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Approximately 37% of US milk production occurs in semiarid regions, providing an opportunity to recycle manure nutrients through a variety of cropping systems. Accurate prediction of nitrogen (N) mineralization is critical to determine manure application suitability in intensive irrigated agriculture as many crops in the region have quality parameters that are sensitive to N. Research was conducted in southcentral Idaho to evaluate N mineralization via a buried bag methodology to develop a predictive N‐mineralization model. The study was arranged in a randomized complete block design with manure application rates of 18, 36, and 52 Mg·ha−1 (dry weight basis) both annually and biennially with synthetic fertilizer and untreated check treatments. The crop rotation included small‐grain and broadleaf crops. In the final year of the study, preplant soil organic carbon, total nitrogen, and NO3–N concentrations were positively linearly correlated with manure application rate. Nearly five times as much N was mineralized annually in the 0‐ to 30‐cm depth as compared to the 30‐ to 60‐cm depth. Increased rates of N mineralization for each kilogram of added N occurred in years when residue from broadleaf crops (slope = 0.17) was applied as compared to years with manure only application (slope = 0.07). Stepwise modeling determined that the most predictive model for seasonal N mineralization (R2 = 0.79) included manure N, residue N, soil organic matter, and electrical conductivity. These results allow preplant N mineralization estimation and will prove critical for managing manure in semiarid regions for agronomic, economic, and environmentally sound crop production. Core Ideas: Tools are needed to estimate nitrogen (N) mineralization from applications of dairy manure in semiarid irrigated soils.N mineralization was affected by manure application rate, timing, and broadleaf residue N.Average manure N mineralization was 27% and 18% of N applied in the first and second years, respectively, following application.The incorporation of broadleaf residue with manure increased N mineralized to 41% of N applied.The best predictors of N mineralization were soil organic matter, soil electrical conductivity, manure N, and broadleaf N residue. [ABSTRACT FROM AUTHOR]

Understanding the S nutritive value of biosolids produced by various processing methods is important for growers who apply biosolids to crop production fields. Our project goals were to determine how processing method and biosolids' properties influence S availability and S fertilizer value. Fourteen biosolids materials were selected for the trial, including those produced with aerobic digestion (n = 2), anaerobic digestion (n = 5), dual digestion (n = 1), composting (n = 2), lagoon storage (n = 2), sawdust blending (n = 1), and alkaline stabilization (n = 1). Biosolids were air‐dried, ground, and added to a Walla Walla silt loam soil at a rate of 100 mg S kg–1 soil. The treated soils were incubated at 25 ℃ and extracted for SO4–S on Days 1, 13, 29, 44, and 83. Mean plant available S was greatest for the alkaline stabilized biosolids (52%), followed by anaerobically digested biosolids (40%), sawdust blended biosolids (37%), lagoon slurry (36%), dual digestion biosolids (31%), aerobically digested biosolids (15%), and composted biosolids (4%). Biosolids pH, organic C/total S, total Ca, total S, and SO4–S concentrations were well correlated to S release rate, plant available S, or both. Sulfur mineralization of organic S compounds is known to be influenced by organic C/total S, whereas Ca and pH effects may be related to gypsum (CaSO4) dissolution and oxidation of hydrogen sulfide compounds. The correlations discussed here may need to be further investigated and verified on additional soil types and under field conditions prior to grower adoption. Core Ideas: Biosolids processing method significantly affected S availability.Biosolids C/S, Ca, and pH were correlated to biosolids S availability.Gypsum dissolution, S mineralization, and S oxidation may be driving S availability. [ABSTRACT FROM AUTHOR]

The yield of sugar beet (Beta vulgaris L.) has almost doubled from 1993 to 2018 in the U.S. There is interest in understanding how increased root yield potential in sugar beet production systems has influenced the in-season nutrient uptake patterns in the plants. In 2014, a study was conducted to evaluate amounts and rates of dry matter, macro- (N, P, K, Ca, Mg, S, and Na) and micro-nutrients (Fe, Mn, Zn, Cu, and B) accumulated by a single herbicide-resistant sugar beet variety (BTS 21RR25) on an irrigated Portneuf silt loam soil of southern Idaho. Nitrogen, P, and K fertilizers were applied at agronomic rates based on soil test values. Whole plants were destructively sampled at 16-d intervals from 9 June (germination) to 30 September 2014 (at harvest), separated into tops and roots, and analyzed for dry matter amount and nutrient concentrations to estimate amounts and rates of nutrient accumulation. Mean root yield was 67.5 tonne ha-1. Mean total accumulation at harvest was approximately 50.2 Mg ha-1, 268, 69, 529, 200, 122, 109, 28, 13, 1.85, 0.64, 0.16, and 0.68 kg ha-1 for dry matter, N, P, K, Na, Ca, Mg, S, Fe, Mn, Zn, Cu, and B, respectively. Dry matter, P, Cu, Mg, Mn, and Fe mean accumulations at harvest were between two-fold and seven-fold greater than previously reported. In contrast, N, K, S, Na, Ca, Zn, and B mean accumulations were within range of previously reported values. Findings from this study may be used to support nutrient management decision-making efforts for irrigated sugar beet production systems. [ABSTRACT FROM AUTHOR]

Increased numbers of swine producers will be removing sludge from their anaerobic waste treatment lagoons in the next few years, due to sludge exceeding designed storage capacity. Information on availability of nitrogen (N) in the sludge is needed to improve application recommendations for crops. The objective of this study was to investigate possible effects of different companies and types of swine operations on the availability of N in sludge from their associated lagoons. A laboratory incubation study was conducted to quantify the availability of N (i.e. initial inorganic N plus the potentially mineralizable organic N) in the sludge. Nine sludge sources from lagoons of sow, nursery and finishing operations of three different swine companies were mixed with a loamy sand soil (200 mg total Kjeldahl N kg-1 soil) and incubated at a water content of 0.19 g. water g-1 dry soil and 25 ± 2 °C for 12 weeks. Samples were taken at eight times over the 12-week period and analyzed for inorganic N (i.e. NH4–N and NO3–N) to determine mineralization of organic N in the sludge. Company and type of swine operation had no significant effects (P<0.05) on the pattern of inorganic N accumulation over time. Thus, inorganic N accumulation from all sludge sources was fit to a first order equation [Nt=Ni+No(1-e-kt)]. This relationship indicated that of the 200 mg of total sludge N added per kg soil, 23.5% was in the form of potentially mineralizable organic N (No) and 17.5% was in the form of inorganic N (Ni). The sum of these two pools (41%) represents an estimate of the proportion of total N in the applied sludge in plant available form after the 12 week incubation. While plant N availability coefficients were not measured in this study, the lack of significant company or type of swine operation effects on sludge N mineralization suggests that use of the same plant N availability coefficient for sludge from different types of lagoons is justifiable. The validity of this interpretation depends on the assumption that variation in other components of different sludge sources such as Cu and Zn does not differentially alter N uptake by the receiver crops. [Copyright &y& Elsevier]

As anaerobic swine lagoons approach maximum sludge storage capacity, producers must periodically remove sludge and apply it to nearby fields. Information regarding the availability of nitrogen (N) in sludge as a nutrient source applied at different seasons of the year could improve crop-use efficiency. A 12-month laboratory study was conducted to quantify the effects of seasonal temperatures on mineralization of N in lagoon sludge. Sludge was mixed with a Coastal Plain soil (Arenic Kandiudult) and incubated for one year at weekly fluctuating temperatures based on Winter, Spring, Summer, and Fall application dates, ranging from a Winter low temperature of 9°C to a Summer maximum temperature of 30°C. Samples were analyzed monthly for NO3-N and NH4-N in 1.0 M KCl extracts of sludge amended soil. Sludge N availability (sum of NO3-N plus NH4-N concentration in 1.0 M KCl extract) was fit to a nonlinear regression model for a first-order reaction. Net N mineralization rate constants (k) derived from these models for the initial season of application increased in the order Fall (0.07) < Winter (0.075) < Spring (0.22) < Summer (0.36). While initial rates of net N mineralization differed, N availability predicted from first order equations was similar for all temperature regimes after one year of incubation and averaged 74% of the total N applied. Forty-two to 53% of the organic N in the sludge was mineralized during the one-year incubation. [ABSTRACT FROM AUTHOR]

Accurate predictions of the short-term reactivity of liming products are needed for situations where rapid soil pH adjustment is desired. Lime efficiency (LE) describes the capacity of a liming material to neutralize soil acidity in comparison with a finely ground CaCO3 standard (LE = 100%). Our objectives were to evaluate LE for calcitic liming materials varying in particle size at 1–12 months after soil incorporation using pH change (LEpH) and CO2 evolution (LECO2) as response indicators, and to evaluate a 15-min citric acid (CA) test as a predictor of LE. We evaluated LE for lime particle size separates from 10 to 200 USA mesh (< 2000 µm to 75 µm) and for three commercial liming products (65, 25 and 11 µm average particle size) in a sandy loam soil. In field microplots, it took 6 months to achieve LE of > 80% with lime particles of <60 mesh (< 250 µm). LEpH was linearly related to LECO2 at one month following lime incorporation into soil. Both LEpH and LECO2 increased as a function of CA test values, as described by logarithmic equations. Lime particle size, CO2 evolution, and CA test values were all useful indicators of short-term LE. [ABSTRACT FROM AUTHOR]

Idaho's Magic Valley is a highly productive agricultural region in the United States due to irrigation. The soils in this region are prone to crusting, have low organic matter, and are high in calcium carbonates, making them susceptible to erosion and water runoff. Soils need to be better managed to enhance aggregate stability to enable increased infiltration of irrigation water and decreased soil erosion in nearby waterways. However, to make management recommendations, the identification of appropriate measurements of aggregate stability needs to be identified, and few relevant studies exist. Thus, the overall goal of this project was to identify appropriate methods for the assessment of soil aggregate stability in the study region. The study sites were located in Southern Idaho and set up using common cropping rotations and agricultural management practices for the region using a variety of nutrient sources, tillage types, and cover cropping. Three methods were used to measure soil aggregate stability: wet sieving, simulated rainfall using a Cornell Sprinkle Infiltrometer (sprinkler height: 30, 90, and 150 cm), and the SLAKES mobile application. No differences in soil aggregate stability were found when the wet sieving or SLAKES methods were used at the three study sites, either due to the method or a general lack of differences between treatments. When using the Cornell Sprinkle Infiltrometer, no treatment differences were found at LT-Manure or GRACEnet; however, differences were observed between treatments at the Cover Crop study site at sprinkler heights of 30 and 90 cm. At a sprinkler height of 30 cm, the average mean weight diameter was the highest when winter forage crops (WFC) and solid dairy manure (SDM) were applied (3.73 mm) and the lowest in the control (3.12 mm). At a sprinkler height of 90 cm, the average mean weight diameter was the highest when WFC and SDM were applied (3.54 mm) and the lowest in the WFC Only treatment (2.46 mm). These results not only have implications for which methods are best for assessing progress but also for what management practices can be utilized to decrease soil erosion from irrigated cropland. This study highlighted that under these soils and management practices, simply increasing soil carbon does not increase aggregate stability, especially when root crops are included in the crop rotation with intensive tillage. In arid and semi-arid regions, the Cornell Sprinkle Infiltrometer may be a more sensitive method of measuring soil aggregate stability compared to traditional wet sieving. [ABSTRACT FROM AUTHOR]

Dairy manure is used in semiarid southern Idaho to improve soil fertility, but campaigns to measure resulting nitrous oxide (N 2 O) emissions over the complete year have not been conducted to date. The objective of this study was to measure N 2 O fluxes throughout the growing (April to Sept) and non-growing (Oct to Mar) seasons in 2020 (sugarbeet) and 2021 (silage corn and triticale) in a field that received inorganic N fertilizer or was previously treated with dairy manure solids on an annual and biennial basis for 8 years. Gas fluxes were measured daily using automated chambers that were connected to a gas chromatograph for in situ analysis of N 2 O. The N 2 O emissions were found to be highly episodic and major pulses were associated with irrigation during the growing season, warming events in the winter, and soil disturbance at harvest. Emissions were greatest from soil that had received manure at the highest annual application rate of 52 Mg ha−1 (dry wt.), with cumulative totals of 3.6 and 3.0 kg N 2 O-N ha−1 in 2020 and 2021, respectively. These cumulative totals were about 3-fold greater than emissions from plots treated with inorganic fertilizer or manure at 17 Mg ha−1 annually or 35 Mg ha−1 biennially. This outcome can be attributed to high concentrations of nitrate produced through mineralization of organic N in manure. Emission factors indicated that up to 1.2% of the total N applied was lost as N 2 O-N, with the greatest loss from inorganic fertilizer treated soil. When breaking down the emissions by season, anywhere from 49%–63% (2020) and 37–58% (2021) of the N 2 O-N emissions occurred during the non-growing season. Growing and non-growing season N 2 O emissions were found to be statistically equivalent for each of the respective fertilizer or manure treatments. This finding stresses the need to also measure N 2 O emissions during the non-growing season as a way to improve the accuracy of annual emission estimates. • Nitrous oxide emissions from semiarid soils were elevated with long-term dairy manure. • Major emission pulses were associated with irrigation, freeze-thaw, and soil disturbances. • Growing and non-growing season nitrous oxide emissions were statistically equivalent. • Nitrous oxide emission factors were ≤ 1.2% of the total N applied per year. [ABSTRACT FROM AUTHOR]

Insufficient characterization of soil organic carbon (SOC) dynamics in semi-arid climates contributes uncertainty to SOC sequestration estimates. This study estimated changes in SOC (0–30 cm depth) due to variations in manure management, tillage regime, winter cover crop, and crop rotation in southern Idaho (USA). Empirical data were used to drive the Denitrification Decomposition (DNDC) model in a "default" and calibrated capacity and forecast SOC levels until 2050. Empirical data indicates: (i) no effect (p = 0.51) of winter triticale on SOC after 3 years; (ii) SOC accumulation (0.6 ± 0.5 Mg ha–1 year–1) under a rotation of corn-barley-alfalfax3 and no change (p = 0.905) in a rotation of wheat-potato-barley-sugarbeet; (iii) manure applied annually at rate 1X is not significantly different (p = 0.75) from biennial application at rate 2X; and (iv) no significant effect of manure application timing (p = 0.41, fall vs. spring). The DNDC model simulated empirical SOC and biomass C measurements adequately in a default capacity, yet specific issues were encountered. By 2050, model forecasting suggested: (i) triticale cover resulted in SOC accrual (0.05–0.27 Mg ha–1 year–1); (ii) when manure is applied, conventional tillage regimes are favored; and (iii) manure applied treatments accrue SOC suggesting a quadratic relationship (all R2 > 0.85 and all p < 0.0001), yet saturation behavior was not realized when extending the simulation to 2100. It is possible that under very large C inputs that C sequestration is favored by DNDC which may influence "NetZero" C initiatives. [ABSTRACT FROM AUTHOR]