Proceedings - Soil Science Society of America最新文献

Human food supply depends on healthy soils, yet lack of metrics to estimate returns from soil-health-improving practices (SHIPs) limits their adoption at ecologically significant scale. To address this limitation, we evaluate a purpose-led framework that quantifies tradeoffs between food production and other ecosystem services. “Proof-of-concept” evaluations of corn-based systems in the central United States estimated returns from adoption of no-till in Kentucky and subsurface drainage in Iowa. No-till returned $172 ha⁻¹ year⁻¹ from improved soil N and water supply, which was associated with greater soil organic carbon (SOC), increased N fertilizer efficiency, and yield. Drainage returned $75 ha⁻¹ year⁻¹ from greater soil N and water supply in an enlarged aerated root zone, which increased N fertilizer efficiency and yields while decreasing greenhouse gas emissions despite a reduction in SOC. SHIPs that impact soil N and water supply had a large influence on profitability and resource use efficiency, which makes them useful soil health indicators, and this finding should be broadly applicable to rainfed, upland cereal systems worldwide.

Phosphorus (P) is a macronutrient influencing soil fertility and nutrient dynamics. To investigate the effects of phosphorus application on soil nutrient availability and sweetpotato (Ipomoea batatas [L.] Lam) productivity, a 3-year field experiment was conducted using cultivars Beauregard B14 and Orleans in Pontotoc, MS. Nutrient concentration data were collected from the soil, leaves, and roots and analyzed for trends and correlations. The results demonstrated that phosphorus fertilization significantly enhanced soil phosphorus availability. Moreover, its interaction with other nutrients influenced their uptake, translocation, assimilation, and storage roots development, ultimately influencing yield. Nutrient dynamics observed in the soil, roots, and leaves revealed complementary roles, synergism and antagonism. These interactions shifted annually from 2022 to 2024. In 2024, nutrient levels reached optimum levels for sweetpotato productivity, as evidenced by the highest marketable yield recorded. US No. 1 roots contributed more strongly to the total marketable yield than canner and jumbo roots. There were no cultivar differences in total marketable yield. The optimum phosphorus fertilization rate of 224 kg/ha produced 11.2 Mg/ha average total marketable root yield and should be recommended to sweetpotato growers in agroclimatic and soil conditions like Pontotoc, MS.

The characteristics used to distinguish between Mor and Moder differ among the various classifications of humus forms. Mor is often associated with ericaceous heathland that develops at high altitude or latitude, or in lowlands when soils are nutrient-poor, sandy, and acidic. This study applies a new micromorphological method on three humus profiles from an alpine heathland in the French Alps (Savoie, altitude 1950 m) to better understand the underlying processes. Microscopic observations of horizontal sections of humus monoliths, gradually cut with dissecting instruments, allow us to characterize the proportions of humus components, the micromorphology of each component, and the microstructural organization of the humus. The analysis shows the importance of millipedes for the biological activity of the humus profile in the alpine ericaceous heath. These animals feed indiscriminately on litter (remains of ericaceous, moss, and herb vegetation), which therefore does not have time to accumulate. They also sometimes feed on humified organic matter when climatic conditions force these animals to live at depth. As a result, humus undergoes macrostructuration (aggregates and galleries). When the level of organic matter accumulation is high, this activity remains within the framework of a holorganic context, but when this level is low, millipedes consume a significant proportion of minerals and create a mineral–organic mixture. This work illustrates the distinctive characteristics of these ecosystems and emphasizes the importance of a thorough description of the humus forms by addressing various criteria, which facilitates the classification of transition humus forms.

Zhou, Q., Mulvaney, R. L., & Nunes, V. L. N. (2025). Improved method for isotopic measurement of free-living nitrogen fixation. Soil Science Society of America Journal, 89(1), e70016. https://doi.org/10.1002/saj2.70016

There was an error in the denominator of Equation (4), which should be “M_ls × (A_inc − A_air)” instead of “M_ls × (A_inc − A_us)”.

The effect of this correction was to slightly decrease calculated rates of N₂ fixation or retention, which has been applied to the data reported in Tables 5 and 6 with updated statistical analyses. There was no effect on interpretation of results. The updated Tables 5 and 6 are below:

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Intensive agricultural practices to meet food demand have led to a decline in soil quality and agricultural productivity, posing significant challenges to environmental sustainability. Consequently, the present research focused on the development of models based on artificial intelligence techniques to predict the soil quality index (SQI) for soybean (Glycine max) cultivation using a total of 89 soil samples taken at 300-m grit system at depths of 0–20 cm. A set of 28 parameters categorized into main physical, chemical (organic matter, pH, EC, etc.), fertility (macro- and micronutrient elements), and biological (soil respiration, metabolic coefficient, and microbial biomass carbon) parameters were used for the total dataset (TDS). The minimum dataset (MDS), which consisted of the most sensitive parameters, was selected using principal component analysis. In this study, SQI was calculated for both TDS and MDS using a neutrosophic fuzzy analytic hierarchy process and standard scoring function. The resulting SQI_TDS and SQI_MDS values were then predicted using machine learning approaches, including multiple linear regression (MLR) and random forest regression (RFR). The accuracy of these predictions was then examined using various metrics such as mean absolute error, mean squared error, and root mean square error. The results show that MLR outperforms RFR for both SQI_TDS and SQI_MDS with significantly lower error indices and higher R² values than RFR through 10-fold cross-validation. In addition, this study statistically compared the obtained SQI_TDS and SQI_MDS values with normalized difference vegetation index (NDVI) values derived from the Sentinel-2A satellite for May 2021. The same satisfactory R² values (0.84) were obtained by statistically comparing both SQI_TDS and SQI_MDS with NDVI values. Furthermore, this study demonstrates the effective integration of advanced techniques such as machine learning models with remote sensing and geographic information system technologies, for the analysis and processing of both original and generated information in the vast domain of SQI.

Chemicals are an integral part of modern agriculture and are applied through a variety of methods. Some agrochemicals used for crop protection are absorbed by the roots prior to translocation to the rest of the plant. To be absorbed by the root, the agrochemical must first be transported through the soil, often by water. Some agrochemicals suffer from poor water-based soil transmission due to their chemical properties, limiting their application as a traditional seed treatment. Two agrochemicals with poor water-based soil transmission are Chlorantraniliprole and Spinosad. Soil protists are an important component of the soil microbial community. Certain soil protists have been shown to facilitate the transport and target delivery of suspended particles and bacteria through soil and soil-like structures. Here, we provide practical evidence that a soil protist, Colpoda sp., when co-inoculated with an agrochemical seed treatment, can substantially and robustly reduce subsequent pest feeding damage versus application of the agrochemical alone. Using maize (Zea mays L.) and fall armyworm, Spodoptera frugiperda (J. E. Smith, 1797) (Lepidoptera: Noctuidae), in a plant damage assay, we compare pest feeding damage and pest mortality for leaf samples from plants whose seeds were treated with only protists, only agrochemical, or agrochemical + protists. We discover, for both agrochemicals tested, that co-inoculation of protists with agrochemical increases protection in leaves versus agrochemical alone. Protist amendment is a simple, natural, chemical-free, soil-based transport enhancer that may be widely useful in a variety of contexts including more sustainable agriculture methods and cost-effective integrated pest management.

Enhancing crop productivity and soil sustainability under climate-smart agriculture involves strategically using soil amendments to improve soil health and resilience. A field experiment at Prairie View A&M University, Texas, studied the effects of soil amendments (chicken and dairy manures and biochar) on some soil health indicators. The experiment used two biochar rates (2268 and 4536 kg ha⁻¹) and two types of manure (chicken and dairy) at three rates (0, 224, and 448 kg total N ha⁻¹ for sweet corn [Zea mays (L.)] and 0, 180, and 360 kg N ha⁻¹ for sorghum [Sorghum bicolor (L.) Moench]) in a factorial design with three replications. Soil macronutrients and micronutrients were measured as chemical soil health indicators, and bulk density, porosity, and saturated hydraulic conductivity were measured as physical soil health indicators. Dairy manure significantly increased soil calcium (Ca) and potassium (K) concentrations. Higher manure application rates improved soil nutrient concentration, with the highest phosphorus (P), Ca, magnesium (Mg), and manganese (Mn) concentration levels at the double recommended rate. Biochar did not affect nutrient concentration but improved soil physical properties by increasing porosity, hydraulic conductivity, and reducing bulk density, especially at higher rates in sweet corn. Correlation analysis showed bulk density was negatively correlated with key nutrients like potassium (K), Ca, and Mg, while porosity and hydraulic conductivity positively influenced nutrient availability. The principal component analysis highlighted that sweet corn and sorghum respond positively to selected soil amendments, while their specific impacts vary based on crop type. The findings emphasize balancing manure and biochar application rates to optimize soil fertility and minimize environmental risks, supporting sustainable soil management strategies.

Galloway, L. A., Gamble, A. V., Guertal, E. A., Feng, Y., & Ogles, C. Z. (2025). Potential of ammonium thiosulfate and potassium thiosulfate to inhibit nitrification in soils. Soil Science Society of America Journal, 89, e70053. https://doi.org/10.1002/saj2.70053

In the first sentence of the fifth paragraph of the Introduction section, the sentence “Ammonium thiosulfate (ATS) and potassium thiosulfate (KTS) are used as liquid fertilizers.” should read, “Ammonium thiosulfate (ATS) and potassium thiosulfate (KTS) are used as liquid fertilizers (KTS is a registered trademark of Tessenderlo Kerley, Inc.).” to acknowledge the legal trademark status of this fertilizer.

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Slope aspect is a significant terrain attribute influencing soil physical and chemical processes. Yet its impact on soil quality and erosion has rarely been studied on gently sloping farmlands. The objective was to evaluate the effects of slope aspect on soil quality and its response to soil erosion in the black soil region of northeast China, a temperate environment featuring gently sloping farmlands. Over a nearly north-south symmetric sloping farmland spanning ∼3500 m, fifteen soil physical and chemical properties were investigated at every 40 m, and an integrated soil quality index (SQI) was calculated combining principal component analysis and scoring functions. The mean annual erosion rate (ER) was estimated using the cesium-137 tracing technique. Compared to the south-facing slope, the north-facing slope possessed significantly lower pH and higher saturated hydraulic conductivity, sand content, and almost all the essential nutrient contents, therefore overall better soil quality (p < 0.05). No statistical difference was spotted in ER between the two slopes (p > 0.05); however, erosion was found to deteriorate soil quality via distinct pathways. On the north-facing slope, erosion affected SQI predominantly through its negative impact on soil organic carbon content and wet-aggregate stability, and conservation tillage practices were suggested. However, on the south-facing slope, the detrimental influence was primarily driven through the depletion of soil nutrient contents, particularly available phosphorus and total nitrogen, and contour tillage and hedgerows were strongly recommended. These findings hold important practical implications for agricultural management in temperate environments.

Clay nanoparticles (NPs) are recognized as natural soil amendments. However, the effects of different types of clay NPs and their application rates on the physical, chemical, and biological characteristics of soils, solute transport, and plant photosynthesis parameters have not been thoroughly investigated. This study focused on amending two soil textures—sandy loam and loam—by adding 3% nano clay. The original and amended soils were packed into soil columns to conduct cultivation experiments with quinoa (Chenopodium quinoa Willd) plants and displacement solute transport experiments. The goal of column experiments was to explore the impact of the nano clay amendment on the photosynthetic properties of quinoa plants and solute transport in soils. The results indicated that adding NPs to loam soil improved photosynthesis and stomatal conductance. Additionally, the introduction of nano clays reduced sub-stomatal CO₂ levels in the amended soils compared to the control soils. In sandy loam soil, both with and without cultivation, the addition of nano clay enhanced saturated hydraulic conductivity, dispersivity, and maximum chloride concentration when compared to the control. However, it also resulted in a decrease in immobile water content and a reduction in peak travel time. In loam soil, the application of nano clay—regardless of cultivation method—increased dispersivity and immobile water contents while reducing maximum chloride concentration. It simultaneously decreased hydraulic conductivity compared to control conditions and also increased it in some instances. This research demonstrates that the nano clay amendment significantly alters soil's physical and chemical properties, affecting solute transport and the photosynthetic parameters of the quinoa cultivar.