Spatial Distribution of Soil Phosphorus, Calcium, and pH after Long-term Broiler Litter Application.

Use of broiler litter (BL) for agronomic purposes requires balancing the amount of nitrogen (N) needed to maximize crop yield while reducing environmental N footprints. This 2‐yr study (2018–2019) compared the effects of N source (BL or urea), application rate [0, 168, and 336 kg total N ha–1), and application timing (single or split) on corn (Zea mays L.) yield and environmental nitrogen loss (ENL) on three Alabama soil types. A field‐scale partial N budget was developed by accounting for known N inputs and outputs. The difference between the input and output in the partial N budget was considered as ENL, which comprised of N losses via runoff, leaching, volatilization, and denitrification. Application of BL increased corn yield relative to urea at only one site. At the responsive site, BL application rate had no significant effect on corn yield, but pre‐plant single application of BL produced 52% greater corn yield compared with split application. At other two sites where yield was lower for corn receiving BL, corn yield increased significantly with increasing BL application rate. Total N loss to the environment ranged between 32 and 52% of the N input. The influence of N source on ENL varied by site however losses increased with increasing N fertilization rates. Application timing did not influence ENL at two of three sites. This study showed that a lower application rate (168 kg ha–1) of BL prior to planting was a better management strategy for increasing corn yield, while reducing environmental N loss.

Poultry litter and tillage influences on corn production and soil nutrients in a Kentucky silt loam soil

Elevation map-based variable rate poultry litter application is a promising method in cotton production

Poultry litter on agricultural lands could introduce nitrogen (N), phosphorus (P), heavy metals in soil and ground water. Native vegetations were identified to assess efficacy for phytoremediation of nutrients and metals from soil and water. Objective was to measure capability of multi-year native species to remove metals, nutrients, and prevent Nitrate-N leaching below the rooting zone. Treatments were distributed in four replicates with/without fertilization. Suction lysimeters were installed at 30, 60, and 90-cm depths in 3 of 4 replicates. Species were identified, recorded, five specified cuttings sampled. Plant, soil, water samples were prepared and analyzed by spectroscopy. Nitrate-N extraction, nitrates in water samples were determined using flow injection analysis. Fertilized plots (NVM) had 39% more biomass yield than unfertilized plots (NVN). In plants, nutrient and metal concentrations varied significantly with 14% increase in Zn, 36% and 26% in K and Mg over NVN for first and second year. Uneven between NVM and NVN, topsoil had higher values for most nutrients and metals. Largest P and (NO3−)−N in plant and water were observed from NVM. Cultivation of native vegetation appears to be an effective approach for remediation of excess nitrates-N, P, heavy metals from surface and sub-surface zones of the soil.

A layered aquifer model of atoll island hydrology: Validation of a computer simulation

Soil quality is essential for sustaining agricultural productivity, globally. Hence, this study evaluated the effects of elevation gradients and soil depths on agricultural land quality in the Seti River watershed, Pokhara Metropolitan City (PMC), Nepal. Using a stratified random sampling method, 60 samples were collected across three elevation gradients (500-700m, 700.1-900m, 900.1-1100m) at depths of 0-15cm and 15-30cm. The soil quality index (SQI) revealed good soil quality across all elevations, with values of 0.88, 0.86, and 0.82 for lower, mid, and higher elevations, respectively, despite variations in individual nutrient levels. Elevated nitrogen (N) and phosphorus (P) levels highlighted the need for regulated fertilizer application. Kruskal-Wallis test identified significant decreases in soil organic matter (SOM) and soil organic carbon (SOC) with increasing elevation. Depth-wise analysis showed that the potential of hydrogen (pH) in the topsoil (0-15cm) was nearly neutral, while the subsoil (15-30cm) exhibited weak acidity. Nutrient concentrations, including N, P, and potassium (K), were significantly higher in the topsoil than in deeper layers, indicating a need for prudent nutrient management to minimize leaching and maintain soil health. Accordingly, PMC soils can be considered favorable for agricultural productivity; however, site-specific management strategies should performed. Reducing excessive fertilizer use in low-elevation areas can prevent nutrient imbalances while monitoring and enhancing SOM in higher elevations through compost or green manure application is recommended. These actions can enhance soil fertility, reduce environmental impacts, and promote agricultural resilience.

The understanding of water movement in the soils plays an important role for crop water availability. Up to now, crop water availability in dryland still has a problem. Rainfall is the main source of crop water availability in dryland, but it is unpredictable to cover crop water requirements. To optimize the crop water availability in dryland, the study of the relationship between water movement, rainfall, and soil pores characteristics in the soils is required. This research was aimed to investigate the water movement in the soils with different soil pores due to the difference of soil management. The study was conducted at three blocks of lands with the soil type of Inceptisols, located at Bojong Village, Kemang Sub DIstrict, Bogor District in 2006. The soils investigated were abandoned large frog (Ipomoea reptans), paddy, and peanuts that reflected soil management. The data measurements were focused on water content, rainfall, climatedata, water flux, transient water movement, and water distribution. The results showed that the water fluxes and the transient water movements were significantly affected by the amount of rainfall. The water fluxes in the abandoned peanuts were significantly higher than those at the other lands, while the transient water movements at abandoned paddy field were significantly higher than those at the land with large frog and peanuts. The soil water content during the growing season at the abandoned paddy field was significantly higher compared to the other lands. The amount of rainfall which are held in the soils during the growing season at the abandoned peanuts was significantly high. The result of this research can be use to estimate crop water requirement for irrigation.

Poultry broiler litter (BL) is widely used as an alternative source of N, P, and K for crops and forages and is often applied at excessive rates of both N and P. Soil samples were periodically collected from experiments with BL at two locations in Alabama, a Coastal Plain site and a Tennessee Valley site, from 1991 though 2000. The objective was to determine the accumulation and movement of plant nutrients and metals in soil profiles when BL is compared with ammonium nitrate (AN) as a source of N for cotton ( Gossypium hirsutum L.) and corn ( Zea mays L.). The Tennessee Valley site was fertilized and cropped for 3 yr, and the Coastal Plain site was fertilized and cropped for 12 yr. The two N sources were applied at rates from 0 to 269 kg N ha −1 based on total N in the material. Incremental soil samples to a depth of 1 m were taken periodically from 1990 through 2000. Broiler litter maintained surface soil pH on the coarse‐textured soil at the Coastal Plain site whereas AN resulted in a decline in pH. There were no significant differences in surface soil pH due to source on the finer textured Tennessee Valley site. Application of BL resulted in increasing accumulations of total soil organic C, total N, and Mehlich‐1 extractable Ca, Mg, P, K, B, Zn, and Cu as the rates increased from 134 to 269 kg N ha −1 as BL (approximately 4.48–8.96 Mg ha −1 yr −1 ) over a 10‐yr period. While differences in NH 4 –N and NO 3 –N were observed to a 1‐m depth due to treatment, soil concentrations were very low compared with standards used in the presidedress soil nitrate test for corn (PSNT). No significant accumulations of heavy metals were observed during the experiments.

Because land application of broiler litter is commonly made in the spring before cropping season and in the fall, it is essential to understand how environmental variations, such as temperature, affect the phosphorus (P) dynamics. A laboratory incubation study was conducted at Waste Management and Forage Research Unit, USDA‐ARS with the objective of determining the effects of temperature and soil properties on water‐soluble P (WSP), Mehlich 3 P, and P fractions in broiler litter‐amended soils. Broiler litter was mixed with three soils (Leeper silty clay, Grenada silt loam, and Ruston sandy loam) at the rate of 10 Mg ha−1. The mixtures were incubated at 18°C, 25°C, and 32°C for up to 90 days and repeated three times. Soil samples were taken at eight time intervals (2, 5, 10, 15, 30, 60, and 90 days) and analyzed for water‐soluble P and Mehlich 3‐extractable P (MEP). Phosphorus also was fractionated chemically into inorganic and organic components by sequential extraction for soil samples taken at the end of incubation period (90 days). Water‐soluble P decreased rapidly after a 15‐day incubation in all soils for all temperatures and followed to a steady state to the end of incubation period. Averaged across temperatures, broiler litter application resulted in a significant increase in all fractions compared with controls. However, the increase was greater for inorganic than for organic fractions. The concentration of calcium (Ca)‐P fraction was highest in calcareous Grenada soil, which suggests that the presence of carbonates influence the fate of P from applied broiler litter. The coarse textured Ruston contained a greater concentration of water‐soluble P (WSP) than the other soils. At 32°C, the concentration of plant‐available P fractions [bicarbonate inorganic P (IP) and hydroxide IP] significantly increased and WSP decreased. It is likely that the higher temperature (32°C) promotes higher biological activity and lower water‐soluble P than lower temperature. Contribution of the Mississippi Agricultural and Forestry Experiment Station, journal paper no. J10120.

BackgroundA three-year field experiment was conducted to examine the responses of corn yield and soil nitrous oxide (N2O) emission to various management practices in middle Tennessee.Methodology/Principal FindingsThe management practices include no-tillage + regular applications of urea ammonium nitrate (NT-URAN); no-tillage + regular applications of URAN + denitrification inhibitor (NT-inhibitor); no-tillage + regular applications of URAN + biochar (NT-biochar); no-tillage + 20% applications of URAN + chicken litter (NT-litter), no-tillage + split applications of URAN (NT-split); and conventional tillage + regular applications of URAN as a control (CT-URAN). Fertilizer equivalent to 217 kg N ha-1 was applied to each of the experimental plots. Results showed that no-tillage (NT-URAN) significantly increased corn yield by 28% over the conventional tillage (CT-URAN) due to soil water conservation. The management practices significantly altered soil N2O emission, with the highest in the CT-URAN (0.48 mg N2O m-2 h-1) and the lowest in the NT-inhibitor (0.20 mg N2O m-2 h-1) and NT-biochar (0.16 mg N2O m-2 h-1) treatments. Significant exponential relationships between soil N2O emission and water filled pore space were revealed in all treatments. However, variations in soil N2O emission among the treatments were positively correlated with the moisture sensitivity of soil N2O emission that likely reflects an interactive effect between soil properties and WFPS.Conclusion/SignificanceOur results indicated that improved fertilizer and soil management have the potential to maintain highly productive corn yield while reducing greenhouse gas emissions.

Plant production can be limited by low levels of available P due to high P‐fixation capacity in soils of the southeastern USA. On the other hand, there is increasing concern about excessive application of P to soil, especially when manure application is based upon N content. We evaluated changes in Mehlich‐I extractable soil P during 5 yr of bermudagrass [ Cynodon dactylon (L.) Pers.] management varying in fertilization [inorganic and broiler chicken ( Gallus gallus ) litter] and harvest strategy (unharvested, low and high cattle ( Bos taurus ) grazing pressure, and haying). Broiler litter supplied eight times more P than inorganic fertilization to meet the N requirement. At a depth of 0 to 6 cm, Mehlich‐I extractable soil P increased 0.8 ± 1.6 mg kg −1 yr −1 (4 ± 8% of total P added) with inorganic‐only fertilization, 2.4 ± 3.0 mg kg −1 yr −1 (9 ± 11% of total P added) with clover ( Trifolium incarnatum L.) cover crop plus inorganic fertilization, and 8.7 ± 9.8 mg kg −1 yr −1 (6 ± 7% of total P added) with broiler litter. Haying kept Mehlich‐I extractable soil P constant with time due to removal of P with harvest of biomass. At the end of 5 yr of broiler litter application to grazed land, Mehlich‐I extractable soil P was 135, 50, 22, and 4 mg kg −1 higher than with inorganic fertilization at depths of 0 to 3, 3 to 6, 6 to 12, and 12 to 20 cm, respectively. Broiler litter fertilization was effective at increasing Mehlich‐I extractable soil P to an agronomically productive level (50 to 60 mg kg −1 15 cm −1 ), but continued application could lead to excessive P accumulation that could threaten water quality from surface runoff unless appreciable soil fixation or removal of forage biomass were to occur.

Analytically, poultry litter contains nearly all essential micronutrients but the extent of phytoavailability of these nutrients and whether cotton (Gossypium hirsutum L.) and other crop plants can receive adequate amounts of these nutrients from litter is not fully known. The objective of this research was to determine whether cotton receives sufficient amounts of Fe, Cu, Mn, and Zn from litter and estimate the efficiency of cotton in extracting these metal nutrients from litter in the absence of any other source of the micronutrients. The greenhouse research used plastic pots filled with approximately 11 kg of a 2:1 (v/v) sand to vermiculite growing mix. Cotton (cv. Stoneville 474) was grown in the pots fertilized with broiler litter at rates of 30, 60, 90, or 120 g pot(-1) in a factorial combination with four supplemental nutrient solution (NS) treatments. The nutrient solutions consisted of full Hoagland's nutrient solution (NS-full); a solution of the macronutrients N, P, K, Ca, and Mg (NS-macro); a solution of the micronutrients Fe, Zn, Mn, Cu, B, and Mo (NS-micro); and water (NS-none). Based on tissue nutrient analysis, a one-time broiler litter application supplied adequate amounts of Fe, Cu, and Mn to bring the concentration of these nutrients in upper leaves within published sufficiency ranges. Zinc, with <17 mg kg(-1) concentration in the upper leaves, was the only micronutrient below the established sufficiency range regardless of the rate of applied litter. Cotton extracted Fe and Mn more efficiently than Cu or Zn, removing as much as 8.8% of Fe and 7.2% of Mn supplied by 30 g litter pot(-1). In contrast, the extraction efficiency was 1.7% for Cu and 1.9% for Zn. Roots accumulated 58% of the total absorbed Fe and 64% of Cu, and leaves accumulated 32% of the Fe and only 13% of the Cu supplied by litter. In contrast, only 16% of the total absorbed Mn and 23% of Zn accumulated in roots while leaves accumulated 64% of the total Mn and 37% of Zn. These results demonstrate that broiler litter is a valuable source of the metal nutrients supplying Fe, Cu, and Mn in full and Zn in part, but a very large fraction of the litter-supplied metal nutrients remained in the growing mix.

Cosmic Rays Neutron Sensing (CRNS) is a well-known method in Hydrology that allows to measure soil water content on a large scale and in depth. It is based on the detection of cosmogenic neutrons, particles generated by the interaction of cosmic rays with the atmosphere, after their interaction with the soil where they can be effectively absorbed by water molecules. The signal collected by a single CRNS probe in terms of neutron count rate is sensitive to soil moisture within a volume spanning up to a dozen hectares and up to 50 cm depth, in real-time, positioning itself in a horizontal spatial scale in between point measurements and satellites.In order to evaluate the effectiveness of CRNS to give information about soil moisture in an agricultural system with different soil conditions, a site in the Alto Monferrato vine-growing area (Piedmont, NW Italy) was equipped with a Finapp CRNS probe since August 2023. The site has two vineyard-field-scale plots with inter-rows managed with conventional tillage (CT) and grass cover (GC), respectively. More than 20 sensors are located in different positions and depths (from 10 to 50 cm) in the vineyard, including the STEMS network that is part of the International Soil Moisture Network. Precipitation measurements on site are available over more than 20 years, show that 2023 was very dry, with Standardized Precipitation Index lower than -1 for most of the year, whereas 2024 was increasingly wet, with exception of first two months of the year.Available soil moisture data from CRNS and sensors have been compared until autumn 2024, using statistical indexes such as the efficiency coefficient of Nash and Sutcliffe (NSE), root mean square error of residuals (RMSE) and the coefficient of determination of the linear regression (R2). The analysis was carried out separately for the two years, which were considered respectively dry and wet.Statistics showed that in the last 5 months of 2023 (dry period) there was a good agreement of soil moisture values measured by sensors between 10 and 20 cm of depth with both soil management, with different results according to the position, the best reported in the middle of the GC inter-row at depth of 20 cm (R2=0.913, NSE=0.756, RMSE=0.25). The results for 2024, which was a wetter year, showed great variability, such as the values recorded by the sensors, with unsatisfactory statistics, since best values for indexes were obtained for the sensor placed in the middle of CT inter-row (R2=0.598, NSE=0.485, RMSE=0.118).Thus, in the dry period the CRNS probe gave good information on soil moisture conditions in the most superficial layer disregarding the soil management of the vineyard. On the contrary, the difficulty in having good agreement in wet conditions can be due to the high spatial variability of soil moisture both in the horizontal and in-depth directions, soil saturation and ponding, in addition to variable conditions of soil conditions (i.e. soil density) depending to soil management and tractor traffic during the growing season.

Sulfurization, acid-sulfate soils and active layer monitoring at the semiarid Seymour Island, Antarctica

Lay AbstractSediments at the bottom of lakes are active biogeochemical zones where settled particulate organic matter is decomposed into dissolved compounds. The latter serve as building materials and energy sources for lake organisms. The amount of the dissolved matter released back to the water column determines, in part, the production and activity of lake biota and directly affects dissolved oxygen levels. However, low‐mixing conditions at the water–sediment interface limit the upward flow of dissolved matter from the sediment to the water. Standing internal waves (seiches), which occur, for example, after changes in wind speed or direction and are inherent for thermally stratified lakes, produce horizontal motions of lake water so that cold deep waters climb over warmer sediment along sloped lake bottoms. This process may initiate pore‐water convection—vertical flow of the interstitial water in the sediment—and accelerate the release of dissolved matter into the water column. We investigated pore‐water convection by using vertical heat flux within the upper sediment as an indicator of convective motions. This was achieved using fine‐resolution temperature measurements within the upper sediment of Lake Arendsee, Germany. Our field study demonstrated that cold water flowing over warmer sediment amplified the vertical heat flux within the sediment. The rate of heat flow increase agreed with theoretical estimates, suggesting that it originates from vertical convective motions. The average velocities of these motions were estimated as ∼0.5 mm s−1, penetrating up to 9 cm deep in the sediments and lasting for 2–4 h. The consequences of this hydrodynamic phenomenon for benthic microorganisms and for transport of solutes have yet to be quantified.