Abstract. Soil salinity and sodicity caused by saline water irrigation are widelyobserved globally. Clay dispersion and swelling are influenced by sodium(Na+) concentration and electrical conductivity (EC) of soil solution.Specifically, soil potassium (K+) also significantly affects soilstructural stability, but for which concern was rarely addressed in previousstudies or irrigation practices. A soil column experiment was carried out toexamine the effects of saline water with different relative concentrationsof K+ to Na+ (K+ / Na+), including K+ / Na+ of 0:1(K0Na1), 1:1 (K1Na1) and 1:0 (K1Na0) at a constant EC (4 dS m−1), anddeionized water as the control (CK), on soil physicochemical properties. Theresults indicated that at the constant EC of 4 dS m−1, the infiltrationrate and water content were significantly (P<0.05) affected byK+ / Na+ values, and K0Na1, K1Na1 and K1Na0 significantly (P<0.05) reduced saturated hydraulic conductivity by 43.62 %, 29.04 % and18.06 %, respectively, compared with CK. The volumetric water content wassignificantly (P<0.05) higher in K0Na1 than CK at both 15 and 30 cm soil depths. K1Na1 and K1Na0 significantly (P<0.05) reduced thedesalination time and required leaching volume. K0Na1 and K1Na1 reached thedesalination standard after the fifth and second infiltration, respectively,as K1Na0 did not exceed the bulk electrical conductivity required forthe desalination prerequisite throughout the whole infiltration cycle at 15 cmsoil layer. Furthermore, due to the transformation of macropores intomicropores spurred by clay dispersion, soil total porosity in K0Na1dramatically decreased compared with CK, and K1Na0 even increased theproportion of soil macropores. The higher relative concentration of K+to Na+ in saline water was more conducive to soil aggregate stability,alleviating the risk of macropores reduction caused by sodicity.
{"title":"The higher relative concentration of K+ to Na+ in saline water improves soil hydraulic conductivity, salt-leaching efficiency and structural stability","authors":"Sihui Yan, Tibin Zhang, Binbin Zhang, Tonggang Zhang, Y. Cheng, Chun Wang, Min Luo, Hao Feng, K. Siddique","doi":"10.5194/soil-9-339-2023","DOIUrl":"https://doi.org/10.5194/soil-9-339-2023","url":null,"abstract":"Abstract. Soil salinity and sodicity caused by saline water irrigation are widely\u0000observed globally. Clay dispersion and swelling are influenced by sodium\u0000(Na+) concentration and electrical conductivity (EC) of soil solution.\u0000Specifically, soil potassium (K+) also significantly affects soil\u0000structural stability, but for which concern was rarely addressed in previous\u0000studies or irrigation practices. A soil column experiment was carried out to\u0000examine the effects of saline water with different relative concentrations\u0000of K+ to Na+ (K+ / Na+), including K+ / Na+ of 0:1\u0000(K0Na1), 1:1 (K1Na1) and 1:0 (K1Na0) at a constant EC (4 dS m−1), and\u0000deionized water as the control (CK), on soil physicochemical properties. The\u0000results indicated that at the constant EC of 4 dS m−1, the infiltration\u0000rate and water content were significantly (P<0.05) affected by\u0000K+ / Na+ values, and K0Na1, K1Na1 and K1Na0 significantly (P<0.05) reduced saturated hydraulic conductivity by 43.62 %, 29.04 % and\u000018.06 %, respectively, compared with CK. The volumetric water content was\u0000significantly (P<0.05) higher in K0Na1 than CK at both 15 and 30 cm soil depths. K1Na1 and K1Na0 significantly (P<0.05) reduced the\u0000desalination time and required leaching volume. K0Na1 and K1Na1 reached the\u0000desalination standard after the fifth and second infiltration, respectively,\u0000as K1Na0 did not exceed the bulk electrical conductivity required for\u0000the desalination prerequisite throughout the whole infiltration cycle at 15 cm\u0000soil layer. Furthermore, due to the transformation of macropores into\u0000micropores spurred by clay dispersion, soil total porosity in K0Na1\u0000dramatically decreased compared with CK, and K1Na0 even increased the\u0000proportion of soil macropores. The higher relative concentration of K+\u0000to Na+ in saline water was more conducive to soil aggregate stability,\u0000alleviating the risk of macropores reduction caused by sodicity.\u0000","PeriodicalId":22015,"journal":{"name":"Soil Science","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82365717","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. Soil and water-efficient management are key factors in ensuring the olive sector's sustainable production practices. The use of compost based on olive waste (alperujo) as fertilizer could enhance ecosystem services while the need to transition to a zero-waste approach based on a circular economy is achieved. The present work includes a comparative study of the effect of alperujo compost (AC) vs. inorganic fertilization under different management systems: a traditional adult olive grove under rainfed conditions and a young hedgerow olive system, in which a factorial test of tree irrigationregimes (full, deficit and no irrigation) is implemented as well. At the hedgerow plots, the addition of AC and soil sampling time greatly impactedsoil chemical parameters and, to a lesser extent, enzymatic activities, whereas irrigation regimes did not exert a marked influence. In the traditional rainfed system, the addition of AC proved to be an efficient tool for carbon sequestration. The first soil sampling revealed a clearstoichiometric relationship between soil organic matter (SOM) and the nitrogen, phosphorus and potassium (NPK) contents in both systems, whereas the correlations were weak and scarce in the second sampling at the hedgerow plots. This fact was related to the decay of the compost effect. Compost in combination with irrigation tendedto trigger a certain priming effect on the native SOM with time since the carbon stocks were reduced between 6 % and 38 % from one sampling to the other in the hedgerow system, depending on the irrigation intensity. However, the deficit irrigation caused a less intense reduction of the SOMand essential nutrients representing the best alternative to maximizing the agronomic effects of the compost under a water-saving strategy. Recurrent application of compost would be necessary to maintain soil quality, especially with high tree densities. The combined management of AC and thedeficit irrigation proved to be an efficient tool toward a zero-waste circular economy and a water conservation strategy.
{"title":"Agricultural use of compost under different irrigation strategies in a hedgerow olive grove under Mediterranean conditions – a comparison with traditional systems","authors":"Laura L. de Sosa, M. Martín-Palomo, P. Castro-Valdecantos, E. Madejón","doi":"10.5194/soil-9-325-2023","DOIUrl":"https://doi.org/10.5194/soil-9-325-2023","url":null,"abstract":"Abstract. Soil and water-efficient management are key factors in ensuring the olive sector's sustainable production practices. The use of compost based on olive waste (alperujo) as fertilizer could enhance ecosystem services while the need to transition to a zero-waste approach based on a circular economy is achieved. The present work includes a comparative study of the effect of alperujo compost (AC) vs. inorganic fertilization under different management systems: a traditional adult olive grove under rainfed conditions and a young hedgerow olive system, in which a factorial test of tree irrigation\u0000regimes (full, deficit and no irrigation) is implemented as well. At the hedgerow plots, the addition of AC and soil sampling time greatly impacted\u0000soil chemical parameters and, to a lesser extent, enzymatic activities, whereas irrigation regimes did not exert a marked influence. In the traditional rainfed system, the addition of AC proved to be an efficient tool for carbon sequestration. The first soil sampling revealed a clear\u0000stoichiometric relationship between soil organic matter (SOM) and the nitrogen, phosphorus and potassium (NPK) contents in both systems, whereas the correlations were weak and scarce in the second sampling at the hedgerow plots. This fact was related to the decay of the compost effect. Compost in combination with irrigation tended\u0000to trigger a certain priming effect on the native SOM with time since the carbon stocks were reduced between 6 % and 38 % from one sampling to the other in the hedgerow system, depending on the irrigation intensity. However, the deficit irrigation caused a less intense reduction of the SOM\u0000and essential nutrients representing the best alternative to maximizing the agronomic effects of the compost under a water-saving strategy. Recurrent application of compost would be necessary to maintain soil quality, especially with high tree densities. The combined management of AC and the\u0000deficit irrigation proved to be an efficient tool toward a zero-waste circular economy and a water conservation strategy.\u0000","PeriodicalId":22015,"journal":{"name":"Soil Science","volume":"36 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79062872","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. In sub-Saharan Africa, maize is one of the most important staple crops, but long-term maize cropping with low external inputs has been associated with the loss of soil fertility. While adding high-quality organic resources combined with mineral fertilizer has been proposed to counteract this fertility loss, the long-term effectivenessand interactions with site properties still require more understanding. This study used repeated measurements over time to assess the effect of different quantities and qualities of organic resource addition combined with mineral nitrogen (N) on the change of soil organic carbon (SOC) contents over time (and SOC stocks in the year 2021) in four ongoing long-term experiments in Kenya. These experiments were established with identical treatments in moist to dry climates, on coarse to clayey soil textures, and have been conducted for at least 16 years. They received organic resources in quantities equivalent to 1.2 and 4 t C ha−1 yr−1 in the form of Tithonia diversifolia (high quality, fast turnover), Calliandra calothyrsus (high quality, intermediate turnover), Zea mays stover (low quality, fast turnover), sawdust (low quality, slow turnover) and local farmyard manure (variable quality, intermediate turnover). Furthermore, the addition of 240 kg N ha−1 yr−1 as mineral N fertilizer or no fertilizer was the split-plot treatment.At all four sites, a loss of SOC was predominantly observed, likely because the sites had been converted to cropland only a few decades before the start of the experiments. Across sites, the average decline of SOC content over 19 years in the 0 to 15 cm topsoil layer ranged from 42 % to 13 % of the initial SOC content for the control and the farmyard manure treatments at 4 t C ha−1 yr−1, respectively. Adding Calliandra or Tithonia at 4 t C ha−1 yr−1 limited the loss of SOC contents to about 24 % of initial SOC, while the addition of sawdust, maize stover (in three of the four sites) and sole mineral N addition showed no significant reduction of SOC loss over the control.Site-specific analyses, however, did show that at the site with the lowest initial SOC content (about 6 g kg−1), the addition of 4 t C ha−1 yr−1 farmyard manure or Calliandra with mineral N led to a gain in SOC contents. The other sites lost SOC in all treatments, albeit at site-specific rates. While subsoil SOC stocks in 2021 were little affected by organic resource additions (no difference in three of the four sites), the topsoil SOC stocks corroborated the results obtained from the SOC content measurements (0–15 cm) over time.The relative annual change of SOC contents showed a higher site specificity in farmyard manure, Calliandra and Tithonia treatments than in the control treatment, suggesting that the drivers of site specificity in SOC buildup (soil mineralogy, soil texture, climate) need to be better understood for effective targeting management of organic resources.Farmyard manure showed the highest potential
摘要在撒哈拉以南非洲，玉米是最重要的主粮作物之一，但长期玉米种植与低外部投入有关，导致土壤肥力丧失。虽然已提出添加优质有机资源与矿物肥料相结合来抵消这种肥力损失，但其长期有效性及其与场地性质的相互作用仍有待进一步了解。在肯尼亚进行的四项长期试验中，本研究利用随时间的重复测量方法，评估了不同数量和质量的有机资源添加与矿物氮(N)结合对土壤有机碳(SOC)含量随时间变化(以及2021年的SOC储量)的影响。这些实验是在潮湿和干燥的气候条件下，在粗糙和粘稠的土壤质地上进行的，并且已经进行了至少16年。他们获得的有机资源数量相当于1.2和4吨碳公顷- 1年- 1，其形式是Tithonia varfolia(高质量，快速周转)、Calliandra calothyrsus(高质量，中等周转)、玉米秸秆(低质量，快速周转)、锯末(低质量，缓慢周转)和当地农家肥(不稳定质量，中等周转)。在分块处理条件下，每隔1年- 1年分别施矿质氮肥或不施氮肥240 kg。在所有四个地点，主要观察到有机碳的损失，可能是因为这些地点在实验开始前几十年才转变为农田。各样地在4 t C / ha - 1 yr - 1处理下，0 ~ 15 cm表层土壤有机碳含量19年平均下降幅度分别为初始有机碳含量的42% ~ 13%。在4 t C / ha - 1 yr - 1条件下添加万年花或铁藤可将土壤有机碳的损失限制在初始有机碳的24%左右，而添加锯末、玉米秸秆(4个地点中的3个)和单独添加矿物氮对土壤有机碳的损失没有显著减少。然而，位点特异性分析表明，在初始有机碳含量最低的位点(约6 g kg - 1)，添加4 t cha - 1 yr - 1农家肥或含矿质氮的万花菜可使有机碳含量增加。其他位点在所有处理中都失去了有机碳，尽管是在特定位点上。虽然2021年地下土壤有机碳储量受有机资源添加量的影响不大(4个站点中有3个站点没有差异)，但表层土壤有机碳储量证实了有机碳含量随时间变化(0-15 cm)的测量结果。土壤有机碳含量的相对年际变化在农家肥、花青菜和铁藤处理中表现出比对照处理更高的立地特异性，表明需要更好地了解土壤矿物学、土壤质地、气候等土壤有机碳积累立地特异性的驱动因素，以便有效地进行有机资源的针对性管理。农家肥显示出减少有机碳损失的最大潜力，但对于非洲的小农来说，建立有机碳所需的数量往往是不现实的。因此，额外的农艺干预措施，如间作、轮作或种植根系延伸的作物，对于维持或增加有机碳是必要的。
{"title":"Managing soil organic carbon in tropical agroecosystems: evidence from four long-term experiments in Kenya","authors":"Moritz Laub, M. Corbeels, Antoine Couëdel, 3. SamuelMathuNdungu, Prof Monicah Wanjiku Mucheru-Muna, D. Mugendi, 6. Magdalena Necpalova 1, Wycliffe Waswa 3, M. Broek, B. Vanlauwe, 1. JohanSix","doi":"10.5194/soil-9-301-2023","DOIUrl":"https://doi.org/10.5194/soil-9-301-2023","url":null,"abstract":"Abstract. In sub-Saharan Africa, maize is one of the most important staple crops, but long-term maize cropping with low external inputs has been associated with the loss of soil fertility. While adding high-quality organic resources combined with mineral fertilizer has been proposed to counteract this fertility loss, the long-term effectiveness\u0000and interactions with site properties still require more understanding. This study used repeated measurements over time to assess the effect of different quantities and qualities of organic resource addition combined with mineral nitrogen (N) on the change of soil organic carbon (SOC) contents over time (and SOC stocks in the year 2021) in four ongoing long-term experiments in Kenya. These experiments were established with identical treatments in moist to dry climates, on coarse to clayey soil textures, and have been conducted for at least 16 years. They received organic resources in quantities equivalent to 1.2 and 4 t C ha−1 yr−1 in the form of Tithonia diversifolia (high quality, fast turnover), Calliandra calothyrsus (high quality, intermediate turnover), Zea mays stover (low quality, fast turnover), sawdust (low quality, slow turnover) and local farmyard manure (variable quality, intermediate turnover). Furthermore, the addition of 240 kg N ha−1 yr−1 as mineral N fertilizer or no fertilizer was the split-plot treatment.\u0000At all four sites, a loss of SOC was predominantly observed, likely because the sites had been converted to cropland only a few decades before the start of the experiments. Across sites, the average decline of SOC content over 19 years in the 0 to 15 cm topsoil layer ranged from 42 % to 13 % of the initial SOC content for the control and the farmyard manure treatments at 4 t C ha−1 yr−1, respectively. Adding Calliandra or Tithonia at 4 t C ha−1 yr−1 limited the loss of SOC contents to about 24 % of initial SOC, while the addition of sawdust, maize stover (in three of the four sites) and sole mineral N addition showed no significant reduction of SOC loss over the control.\u0000Site-specific analyses, however, did show that at the site with the lowest initial SOC content (about 6 g kg−1), the addition of 4 t C ha−1 yr−1 farmyard manure or Calliandra with mineral N led to a gain in SOC contents. The other sites lost SOC in all treatments, albeit at site-specific rates. While subsoil SOC stocks in 2021 were little affected by organic resource additions (no difference in three of the four sites), the topsoil SOC stocks corroborated the results obtained from the SOC content measurements (0–15 cm) over time.\u0000The relative annual change of SOC contents showed a higher site specificity in farmyard manure, Calliandra and Tithonia treatments than in the control treatment, suggesting that the drivers of site specificity in SOC buildup (soil mineralogy, soil texture, climate) need to be better understood for effective targeting management of organic resources.\u0000Farmyard manure showed the highest potential","PeriodicalId":22015,"journal":{"name":"Soil Science","volume":"57 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89007857","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. A major obstacle to selecting the most appropriate crops andclosing the yield gap in many areas of the world is a lack of site-specificsoil information. Accurate information on soil properties is critical foridentifying soil limitations and the management practices needed to improvecrop yields. However, acquiring accurate soil information is often difficultdue to the high spatial and temporal variability of soil properties at finescales and the cost and inaccessibility of laboratory-based soil analyses.With recent advancements in predictive soil mapping, there is a growingexpectation that soil map predictions can provide much of the informationneeded to inform soil management. Yet, it is unclear how accurate currentsoil map predictions are at scales relevant to management. The mainobjective of this study was to address this issue by evaluating thesite-specific accuracy of regional-to-global soil maps, using Ghana as atest case. Four web-based soil maps of Ghana were evaluated using a datasetof 6514 soil profile descriptions collected on smallholder farms using theLandPKS mobile application. Results from this study revealed that publiclyavailable soil maps in Ghana lack the needed accuracy (i.e., correctidentification of soil limitations) to reliably inform soil managementdecisions at the 1–2 ha scale common to smallholders. Standard measures ofmap accuracy for soil texture class and rock fragment class predictionsshowed that all soil maps had similar performance in estimating the correctproperty class. Overall soil texture class accuracies ranged from 8 %–14 %but could be as high as 38 %–64 % after accounting for uncertainty in theevaluation dataset. Soil rock fragment class accuracies ranged from26 %–29 %. However, despite these similar overall accuracies, there weresubstantial differences in soil property predictions among the four maps,highlighting that soil map errors are not uniform between maps. To betterunderstand the functional implications of these soil property differences,we used a modified version of the FAO Global Agro-Ecological Zone (GAEZ)soil suitability modeling framework to derive soil suitability ratings foreach soil data source. Using a low-input, rain-fed, maize productionscenario, we evaluated the functional accuracy of map-based soil propertyestimates. This analysis showed that soil map data significantlyoverestimated crop suitability for over 65 % of study sites, potentiallyleading to ineffective agronomic investments by farmers, includingcash-constrained smallholders.
{"title":"Accuracy of regional-to-global soil maps for on-farm decision-making: are soil maps “good enough”?","authors":"J. Maynard, E. Yeboah, S. Owusu, Michaela Buenemann, J. Neff, J. Herrick","doi":"10.5194/soil-9-277-2023","DOIUrl":"https://doi.org/10.5194/soil-9-277-2023","url":null,"abstract":"Abstract. A major obstacle to selecting the most appropriate crops and\u0000closing the yield gap in many areas of the world is a lack of site-specific\u0000soil information. Accurate information on soil properties is critical for\u0000identifying soil limitations and the management practices needed to improve\u0000crop yields. However, acquiring accurate soil information is often difficult\u0000due to the high spatial and temporal variability of soil properties at fine\u0000scales and the cost and inaccessibility of laboratory-based soil analyses.\u0000With recent advancements in predictive soil mapping, there is a growing\u0000expectation that soil map predictions can provide much of the information\u0000needed to inform soil management. Yet, it is unclear how accurate current\u0000soil map predictions are at scales relevant to management. The main\u0000objective of this study was to address this issue by evaluating the\u0000site-specific accuracy of regional-to-global soil maps, using Ghana as a\u0000test case. Four web-based soil maps of Ghana were evaluated using a dataset\u0000of 6514 soil profile descriptions collected on smallholder farms using the\u0000LandPKS mobile application. Results from this study revealed that publicly\u0000available soil maps in Ghana lack the needed accuracy (i.e., correct\u0000identification of soil limitations) to reliably inform soil management\u0000decisions at the 1–2 ha scale common to smallholders. Standard measures of\u0000map accuracy for soil texture class and rock fragment class predictions\u0000showed that all soil maps had similar performance in estimating the correct\u0000property class. Overall soil texture class accuracies ranged from 8 %–14 %\u0000but could be as high as 38 %–64 % after accounting for uncertainty in the\u0000evaluation dataset. Soil rock fragment class accuracies ranged from\u000026 %–29 %. However, despite these similar overall accuracies, there were\u0000substantial differences in soil property predictions among the four maps,\u0000highlighting that soil map errors are not uniform between maps. To better\u0000understand the functional implications of these soil property differences,\u0000we used a modified version of the FAO Global Agro-Ecological Zone (GAEZ)\u0000soil suitability modeling framework to derive soil suitability ratings for\u0000each soil data source. Using a low-input, rain-fed, maize production\u0000scenario, we evaluated the functional accuracy of map-based soil property\u0000estimates. This analysis showed that soil map data significantly\u0000overestimated crop suitability for over 65 % of study sites, potentially\u0000leading to ineffective agronomic investments by farmers, including\u0000cash-constrained smallholders.\u0000","PeriodicalId":22015,"journal":{"name":"Soil Science","volume":"47 15 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76420951","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. Since the 1950s, heavy plowing of Mollisols, combinedwith a lack of organic matter intake, has resulted in severe soildegradation in northeast China. The use of biochar in combination withfertilizer is a sustainable method of improving soil quality. In this paper,we conducted field experiments to explore the response of the stabilitymechanism of the soil aggregate, the dynamic properties of organic carbon,and changes in the microbial community structure to biochar. The biocharinput levels were C1, C2, and C3 (9.8, 19.6, and 29.4 Mg C ha−1,respectively), while the nitrogen (N) fertilizer rates were N1/2 (300 kg N ha−1) and N (600 kg N ha−1). Results indicated that biocharcombined with N fertilizer effectively increases soil carbon storage andaggregates stability (P<0.05). And C2N treatment increased theaggregate contents of the >2 mm and 0.25–2 mm fractions by56.59 % and 23.41 %, respectively. The phospholipid fatty acid (PLFA)analysis revealed that microbial community structure was effectivelyimproved with biochar combined with N fertilizer application (P<0.05). The F/B ratio increased by 25.22 % and the gram-positive(Gm+) to gram-negative (Gm−) ratio by 4.65 % under the C2N1/2treatment. This study concluded that the response of Mollisols to biochar isprimarily determined by the interplay of aggregate, organic carbon, andmicroorganisms. Therefore, the use of biochar combined with N fertilizermight mitigate soil degradation of Mollisols under an optimal applicationratio, but the underlying mechanism still requires further exploration. Thisstudy will provide a scientific basis for the conservation and sustainableutilization of Mollisols resources.
摘要自20世纪50年代以来，由于大量耕作，再加上有机质摄入不足，导致东北地区土壤严重退化。生物炭与肥料结合使用是一种改善土壤质量的可持续方法。本文通过田间试验，探讨了土壤团聚体稳定性机制、有机碳动态特性和微生物群落结构变化对生物炭的响应。生物炭投入水平为C1、C2和C3(分别为9.8、19.6和29.4 Mg C ha - 1)，施氮量为N /2 (300 kg N ha - 1)和N (600 kg N ha - 1)。结果表明，生物炭配施氮肥可有效提高土壤碳储量和团聚体稳定性(P2 mm和0.25-2 mm)，分别提高56.59%和23.41%。磷脂脂肪酸(PLFA)分析显示，生物炭配施氮肥能有效改善土壤微生物群落结构(P<0.05)。在c2n2 /2处理下，F/B比提高了25.22%，革兰氏阳性(Gm+)与革兰氏阴性(Gm−)比提高了4.65%。本研究的结论是，软土对生物炭的反应主要是由团聚体、有机碳和微生物的相互作用决定的。因此，在最佳施肥比下，生物炭与氮肥配合施用可能会减缓Mollisols的土壤退化，但其潜在机制仍需进一步探索。本研究将为贻贝资源的保护和可持续利用提供科学依据。
{"title":"Biochar promotes soil aggregate stability and associated organic carbon sequestration and regulates microbial community structures in Mollisols from northeast China","authors":"Jing Sun, Xinrui Lu, Guoshuang Chen, Nana Luo, Qi-long Zhang, Xiujun Li","doi":"10.5194/soil-9-261-2023","DOIUrl":"https://doi.org/10.5194/soil-9-261-2023","url":null,"abstract":"Abstract. Since the 1950s, heavy plowing of Mollisols, combined\u0000with a lack of organic matter intake, has resulted in severe soil\u0000degradation in northeast China. The use of biochar in combination with\u0000fertilizer is a sustainable method of improving soil quality. In this paper,\u0000we conducted field experiments to explore the response of the stability\u0000mechanism of the soil aggregate, the dynamic properties of organic carbon,\u0000and changes in the microbial community structure to biochar. The biochar\u0000input levels were C1, C2, and C3 (9.8, 19.6, and 29.4 Mg C ha−1,\u0000respectively), while the nitrogen (N) fertilizer rates were N1/2 (300 kg N ha−1) and N (600 kg N ha−1). Results indicated that biochar\u0000combined with N fertilizer effectively increases soil carbon storage and\u0000aggregates stability (P<0.05). And C2N treatment increased the\u0000aggregate contents of the >2 mm and 0.25–2 mm fractions by\u000056.59 % and 23.41 %, respectively. The phospholipid fatty acid (PLFA)\u0000analysis revealed that microbial community structure was effectively\u0000improved with biochar combined with N fertilizer application (P<0.05). The F/B ratio increased by 25.22 % and the gram-positive\u0000(Gm+) to gram-negative (Gm−) ratio by 4.65 % under the C2N1/2\u0000treatment. This study concluded that the response of Mollisols to biochar is\u0000primarily determined by the interplay of aggregate, organic carbon, and\u0000microorganisms. Therefore, the use of biochar combined with N fertilizer\u0000might mitigate soil degradation of Mollisols under an optimal application\u0000ratio, but the underlying mechanism still requires further exploration. This\u0000study will provide a scientific basis for the conservation and sustainable\u0000utilization of Mollisols resources.\u0000","PeriodicalId":22015,"journal":{"name":"Soil Science","volume":"41 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86948528","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. Enhanced efficiency fertilizer (EEF) technologies thatemploy product coatings to delay nitrogen (N) release or are chemicallystabilized to inhibit key steps of N transformations in soil offerpotential for improving N use efficiency (NUE) in agricultural systems.However, the dynamics of N release and transformation from singletechnologies may result in a spatial or temporal mismatch of N supply anddemand during a growing season. This may be overcome by use of blends ofdifferent technologies, provided the reduction in the concentration ofstabilizing products does not reduce effectiveness. Laboratory incubationsquantified the N dynamics around bands of controlled-release fertilizer(CRF) and nitrification-inhibited (NI) urea and varying blends of thesetechnologies and referenced this against conventional urea andbiodegradable, plant-oil-coated urea (POCU) applied at the same rates in twocontrasting soils over 60 d. Blends of NI urea (3,4-dimethylpyrazolephosphate, DMPP urea) and a CRF (polymer-coated urea, PCU) typicallyresulted in N concentrations and distribution that were intermediate to thoseof the constituent products in unblended applications. Changes in theproportions of each product were mirrored by urea nitrogen (urea-N) concentrations aroundthe bands in both soils, while the proportions of DMPP urea in each blendwere only related to the extent of nitrification inhibition in the Vertisol.A proportion of the POCU granules burst during the early stages ofincubation, resulting in initially higher mineral N concentrations compared to PCU.However, both CRFs delayed N release and formation of nitrate nitrogen (NO3-N) relative togranular urea, and mineral N distribution was similar within each soil. Soiltype had a significant impact on banded N dynamics. Where there was littleeffect of N-fertilizer treatment on NO3-N production in the Ferralsol,the higher impedance to solute transport in the Vertisol contributed to asignificant inhibitory effect of NI urea on nitrification in both pure andblended DMPP urea treatments. Using NO3-N production as a benchmark forthe risk of environmental loss, the efficacy of fertilizer treatments inthis soil was of DMPP urea / PCU blends (higher ratio of PCU may offer smallbut insignificant benefit) > DMPP urea = PCU > urea.These findings highlight the importance of soil properties in determiningthe N dynamics from different banded EEF products. Insights into theefficacy of biodegradable alternatives to polymer coatings and the efficacyof blended EEF products can improve the reliability of N supply whilereducing environmental impacts, therefore offering greater opportunities tosustainably improve fertilizer NUE in cropping systems.
{"title":"Impact of contrasting fertilizer technologies on N dynamics from subsurface bands of “pure” or blended fertilizer applications","authors":"Chelsea K. Janke, M. Bell","doi":"10.5194/soil-9-243-2023","DOIUrl":"https://doi.org/10.5194/soil-9-243-2023","url":null,"abstract":"Abstract. Enhanced efficiency fertilizer (EEF) technologies that\u0000employ product coatings to delay nitrogen (N) release or are chemically\u0000stabilized to inhibit key steps of N transformations in soil offer\u0000potential for improving N use efficiency (NUE) in agricultural systems.\u0000However, the dynamics of N release and transformation from single\u0000technologies may result in a spatial or temporal mismatch of N supply and\u0000demand during a growing season. This may be overcome by use of blends of\u0000different technologies, provided the reduction in the concentration of\u0000stabilizing products does not reduce effectiveness. Laboratory incubations\u0000quantified the N dynamics around bands of controlled-release fertilizer\u0000(CRF) and nitrification-inhibited (NI) urea and varying blends of these\u0000technologies and referenced this against conventional urea and\u0000biodegradable, plant-oil-coated urea (POCU) applied at the same rates in two\u0000contrasting soils over 60 d. Blends of NI urea (3,4-dimethylpyrazole\u0000phosphate, DMPP urea) and a CRF (polymer-coated urea, PCU) typically\u0000resulted in N concentrations and distribution that were intermediate to those\u0000of the constituent products in unblended applications. Changes in the\u0000proportions of each product were mirrored by urea nitrogen (urea-N) concentrations around\u0000the bands in both soils, while the proportions of DMPP urea in each blend\u0000were only related to the extent of nitrification inhibition in the Vertisol.\u0000A proportion of the POCU granules burst during the early stages of\u0000incubation, resulting in initially higher mineral N concentrations compared to PCU.\u0000However, both CRFs delayed N release and formation of nitrate nitrogen (NO3-N) relative to\u0000granular urea, and mineral N distribution was similar within each soil. Soil\u0000type had a significant impact on banded N dynamics. Where there was little\u0000effect of N-fertilizer treatment on NO3-N production in the Ferralsol,\u0000the higher impedance to solute transport in the Vertisol contributed to a\u0000significant inhibitory effect of NI urea on nitrification in both pure and\u0000blended DMPP urea treatments. Using NO3-N production as a benchmark for\u0000the risk of environmental loss, the efficacy of fertilizer treatments in\u0000this soil was of DMPP urea / PCU blends (higher ratio of PCU may offer small\u0000but insignificant benefit) > DMPP urea = PCU > urea.\u0000These findings highlight the importance of soil properties in determining\u0000the N dynamics from different banded EEF products. Insights into the\u0000efficacy of biodegradable alternatives to polymer coatings and the efficacy\u0000of blended EEF products can improve the reliability of N supply while\u0000reducing environmental impacts, therefore offering greater opportunities to\u0000sustainably improve fertilizer NUE in cropping systems.\u0000","PeriodicalId":22015,"journal":{"name":"Soil Science","volume":"64 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86799380","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 quality and quantity of soil organic matter (SOM) arekey elements that impact soil health and climate regulation by soils. TheRock-Eval® thermal analysis technique is becoming more commonly used, asit represents a powerful method for SOM characterization by providinginsights into bulk SOM chemistry and thermal stability. In this study, weapplied this technique on a large soil sample set from the first campaign(2000–2009) of the French Soil Quality Monitoring Network (RMQS – Réseau de mesures de la qualité des sols). Based onour analyses of ca. 2000 composite surface (0–30 cm) samples collected acrossmainland France, we observed a significant impact of land cover on both the SOMthermal stability and elemental stoichiometry. Cropland soils had a lowermean hydrogen index value (a proxy for the SOM H/C ratio) and a higherthermal stability than grasslands and forests. Regarding the oxygen index (aproxy for the SOM O/C ratio), we observed significant differences among the values forcroplands, grasslands, and forests. Positive correlations of thetemperature parameters with the clay content and pH highlight the protective effect of clay on organic matter as well as theimpact of pH on microorganisms' mineralization activity. Surprisingly, wefound weak effects of climatic parameters on the thermal stability andstoichiometry of SOM. Our data suggest that topsoil SOM is on average moreoxidized and biogeochemically stable in croplands. More generally, the highnumber and even distribution of data across the whole French territory allow one tobuild a national interpretative reference for these indicators in surfacesoils.
摘要土壤有机质(SOM)的质量和数量是影响土壤健康和土壤调节气候的关键因素。rock - eval®热分析技术正变得越来越常用，因为它通过提供对大块SOM化学和热稳定性的见解，代表了SOM表征的强大方法。在这项研究中，我们将该技术应用于法国土壤质量监测网络(RMQS - r seau de measures de la qualit des sols)第一次活动(2000-2009年)的大型土壤样本集。通过对法国大陆约2000个复合表面(0-30 cm)样品的分析，我们观察到土地覆盖对soms热稳定性和元素化学计量学的显著影响。与草地和森林相比，农田土壤的平均氢指数(SOM H/C比的代表)较低，热稳定性较高。在氧指数(SOM O/C比值的代表)方面，我们观察到农田、草地和森林的氧指数存在显著差异。温度参数与粘土含量和pH呈正相关，表明粘土对有机质的保护作用以及pH对微生物矿化活性的影响。令人惊讶的是，我们发现气候参数对SOM的热稳定性和化学计量学的影响很小。我们的数据表明，农田表层土壤SOM平均氧化程度较高，生物地球化学稳定。更一般地说，整个法国领土上数据的高数量和均匀分布使人们能够为表面土壤中的这些指标建立一个全国性的解释性参考。
{"title":"Elemental stoichiometry and Rock-Eval® thermal stability of organic matter in French topsoils","authors":"Amicie Delahaie, P. Barré, F. Baudin, D. Arrouays, A. Bispo, L. Boulonne, C. Chenu, C. Jolivet, M. Martin, C. Ratié, N. Saby, Florence Savignac, L. Cécillon","doi":"10.5194/soil-9-209-2023","DOIUrl":"https://doi.org/10.5194/soil-9-209-2023","url":null,"abstract":"Abstract. The quality and quantity of soil organic matter (SOM) are\u0000key elements that impact soil health and climate regulation by soils. The\u0000Rock-Eval® thermal analysis technique is becoming more commonly used, as\u0000it represents a powerful method for SOM characterization by providing\u0000insights into bulk SOM chemistry and thermal stability. In this study, we\u0000applied this technique on a large soil sample set from the first campaign\u0000(2000–2009) of the French Soil Quality Monitoring Network (RMQS – Réseau de mesures de la qualité des sols). Based on\u0000our analyses of ca. 2000 composite surface (0–30 cm) samples collected across\u0000mainland France, we observed a significant impact of land cover on both the SOM\u0000thermal stability and elemental stoichiometry. Cropland soils had a lower\u0000mean hydrogen index value (a proxy for the SOM H/C ratio) and a higher\u0000thermal stability than grasslands and forests. Regarding the oxygen index (a\u0000proxy for the SOM O/C ratio), we observed significant differences among the values for\u0000croplands, grasslands, and forests. Positive correlations of the\u0000temperature parameters with the clay content and pH highlight the protective effect of clay on organic matter as well as the\u0000impact of pH on microorganisms' mineralization activity. Surprisingly, we\u0000found weak effects of climatic parameters on the thermal stability and\u0000stoichiometry of SOM. Our data suggest that topsoil SOM is on average more\u0000oxidized and biogeochemically stable in croplands. More generally, the high\u0000number and even distribution of data across the whole French territory allow one to\u0000build a national interpretative reference for these indicators in surface\u0000soils.\u0000","PeriodicalId":22015,"journal":{"name":"Soil Science","volume":"39 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89553132","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. Biological soil crusts (biocrusts) are key contributors to desert ecosystemfunctions, therefore, biocrust restoration following mechanical disturbancesis imperative. In the Negev Desert hyperarid regions, phosphate mining hasbeen practiced for over 60 years, destroying soil habitats and fragmentingthe landscape. In this study, we selected one mining site restored in 2007,and we used DNA stable isotope probing (DNA-SIP) to identify which bacteriagrow in post-mining and adjacent natural biocrusts. Since biocrustcommunities activate only after wetting, we incubated the biocrusts withH218O for 96 h under ambient conditions. We then evaluated thephysicochemical soil properties, chlorophyll a concentrations, activation,and functional potential of the biocrusts. The DNA-SIP assay revealed lowbacterial activity in both plot types and no significant differences in theproliferated communities' composition when comparing post-mining and naturalbiocrusts. We further found no significant differences in the microbialfunctional potential, photosynthetic rates, or soil properties. Our resultssuggest that growth of hyperarid biocrust bacteria after wetting is minimal.We hypothesize that due to the harsh climatic conditions, during wetting,bacteria devote their meager resources to prepare for the coming drought, byfocusing on damage repair and organic compound synthesis and storage ratherthan on growth. These low growth rates contribute to the sluggish recoveryof desert biocrusts following major disturbances such as mining. Therefore,our findings highlight the need for implementing active restorationpractices following mining.
{"title":"Only a minority of bacteria grow after wetting in both natural and post-mining biocrusts in a hyperarid phosphate mine","authors":"Talia Gabay, Eva Petrova, O. Gillor, Y. Ziv, Roey Angel","doi":"10.5194/soil-9-231-2023","DOIUrl":"https://doi.org/10.5194/soil-9-231-2023","url":null,"abstract":"Abstract. Biological soil crusts (biocrusts) are key contributors to desert ecosystem\u0000functions, therefore, biocrust restoration following mechanical disturbances\u0000is imperative. In the Negev Desert hyperarid regions, phosphate mining has\u0000been practiced for over 60 years, destroying soil habitats and fragmenting\u0000the landscape. In this study, we selected one mining site restored in 2007,\u0000and we used DNA stable isotope probing (DNA-SIP) to identify which bacteria\u0000grow in post-mining and adjacent natural biocrusts. Since biocrust\u0000communities activate only after wetting, we incubated the biocrusts with\u0000H218O for 96 h under ambient conditions. We then evaluated the\u0000physicochemical soil properties, chlorophyll a concentrations, activation,\u0000and functional potential of the biocrusts. The DNA-SIP assay revealed low\u0000bacterial activity in both plot types and no significant differences in the\u0000proliferated communities' composition when comparing post-mining and natural\u0000biocrusts. We further found no significant differences in the microbial\u0000functional potential, photosynthetic rates, or soil properties. Our results\u0000suggest that growth of hyperarid biocrust bacteria after wetting is minimal.\u0000We hypothesize that due to the harsh climatic conditions, during wetting,\u0000bacteria devote their meager resources to prepare for the coming drought, by\u0000focusing on damage repair and organic compound synthesis and storage rather\u0000than on growth. These low growth rates contribute to the sluggish recovery\u0000of desert biocrusts following major disturbances such as mining. Therefore,\u0000our findings highlight the need for implementing active restoration\u0000practices following mining.\u0000","PeriodicalId":22015,"journal":{"name":"Soil Science","volume":"48 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78236348","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. Seagrass meadows are among the most valuable ecosystems on Earth. However, in tropical countries, there is a substantial knowledge gap in “seagrass science”. To address this gap, seagrass soils from threeBrazilian coastal regions were investigated (the northeastern, southeastern, and southern coasts). Soil profiles from different geological and bioclimatic settings were sampled,described, and analyzed. Thus, detailed macromorphological descriptions, soil classification, physicochemical analysis (soil particle size, soil pH,pHoxidation, Eh, total organic carbon: TOC), Fe partitioning, and X-ray diffractometry were performed. Additionally, water samples were analyzed forpH, salinity, and ion concentrations. Different environmental settings inthe coastal compartments produced contrasting geochemical conditions, whichcaused different intensities of pedogenetic processes. On the northeastern coast, the denser plant coverage favored higher TOC contents (2.5 ± 0.1 %) andan anaerobic environment (Eh = +134 ± 142 mV) prone to an intense sulfidization (i.e., pyrite formation: Py-Fe). Py-Fe contents in northeastern soils were 6- and 2-fold higher than in southeastern and southern coastal soils, respectively.Conversely, lower TOC contents (0.35 ± 0.15 %) and a suboxicenvironment (Eh + 203 ± 55 mV) in the southeastern soils, along with the Fe-rich geological surroundings, decreased the intensity of gleization. Thecontrasting intensities in the soil processes, related to the (seeminglysubtle) differences in the geochemistry of each environment, ultimatelycaused relevant pedodiversity among the studied sites. Our findings contribute to a better understanding of the general functioning of tropicalseagrass meadows but also have significant environmental implications forstudies focused on carbon sequestration in these ecosystems.
{"title":"Masked diversity and contrasting soil processes in tropical seagrass meadows: the control of environmental settings","authors":"G. N. Nóbrega, X. L. Otero, D. J. Romero, H. M. Queiroz, D. Gorman, Margareth S. Copertino, M. Piccolo, T. O. Ferreira","doi":"10.5194/soil-9-189-2023","DOIUrl":"https://doi.org/10.5194/soil-9-189-2023","url":null,"abstract":"Abstract. Seagrass meadows are among the most valuable ecosystems on Earth. However, in tropical countries, there is a substantial knowledge gap in “seagrass science”. To address this gap, seagrass soils from three\u0000Brazilian coastal regions were investigated (the northeastern, southeastern, and southern coasts). Soil profiles from different geological and bioclimatic settings were sampled,\u0000described, and analyzed. Thus, detailed macromorphological descriptions, soil classification, physicochemical analysis (soil particle size, soil pH,\u0000pHoxidation, Eh, total organic carbon: TOC), Fe partitioning, and X-ray diffractometry were performed. Additionally, water samples were analyzed for\u0000pH, salinity, and ion concentrations. Different environmental settings in\u0000the coastal compartments produced contrasting geochemical conditions, which\u0000caused different intensities of pedogenetic processes. On the northeastern coast, the denser plant coverage favored higher TOC contents (2.5 ± 0.1 %) and\u0000an anaerobic environment (Eh = +134 ± 142 mV) prone to an intense sulfidization (i.e., pyrite formation: Py-Fe). Py-Fe contents in northeastern soils were 6- and 2-fold higher than in southeastern and southern coastal soils, respectively.\u0000Conversely, lower TOC contents (0.35 ± 0.15 %) and a suboxic\u0000environment (Eh + 203 ± 55 mV) in the southeastern soils, along with the Fe-rich geological surroundings, decreased the intensity of gleization. The\u0000contrasting intensities in the soil processes, related to the (seemingly\u0000subtle) differences in the geochemistry of each environment, ultimately\u0000caused relevant pedodiversity among the studied sites. Our findings contribute to a better understanding of the general functioning of tropical\u0000seagrass meadows but also have significant environmental implications for\u0000studies focused on carbon sequestration in these ecosystems.\u0000","PeriodicalId":22015,"journal":{"name":"Soil Science","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89029969","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. Effects of oil-palm (Elaeis guineensis Jacq.) management on silicon (Si) cycling under smallholder oil-palm plantations have hardly been investigated. As oil palms are Si accumulators, we hypothesized that management practices and topsoil erosion may cause Si losses and changes in spatial Si concentration patterns in topsoils under oil-palm cultivation. To test this hypothesis, we took topsoil samples under mature oil-palm plantations in well-drained and riparian areas of Jambi Province, Indonesia. The samples were taken from four different management zones within each oil-palm plot: palm circles, oil-palm rows, interrows, and below frond piles. We quantified mobile Si (SiM) and Si in amorphous silica (SiAm) by the extraction of CaCl2 and NaCO3, respectively. Both fractions are important Si pools in soils and are essential for plant–soil Si cycling. We further installed sediment traps on sloping, well-drained oil-palm plantations to estimate the annual loss of soil and SiAm caused by erosion. In well-drained areas, mean topsoil SiAm concentrations were significantly higher below frond piles (3.97 ± 1.54 mg g−1) compared to palm circles (1.71 ± 0.35 mg g−1), oil-palm rows (1.87 ± 0.51 mg g−1), and interrows (1.88 ± 0.39 mg g−1). In riparian areas, the highest mean topsoil SiAm concentrations were also found below frondpiles (2.96 ± 0.36 mg g−1) and in grass-covered interrows (2.71 ± 0.13 mg g−1), whereas topsoil SiAm concentrations of palm circles were much lower (1.44 ± 0.55 mg g−1). We attributed the high SiAm concentrations in topsoils under frond piles and in grass-covered interrows to phytolith release from decaying oil-palm fronds, grasses, and sedges. The significantly lower SiAm concentrations in palm circles (in both well-drained and riparian areas), oil-palm rows, and unvegetated interrows (only in well-drained areas) were explained by a lack of litter return to these management zones. Mean topsoil SiMconcentrations were in the range of ∼ 10–20 µg g−1. They tended to be higher in riparian areas, but the differences between well-drained and riparian sites were not statistically significant.Soil-loss calculations based on erosion traps confirmed that topsoil erosion was considerable in oil-palm interrows on slopes. Erosion estimates were in the range of 4–6 Mg ha−1 yr−1, involving SiAm losses in a range of 5–9 kg−1 ha−1 yr−1. Based on the observed spatialSi patterns, we concluded that smallholders could efficiently reduce erosion and support Si cycling within the system by (1) maintaining a grass cover in oil-palm rows and interrows, (2) incorporating oil-palm litter into plantation management, and (3) preventing soil compaction and surface-crust formation.
摘要油棕管理对小农油棕人工林硅循环的影响研究甚少。由于油棕是硅的蓄积物，我们假设管理措施和表土侵蚀可能导致油棕种植下表土硅的损失和空间硅浓度格局的变化。为了验证这一假设，我们在印度尼西亚占壁省排水良好的河岸地区的成熟油棕种植园下采集了表土样本。样本取自每个油棕地块内的四个不同管理区域:油棕圈、油棕行、油棕行间和叶桩下方。我们分别通过萃取CaCl2和NaCO3来量化可移动硅(SiM)和非晶二氧化硅(SiAm)中的硅。两者都是土壤中重要的硅库，对植物-土壤硅循环至关重要。我们进一步在排水良好的倾斜油棕种植园安装了沉积物收集器，以估计每年因侵蚀造成的土壤和暹罗的损失。在排水良好的地区，与棕榈圈(1.71±0.35 mg g−1)、油棕行(1.87±0.51 mg g−1)和行间(1.88±0.39 mg g−1)相比，前桩下的平均表土SiAm浓度(3.97±1.54 mg g−1)显著高于前桩下(3.97±1.54 mg g−1)。在河岸地区，平均表层土壤SiAm浓度最高的区域还包括树桩下方(2.96±0.36 mg g - 1)和草覆盖行间(2.71±0.13 mg g - 1)，而棕榈圈表层土壤SiAm浓度则低得多(1.44±0.55 mg g - 1)。我们将叶桩下表层土壤和草覆盖的交错层中的高暹罗浓度归因于腐烂的油棕叶、草和莎草释放的植石。在棕榈圈(在排水良好的地区和河岸地区)、油棕行和无植被的行间(仅在排水良好的地区)，SiAm浓度显著降低的原因是这些管理区域缺乏凋落物的回归。表层土壤simm平均浓度在~ 10 ~ 20µg g−1之间。它们往往在河岸地区较高，但在排水良好的地区和河岸地区之间的差异没有统计学意义。基于侵蚀陷阱的土壤流失量计算证实，在斜坡上的油棕丛丛中，表层土壤侵蚀相当严重。侵蚀估计在4-6毫克公顷−1年−1之间，其中SiAm损失在5-9公斤−1公顷−1年−1之间。基于观察到的Si空间格局，我们得出结论，小农可以通过(1)保持油棕行间的草覆盖，(2)将油棕凋落物纳入人工林管理，(3)防止土壤压实和表壳形成，有效地减少系统内的侵蚀和支持Si循环。
{"title":"Oil-palm management alters the spatial distribution of amorphous silica and mobile silicon in topsoils","authors":"Britta Greenshields, Barbara von der Lühe, H. Hughes, C. Stiegler, S. Tarigan, A. Tjoa, D. Sauer","doi":"10.5194/soil-9-169-2023","DOIUrl":"https://doi.org/10.5194/soil-9-169-2023","url":null,"abstract":"Abstract. Effects of oil-palm (Elaeis guineensis Jacq.) management on silicon (Si) cycling under smallholder oil-palm plantations have hardly been investigated. As oil palms are Si accumulators, we hypothesized that management practices and topsoil erosion may cause Si losses and changes in spatial Si concentration patterns in topsoils under oil-palm cultivation. To test this hypothesis, we took topsoil samples under mature oil-palm plantations in well-drained and riparian areas of Jambi Province, Indonesia. The samples were taken from four different management zones within each oil-palm plot: palm circles, oil-palm rows, interrows, and below frond piles. We quantified mobile Si (SiM) and Si in amorphous silica (SiAm) by the extraction of CaCl2 and NaCO3, respectively. Both fractions are important Si pools in soils and are essential for plant–soil Si cycling. We further installed sediment traps on sloping, well-drained oil-palm plantations to estimate the annual loss of soil and SiAm caused by erosion. In well-drained areas, mean topsoil SiAm concentrations were significantly higher below frond piles (3.97 ± 1.54 mg g−1) compared to palm circles (1.71 ± 0.35 mg g−1), oil-palm rows (1.87 ± 0.51 mg g−1), and interrows (1.88 ± 0.39 mg g−1). In riparian areas, the highest mean topsoil SiAm concentrations were also found below frond\u0000piles (2.96 ± 0.36 mg g−1) and in grass-covered interrows (2.71 ± 0.13 mg g−1), whereas topsoil SiAm concentrations of palm circles were much lower (1.44 ± 0.55 mg g−1). We attributed the high SiAm concentrations in topsoils under frond piles and in grass-covered interrows to phytolith release from decaying oil-palm fronds, grasses, and sedges. The significantly lower SiAm concentrations in palm circles (in both well-drained and riparian areas), oil-palm rows, and unvegetated interrows (only in well-drained areas) were explained by a lack of litter return to these management zones. Mean topsoil SiM\u0000concentrations were in the range of ∼ 10–20 µg g−1. They tended to be higher in riparian areas, but the differences between well-drained and riparian sites were not statistically significant.\u0000Soil-loss calculations based on erosion traps confirmed that topsoil erosion was considerable in oil-palm interrows on slopes. Erosion estimates were in the range of 4–6 Mg ha−1 yr−1, involving SiAm losses in a range of 5–9 kg−1 ha−1 yr−1. Based on the observed spatial\u0000Si patterns, we concluded that smallholders could efficiently reduce erosion and support Si cycling within the system by (1) maintaining a grass cover in oil-palm rows and interrows, (2) incorporating oil-palm litter into plantation management, and (3) preventing soil compaction and surface-crust formation.\u0000","PeriodicalId":22015,"journal":{"name":"Soil Science","volume":"67 11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91315683","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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