Proceedings - Soil Science Society of America最新文献

In the karst region of southwestern China, limited land resources and intense human-land conflict pose challenges to sugarcane (Saccharum officinarum L.) cultivation, a key economic crop. Sloping farmland is particularly vulnerable to water erosion, causing soil, water, and nutrient losses that hinder sustainable agriculture. Results show that runoff and sediment production vary significantly (p < 0.05) with rainfall intensity and sugarcane growth stages. Compared to conventional downslope tillage, contour tillage combined with straw mulching and trenching reduced runoff and sediment yield by 39.90% and 88.32%, respectively. Nutrient loss was mainly driven by sediment transport, with nutrient retention varying among tillage methods. Contour tillage with straw mulching and trenching effectively retained soil organic carbon, total phosphorus, alkali-hydrolyzable nitrogen, available phosphorus, and available potassium, while contour deep tillage with biochar was more effective in preserving total nitrogen and total potassium. Path analysis revealed that sediment yield had stronger correlations and path coefficients with nutrient losses than with runoff. These findings provide a scientific basis for soil and water conservation strategies and the selection of sustainable tillage practices for sloping farmland in karst regions.

Tropical peatlands are globally significant carbon (C) pools, and effective monitoring of their condition is crucial to preserving these stores and preventing further carbon loss. Spectroscopic techniques provide valuable insights into the specific carbon functional groups within organic matter, offering a rapid and cost-effective alternative to conventional soil analyses. Despite increasing recognition of their potential, no attempt has been made to evaluate the existing scientific literature on the application of spectroscopy on tropical peat soils. This paper reports on the results of a quantitative systematic review of 32 peer-reviewed English-language scientific literature that have applied spectroscopy to whole tropical peat soils. Most of these studies were undertaken in Malaysia (12) and Indonesia (10), areas experiencing the most rapid land use conversion of tropical peatlands. However, there is a notable scarcity of studies from other areas where large areas of tropical peatland occur, including Africa and South America. Infrared spectroscopy in the mid-infrared range and ¹³C nuclear magnetic resonance spectroscopy were the most reported spectroscopic techniques. Most studies using Fourier transform infrared spectroscopy employed attenuated total reflectance mode (nine), while two studies used diffuse reflectance infrared Fourier-transform mode, and seven studies used the classic KBr pellet transmission method. One study utilized Raman spectroscopy, one used visible near-infrared, and none applied photoacoustic spectroscopy, the latter being theoretically promising for highly absorbing organic samples especially where pyrogenic carbon is present. This review identifies key research gaps, including assessing the potential application of spectroscopy combined with chemometric techniques to predict a wide range of tropical peat soil properties. The importance of international collaboration and the development of standard sample preparation methods to enable comparison between studies is highlighted. Implementation of these recommendations could help to fast track the development of rapid and cost-effective spectroscopic approaches to monitor peatland condition.

The efficacy of empty oil palm fruit bunch (EFB) on crop productivity was evaluated by examining the effect of a one-time application of EFB biochar and compost on soil properties, okra (Abelmoschus esculentus L.) nitrogen and phosphorus use efficiency, and yields across two cropping cycles. Treatments involved EFB biochar at 10 and 20 t ha⁻¹ (B10 and B20), EFB compost at 20 t ha⁻¹ (CP20), combinations of biochar and compost (B10CP20 and B20CP20), an unamended control (B0), and an inorganic fertilizer treatment (NPK). Soil chemical properties, okra yield, and microbial biomass were assessed using the whole-cell fatty acid (WCFA) profiling method. The results showed that both single and combined applications of EFB biochar and compost significantly improved okra pod yields, with increases up to 283% in the first cropping cycle. CP20 and B20CP20 treatments increased yield by 58% and 100%, respectively, compared to the mineral fertilizer treatment. These treatments also enhanced phosphorus uptake and recovery efficiency, primarily due to increased soil pH and improved nutrient availability. B20CP20 was especially effective in boosting cation exchange capacity (CEC) and micronutrient content. The presence of arbuscular mycorrhizal fungi in the CP20 treatment was associated with improved phosphorus uptake and recovery in the second cycle. However, an overall decline in soil CEC and total organic carbon by an average of 16% and 25%, respectively, resulted in a threefold yield reduction in the second cycle. Importantly, only the B20CP20 treatment sustained yield increases into the second cycle. The study demonstrates that a one-time co-application of EFB biochar and compost can enhance soil fertility and soil microbial properties and increase nitrogen and phosphorus use efficiencies, resulting in increased okra yields.

de Lima, R. P., Tormena, C.A., Menillo, R. B., La Scala Júnior, N., da Silva, A.R., Souza, Z. M., Cerri, C. E. P., & Cherubin, M. R. (2025). Correlation of total organic C, particulate and mineral-associated C fractions with strength indicators in Oxisols. Soil Science Society of America Journal, 89, e70141. https://doi.org/10.1002/saj2.70141

A funding source was inadvertently left out of the Funding Information and Acknowledgments. The Center for Carbon Research in Tropical Agriculture (CCARBON) – São Paulo Research Foundation (FAPESP, grant 21/10573-4) has now been added to the Funding Information on the title page. The Acknowledgments section has also been updated to add the following sentence “We gratefully acknowledge support from the Center for Carbon Research in Tropical Agriculture (CCARBON) – São Paulo Research Foundation (FAPESP, grant 21/10573-4).”

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Roel-Rezk, V., Horwath, W. R., & Pittelkow, C. M. (2025). Is soil health research meeting its potential? Analysis of studies in California and implications for ecosystem services. Soil Science Society of America Journal, 89, e70139. https://doi.org/10.1002/saj2.70139

Data presented in the left panel of Figure 1, 1 is incorrect and does not match the correct data mentioned in the text. The total numbers should have been 22 articles (updated from 17) measured in the three dimensions and represent 51% of the papers (updated from 52%). Four articles measure a biological and a chemical indicator (updated from 2), and five only a chemical indicator (updated from 2).

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The corrected figure with the corrected numbers appears below:

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Soil health underpins ecosystem services and sustainable agriculture. This study compared soil health properties among three long-term land-use systems in Trans Nzoia, western Kenya: biointensive agriculture (BIA), natural shrubland reserve, and conventional maize monocropping. Soil health was assessed primarily through chemical and biological indicators, with bulk density (BD) included as the measured physical property. Soil texture was also determined across sites, providing context as an inherent and potentially management-influenced property. Soil samples (from 0- to 5-cm, 5- to 15-cm, 15- to 30-cm, 30- to 60-cm, and 60- to 100-cm depths) were analyzed for microbial biomass carbon and nitrogen (MBC), dissolved organic C, total dissolved N (TDN), potential mineralizable C and N, total N (TN), total C (TC), TN stocks, TC stocks, bulk density, and soil texture. Several soil health indicators were higher in BIA and shrubland than in maize, especially at 0–5 cm. At this depth, MBC (BIA vs. maize: +117%) and TDN (nature reserve vs. maize: +141%) were greater. TC (BIA vs. maize: +69%) and TN (shrubland vs. maize: +58%) stocks were also higher. BIA had the lowest BD (1.07 g cm⁻³ at 0–5 cm) compared to maize (1.27 g cm⁻³), consistent with better aeration and root penetration. While recognizing that observed differences reflect the combined influence of management history and inherent site properties, these case comparisons suggest that BIA management is associated with higher C and N stocks, enhanced microbial biomass, and reduced compaction. Adopting BIA could help mitigate soil degradation and support agricultural sustainability in smallholder systems.

Tillage and cover cropping are known to affect soil water dynamics and crop evapotranspiration (ET), and consequently, water footprint (WF) of crop production and economic return. In this study, two tillage practices (conventional tillage [CT] and no-tillage [NT]) and cover crop (CC) treatments (Austrian winter pea [Pisum sativum] CC and no-CC [NC]) were investigated to quantify soil water balance, ET, and WF of yield and revenue for cotton (Gossypium hirsutum) and sorghum (Sorghum bicolor) production. Soil volumetric water content was measured from 0- to 120-cm depth from May to October in 2020 and 2021. Runoff, deep percolation, and ET were modeled using the root zone water quality model (RZWQM2), and WF was determined as m³ of water consumed per kg of yield or unit revenue. The RZWQM2 performance was acceptable, validated by low residual errors. Pooled across years, CT treatments depleted soil water storage by 9% and 7% over the season in cotton and sorghum, respectively, which was 6% and 7% for NT. No-till reduced the runoff by 31% over CT when averaged across years and cash crops. The NTCC (no-tillage, cover crop) minimized ET, compared to NTNC (no-tillage, no cover crop) and CT treatments, particularly in sorghum. Tillage increased the WF of yield and revenue for cotton by 7% and 6% over NT treatments, respectively. In sorghum, neither tillage nor cover cropping altered the WF outcomes. Overall, cover cropping and conservation tillage could be used to complement each other to minimize the WF of cotton and sorghum production in the humid Lower Mississippi River Basin.

Soil structure is an important feature that facilitates water infiltration, storage, and transport into the profile, as well as affecting soil organic matter storage, habitat for soil organisms, and nutrient cycling. How land use and grassland management affect soil structural characteristics in the warm, humid region of the southeastern US remains poorly described. A cross-sectional study from 308 grassland fields and 29 woodlots was sampled at 0- to 10-cm depth in North Carolina. Soils were mostly Ultisols (90%) and included some Alfisols, Inceptisols, and Entisols. Soil texture classes included sand (6%), loamy sand (7%), sandy loam (21%), sandy clay loam (27%), loam (17%), clay loam (13%), silt loam (7%), and silty clay loam (1%). Overall, soil bulk density was greater under grassland than under woodland (1.26 vs. 1.06 Mg m⁻³, respectively) but the difference narrowed with finer soil texture. Mean-weight diameter of water-stable aggregation was greater under grassland than under woodland in fine-textured soils but not in other soils. Soil stability index was not different between grassland and woodland, possibly due to high levels (>90%) in both land uses. Several grassland management factors influenced soil structural characteristics, including prior land-use history, pasture age, stocking density, and forage utilization. Soil structural characteristics were strongly negatively associated with sand concentration and positively associated with soil-test biological activity. Older pastures with moderate grazing pressure exhibited the strongest soil structural characteristics on medium- and fine-textured soils, thereby delivering vital ecosystem services from this widely prevalent land use in the eastern United States.

Poly-γ-glutamic acid (γ-PGA) has great agricultural potential due to its water-retention ability, but its effects at different application amounts on soybean [Glycine max (L.) Merr.] productivity and soil properties remain unclear. In this study, γ-PGA was applied at five amounts (0, 10, 20, 40, and 80 kg ha⁻¹, denoted as CK, T10, T20, T40, and T80, respectively) via drip irrigation to soybean plants to evaluate its impact on soil physical and hydraulic properties, nutrient availability, crop growth, and yield. The results showed that γ-PGA application increased soil porosity, reduced bulk density, and improved soil temperature in the 0–25 cm layer. Soil hydraulic parameters, including field capacity and plant-available water, also improved with γ-PGA application. However, γ-PGA application reduced soil nitrogen, phosphorus, and potassium levels at harvest. Nutrient uptake efficiency and soybean growth initially increased and then declined with higher γ-PGA application amounts, with the highest yield observed under the T40 treatment. Overall, applying γ-PGA at 40 kg ha⁻¹ effectively enhanced soil properties and nutrient uptake, leading to improved soybean productivity.