granular urea fairly consistently reduces N2O emissions in canola production in southern Manitoba, whereas nitrogen placement had variable effects depending on growing season rainfall. However, with little agronomic benefit, the added cost of enhanced efficiency fertilizers must be overcome for widespread adoption and to achieve greenhouse gas reduction targets for the Canadian agriculture sector.

Managing cover crop C:N ratio and subsurface‐banded poultry litter rate for optimal corn yields

AbstractCover crops can be used to provide some of the nitrogen (N) needs of a cash crop to complement mineral fertilizers or manure, but there has yet been limited work to describe corn (Zea mays L.) yield as a function of cover crop quality and N inputs. We investigated the response of corn yield to gradients of both preceding cover crop C:N ratio and poultry litter (PL) application rates in Beltsville, MD during 2012–2014. To achieve different C:N ratios of the cover crops, hairy vetch (Vicia villosa Roth. "Groff") and cereal rye (Secale cereale L. "Aroostook") were seeded in a replacement series of six seeding rate proportions, resulting in shoot C:N ratios of 9.2:1 to 152:1 across years. For each hairy vetch/cereal rye sown proportions, PL was side‐dressed at corn V5–V8 stage in subsurface bands (SSB) at four targeted rates: Zero, P‐based (67 kg plant available nitrogen [PAN] ha−1), N‐based (135 kg PAN ha−1), and excess N and P (269 kg PAN ha−1). We found that corn yield followed a linear‐plateau relationship across these two dimensions. Within the linear region, each unit increase in log‐scaled cover crop C:N ratio resulted in a yield decrease of 2.56 ± 0.26 Mg ha−1 at a given rate of SSB PL. To optimize corn yields, we describe a model where each unit increase in log‐scaled cover crop C:N ratio required an additional 45.9 ± 6.22 kg PAN ha−1 from SSB PL. Yields following winter fallow were typically intermediate to the range of yields observed following the gradient of cover crop C:N ratios. We did not find significant differences in corn yield responses when comparing SSB PL to at‐planting incorporated or broadcast PL; we also found no significant differences between SSB PL and surface‐banded urea ammonium nitrate. Taken together, our approach of modeling yield response across two dimensions can be widely used to guide adaptive N management in subsequent cash crops following winter cover crops, thereby balancing both economic and environmental objectives in cover crop‐based cropping systems.

Impact of contrasting fertilizer technologies on N dynamics from subsurface bands of “pure” or blended fertilizer applications

Abstract. Enhanced efficiency fertilizer (EEF) technologies that employ product coatings to delay nitrogen (N) release or are chemically stabilized to inhibit key steps of N transformations in soil offer potential for improving N use efficiency (NUE) in agricultural systems. However, the dynamics of N release and transformation from single technologies may result in a spatial or temporal mismatch of N supply and demand during a growing season. This may be overcome by use of blends of different technologies, provided the reduction in the concentration of stabilizing products does not reduce effectiveness. Laboratory incubations quantified the N dynamics around bands of controlled-release fertilizer (CRF) and nitrification-inhibited (NI) urea and varying blends of these technologies and referenced this against conventional urea and biodegradable, plant-oil-coated urea (POCU) applied at the same rates in two contrasting soils over 60 d. Blends of NI urea (3,4-dimethylpyrazole phosphate, DMPP urea) and a CRF (polymer-coated urea, PCU) typically resulted in N concentrations and distribution that were intermediate to those of the constituent products in unblended applications. Changes in the proportions of each product were mirrored by urea nitrogen (urea-N) concentrations around the bands in both soils, while the proportions of DMPP urea in each blend were only related to the extent of nitrification inhibition in the Vertisol. A proportion of the POCU granules burst during the early stages of incubation, resulting in initially higher mineral N concentrations compared to PCU. However, both CRFs delayed N release and formation of nitrate nitrogen (NO3-N) relative to granular urea, and mineral N distribution was similar within each soil. Soil type had a significant impact on banded N dynamics. Where there was little effect of N-fertilizer treatment on NO3-N production in the Ferralsol, the higher impedance to solute transport in the Vertisol contributed to a significant inhibitory effect of NI urea on nitrification in both pure and blended DMPP urea treatments. Using NO3-N production as a benchmark for the risk of environmental loss, the efficacy of fertilizer treatments in this soil was of DMPP urea / PCU blends (higher ratio of PCU may offer small but insignificant benefit) > DMPP urea = PCU > urea. These findings highlight the importance of soil properties in determining the N dynamics from different banded EEF products. Insights into the efficacy of biodegradable alternatives to polymer coatings and the efficacy of blended EEF products can improve the reliability of N supply while reducing environmental impacts, therefore offering greater opportunities to sustainably improve fertilizer NUE in cropping systems.

Influence of broiler litter band positioning on cotton growth and yield in a Blackland Prairie soil

AbstractSubsurface band application of broiler litter in soil is being evaluated across the United States as a potential management practice for curbing phosphorus loss and improving nutrient retention. This management practice also shows promise for increasing yields of row crop systems. Determining the optimum plant distance from the subsurface banded broiler litter (BL) could be useful to optimize crop yields. Thus, a cotton (Gossypium hirsutum L.) experiment was established to investigate the distance of a subsurface BL band from the planted row on cotton growth and yield. Treatments consisted of subsurface banding BL at 0, 10, 20, 30 cm from the crop row plus a non‐fertilized check, broadcast BL, and banding of urea‐ammonium nitrate (UAN) at 20 cm to the side of rows as controls. Subsurface band placement of BL and UAN occurred just prior to sowing at a depth of 10 cm. Placing BL in subsurface bands tended to increase cotton yield compared to surface broadcasting the litter. When comparing BL band positions, cotton lint yield was generally greatest when BL was placed in subsurface bands 20 cm or less from the planted row. Minimal differences in cotton fiber quality were observed among treatments. Results suggest the reduced distance between the cotton row and a subsurface BL band can increase cotton growth and yield.

Availability of Nitrogen in Soil for Irrigated Cotton Following Application of Urea and 3,4-Dimethylpyrazole Phosphate-Coated Urea in Concentrated Bands.

Low nitrogen (N) fertilizer use efficiency for irrigated cotton has been attributed to the limited ability of tap roots to access N from concentrated subsurface bands, or the preferential root uptake of microbially-mineralized dissolved organic N. This work investigated how applying high-rate banded urea affects the availability of N in soil and the capacity of cotton roots to take up N. Soil was analyzed for water-extractable total dissolved N and inorganic N species after urea or urea coated with 3,4-dimethylpyrazole phosphate (DMPP) was applied at concentrations of 261, 455, 461, and 597 mg N kg-1 of (air-dry) soil (mean bulk density: 1.01 g cm-3). A mass balance was used to compare N applied as fertilizer and in unfertilized soil (supplied N) with the N recovered from soil within the cylinders (recovered N) at five plant growth phases. Root uptake was estimated by comparing ammonium-N (NH4-N) and nitrate-N (NO3-N) in soil sampled from within cylinders with soil sampled from immediately outside. Recovered N was up to 100% above supplied N within 30 days of applying urea above 261 mg N kg-1 of soil. Significantly lower NO3-N in soil sampled from immediately outside the cylinders suggests urea application stimulates cotton root uptake. The use of DMPP-coated urea prolonged high NH4-N in soil and inhibited the mineralization of released organic N. These results imply the release of previously sequestered soil organic N within 30 days of applying concentrated urea enhances the availability of NO3-N in the rhizosphere, reducing N fertilizer use efficiency.

Strategies for mitigating N2O and N2 emissions from an intensive sugarcane cropping system

In sugarcane cropping systems, high rates of N fertiliser are typically applied as sub-surface bands creating localised zones of high mineral N concentrations. This in combination with high levels of crop residue (trash) retention and a warm and humid climate creates conditions that are known to promote soil denitrification, resulting in high emissions of the potent greenhouse gas N2O. These losses illustrate inefficient use of N fertilisers but total denitrification losses in the form of N2 and N2O remain largely unknown. We used the 15N gas flux method to investigate the effect of cane trash removal and the use of the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) on N2 and N2O emissions on a commercial sugarcane farm at Bundaberg, Australia. High gaseous N losses were observed under the standard grower practice where cane trash retention and N fertiliser application (145 kg N ha−1 as urea) resulted in N2 and N2O emissions (36.1 kg N ha−1) from the subsurface N fertiliser band, with more than 50% of these losses emitted as N2O. Cane trash removal reduced N2 emission by 34% and N2O emission by 51%, but had no effect on the N2O/(N2 + N2O) ratio. The use of DMPP lowered N2 and N2O emission by 35% and 98%, respectively, reducing the percentage of these losses (N2 + N2O) emitted as N2O to only 4%. We conclude that the use of DMPP is an effective strategy to reduce N losses, minimise N2O emissions, while keeping the benefits of cane trash retention in sugarcane cropping systems.

Nitrogen‐15 evaluation of fertilizer placement at planting for corn production

AbstractNumerous studies have been reported to ascertain the benefits of starter fertilization for corn (Zea mays L.) production, but most rely on data collected by measuring early growth or grain yield at harvest. As a more conclusive evaluation, five field trials were conducted using 15N‐labeled urea‐ammonium nitrate (UAN) solution (90 kg N ha−1) to compare single and dual subsurface band placement, as well as surface dribble and broadcasting with incorporation. Significant differences in dry matter production and total N uptake occurred between fertilized and unfertilized treatments, but not among the different placements studied. In contrast, fertilizer 15N uptake efficiency (F15NUE) tended to be greater for either type of subsurface banding than for the dribble treatment, demonstrating the added sensitivity that can be achieved through isotopic measurements. More importantly, band placement consistently outperformed broadcasting, according to estimates of F15NUE for total aboveground biomass that ranged from 11% to 46% when UAN was banded and from 7% to 34% for broadcast applications.

Subsurface banding of blended controlled-release urea can optimize rice yields while minimizing yield-scaled greenhouse gas emissions

Controlled-release urea (CRU) is widely reported to supply crop nitrogen (N) demand with one basal application, thus effectively replacing split applications of urea without diminishing grain yield and N use efficiency (NUE). However, its use for replacement for high-yield split applications of urea (CK) for rice is untested. In addition, the degree to which greenhouse gas (GHG) emissions in rice systems are affected when CRU is substituted for CK remains unclear. During 2017 and 2018, we sampled plant growth and gas emissions in a rice paddy field treated with three CRU types (sulfur-coated urea [SCU], polymer-coated urea [PCU], and bulk blended CRU [BBU]) applied via two methods (surface broadcasting on the soil and subsurface banding at 5 cm depth), with CK as a control. The three CRUs led to different soil NH4+-N dynamics, and the N supply pattern under BBU was more beneficial for rice seedling establishment than under SCU and PCU, resulting in grain yield and NUE comparable to those under CK. CRU type showed no significant effect on either CH4 emissions or N2O emissions, and broadcast CRUs exhibited significantly higher total GHG emissions than CK. However, banded CRUs significantly reduced the total GHG emissions in comparison with broadcast CRUs, by 9.2% averaged across the two years. Reduced CH4 emissions, particularly during the period prior to the middle drainage, contributed largely to the GHG difference. With comparably high grain yield and low total GHG emissions, banded BBU showed a low yield-scaled GHG (GHG emissions divided by grain yield) comparable to that under CK in both years. Overall, our study suggested that N management synchronized with rice demand and contributing to a high NUE tended to minimize yield-scaled GHG. Broadcast CRU can hardly substitute for CK in terms of either grain yield or GHG emissions, but banded BBU is a promising N management strategy for sustaining rice production while minimizing environmental impacts.

Fertilizer value of poultry litter applied by subsurface band vs. surface broadcast in corn production

Optimal yield of corn fertilized with poultry litter (PL) may be achieved with less PL if applied by subsurface banding (LSS). The objective of this study was to determine, using economic analysis, if profit maximizing PL rate can be reduced if applied by LSS relative to the conventional surface broadcast (LBC) in corn production. Corn was grown with six PL rates ranging from 4.4 to 27.0 Mg ha−1 applied by LSS or LBC and with seven synthetic N (sN) rates ranging from 0 to 292 kg ha−1. Rates of PL or sN that maximized yield or profit were determined from yield response curves. The results showed that yield maximizing PL was greater than profit maximizing PL by as much as 25% regardless of the application method showing that targeting maximum yield is wasteful and may reduce profit. Both yield and profit maximizing PL rates were less if applied by LSS than by LBC while the respective yields did not differ greatly. As much as 17% more grain was produced by 1 Mg ha−1 profit maximizing PL if applied by LSS than by LBC. Availability of N from PL was <37% if applied by LBC vs. >40% if applied by LSS. These results show that applying PL by subsurface banding conserves N, leads to greater grain yield per 1 Mg PL, and thus the same corn yield may be obtained with less PL if applied by banding than by surface broadcasting.

Visualization of indentation induced sub-surface shear bands of Zr-based metallic glass by nanosecond pulse laser irradiation

Characterizing the shear band of metallic glasses (MGs) is meaningful to understand its plastic deformation mechanism. However, the direct method for detecting the internal shear bands of deformed MGs with large field of view is still lacking. Inspired by the fact that surface defects have the enhanced absorption of laser energy, this study attempted to visualize the indentation induced sub-surface shear bands of Zr-based MG by nanosecond pulse laser irradiation in argon. The principle was first verified by laser irradiation of the surface scratch, and then implemented on the visualization of sub-surface shear bands. The experimental results demonstrated that the indentation induced sub-surface shear bands were successfully visualized by nanosecond pulse laser irradiation, and meanwhile, the laser irradiated surface maintained the amorphous characteristic. This study may open a new window for exploring the shear band characteristics of MGs upon external loads.

Subsurface banding poultry litter influences edamame yield, forage quality, and leaf greenness

AbstractPoultry litter is generated in large quantities throughout the southeastern United States and is an excellent nutrient source for increasing crop yields. However, surface applications result in nutrient losses to air, soil, and water. Subsurface banding poultry litter is a promising technology for reducing nutrient losses to surface and groundwater, but information is needed on optimum crop seeding distance from bands. This study evaluated edamame [Glycine max (L.) Merr. ‘Edamame’] yield (residue, pod, and total plant), crop quality, and leaf greenness. Subsurface banded poultry litter and crop row distances (13, 25, and 38 cm) were compared with surface‐applied poultry litter (all received 168 kg ha−1 total N) under irrigated and nonirrigated conditions from 2019 to 2020. Both chlorophyll and edamame total yields were greatest (P ≤ .05) under subsurface banding litter, relative to surface applications, regardless of distance. Overall, greatest total crop yields were observed for 13‐ and 25‐cm banding distances under irrigation and the 38‐cm distance, irrespective of irrigation, relative to surface applications. Residue nutritive value for the 13‐cm distance was greater under irrigation than dryland. Both systems provided high levels of nutritive residual mass, thus edamame could be used as a vegetable crop and a forage following harvest. Overall, subsurface banding poultry litter in conservation tillage systems is a viable replacement to surface applications for edamame production (vegetable and fodder), particularly in organic systems. Results can be used to develop nutrient management plans for organic edamame and other specialty crop production systems in the Mid‐South.

The synergistic effect of nitrogen and phosphorus starter fertilization sub-surface banded at sowing on the early vigor, grain yield and quality of maize

Maize grain yields and profitability are enhanced in temperate growing areas as a result of an early sowing. However, cool conditions may constrain the uptake of nitrogen (N) and phosphorus (P) by the root system during the early and more susceptible growth stages. The application of starter fertilizers near the plant roots could ensure better N and P availability and improve early vigor of the crop. The aim of this study has been to quantify the overall benefits of a localized starter fertilization with N or P, or their combination, on maize (early development, grain yield, grain quality and sanitary traits). A 4-year field experiment was conducted in NW Italy during the 2014–17 growing seasons. The trial compared the sub-surface placement of N, P and NP in bands close to the maize seed furrows, as a starter fertilization strategy, with unfertilized controls on sandy silt loam (SSL), silt loam (SL) and silty clay loam (SCL) soils. These soils were placed side by side, and were characterized by low, high and medium N and plant-available P contents, respectively. The results showed that when N and P were applied together, the early vigor (plant height) and canopy development (NDVI values) of the maize were significantly enhanced, compared to both the controls and to the application of the single elements in all the soils. The positive growth responses to starter NP fertilization were combined with accelerated crop phenological development, so that anthesis occurred 2.4–3.1 days earlier. Thus, the grain yield was enhanced following the NP sub-surface placement (+7%, +15% and +11%, in SSL, SL and SCL, respectively), mainly due to an increase in the number of kernels per ear (+10%), while the grain moisture content was reduced, compared to the controls, in all the soils (−2.2%). The application of N or P alone did not consistently affect either the grain yield or the moisture content in any of the three soils. The starter fertilization strategy also affected both the qualitative and sanitary grain traits. NP and N both resulted in an increase in the grain hardness in the SL and SCL soils, but when P was applied alone, no significant effects were observed. The use of NP starter fertilization significantly reduced the ear injuries caused by European Corn Borer in all three soils (−44%), and reduced ear rot severity in the SSL and SL soils and the fumonisin content (−72%) in the SL and SCL soils, compared to the untreated controls. The synergistic effect of N and P applied as a sub-surface band at sowing had a consistent positive effect on the advancement of the flowering dates at different sites in different years, even in soils that have tested high to P or N. Thus, the application of NP starter fertilizer is a crop practice that should be considered in North Italy and for similar soils and environments.

Subsurface Banding Litter Reduces Nutrient Losses and Improves Yields

Subsurface Banding Litter Reduces Nutrient Losses and Improves Yields