D. Gelardi, Irfan Ainuddin, D. Rippner, J. Patiño, M. A. Abou Najm, S. Parikh
Abstract. Biochar is purported to provide agricultural benefits when added to the soil, through changes in saturated hydraulic conductivity (Ksat) and increased nutrient retention through chemical or physical means. Despite increased interest and investigation, there remains uncertainty regarding the ability of biochar to deliver these agronomic benefits due to differences in biochar feedstock, production method, production temperature, and soil texture. In this project, a suite of experiments was carried out using biochars of diverse feedstocks and production temperatures, in order to determine the biochar parameters which may optimize agricultural benefits. Sorption experiments were performed with seven distinct biochars to determine sorption efficiencies for ammonium and nitrate. Only one biochar effectively retained nitrate, while all biochars bound ammonium. The three biochars with the highest binding capacities (produced from almond shell at 500 and 800 ∘C (AS500 and AS800) and softwood at 500 ∘C (SW500)) were chosen for column experiments. Biochars were amended to a sandy loam and a silt loam at 0 % and 2 % (w/w), and Ksat was measured. Biochars reduced Ksat in both soils by 64 %–80 %, with the exception of AS800, which increased Ksat by 98 % in the silt loam. Breakthrough curves for nitrate and ammonium, as well as leachate nutrient concentration, were also measured in the sandy loam columns. All biochars significantly decreased the quantity of ammonium in the leachate, by 22 % to 78 %, and slowed its movement through the soil profile. Ammonium retention was linked to high cation exchange capacity and a high oxygen-to-carbon ratio, indicating that the primary control of ammonium retention in biochar-amended soils is the chemical affinity between biochar surfaces and ammonium. Biochars had little to no effect on the timing of nitrate release, and only SW500 decreased total quantity, by 27 % to 36 %. The ability of biochar to retain nitrate may be linked to high micropore specific surface area, suggesting a physical entrapment rather than a chemical binding. Together, this work sheds new light on the combined chemical and physical means by which biochar may alter soils to impact nutrient leaching and hydraulic conductivity for agricultural production.
{"title":"Biochar alters hydraulic conductivity and impacts nutrient leaching in two agricultural soils","authors":"D. Gelardi, Irfan Ainuddin, D. Rippner, J. Patiño, M. A. Abou Najm, S. Parikh","doi":"10.5194/soil-7-811-2021","DOIUrl":"https://doi.org/10.5194/soil-7-811-2021","url":null,"abstract":"Abstract. Biochar is purported to provide agricultural benefits when added\u0000to the soil, through changes in saturated hydraulic conductivity (Ksat)\u0000and increased nutrient retention through chemical or physical means. Despite\u0000increased interest and investigation, there remains uncertainty regarding\u0000the ability of biochar to deliver these agronomic benefits due to\u0000differences in biochar feedstock, production method, production temperature,\u0000and soil texture. In this project, a suite of experiments was carried out\u0000using biochars of diverse feedstocks and production temperatures, in order\u0000to determine the biochar parameters which may optimize agricultural\u0000benefits. Sorption experiments were performed with seven distinct biochars\u0000to determine sorption efficiencies for ammonium and nitrate. Only one\u0000biochar effectively retained nitrate, while all biochars bound ammonium. The\u0000three biochars with the highest binding capacities (produced from almond\u0000shell at 500 and 800 ∘C (AS500 and AS800) and softwood at 500 ∘C (SW500)) were chosen for column experiments. Biochars were\u0000amended to a sandy loam and a silt loam at 0 % and 2 % (w/w), and Ksat\u0000was measured. Biochars reduced Ksat in both soils by 64 %–80 %, with\u0000the exception of AS800, which increased Ksat by 98 % in the silt\u0000loam. Breakthrough curves for nitrate and ammonium, as well as leachate\u0000nutrient concentration, were also measured in the sandy loam columns. All\u0000biochars significantly decreased the quantity of ammonium in the leachate,\u0000by 22 % to 78 %, and slowed its movement through the soil profile. Ammonium\u0000retention was linked to high cation exchange capacity and a high oxygen-to-carbon ratio, indicating that the primary control of ammonium retention in\u0000biochar-amended soils is the chemical affinity between biochar surfaces and\u0000ammonium. Biochars had little to no effect on the timing of nitrate release,\u0000and only SW500 decreased total quantity, by 27 % to 36 %. The ability of\u0000biochar to retain nitrate may be linked to high micropore specific surface\u0000area, suggesting a physical entrapment rather than a chemical binding.\u0000Together, this work sheds new light on the combined chemical and physical\u0000means by which biochar may alter soils to impact nutrient leaching and\u0000hydraulic conductivity for agricultural production.\u0000","PeriodicalId":22015,"journal":{"name":"Soil Science","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85714334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. Soils and landscapes can show complex, non-linear evolution, especially under changing climate or land use. Soil-landscape evolution models (SLEMs) are increasingly equipped to simulate the development of soils and landscapes over long timescales under these changing drivers, but provide large data output that can be difficult to interpret and communicate. New tools are required to analyse and communicate large model output. In this work, I show how spatial and temporal trends in previously published model results can be summarized and conceptualized with evolutionary pathways, which are possible trajectories of the development of soil patterns. Simulated differences in rainfall and land use control progressive or regressive soil development and convergence or divergence of the soil pattern. These changes are illustrated with real-world examples of soil development and soil complexity. The use of evolutionary pathways for analysing the results of SLEMs is not limited to the examples in this paper, but they can be used on a wide variety of soil properties, soil pattern statistics and models. With that, evolutionary pathways provide a promising tool to analyse and communicate soil model output, not only for studying past changes in soils, but also for evaluating future spatial and temporal effects of soil management practices in the context of sustainability.
{"title":"Evolutionary pathways in soil-landscape evolution models","authors":"W. M. van der Meij","doi":"10.5194/soil-2021-133","DOIUrl":"https://doi.org/10.5194/soil-2021-133","url":null,"abstract":"Abstract. Soils and landscapes can show complex, non-linear evolution, especially under changing climate or land use. Soil-landscape evolution models (SLEMs) are increasingly equipped to simulate the development of soils and landscapes over long timescales under these changing drivers, but provide large data output that can be difficult to interpret and communicate. New tools are required to analyse and communicate large model output. In this work, I show how spatial and temporal trends in previously published model results can be summarized and conceptualized with evolutionary pathways, which are possible trajectories of the development of soil patterns. Simulated differences in rainfall and land use control progressive or regressive soil development and convergence or divergence of the soil pattern. These changes are illustrated with real-world examples of soil development and soil complexity. The use of evolutionary pathways for analysing the results of SLEMs is not limited to the examples in this paper, but they can be used on a wide variety of soil properties, soil pattern statistics and models. With that, evolutionary pathways provide a promising tool to analyse and communicate soil model output, not only for studying past changes in soils, but also for evaluating future spatial and temporal effects of soil management practices in the context of sustainability.\u0000","PeriodicalId":22015,"journal":{"name":"Soil Science","volume":"15 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72373611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-11-16DOI: 10.5194/soil-2021-124-supplement
N. Gentsch, Diana Heuermann, J. Boy, Steffen Schierding, N. von Wirén, Dörte Schweneker, U. Feuerstein, G. Guggenberger
Abstract. Improving N cycling in agroecosystems is one of the key challenges in reducing the environmental footprint of agriculture. Further, uncertainty in precipitation makes crop water management relevant in regions where it has not been necessary thus far. Here, we focus on the potential of winter-killed catch crops to reduce N leaching losses from N mineralization over the winter and soil water management. We compared four single catch crops (white mustard, phacelia, Egyptian clover and bristle oat) and a fallow treatment with two catch crop mixtures with 4 and 12 plant species (Mix4 and Mix12). High-resolution soil mineral N (Nmin) monitoring in combination with modelling of spatiotemporal dynamics served to assess N cycling under winter-killed catch crops, while soil water was continuously monitored in the rooting zone. Catch crops depleted the residual Nmin pools by between 40 and 72 % compared to the fallow. The amount of residual N uptake was lowest for clover and not significantly different among the other catch crops. Catch crops that produce high N litter materials, such as clover and mustard leaves, showed an early N mineralization flush immediately after their termination and the highest leaching losses from litter mineralization over the winter. Except for clover, all catch crops showed Nmin values between 18 and 92 % higher on the sowing date of the following maize crop. However, only Mix12 was statistically significant. Catch crops depleted the soil water storage in the rooting zone during their growth in autumn and early winter, but preserved water later on when their residues cover the ground. The shallow incorporation of catch crop residues increased water storage capacity during the cropping season of the main crop even under drought conditions. Hence, catch cropping is not just a simple plant cover during the winter but improved the growth conditions for the following crop at decreased N losses. Mixtures have been shown to compensate for the weaknesses of individual catch crop species in terms of nutrient capture, mineralization and transfer to the following main crop as well as for soil water management. Detailed knowledge about plant performance during growth and litter mineralization patterns is necessary to make optimal use of their full potential.
{"title":"Supplementary material to \"Soil nitrogen and water management by winter-killed catch crops\"","authors":"N. Gentsch, Diana Heuermann, J. Boy, Steffen Schierding, N. von Wirén, Dörte Schweneker, U. Feuerstein, G. Guggenberger","doi":"10.5194/soil-2021-124-supplement","DOIUrl":"https://doi.org/10.5194/soil-2021-124-supplement","url":null,"abstract":"Abstract. Improving N cycling in agroecosystems is one of the key challenges in reducing the environmental footprint of agriculture. Further, uncertainty in precipitation makes crop water management relevant in regions where it has not been necessary thus far. Here, we focus on the potential of winter-killed catch crops to reduce N leaching losses from N mineralization over the winter and soil water management. We compared four single catch crops (white mustard, phacelia, Egyptian clover and bristle oat) and a fallow treatment with two catch crop mixtures with 4 and 12 plant species (Mix4 and Mix12). High-resolution soil mineral N (Nmin) monitoring in combination with modelling of spatiotemporal dynamics served to assess N cycling under winter-killed catch crops, while soil water was continuously monitored in the rooting zone. Catch crops depleted the residual Nmin pools by between 40 and 72 % compared to the fallow. The amount of residual N uptake was lowest for clover and not significantly different among the other catch crops. Catch crops that produce high N litter materials, such as clover and mustard leaves, showed an early N mineralization flush immediately after their termination and the highest leaching losses from litter mineralization over the winter. Except for clover, all catch crops showed Nmin values between 18 and 92 % higher on the sowing date of the following maize crop. However, only Mix12 was statistically significant. Catch crops depleted the soil water storage in the rooting zone during their growth in autumn and early winter, but preserved water later on when their residues cover the ground. The shallow incorporation of catch crop residues increased water storage capacity during the cropping season of the main crop even under drought conditions. Hence, catch cropping is not just a simple plant cover during the winter but improved the growth conditions for the following crop at decreased N losses. Mixtures have been shown to compensate for the weaknesses of individual catch crop species in terms of nutrient capture, mineralization and transfer to the following main crop as well as for soil water management. Detailed knowledge about plant performance during growth and litter mineralization patterns is necessary to make optimal use of their full potential.\u0000","PeriodicalId":22015,"journal":{"name":"Soil Science","volume":"2007 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86213197","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. The nitrogen-15 (15N) natural abundance composition (δ15N) in soils or plants is a useful tool to indicate the openness of ecosystem N cycling. This study aimed to evaluate the influence of the experimental warming on soil and plant δ15N. We applied a global meta-analysis method to synthesize 79 and 76 paired observations of soil and plant δ15N from 20 published studies, respectively. Results showed that the mean effect sizes of the soil and plant δ15N under experimental warming were −0.524 (95 % CI (confidence interval): −0.987 to −0.162) and 0.189 (95 % CI: −0.210 to 0.569), respectively. This indicated that soil δ15N had negative response to warming at the global scale, where warming had no significant effect on plant δ15N. Experimental warming significantly (p<0.05) decreased soil δ15N in Alkali and medium-textured soils, in grassland/meadow, under air warming, for a 4–10-year warming period and for an increase of >3 ∘C in temperature, whereas it significantly (p<0.05) increased soil δ15N in neutral and fine-textured soils and for an increase of 1.5–3 ∘C in temperature. Plant δ15N significantly (p<0.05) increased with increasing temperature in neutral and fine-textured soils and significantly (p<0.05) decreased in alkali soil. Latitude did not affect the warming effects on both soil and plant δ15N. However, the warming effect on soil δ15N was positively controlled by the mean annual temperature, which is related to the fact that the higher temperature can strengthen the activity of soil microbes. The effect of warming on plant δ15N had weaker relationships with environmental variables compared with that on soil δ15N. This implied that soil δ15N was more effective than plant δ15N in indicating the openness of global ecosystem N cycling.
{"title":"Soil δ15N is a better indicator of ecosystem nitrogen cycling than plant δ15N: A global meta-analysis","authors":"K. Liao, X. Lai, Q. Zhu","doi":"10.5194/soil-7-733-2021","DOIUrl":"https://doi.org/10.5194/soil-7-733-2021","url":null,"abstract":"Abstract. The nitrogen-15 (15N) natural abundance composition\u0000(δ15N) in soils or plants is a useful tool to indicate the\u0000openness of ecosystem N cycling. This study aimed to evaluate the\u0000influence of the experimental warming on soil and plant δ15N.\u0000We applied a global meta-analysis method to synthesize 79 and 76 paired\u0000observations of soil and plant δ15N from 20 published studies,\u0000respectively. Results showed that the mean effect sizes of the soil and\u0000plant δ15N under experimental warming were −0.524 (95 % CI (confidence interval):\u0000−0.987 to −0.162) and 0.189 (95 % CI: −0.210 to 0.569), respectively. This\u0000indicated that soil δ15N had negative response to warming at\u0000the global scale, where warming had no significant effect on plant δ15N. Experimental warming significantly (p<0.05) decreased\u0000soil δ15N in Alkali and medium-textured soils, in\u0000grassland/meadow, under air warming, for a 4–10-year warming period and for an\u0000increase of >3 ∘C in temperature, whereas it significantly\u0000(p<0.05) increased soil δ15N in neutral and\u0000fine-textured soils and for an increase of 1.5–3 ∘C in temperature.\u0000Plant δ15N significantly (p<0.05) increased with\u0000increasing temperature in neutral and fine-textured soils and significantly\u0000(p<0.05) decreased in alkali soil. Latitude did not affect the\u0000warming effects on both soil and plant δ15N. However, the\u0000warming effect on soil δ15N was positively controlled by the\u0000mean annual temperature, which is related to the fact that the higher\u0000temperature can strengthen the activity of soil microbes. The effect of\u0000warming on plant δ15N had weaker relationships with\u0000environmental variables compared with that on soil δ15N. This\u0000implied that soil δ15N was more effective than plant δ15N in indicating the openness of global ecosystem N cycling.\u0000","PeriodicalId":22015,"journal":{"name":"Soil Science","volume":"70 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81801273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Philipp Baumann, Juhwan Lee, E. Frossard, Laurie Paule Schönholzer, L. Diby, V. K. Hgaza, D. I. Kiba, A. Sila, Keith Sheperd, J. Six
Abstract. Low soil fertility is challenging the sustainable production of yam and other staple crops in the yam belt of West Africa. Quantitative soil measures are needed to assess soil fertility decline and to improve crop nutrient supply in the region. We developed and tested a mid-infrared (mid-IR) soil spectral library to enable timely and cost-efficient assessments of soil properties. Our collection included 80 soil samples from four landscapes (10 km × 10 km) and 20 fields per landscape across a gradient from humid forest to savannah and 14 additional samples from one landscape that had been sampled within the Land Health Degradation Framework. We derived partial least squares regression models to spectrally estimate soil properties. The models produced accurate cross-validated estimates of total carbon, total nitrogen, total sulfur, total iron, total aluminum, total potassium, total calcium, exchangeable calcium, effective cation exchange capacity, and diethylenetriaminepentaacetic acid (DTPA)-extractable iron and clay content (R2>0.75). The estimates of total zinc, pH, exchangeable magnesium, bioavailable copper, and manganese were less predictable (R2>0.50). Our results confirm that mid-IR spectroscopy is a reliable and quick method to assess the regional-level variation of most soil properties, especially the ones closely associated with soil organic matter. Although the relatively small mid-IR library shows satisfactory performance, we expect that frequent but small model updates will be needed to adapt the library to the variation of soil quality within individual fields in the regions and their temporal fluctuations.
{"title":"Estimation of soil properties with mid-infrared soil spectroscopy across yam production landscapes in West Africa","authors":"Philipp Baumann, Juhwan Lee, E. Frossard, Laurie Paule Schönholzer, L. Diby, V. K. Hgaza, D. I. Kiba, A. Sila, Keith Sheperd, J. Six","doi":"10.5194/soil-7-717-2021","DOIUrl":"https://doi.org/10.5194/soil-7-717-2021","url":null,"abstract":"Abstract. Low soil fertility is challenging the sustainable production of yam and other staple crops in the yam belt of West Africa. Quantitative soil measures are needed to assess soil fertility decline and to improve crop nutrient supply in the region. We developed and tested a mid-infrared (mid-IR) soil spectral library to enable timely and cost-efficient assessments of soil properties. Our collection included 80 soil samples from four landscapes (10 km × 10 km) and 20 fields per landscape across a gradient from humid forest to savannah and 14 additional samples from one landscape that had been sampled within the Land Health Degradation Framework. We derived partial least squares regression models to spectrally estimate soil properties. The models produced accurate cross-validated estimates of total carbon, total nitrogen, total sulfur, total iron, total aluminum, total potassium, total calcium, exchangeable calcium, effective cation exchange capacity, and diethylenetriaminepentaacetic acid (DTPA)-extractable iron and clay content (R2>0.75). The estimates of total zinc, pH, exchangeable magnesium, bioavailable copper, and manganese were less predictable (R2>0.50). Our results confirm that mid-IR spectroscopy is a reliable and quick method to assess the regional-level variation of most soil properties, especially the ones closely associated with soil organic matter. Although the relatively small mid-IR library shows satisfactory performance, we expect that frequent but small model updates will be needed to adapt the library to the variation of soil quality within individual fields in the regions and their temporal fluctuations.\u0000","PeriodicalId":22015,"journal":{"name":"Soil Science","volume":"40 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83581364","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Laura Summerauer, Philipp Baumann, L. Ramirez-Lopez, M. Barthel, M. Bauters, Benjamin Bukombe, M. Reichenbach, P. Boeckx, E. Kearsley, K. Van Oost, B. Vanlauwe, Dieudonné Chiragaga, A. B. Heri‐Kazi, P. Moonen, A. Sila, K. Shepherd, Basile Bazirake Mujinya, E. Van Ranst, G. Baert, S. Doetterl, J. Six
Abstract. Information on soil properties is crucial for soil preservation, the improvement of food security, and the provision of ecosystem services. In particular, for the African continent, spatially explicit information on soils and their ability to sustain these services is still scarce. To address data gaps, infrared spectroscopy has achieved great success as a cost-effective solution to quantify soil properties in recent decades. Here, we present a mid-infrared soil spectral library (SSL) for central Africa (CSSL) that can predict key soil properties, allowing for future soil estimates with a minimal need for expensive and time-consuming wet chemistry. Currently, our CSSL contains over 1800 soil samples from 10 distinct geoclimatic regions throughout the Congo Basin and along the Albertine Rift. For the analysis, we selected six regions from the CSSL, for which we built predictive models for total carbon (TC) and total nitrogen (TN) using an existing continental SSL (African Soil Information Service, AfSIS SSL; n=1902) that does not include central African soils. Using memory-based learning (MBL), we explored three different strategies at decreasing degrees of geographic extrapolation, using models built with (1) the AfSIS SSL only, (2) AfSIS SSL combined with the five remaining central African regions, and (3) a combination of AfSIS SSL, the remaining five regions, and selected samples from the target region (spiking). For this last strategy we introduce a method for spiking MBL models. We found that when using the AfSIS SSL only to predict the six central African regions, the root mean square error of the predictions (RMSEpred) was between 3.85–8.74 and 0.40–1.66 g kg−1 for TC and TN, respectively. The ratio of performance to the interquartile distance (RPIQpred) ranged between 0.96–3.95 for TC and 0.59–2.86 for TN. While the effect of the second strategy compared to the first strategy was mixed, the third strategy, spiking with samples from the target regions, could clearly reduce the RMSEpred to 3.19–7.32 g kg−1 for TC and 0.24–0.89 g kg−1 for TN. RPIQpred values were increased to ranges of 1.43–5.48 and 1.62–4.45 for TC and TN, respectively. In general, predicted TC and TN for soils of each of the six regions were accurate; the effect of spiking and avoiding geographical extrapolation was noticeably large. We conclude that our CSSL adds valuable soil diversity that can improve predictions for the Congo Basin region compared to using the continental AfSIS SSL alone; thus, analyses of other soils in central Africa will be able to profit from a more diverse spectral feature space. Given these promising results, the library comprises an important tool to facilitate economical soil analyses and predict soil properties in an understudied yet critical region of Africa. Our SSL is openly available for application and for enlargement with more spectral and reference data to further improve soil diagnostic accuracy and cost-effectiveness.
摘要土壤性质信息对土壤保持、改善粮食安全和提供生态系统服务至关重要。特别是在非洲大陆，关于土壤及其维持这些服务能力的空间明确信息仍然很少。为了解决数据缺口，近几十年来，红外光谱作为一种具有成本效益的土壤特性量化解决方案取得了巨大成功。在这里，我们提出了中非(CSSL)的中红外土壤光谱库(SSL)，它可以预测关键的土壤特性，允许未来的土壤估计，而不需要昂贵和耗时的湿化学。目前，我们的csl包含来自刚果盆地和艾伯丁裂谷沿线10个不同地理气候区域的1800多个土壤样本。为了进行分析，我们从CSSL中选择了6个区域，并使用现有的大陆SSL(非洲土壤信息服务，AfSIS SSL;n=1902)，不包括中非土壤。使用基于记忆的学习(MBL)，我们在降低地理外推程度的情况下探索了三种不同的策略，使用以下模型:(1)仅使用AfSIS SSL， (2) AfSIS SSL与剩余五个中非地区相结合，以及(3)AfSIS SSL与剩余五个地区的组合，并从目标地区(峰值)中选择样本。对于最后一种策略，我们引入了一种对MBL模型进行尖峰处理的方法。我们发现，当使用AfSIS SSL仅预测6个中非地区时，预测的均方根误差(RMSEpred)分别在3.85-8.74和0.40-1.66 g kg - 1之间。四分位数距离(RPIQpred)在0.96-3.95之间，TN在0.59-2.86之间。与第一种策略相比，第二种策略的效果并不明显，而第三种策略，即从目标区域采集样本，可以明显降低TC的RMSEpred至3.19-7.32 g kg - 1, TN的RPIQpred值为0.24-0.89 g kg - 1, TC和TN的RPIQpred值分别提高至1.43-5.48和1.62-4.45。总体而言，6个区域土壤的总热、全氮预测值较准确;峰值和避免地理外推的效果明显很大。我们的结论是，与单独使用大陆AfSIS SSL相比，我们的CSSL增加了宝贵的土壤多样性，可以改善对刚果盆地地区的预测;因此，对中非其他土壤的分析将能够从更多样化的光谱特征空间中获益。鉴于这些有希望的结果，该库包括一个重要的工具，以促进经济土壤分析和预测土壤性质在一个研究不足但关键的非洲地区。我们的SSL是开放的应用程序和扩大更多的光谱和参考数据，以进一步提高土壤诊断的准确性和成本效益。
{"title":"The central African soil spectral library: a new soil infrared repository and a geographical prediction analysis","authors":"Laura Summerauer, Philipp Baumann, L. Ramirez-Lopez, M. Barthel, M. Bauters, Benjamin Bukombe, M. Reichenbach, P. Boeckx, E. Kearsley, K. Van Oost, B. Vanlauwe, Dieudonné Chiragaga, A. B. Heri‐Kazi, P. Moonen, A. Sila, K. Shepherd, Basile Bazirake Mujinya, E. Van Ranst, G. Baert, S. Doetterl, J. Six","doi":"10.5194/soil-7-693-2021","DOIUrl":"https://doi.org/10.5194/soil-7-693-2021","url":null,"abstract":"Abstract. Information on soil properties is crucial for soil preservation, the improvement of food security, and the provision of ecosystem services. In particular, for the African continent, spatially explicit information on soils and their ability to sustain these services is still scarce. To address data gaps, infrared spectroscopy has achieved great success as a cost-effective solution to quantify soil properties in recent decades. Here, we present a mid-infrared soil spectral library (SSL) for central Africa (CSSL) that can predict key soil properties, allowing for future soil estimates with a minimal need for expensive and time-consuming wet chemistry. Currently, our CSSL contains over 1800 soil samples from 10 distinct geoclimatic regions throughout the Congo Basin and along the Albertine Rift. For the analysis, we selected six regions from the CSSL, for which we built predictive models for total carbon (TC) and total nitrogen (TN) using an existing continental SSL (African Soil Information Service, AfSIS SSL; n=1902) that does not include central African soils. Using memory-based learning (MBL), we explored three different strategies at decreasing degrees of geographic extrapolation, using models built with (1) the AfSIS SSL only, (2) AfSIS SSL combined with the five remaining central African regions, and (3) a combination of AfSIS SSL, the remaining five regions, and selected samples from the target region (spiking). For this last strategy we introduce a method for spiking MBL models. We found that when using the AfSIS SSL only to predict the six central African regions, the root mean square error of the predictions (RMSEpred) was between 3.85–8.74 and 0.40–1.66 g kg−1 for TC and TN, respectively. The ratio of performance to the interquartile distance (RPIQpred) ranged between 0.96–3.95 for TC and 0.59–2.86 for TN. While the effect of the second strategy compared to the first strategy was mixed, the third strategy, spiking with samples from the target regions, could clearly reduce the RMSEpred to 3.19–7.32 g kg−1 for TC and 0.24–0.89 g kg−1 for TN. RPIQpred values were increased to ranges of 1.43–5.48 and 1.62–4.45 for TC and TN, respectively. In general, predicted TC and TN for soils of each of the six regions were accurate; the effect of spiking and avoiding geographical extrapolation was noticeably large. We conclude that our CSSL adds valuable soil diversity that can improve predictions for the Congo Basin region compared to using the continental AfSIS SSL alone; thus, analyses of other soils in central Africa will be able to profit from a more diverse spectral feature space. Given these promising results, the library comprises an important tool to facilitate economical soil analyses and predict soil properties in an understudied yet critical region of Africa. Our SSL is openly available for application and for enlargement with more spectral and reference data to further improve soil diagnostic accuracy and cost-effectiveness.\u0000","PeriodicalId":22015,"journal":{"name":"Soil Science","volume":"28 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85080047","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yifeng Zhang, S. Dou, B. S. Ndzelu, Rui-ping Ma, Dandan Zhang, Xiaowei Zhang, S. Ye, Hongrui Wang
Abstract. In our previous studies, we filtered out fungus (Trichoderma reesei) to have the best ability to transform corn straw into a humic acid-like substance through laboratory incubation experiments. In order to further verify our former findings, we set up a 360 day-field experiment that included three treatments applied under equal C mass: (i) corn straw returned to the field (CS), (ii) fermented corn straw treated with Trichoderma reesei returned to the field (FCS-T), and (iii) blank control treatment (CK). Soil organic carbon (SOC), soil labile organic C components, soil humus composition, and the management levels of SOC pools under the three treatments were analyzed and compared. The results showed that the SOC content of CS and FCS-T treatments increased by 12.71 % and 18.81 %, respectively, compared with CK at 360 d. The humic acid carbon (HA-C) content of the FCS-T treatment was 0.77 g/kg higher than in the CS treatment. Application of FCS-T appeared to promote the significant increase of SOC, carbon pool activity index (CPAI) and carbon pool management index (CPMI) through accumulation of HA-C, humin carbon (HM-C), and easily oxidizable organic carbon (EOC) contents. Application of fermented corn straw treated with Trichoderma reesei (FCS-T) is more valuable and conducive to increasing soil EOC and humus C content than direct application of corn straw.
{"title":"Effects of returning corn straw and fermented corn straw to fields on the soil organic carbon pools and humus composition","authors":"Yifeng Zhang, S. Dou, B. S. Ndzelu, Rui-ping Ma, Dandan Zhang, Xiaowei Zhang, S. Ye, Hongrui Wang","doi":"10.5194/soil-2021-105","DOIUrl":"https://doi.org/10.5194/soil-2021-105","url":null,"abstract":"Abstract. In our previous studies, we filtered out fungus (Trichoderma reesei) to have the best ability to transform corn straw into a humic acid-like substance through laboratory incubation experiments. In order to further verify our former findings, we set up a 360 day-field experiment that included three treatments applied under equal C mass: (i) corn straw returned to the field (CS), (ii) fermented corn straw treated with Trichoderma reesei returned to the field (FCS-T), and (iii) blank control treatment (CK). Soil organic carbon (SOC), soil labile organic C components, soil humus composition, and the management levels of SOC pools under the three treatments were analyzed and compared. The results showed that the SOC content of CS and FCS-T treatments increased by 12.71 % and 18.81 %, respectively, compared with CK at 360 d. The humic acid carbon (HA-C) content of the FCS-T treatment was 0.77 g/kg higher than in the CS treatment. Application of FCS-T appeared to promote the significant increase of SOC, carbon pool activity index (CPAI) and carbon pool management index (CPMI) through accumulation of HA-C, humin carbon (HM-C), and easily oxidizable organic carbon (EOC) contents. Application of fermented corn straw treated with Trichoderma reesei (FCS-T) is more valuable and conducive to increasing soil EOC and humus C content than direct application of corn straw.\u0000","PeriodicalId":22015,"journal":{"name":"Soil Science","volume":"91 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72812881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Anne Daebeler, Eva Petrová, E. Kinz, Susanne Grausenburger, H. Berthold, T. Sandén, Roey Angel
Abstract. Including information about soil microbial communities into global decomposition models is critical for predicting and understanding how ecosystem functions may shift in response to global change. Here we combined a standardised litter bag method for estimating decomposition rates, Tea Bag Index (TBI), with high-throughput sequencing of the microbial communities colonising the plant litter in the bags. Together with students of the Federal College for Viticulture and Fruit Growing, Klosterneuburg, Austria, acting as citizen scientists, we used this approach to investigate the diversity of prokaryotes and fungi colonising recalcitrant (rooibos) and labile (green tea) plant litter buried in three different soil types and during four seasons with the aim of (i) comparing litter decomposition [decomposition rates (k) and stabilisation factors (S)] between soil types and seasons, (ii) comparing the microbial communities colonising labile and recalcitrant plant litter between soil types and seasons (iii) correlating microbial diversity and taxa relative abundance patterns of colonisers with litter decomposition rates (k)and stabilisation factors (S). Stabilisation factor (S), but not decomposition rate (k), correlated with the season and was significantly lower in the summer. This finding highlights the necessity to include colder seasons in the efforts of determining decomposition dynamics in order to quantify nutrient cycling in soils accurately. With our approach, we further showed selective colonisation of plant litter by fungal and prokaryotic taxa sourced from the soil. The community structures of these microbial colonisers differed most profoundly between summer and winter, and rooibos litter was generally a stronger selector than green tea litter. Moreover, this study indicates an equal, if not higher, importance of fungal versus prokaryotic degraders for recalcitrant and labile plant litter decomposition. Our results collectively demonstrate the importance of analysing decomposition dynamics over multiple seasons and isolating the effect of the active component of the microbial community.
摘要将有关土壤微生物群落的信息纳入全球分解模型对于预测和理解生态系统功能如何响应全球变化而发生变化至关重要。在这里，我们结合了一个标准化的凋落物袋方法来估计分解率，茶袋指数(Tea bag Index, TBI)，以及在袋中定植的植物凋落物的微生物群落的高通量测序。与奥地利克洛斯特纽堡联邦葡萄栽培和水果种植学院的学生一起，作为公民科学家，我们使用这种方法调查了埋在三种不同土壤类型和四季中的顽固(路易波士)和不稳定(绿茶)植物凋落物的原核生物和真菌的多样性，目的是(i)比较土壤类型和季节之间凋落物的分解[分解率(k)和稳定因子(S)];(ii)比较不同土壤类型和季节下易变和难变凋落物的定殖微生物群落;(iii)将微生物多样性和定殖菌类群相对丰度模式与凋落物分解率(k)和稳定因子(S)相关联。稳定因子(S)与季节相关，但与分解率(k)无关，在夏季显著降低。这一发现强调了在确定分解动力学的努力中包括寒冷季节的必要性，以便准确地量化土壤中的养分循环。通过我们的方法，我们进一步证明了来自土壤的真菌和原核分类群对植物凋落物的选择性定植。这些微生物的群落结构在夏季和冬季之间差异最大，路易波士凋落物通常比绿茶凋落物具有更强的选择力。此外，该研究表明，真菌降解物与原核降解物对于顽固和不稳定的植物凋落物的分解具有同等的重要性。我们的结果共同证明了在多个季节分析分解动态和分离微生物群落活性成分的影响的重要性。
{"title":"Pairing litter decomposition with microbial community structures using the Tea Bag Index (TBI)","authors":"Anne Daebeler, Eva Petrová, E. Kinz, Susanne Grausenburger, H. Berthold, T. Sandén, Roey Angel","doi":"10.5194/soil-2021-110","DOIUrl":"https://doi.org/10.5194/soil-2021-110","url":null,"abstract":"Abstract. Including information about soil microbial communities into global decomposition models is critical for predicting and understanding how ecosystem functions may shift in response to global change. Here we combined a standardised litter bag method for estimating decomposition rates, Tea Bag Index (TBI), with high-throughput sequencing of the microbial communities colonising the plant litter in the bags. Together with students of the Federal College for Viticulture and Fruit Growing, Klosterneuburg, Austria, acting as citizen scientists, we used this approach to investigate the diversity of prokaryotes and fungi colonising recalcitrant (rooibos) and labile (green tea) plant litter buried in three different soil types and during four seasons with the aim of (i) comparing litter decomposition [decomposition rates (k) and stabilisation factors (S)] between soil types and seasons, (ii) comparing the microbial communities colonising labile and recalcitrant plant litter between soil types and seasons (iii) correlating microbial diversity and taxa relative abundance patterns of colonisers with litter decomposition rates (k)and stabilisation factors (S). Stabilisation factor (S), but not decomposition rate (k), correlated with the season and was significantly lower in the summer. This finding highlights the necessity to include colder seasons in the efforts of determining decomposition dynamics in order to quantify nutrient cycling in soils accurately. With our approach, we further showed selective colonisation of plant litter by fungal and prokaryotic taxa sourced from the soil. The community structures of these microbial colonisers differed most profoundly between summer and winter, and rooibos litter was generally a stronger selector than green tea litter. Moreover, this study indicates an equal, if not higher, importance of fungal versus prokaryotic degraders for recalcitrant and labile plant litter decomposition. Our results collectively demonstrate the importance of analysing decomposition dynamics over multiple seasons and isolating the effect of the active component of the microbial community.","PeriodicalId":22015,"journal":{"name":"Soil Science","volume":"117 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89857191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Solène Quéro, C. Hatté, S. Cornu, A. Duvivier, Nithavong Cam, Floriane Jamoteau, D. Borschneck, I. Basile-Doelsch
Abstract. Few studies have focused on arenosols with regard to soil carbon dynamics despite the fact that they represent 8 % of the world's soils and are present in key areas where food security is a major issue (e.g. in Sahelian regions). As for other soil types, land use changes (from forest or grassland to cropland) lead to a loss of substantial soil organic carbon (SOC) stocks and have a lasting impact on the SOC turnover. Here we quantified long-term variations in carbon stocks and their dynamics in a 80 cm deep Mediterranean Arenosol that had undergone a land use change from forest to vineyard over more than 100 years ago. Paired-sites of adjacent plots combined with carbon and nitrogen quantification and natural radiocarbon (14C) abundance analyses revealed a stock of 50 GtC ha−1 in the 0–30 cm forest soil horizon, which was reduced to 3 GtC ha−1 after long-term grape cultivation. TOC in vineyard was dramatically low, with around 1 gC kg−1 and no vertical gradient as a function of depth. 14C showed that deep ploughing (50 cm) in vineyard plot redistributed the remaining carbon both vertically and horizontally. This remaining carbon was old carbon (compared to that of the forest), which had a C : N ratio characteristic of microbial OM and was probably stabilized within organomineral associations. Despite the drastic degradation of the OM pool in this Arenosol, this soil would have a high carbon storage potential if agricultural practices, such as grassing or organic amendment applications, were to be implemented within the framework of the 4 per 1000 Initiative.
摘要很少有研究集中在土壤碳动态方面，尽管它们占世界土壤的8%，并且存在于粮食安全是一个主要问题的关键地区(例如在萨赫勒地区)。对于其他土壤类型，土地利用变化(从森林或草地到农田)导致大量土壤有机碳(SOC)储量的损失，并对SOC周转产生持久影响。在这里，我们量化了80厘米深的地中海沙漠中碳储量的长期变化及其动态，该沙漠在100多年前经历了从森林到葡萄园的土地利用变化。结合碳氮定量和天然放射性碳(14C)丰度分析，对相邻样地进行配对分析，发现0-30 cm森林土壤层的储量为50 GtC ha - 1，长期种植葡萄后减少到3 GtC ha - 1。葡萄园的TOC非常低，约为1 gC kg - 1，并且没有垂直梯度作为深度的函数。14C表明，深耕(50 cm)对剩余碳进行了纵向和横向再分配。剩余碳为老碳(与森林相比)，具有微生物有机质的C: N比值特征，可能稳定在有机组合中。尽管阿罗诺索尔的有机质库急剧退化，但如果在每1000人4倡议的框架内实施农业实践，如种草或有机改进剂的应用，这片土壤将具有很高的碳储存潜力。
{"title":"Dynamics of carbon loss from an arenosol by a forest/vineyard land use change on a centennial scale","authors":"Solène Quéro, C. Hatté, S. Cornu, A. Duvivier, Nithavong Cam, Floriane Jamoteau, D. Borschneck, I. Basile-Doelsch","doi":"10.5194/soil-2021-115","DOIUrl":"https://doi.org/10.5194/soil-2021-115","url":null,"abstract":"Abstract. Few studies have focused on arenosols with regard to soil carbon dynamics despite the fact that they represent 8 % of the world's soils and are present in key areas where food security is a major issue (e.g. in Sahelian regions). As for other soil types, land use changes (from forest or grassland to cropland) lead to a loss of substantial soil organic carbon (SOC) stocks and have a lasting impact on the SOC turnover. Here we quantified long-term variations in carbon stocks and their dynamics in a 80 cm deep Mediterranean Arenosol that had undergone a land use change from forest to vineyard over more than 100 years ago. Paired-sites of adjacent plots combined with carbon and nitrogen quantification and natural radiocarbon (14C) abundance analyses revealed a stock of 50 GtC ha−1 in the 0–30 cm forest soil horizon, which was reduced to 3 GtC ha−1 after long-term grape cultivation. TOC in vineyard was dramatically low, with around 1 gC kg−1 and no vertical gradient as a function of depth. 14C showed that deep ploughing (50 cm) in vineyard plot redistributed the remaining carbon both vertically and horizontally. This remaining carbon was old carbon (compared to that of the forest), which had a C : N ratio characteristic of microbial OM and was probably stabilized within organomineral associations. Despite the drastic degradation of the OM pool in this Arenosol, this soil would have a high carbon storage potential if agricultural practices, such as grassing or organic amendment applications, were to be implemented within the framework of the 4 per 1000 Initiative.\u0000","PeriodicalId":22015,"journal":{"name":"Soil Science","volume":"45 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84056747","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. Conservation agriculture (CA) relies on two key practices to improve agricultural sustainability—reduced tillage and cover crop usage. Despite known soil physics benefits (reduced soil compaction and strength, enhanced soil porosity and permeability), inconsistent reports on short-term CA results have limited its adoption in European agroecosystems. To elucidate the short-term effects, a three-year experiment in the low-lying Venetian plain (Northern Italy) was undertaken. Bulk density, penetration resistance, and soil hydraulic measures were used to evaluate results obtained by combining three tillage intensities (conventional tillage (CT), minimum tillage (MT), no tillage (NT)) with three winter soil coverages (bare soil (BS), tillage radish cover crop (TR), winter wheat cover crop (WW)). Among the tillage methods and soil layers, CT, on average, reduced BD (1.42 g cm−3) and PR (1.64 MPa) better in the 0–30 cm tilled layer. Other treatments yielded higher values (+4 % BD and +3.1 % PR) in the same layer. Across the soil profile, reduced tillage coupled with WW improved soil physics even below the tilled layer, as evidenced by root growth-limiting threshold declines (−11 % in BD values > 1.55 g cm−3 and −7 % in PR values > 2.5 MPa). Soil hydraulic measures confirmed this positive behaviour; NT combined with either BS or WW produced a soil saturated conductivity of 2.12 × 10−4 m s−1 (four-fold that of all other treatments). Likewise, sorptivity increased in NT combined with BS versus other treatments (3.64 × 10−4 m s−1 vs an all-treatment average of 7.98 × 10−5 m s−1). Our results suggest that despite some measure declines due to reduced tillage, the strategy enhances soil physics. In the short term, cover crop WW moderately increased physical soil parameters, whereas TR had negligible effects. This study demonstrates that CA effects require monitoring several soil physical parameters.
摘要保护性农业(CA)依靠两种关键做法来提高农业可持续性:减少耕作和覆盖作物的利用。尽管已知的土壤物理效益(减少土壤压实和强度，提高土壤孔隙度和渗透性)，但关于短期CA结果的不一致报告限制了其在欧洲农业生态系统中的采用。为了阐明短期效果，在低洼的威尼斯平原(意大利北部)进行了为期三年的实验。利用容重、抗侵透性和土壤水力指标对3种耕作强度(常规耕作(CT)、最少耕作(MT)、免耕(NT))和3种冬季土壤覆盖(裸土(BS)、耕作萝卜覆盖作物(TR)、冬小麦覆盖作物(WW))相结合的结果进行评价。在不同的耕作方式和土层中，CT在0 ~ 30 cm的耕作层平均降低了1.42 g cm−3的BD和1.64 MPa的PR。其他处理在同一层中获得更高的值(+ 4% BD和+ 3.1% PR)。在整个土壤剖面上，减少耕作加上WW改善了土壤物理特性，甚至在耕作层以下，根系生长限制阈值下降(BD值> 1.55 g cm - 3时为- 11%，PR值> 2.5 MPa时为- 7%)。土壤水力测量证实了这种积极的行为;NT与BS或WW结合，土壤饱和电导率为2.12 × 10−4 m s−1(是所有其他处理的4倍)。同样，与其他处理相比，NT联合BS的吸附性增加(3.64 × 10−4 m s−1，而所有处理的平均值为7.98 × 10−5 m s−1)。我们的研究结果表明，尽管由于减少耕作而导致一些措施下降，但该策略增强了土壤物理特性。在短期内，覆盖作物WW适度增加了土壤物理参数，而TR的影响可以忽略不计。本研究表明，CA效应需要监测多个土壤物理参数。
{"title":"Transition to conservation agriculture: how tillage intensity and covering affect soil physical parameters","authors":"F. Sartori, I. Piccoli, R. Polese, A. Berti","doi":"10.5194/soil-2021-113","DOIUrl":"https://doi.org/10.5194/soil-2021-113","url":null,"abstract":"Abstract. Conservation agriculture (CA) relies on two key practices to improve agricultural sustainability—reduced tillage and cover crop usage. Despite known soil physics benefits (reduced soil compaction and strength, enhanced soil porosity and permeability), inconsistent reports on short-term CA results have limited its adoption in European agroecosystems. To elucidate the short-term effects, a three-year experiment in the low-lying Venetian plain (Northern Italy) was undertaken. Bulk density, penetration resistance, and soil hydraulic measures were used to evaluate results obtained by combining three tillage intensities (conventional tillage (CT), minimum tillage (MT), no tillage (NT)) with three winter soil coverages (bare soil (BS), tillage radish cover crop (TR), winter wheat cover crop (WW)). Among the tillage methods and soil layers, CT, on average, reduced BD (1.42 g cm−3) and PR (1.64 MPa) better in the 0–30 cm tilled layer. Other treatments yielded higher values (+4 % BD and +3.1 % PR) in the same layer. Across the soil profile, reduced tillage coupled with WW improved soil physics even below the tilled layer, as evidenced by root growth-limiting threshold declines (−11 % in BD values > 1.55 g cm−3 and −7 % in PR values > 2.5 MPa). Soil hydraulic measures confirmed this positive behaviour; NT combined with either BS or WW produced a soil saturated conductivity of 2.12 × 10−4 m s−1 (four-fold that of all other treatments). Likewise, sorptivity increased in NT combined with BS versus other treatments (3.64 × 10−4 m s−1 vs an all-treatment average of 7.98 × 10−5 m s−1). Our results suggest that despite some measure declines due to reduced tillage, the strategy enhances soil physics. In the short term, cover crop WW moderately increased physical soil parameters, whereas TR had negligible effects. This study demonstrates that CA effects require monitoring several soil physical parameters.\u0000","PeriodicalId":22015,"journal":{"name":"Soil Science","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86240424","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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