Pub Date : 2024-12-19DOI: 10.1016/j.still.2024.106424
Yao Guo, Quanyi Hu, Tianqi Liu, Yunfeng Du, Chengfang Li, Xuelin Zhang, Juan Liu, Cougui Cao
Rice–crayfish coculture (RC) has emerged as a transformative agricultural practice in China, significantly influencing soil microorganisms and enhancing soil organic carbon (SOC) accumulation. However, the contribution of plant residues and microbial necromass to the increased SOC within RC systems remains uncertain. This study aimed to investigate phospholipid fatty acids (PLFAs), microbial necromass C (MNC, with amino sugars as biomarkers), plant-derived C (VSC, with lignin phenols as biomarkers) levels, along with soil properties across conventional rice monoculture (RM) and RC systems of 5-, 10-, and 15-yr durations (RC5, RC10, and RC15, respectively). The results showed that long-term RC fields exhibited stronger aggregation, higher soil nutrient levels, organically complexed Fe oxides (Fep), and lower bulk density and oxidation–reduction potential than those with RM. The SOC levels were significantly higher in RC10 and RC15 than in RM, by 31.8 % and 37.2 %, respectively. Moreover, RC significantly reduced the levels of bacterial (25.3–35.4 %) and fungal (19.5–34.7 %) PLFAs compared with RM, with RC10 exhibiting the lowest levels. With RC duration increasing to 10–15 years, MNC and VSC were respectively higher by 12.4–25.3 % and 48.8–72.4 % than those in RM. Specifically, fungal necromass C, as well as vanillyl- and syringyl-type phenols, showed the most pronounced enhancements. Concurrently, the contribution of VSC to SOC (12.4–25.3 %) significantly increased in the 10 −15-yr RC period compared with RM, whereas MNC decreased proportionally (17.5–18.5 %). SOC and Fep were the primary factors regulating the contribution of MNC to SOC, whereas the contribution of VSC to SOC was mainly influenced by soil aggregation. Thus, long-term RC improved soil C sequestration primarily by increasing the contribution of plant-derived C rather than that of microbe-derived C. However, the findings of this study indicated that long-term RC might limit microbial biomass, thereby raising concerns about the long-term sustainability of microbial communities in these systems.
{"title":"Long-term rice–crayfish coculture increases plant lignin but not microbial necromass contribution to soil organic carbon","authors":"Yao Guo, Quanyi Hu, Tianqi Liu, Yunfeng Du, Chengfang Li, Xuelin Zhang, Juan Liu, Cougui Cao","doi":"10.1016/j.still.2024.106424","DOIUrl":"https://doi.org/10.1016/j.still.2024.106424","url":null,"abstract":"Rice–crayfish coculture (RC) has emerged as a transformative agricultural practice in China, significantly influencing soil microorganisms and enhancing soil organic carbon (SOC) accumulation. However, the contribution of plant residues and microbial necromass to the increased SOC within RC systems remains uncertain. This study aimed to investigate phospholipid fatty acids (PLFAs), microbial necromass C (MNC, with amino sugars as biomarkers), plant-derived C (VSC, with lignin phenols as biomarkers) levels, along with soil properties across conventional rice monoculture (RM) and RC systems of 5-, 10-, and 15-yr durations (RC5, RC10, and RC15, respectively). The results showed that long-term RC fields exhibited stronger aggregation, higher soil nutrient levels, organically complexed Fe oxides (Fe<ce:inf loc=\"post\">p</ce:inf>), and lower bulk density and oxidation–reduction potential than those with RM. The SOC levels were significantly higher in RC10 and RC15 than in RM, by 31.8 % and 37.2 %, respectively. Moreover, RC significantly reduced the levels of bacterial (25.3–35.4 %) and fungal (19.5–34.7 %) PLFAs compared with RM, with RC10 exhibiting the lowest levels. With RC duration increasing to 10–15 years, MNC and VSC were respectively higher by 12.4–25.3 % and 48.8–72.4 % than those in RM. Specifically, fungal necromass C, as well as vanillyl- and syringyl-type phenols, showed the most pronounced enhancements. Concurrently, the contribution of VSC to SOC (12.4–25.3 %) significantly increased in the 10 −15-yr RC period compared with RM, whereas MNC decreased proportionally (17.5–18.5 %). SOC and Fe<ce:inf loc=\"post\">p</ce:inf> were the primary factors regulating the contribution of MNC to SOC, whereas the contribution of VSC to SOC was mainly influenced by soil aggregation. Thus, long-term RC improved soil C sequestration primarily by increasing the contribution of plant-derived C rather than that of microbe-derived C. However, the findings of this study indicated that long-term RC might limit microbial biomass, thereby raising concerns about the long-term sustainability of microbial communities in these systems.","PeriodicalId":501007,"journal":{"name":"Soil and Tillage Research","volume":"112 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142867509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-19DOI: 10.1016/j.still.2024.106422
Peter B. Obour, Yushu Xia, Carmen M. Ugarte, Tony E. Grift, Michelle M. Wander
This study investigated changes in soil physical quality and water dynamics arising from continuous cropping at the Morrow Plots, the oldest agricultural experiment in North America. The objectives were to examine the effects of continuous cultivation on soil water retention and determine the optimum water content for tillage (θOPT) in a prime agricultural soil. Soil samples collected at 0–5, 5–10, and 10–15 cm depths were used to measure bulk density and water retention using the HyProp 2 and WP4-T Dewpoint Potentiometer. Soil organic carbon (SOC) and soil penetration resistance (PR) were measured to a depth of 15 cm. The soil water retention data were fitted with the Dexter double exponential and van Genuchten models. Neither model consistently fitted all the water retention data across the different management practices. The corn-oat-hay (COH) rotation generally reduced soil bulk density within the 0–15 cm depth by an average of 9 % and PR by 21 % compared to the continuous corn (CC) treatment. The COH rotation slightly increased topsoil water-holding capacity (0–15 cm), although trends varied with fertility regimes. The θOPT for the COH and CC estimated by the van Genuchten model was generally wetter than the water content at field capacity (θFC). In contrast, the θOPT estimated by the Dexter model was slightly drier than θFC. Despite limitations due to the lack of true replicates and the small sample size at the Morrow Plots, this research underscores the long-term impact of crop rotation on soil hydraulic properties in prime agricultural soils.
{"title":"Soil physical properties and water dynamics under contrasting management regimes at the Morrow Plots","authors":"Peter B. Obour, Yushu Xia, Carmen M. Ugarte, Tony E. Grift, Michelle M. Wander","doi":"10.1016/j.still.2024.106422","DOIUrl":"https://doi.org/10.1016/j.still.2024.106422","url":null,"abstract":"This study investigated changes in soil physical quality and water dynamics arising from continuous cropping at the Morrow Plots, the oldest agricultural experiment in North America. The objectives were to examine the effects of continuous cultivation on soil water retention and determine the optimum water content for tillage (<ce:italic>θ</ce:italic><ce:inf loc=\"post\">OPT</ce:inf>) in a prime agricultural soil. Soil samples collected at 0–5, 5–10, and 10–15 cm depths were used to measure bulk density and water retention using the HyProp 2 and WP4-T Dewpoint Potentiometer. Soil organic carbon (SOC) and soil penetration resistance (PR) were measured to a depth of 15 cm. The soil water retention data were fitted with the Dexter double exponential and van Genuchten models. Neither model consistently fitted all the water retention data across the different management practices. The corn-oat-hay (COH) rotation generally reduced soil bulk density within the 0–15 cm depth by an average of 9 % and PR by 21 % compared to the continuous corn (CC) treatment. The COH rotation slightly increased topsoil water-holding capacity (0–15 cm), although trends varied with fertility regimes. The <ce:italic>θ</ce:italic><ce:inf loc=\"post\">OPT</ce:inf> for the COH and CC estimated by the van Genuchten model was generally wetter than the water content at field capacity (<ce:italic>θ</ce:italic><ce:inf loc=\"post\">FC</ce:inf><ce:italic>)</ce:italic>. In contrast, the <ce:italic>θ</ce:italic><ce:inf loc=\"post\">OPT</ce:inf> estimated by the Dexter model was slightly drier than <ce:italic>θ</ce:italic><ce:inf loc=\"post\">FC</ce:inf>. Despite limitations due to the lack of true replicates and the small sample size at the Morrow Plots, this research underscores the long-term impact of crop rotation on soil hydraulic properties in prime agricultural soils.","PeriodicalId":501007,"journal":{"name":"Soil and Tillage Research","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142867547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In Okinawa, Japan, controlled-release N fertilizers (CRFs) are promoted to reduce labor and to increase fertilizer use efficiency. However, N2O emissions from N fertilizer applied to the widely prevalent Kunigami mahji (red-yellow soil), a local soil in the region, have not been examined so far. We conducted two laboratory experiments during winter and spring to compare N2O emissions between CRF and standard fertilizer (ammonium sulfate: AS) in kunigami mahji. Two seasons were selected to explore the effects of moisture and temperature on N2O emissions in relation to N fertilization. For each experiment, three soil chambers were used, each containing 1.4 kg of soil: one served as a control, and the other two received 1 g of nitrogen from either a linear-release-type CRF with 42 % N or AS with 21 % N. Over 9 weeks, N₂O emissions from the headspace of each chamber were measured every minute for 20 min, followed by 70 min of ventilation, in a continuous 90-minute cycle repeated throughout the study. Soil moisture, soil temperature, NO, and NO3-N and NH4-N in leachate were also analyzed. In exp A (winter), nitrification was dominant, and N2O emission from CRF (emission factor, EF, 0.4 %) was 88 % lower than that from AS (EF 3.9 %). In exp B (spring), denitrification was dominant, and N2O emission from CRF (EF 1.9 %) was 53 % lower than that from AS (EF 4 %). The frequently lower water-filled pore space (WFPS) in exp A than in exp B facilitated higher NO emission from AS than from CRF. Due to the consistently high WFPS in Exp B, most of the NO3− in the soil was reduced to N2O and N2. N is more readily available in AS than in CRF, facilitating higher cumulative leaching of NH4-N from AS. However, in both experiments, AS was denitrified more than CRF, producing more N2O and resulting in lower leaching of NO3-N. Our results highlight that choosing the appropriate form of fertilizer and good management of soil moisture content can reduce N2O emissions and leaching of NO3− and NH4+.
{"title":"N2O emissions from controlled-release and conventional N-fertilizers applied to red-yellow soil in Okinawa, Japan","authors":"W.B.M.A.C. Bandara, Kazuhito Sakai, Mitsumasa Anan, Shinya Nakamura, Hideki Setouchi, Kosuke Noborio, Toshimitsu Kaif, R.H.K. Rathnappriya","doi":"10.1016/j.still.2024.106376","DOIUrl":"https://doi.org/10.1016/j.still.2024.106376","url":null,"abstract":"In Okinawa, Japan, controlled-release N fertilizers (CRFs) are promoted to reduce labor and to increase fertilizer use efficiency. However, N<ce:inf loc=\"post\">2</ce:inf>O emissions from N fertilizer applied to the widely prevalent <ce:italic>Kunigami mahji</ce:italic> (red-yellow soil), a local soil in the region, have not been examined so far. We conducted two laboratory experiments during winter and spring to compare N<ce:inf loc=\"post\">2</ce:inf>O emissions between CRF and standard fertilizer (ammonium sulfate: AS) in <ce:italic>kunigami mahji</ce:italic>. Two seasons were selected to explore the effects of moisture and temperature on N<ce:inf loc=\"post\">2</ce:inf>O emissions in relation to N fertilization. For each experiment, three soil chambers were used, each containing 1.4 kg of soil: one served as a control, and the other two received 1 g of nitrogen from either a linear-release-type CRF with 42 % N or AS with 21 % N. Over 9 weeks, N₂O emissions from the headspace of each chamber were measured every minute for 20 min, followed by 70 min of ventilation, in a continuous 90-minute cycle repeated throughout the study. Soil moisture, soil temperature, NO, and NO<ce:inf loc=\"post\">3</ce:inf>-N and NH<ce:inf loc=\"post\">4</ce:inf>-N in leachate were also analyzed. In exp A (winter), nitrification was dominant, and N<ce:inf loc=\"post\">2</ce:inf>O emission from CRF (emission factor, EF, 0.4 %) was 88 % lower than that from AS (EF 3.9 %). In exp B (spring), denitrification was dominant, and N<ce:inf loc=\"post\">2</ce:inf>O emission from CRF (EF 1.9 %) was 53 % lower than that from AS (EF 4 %). The frequently lower water-filled pore space (WFPS) in exp A than in exp B facilitated higher NO emission from AS than from CRF. Due to the consistently high WFPS in Exp B, most of the NO<ce:inf loc=\"post\">3</ce:inf><ce:sup loc=\"post\">−</ce:sup> in the soil was reduced to N<ce:inf loc=\"post\">2</ce:inf>O and N<ce:inf loc=\"post\">2</ce:inf>. N is more readily available in AS than in CRF, facilitating higher cumulative leaching of NH<ce:inf loc=\"post\">4</ce:inf>-N from AS. However, in both experiments, AS was denitrified more than CRF, producing more N<ce:inf loc=\"post\">2</ce:inf>O and resulting in lower leaching of NO<ce:inf loc=\"post\">3</ce:inf>-N. Our results highlight that choosing the appropriate form of fertilizer and good management of soil moisture content can reduce N<ce:inf loc=\"post\">2</ce:inf>O emissions and leaching of NO<ce:inf loc=\"post\">3</ce:inf><ce:sup loc=\"post\">−</ce:sup> and NH<ce:inf loc=\"post\">4</ce:inf><ce:sup loc=\"post\">+</ce:sup>.","PeriodicalId":501007,"journal":{"name":"Soil and Tillage Research","volume":"78 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142867512","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The conservation agricultural effects on soil physical properties are not immediately visible and are variable but might be observed in medium to long-term studies. The objective of this study was to assess the medium-term (ten year) effect of conservation agricultural practices on selected soil physical properties in a sub-humid region of Eastern Cape, South Africa. The assessment was performed on a conservation agriculture (CA) field trial established in 2012, laid out in a randomized complete block design (RCBD) with split split-plot treatment structure consisting of 16 treatment combinations replicated into 3 blocks. The main plots, sub plots and sub sub plots were allocated to tillage (no-tillage (NT) and conventional tillage (CT)), crop rotations (maize-fallow-maize (MFM); maize-soybean-maize (MFS); maize-wheat-maize (MWM); maize-wheat-soybean (MWS)), and crop residue management practices (residue retention (R+) and residue removal (R-)), respectively. Soil samples were collected from 0 – 10, 10 – 20 and 20 – 30 cm depths in the 2023/24 cropping season. The results showed that tillage practices had a significantly greater impact on bulk density (BD), porosity (ϕ) and aggregate stability (AGS)/ stability index (SI) compared to crop rotations and residue management. Soybean rotation treatments: MFS and MWS had 3.42 % and 2.08 % lower BD values compared with MFM and MWM, respectively. This is likely due to the quick decomposition of soybean residues, indicating potential improvement in soil health and soil quality with legume inclusion in rotations. Additionally, R+ plots had 24.24 % higher gravimetric water content and 25.04 % higher volumetric water content than R- plots, due to the substantial amount of SOM returned by residue decomposition. There were no significant differences observed in Ks, which could be attributed to the nature of the particle size distribution, as water moves more easily on sandy soils. These medium-term results present continual benefits from proper implementation of CA in sustainable farming and resource conservation.
{"title":"Medium-term effects of tillage, crop rotation and crop residue management practices on selected soil physical properties in the sub-humid region of Eastern Cape, South Africa","authors":"Cossy Shayne Nonxuba, Dimpho Elvis Elephant, Adornis Dakarai Nciizah, Alen Manyevere","doi":"10.1016/j.still.2024.106420","DOIUrl":"https://doi.org/10.1016/j.still.2024.106420","url":null,"abstract":"The conservation agricultural effects on soil physical properties are not immediately visible and are variable but might be observed in medium to long-term studies. The objective of this study was to assess the medium-term (ten year) effect of conservation agricultural practices on selected soil physical properties in a sub-humid region of Eastern Cape, South Africa. The assessment was performed on a conservation agriculture (CA) field trial established in 2012, laid out in a randomized complete block design (RCBD) with split split-plot treatment structure consisting of 16 treatment combinations replicated into 3 blocks. The main plots, sub plots and sub <ce:glyph name=\"sbnd\"></ce:glyph> sub plots were allocated to tillage (no-tillage (NT) and conventional tillage (CT)), crop rotations (maize-fallow-maize (MFM); maize-soybean-maize (MFS); maize-wheat-maize (MWM); maize-wheat-soybean (MWS)), and crop residue management practices (residue retention (R+) and residue removal (R-)), respectively. Soil samples were collected from 0 – 10, 10 – 20 and 20 – 30 cm depths in the 2023/24 cropping season. The results showed that tillage practices had a significantly greater impact on bulk density (BD), porosity (ϕ) and aggregate stability (AGS)/ stability index (SI) compared to crop rotations and residue management. Soybean rotation treatments: MFS and MWS had 3.42 % and 2.08 % lower BD values compared with MFM and MWM, respectively. This is likely due to the quick decomposition of soybean residues, indicating potential improvement in soil health and soil quality with legume inclusion in rotations. Additionally, R+ plots had 24.24 % higher gravimetric water content and 25.04 % higher volumetric water content than R- plots, due to the substantial amount of SOM returned by residue decomposition. There were no significant differences observed in Ks, which could be attributed to the nature of the particle size distribution, as water moves more easily on sandy soils. These medium-term results present continual benefits from proper implementation of CA in sustainable farming and resource conservation.","PeriodicalId":501007,"journal":{"name":"Soil and Tillage Research","volume":"83 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142867513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-18DOI: 10.1016/j.still.2024.106426
Chengshu Wang, Guanghui Zhang, Shiqi Chen
The reduction of soil function in croplands is widespread over the world resulting from land degradation induced by intensified agricultural practices. Straw incorporation likely affects soil function in sloping croplands. However, the quantitative influences of incorporated straw on the seasonal dynamics of soil function in croplands with different degradation degrees are still uncertain. The objective of the study is to identify the seasonal variations of different soil functions affected by straw incorporation in different degraded croplands in the black soil region of China. The results of network analysis denoted that soil functions could be fully quantified by eight factors. They were water-stable aggregate, available nitrogen, available phosphorus, humin acid, cation exchange capacity, soil organic matter, invertase and catalase. Significant seasonal variations were observed in soil function factors of different degraded croplands under straw incorporation treatment and its control (p < 0.05). Correspondingly, soil functions exhibited significant seasonal variations in various degraded croplands (p < 0.05). Soil functions were greatly enhanced by incorporated straw. In comparison to the without straw incorporation treatment, soil functions increased by 0.8 %-47.4 % during the growing season. The promotions in soil functions by straw incorporation were closely related to land degradation degree. Compared to cropland of non-degradation, the enhancements of soil functions declined by 6.2 %-58.5 %, 6.5 %-81.7 % and 11.7 %-95.2 % in the light, moderate and strong degradation croplands, respectively. Incorporated straw stimulated crop growth by improving soil functions and the crop yield increased by 12.7 %-18.7 %. Straw incorporation enhances soil functions and crop growth via improved water-stable aggregate, soil organic matter, cation exchange capacity and humin acid of different degraded croplands. The results highlight the significance of straw incorporation in degraded croplands to ameliorate soil functions and crop growth in intensive agricultural regions.
{"title":"Seasonal variations of soil functions affected by straw incorporation in croplands with different degradation degrees","authors":"Chengshu Wang, Guanghui Zhang, Shiqi Chen","doi":"10.1016/j.still.2024.106426","DOIUrl":"https://doi.org/10.1016/j.still.2024.106426","url":null,"abstract":"The reduction of soil function in croplands is widespread over the world resulting from land degradation induced by intensified agricultural practices. Straw incorporation likely affects soil function in sloping croplands. However, the quantitative influences of incorporated straw on the seasonal dynamics of soil function in croplands with different degradation degrees are still uncertain. The objective of the study is to identify the seasonal variations of different soil functions affected by straw incorporation in different degraded croplands in the black soil region of China. The results of network analysis denoted that soil functions could be fully quantified by eight factors. They were water-stable aggregate, available nitrogen, available phosphorus, humin acid, cation exchange capacity, soil organic matter, invertase and catalase. Significant seasonal variations were observed in soil function factors of different degraded croplands under straw incorporation treatment and its control (p < 0.05). Correspondingly, soil functions exhibited significant seasonal variations in various degraded croplands (p < 0.05). Soil functions were greatly enhanced by incorporated straw. In comparison to the without straw incorporation treatment, soil functions increased by 0.8 %-47.4 % during the growing season. The promotions in soil functions by straw incorporation were closely related to land degradation degree. Compared to cropland of non-degradation, the enhancements of soil functions declined by 6.2 %-58.5 %, 6.5 %-81.7 % and 11.7 %-95.2 % in the light, moderate and strong degradation croplands, respectively. Incorporated straw stimulated crop growth by improving soil functions and the crop yield increased by 12.7 %-18.7 %. Straw incorporation enhances soil functions and crop growth via improved water-stable aggregate, soil organic matter, cation exchange capacity and humin acid of different degraded croplands. The results highlight the significance of straw incorporation in degraded croplands to ameliorate soil functions and crop growth in intensive agricultural regions.","PeriodicalId":501007,"journal":{"name":"Soil and Tillage Research","volume":"15 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142867544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-17DOI: 10.1016/j.still.2024.106400
Renato Paiva de Lima, Cássio Antonio Tormena, Moacir Tuzzin de Moraes, Zigomar Menezes de Souzar, Mário Monteiro Rolim, Maurício Roberto Cherubin
Mechanical impedance has been reported as a major factor reducing root elongation. Penetrometer is the main tool for diagnosing mechanical soil conditions regarding root growth; however, soil mechanics processes influence root cavity expansion, friction and adhesion at the soil-metal interface which can induce root-related measurement overestimations. Models based on penetrometers have been used to estimate root elongation and assign penetration resistance thresholds, which have been used to determine soil physical limitation for plant development. In this paper, we revisited soil mechanical aspects modeling considering root-soil and penetrometer-soil interfaces, including calculation examples. Moreover, we revisited the application of penetration resistance threshold in soil integrated physical indices for root and plant growth. Our calculations showed that friction is a major factor inducing overestimates at penetrometer-soil interfaces. However, current mathematical models enable estimating normal stress for cavity expansion by removing the effect of soil adhesion and friction, and reducing the impact of penetrometer cone tip angle on soil-metal friction. Additionally, we estimated root elongation rate for a series of plant species as a function of penetrometer resistance which could be applied to soil physical indices for estimating limit plant growth threshold.
{"title":"Revisiting penetrometer models for estimating root elongation","authors":"Renato Paiva de Lima, Cássio Antonio Tormena, Moacir Tuzzin de Moraes, Zigomar Menezes de Souzar, Mário Monteiro Rolim, Maurício Roberto Cherubin","doi":"10.1016/j.still.2024.106400","DOIUrl":"https://doi.org/10.1016/j.still.2024.106400","url":null,"abstract":"Mechanical impedance has been reported as a major factor reducing root elongation. Penetrometer is the main tool for diagnosing mechanical soil conditions regarding root growth; however, soil mechanics processes influence root cavity expansion, friction and adhesion at the soil-metal interface which can induce root-related measurement overestimations. Models based on penetrometers have been used to estimate root elongation and assign penetration resistance thresholds, which have been used to determine soil physical limitation for plant development. In this paper, we revisited soil mechanical aspects modeling considering root-soil and penetrometer-soil interfaces, including calculation examples. Moreover, we revisited the application of penetration resistance threshold in soil integrated physical indices for root and plant growth. Our calculations showed that friction is a major factor inducing overestimates at penetrometer-soil interfaces. However, current mathematical models enable estimating normal stress for cavity expansion by removing the effect of soil adhesion and friction, and reducing the impact of penetrometer cone tip angle on soil-metal friction. Additionally, we estimated root elongation rate for a series of plant species as a function of penetrometer resistance which could be applied to soil physical indices for estimating limit plant growth threshold.","PeriodicalId":501007,"journal":{"name":"Soil and Tillage Research","volume":"55 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142867508","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yaoba Oasis is a traditional tillage farmland completely dependent on irrigation with groundwater. Previous investigations (1980–2015) have revealed that over-extraction of groundwater, deterioration of water quality, and soil salinization are the primary factors limiting the development of the regional agricultural economy. This study aimed to determine the impact of human activities, specifically groundwater exploitation and agricultural irrigation, on the migration of soil salinization since 1980 in the Yaoba Oasis. Specifically, water and soil samples were collected and analyzed from 90 wells and 21 soil sites. Results indicated that the groundwater level in the oasis has steadily declined at a rate of 0.04–0.59 m per year, primarily due to groundwater overexploitation. The annual average soil salt accumulation was approximately 91.1–155.2 mg/kg. Soil salinity was strongly correlated with the hydrochemical composition, with all indicators increasing along the flow path. Irrigation infiltration resulted in salt accumulation below 20 cm, with residual salts being leached by the irrigation return water. Overall, residual salt dissolution under flood irrigation and saltwater intrusion in desert salt lakes are the main reasons for soil salt accumulation and groundwater quality deterioration. To mitigate these issues and maintain the ecological balance of desert oases, it is imperative to limit the overexploitation of groundwater and reduce the amount of irrigation, thereby preventing groundwater contamination and soil salinization.
{"title":"Soil salinity accumulation and groundwater degradation due to overexploitation over recent 40-year period in Yaoba Oasis, China","authors":"Ting Lu, Pingping Luo, Jucui Wang, Yudong Lu, Aidi Huo, Liming Liu","doi":"10.1016/j.still.2024.106398","DOIUrl":"https://doi.org/10.1016/j.still.2024.106398","url":null,"abstract":"Yaoba Oasis is a traditional tillage farmland completely dependent on irrigation with groundwater. Previous investigations (1980–2015) have revealed that over-extraction of groundwater, deterioration of water quality, and soil salinization are the primary factors limiting the development of the regional agricultural economy. This study aimed to determine the impact of human activities, specifically groundwater exploitation and agricultural irrigation, on the migration of soil salinization since 1980 in the Yaoba Oasis. Specifically, water and soil samples were collected and analyzed from 90 wells and 21 soil sites. Results indicated that the groundwater level in the oasis has steadily declined at a rate of 0.04–0.59 m per year, primarily due to groundwater overexploitation. The annual average soil salt accumulation was approximately 91.1–155.2 mg/kg. Soil salinity was strongly correlated with the hydrochemical composition, with all indicators increasing along the flow path. Irrigation infiltration resulted in salt accumulation below 20 cm, with residual salts being leached by the irrigation return water. Overall, residual salt dissolution under flood irrigation and saltwater intrusion in desert salt lakes are the main reasons for soil salt accumulation and groundwater quality deterioration. To mitigate these issues and maintain the ecological balance of desert oases, it is imperative to limit the overexploitation of groundwater and reduce the amount of irrigation, thereby preventing groundwater contamination and soil salinization.","PeriodicalId":501007,"journal":{"name":"Soil and Tillage Research","volume":"32 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142821048","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-12DOI: 10.1016/j.still.2024.106418
Di He, Guihua Li, Zhongkui Luo, Enli Wang
Fertiliser application in agricultural ecosystems affects not only the potential carbon input (via crop biomass and/or manure) into the soil, but also a series of soil processes regulating soil organic carbon (SOC) decomposition. A detailed mechanistic understanding of how fertiliser regimes affect SOC dynamics is still needed. Here we constrained the Agricultural Production Systems sIMulator (APSIM model) to long-term (> 20 years) crop and SOC measurement data collected from four trials under contrasting climatic and edaphic conditions in China. By optimizing the three most influential model parameters for SOC dynamics, i.e., the decomposition rate constant of the slow humic pool (rd_hum), the fraction of stable (non-decomposable) pool (Finert), and microbial carbon use efficiency (CUE), we analysed their responses to fertiliser application regimes to infer potential mechanisms underpinning SOC changes. Our results revealed strong effects of fertiliser regimes and sites on CUE. Sites, fertiliser regimes and their interactions explained 67 % and 1.4 % of the variation in the derived CUE and rd_hum values, respectively. Linear mixed-effects modelling showed that soil C:N ratio together with carbon input amount as a random effect explained 90 % of the variation in optimised CUE values across sites and treatments. Such impact on CUE could partly explain the impact of fertiliser and carbon input on the priming effect. Fertilisers with more carbon input (i.e., straw or manure) increased CUE by 27 % - 57 % compared with chemical fertilisers in three of four sites. However, their impacts on rd_hum was divergent when decomposition of carbon pools was simulated with first-order processes. Our results demonstrate the significant effects of fertiliser regimes on CUE and thus SOC dynamics, highlighting the importance of site-specific calibration of the current SOC models and the need to quantify uncertainty bounds of any model simulated further SOC sequestration. This study also calls for developing a clear understanding to quantify the relationship between carbon input and CUE under different environment.
{"title":"Effects of long-term fertiliser application on cropland soil carbon dynamics mediated by potential shifts in microbial carbon use efficiency","authors":"Di He, Guihua Li, Zhongkui Luo, Enli Wang","doi":"10.1016/j.still.2024.106418","DOIUrl":"https://doi.org/10.1016/j.still.2024.106418","url":null,"abstract":"Fertiliser application in agricultural ecosystems affects not only the potential carbon input (via crop biomass and/or manure) into the soil, but also a series of soil processes regulating soil organic carbon (SOC) decomposition. A detailed mechanistic understanding of how fertiliser regimes affect SOC dynamics is still needed. Here we constrained the Agricultural Production Systems sIMulator (APSIM model) to long-term (> 20 years) crop and SOC measurement data collected from four trials under contrasting climatic and edaphic conditions in China. By optimizing the three most influential model parameters for SOC dynamics, i.e., the decomposition rate constant of the slow humic pool (<ce:italic>rd_hum</ce:italic>), the fraction of stable (non-decomposable) pool (<ce:italic>Finert</ce:italic>), and microbial carbon use efficiency (CUE), we analysed their responses to fertiliser application regimes to infer potential mechanisms underpinning SOC changes. Our results revealed strong effects of fertiliser regimes and sites on CUE. Sites, fertiliser regimes and their interactions explained 67 % and 1.4 % of the variation in the derived CUE and <ce:italic>rd_hum</ce:italic> values, respectively. Linear mixed-effects modelling showed that soil C:N ratio together with carbon input amount as a random effect explained 90 % of the variation in optimised CUE values across sites and treatments. Such impact on CUE could partly explain the impact of fertiliser and carbon input on the priming effect. Fertilisers with more carbon input (i.e., straw or manure) increased CUE by 27 % - 57 % compared with chemical fertilisers in three of four sites. However, their impacts on <ce:italic>rd_hum</ce:italic> was divergent when decomposition of carbon pools was simulated with first-order processes. Our results demonstrate the significant effects of fertiliser regimes on CUE and thus SOC dynamics, highlighting the importance of site-specific calibration of the current SOC models and the need to quantify uncertainty bounds of any model simulated further SOC sequestration. This study also calls for developing a clear understanding to quantify the relationship between carbon input and CUE under different environment.","PeriodicalId":501007,"journal":{"name":"Soil and Tillage Research","volume":"90 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142821056","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Grass coverage in orchards has increasingly become a sustainable practice to improve soil quality, reduce soil erosion, increase water infiltration, and enhance biodiversity and ecosystem services. It is likely to gain further adoption as a promising nature-based measure to increase organic carbon and nitrogen storage in soil. However, there is still a lack of comprehensive global quantification regarding the accumulation and availability of soil organic carbon (SOC) and total nitrogen (STN) after grass coverage in citrus orchards. A global meta-analysis was conducted to comprehensively evaluate the effects of grass coverage on SOC and STN dynamics in citrus orchards, as well as the patterns influenced by various factors. Compared to clean tillage, the accumulation rates of SOC and STN were significantly enhanced with grass coverage, with an increase of 19.98 Mg ha⁻¹ yr⁻¹ and 2.27 Mg ha⁻¹ yr⁻¹ , respectively. The microbial biomass carbon (MBC), dissolved organic carbon (DOC) and available nitrogen (AN) exhibited significantly increases following grass coverage, with average enhancements of 13.90 %, 17.94 %, and 18.04 %, respectively. The primary factors influencing the variation in SOC and STN were identified as grass age and growth modes. When grass coverage reached or exceeded 10 years and was applied uniformly across the entire orchard (full coverage), there was a more pronounced increase in SOC and STN levels. The present study provides policymakers and orchard managers with science-based evidence to guide adaptive management practices that enhance SOC and STN stocks, improve soil conditions, and increase orchard resilience to climate change.
{"title":"Nature-based accumulation of organic carbon and nitrogen in citrus orchard soil with grass coverage","authors":"Ludan Chen, Yuhai Bao, Xiubin He, Jie Yang, Qiao Wu, Jiaorong Lv","doi":"10.1016/j.still.2024.106419","DOIUrl":"https://doi.org/10.1016/j.still.2024.106419","url":null,"abstract":"Grass coverage in orchards has increasingly become a sustainable practice to improve soil quality, reduce soil erosion, increase water infiltration, and enhance biodiversity and ecosystem services. It is likely to gain further adoption as a promising nature-based measure to increase organic carbon and nitrogen storage in soil. However, there is still a lack of comprehensive global quantification regarding the accumulation and availability of soil organic carbon (SOC) and total nitrogen (STN) after grass coverage in citrus orchards. A global meta-analysis was conducted to comprehensively evaluate the effects of grass coverage on SOC and STN dynamics in citrus orchards, as well as the patterns influenced by various factors. Compared to clean tillage, the accumulation rates of SOC and STN were significantly enhanced with grass coverage, with an increase of 19.98 Mg ha⁻¹ yr⁻¹ and 2.27 Mg ha⁻¹ yr⁻¹ , respectively. The microbial biomass carbon (MBC), dissolved organic carbon (DOC) and available nitrogen (AN) exhibited significantly increases following grass coverage, with average enhancements of 13.90 %, 17.94 %, and 18.04 %, respectively. The primary factors influencing the variation in SOC and STN were identified as grass age and growth modes. When grass coverage reached or exceeded 10 years and was applied uniformly across the entire orchard (full coverage), there was a more pronounced increase in SOC and STN levels. The present study provides policymakers and orchard managers with science-based evidence to guide adaptive management practices that enhance SOC and STN stocks, improve soil conditions, and increase orchard resilience to climate change.","PeriodicalId":501007,"journal":{"name":"Soil and Tillage Research","volume":"142 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142821047","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-10DOI: 10.1016/j.still.2024.106414
Muhammad Usman, Mengyuan Wang, Yang Liu, Lan Li, Xiumin Zhang, Tianhao Xiao, Fujiang Hou
Grasslands are one of the major terrestrial ecosystems facing severe degradation due to climatic changes and anthropogenic activities. In northwest China, the Typical steppe and alpine meadows are the major grasslands with diverse ecosystems. These grasslands are facing degradation due to excessive livestock grazing and nitrogen (N) deposition that can alter the overall grassland ecosystem, along with the soil bacterial communities and their role in the ecosystem. The bacterial community is vital for the sustainability of grassland ecosystems as it plays a crucial role in decomposing the dead organic matter and nutrient cycling. This study conducted a grazing and N addition experiment in alpine meadows and typical steppe. The impact of short-term N application and grazing on both grasslands' soil, plant, and bacterial communities was explored. Alpine meadows had higher bacterial richness (OTUs>2000) and diversity (Shannon index>6) than the typical steppe (OTUs<900; Shannon index<5.5) due to changes in climate and ecosystem. The alpha diversity (Shannon index) of the bacterial community was observed to increase under low grazing without N addition while adding medium N (100 kg/ha) without grazing increased the diversity. The combination of medium N (100 kg/ha) addition and low grazing resulted in the highest bacterial diversity in both grasslands. In contrast, the combination of N and high grazing decreased bacterial richness and diversity. The N addition and grazing affected the bacterial community composition in the typical steppe. The co-occurrence networks revealed that the network complexity in bacterial communities of alpine meadows was higher than that of typical steppe. The rich bacterial community and high soil nutrients in alpine meadows might have led to diverse microbial functionality, which provided stability to the bacterial network. The low nutrients and water availability in typical steppe lead to a lower bacterial richness, making the bacterial community vulnerable to the changes due to grazing and N. Climate is a significant factor in shaping the grassland ecosystem and its bacterial community. The changes in the grassland’s ecosystem due to high grazing and N deposition would highly affect the distressed microbial communities in arid and semiarid regions. Further, in-depth studies are required to understand the fate of these vulnerable grasslands and design management strategies for their protection.
{"title":"High soil bacterial diversity increases the stability of the community under grazing and nitrogen","authors":"Muhammad Usman, Mengyuan Wang, Yang Liu, Lan Li, Xiumin Zhang, Tianhao Xiao, Fujiang Hou","doi":"10.1016/j.still.2024.106414","DOIUrl":"https://doi.org/10.1016/j.still.2024.106414","url":null,"abstract":"Grasslands are one of the major terrestrial ecosystems facing severe degradation due to climatic changes and anthropogenic activities. In northwest China, the Typical steppe and alpine meadows are the major grasslands with diverse ecosystems. These grasslands are facing degradation due to excessive livestock grazing and nitrogen (N) deposition that can alter the overall grassland ecosystem, along with the soil bacterial communities and their role in the ecosystem. The bacterial community is vital for the sustainability of grassland ecosystems as it plays a crucial role in decomposing the dead organic matter and nutrient cycling. This study conducted a grazing and N addition experiment in alpine meadows and typical steppe. The impact of short-term N application and grazing on both grasslands' soil, plant, and bacterial communities was explored. Alpine meadows had higher bacterial richness (OTUs>2000) and diversity (Shannon index>6) than the typical steppe (OTUs<900; Shannon index<5.5) due to changes in climate and ecosystem. The alpha diversity (Shannon index) of the bacterial community was observed to increase under low grazing without N addition while adding medium N (100 kg/ha) without grazing increased the diversity. The combination of medium N (100 kg/ha) addition and low grazing resulted in the highest bacterial diversity in both grasslands. In contrast, the combination of N and high grazing decreased bacterial richness and diversity. The N addition and grazing affected the bacterial community composition in the typical steppe. The co-occurrence networks revealed that the network complexity in bacterial communities of alpine meadows was higher than that of typical steppe. The rich bacterial community and high soil nutrients in alpine meadows might have led to diverse microbial functionality, which provided stability to the bacterial network. The low nutrients and water availability in typical steppe lead to a lower bacterial richness, making the bacterial community vulnerable to the changes due to grazing and N. Climate is a significant factor in shaping the grassland ecosystem and its bacterial community. The changes in the grassland’s ecosystem due to high grazing and N deposition would highly affect the distressed microbial communities in arid and semiarid regions. Further, in-depth studies are required to understand the fate of these vulnerable grasslands and design management strategies for their protection.","PeriodicalId":501007,"journal":{"name":"Soil and Tillage Research","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142821053","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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