Agriculture, Ecosystems & Environment最新文献_第2页

Comparative pollinator conservation potential of coffee agroforestry relative to coffee monoculture and tropical rainforest in the DR Congo 刚果（金）咖啡农林业相对于咖啡单一种植和热带雨林的授粉者保护潜力比较

IF 6 1区农林科学 Q1 AGRICULTURE, MULTIDISCIPLINARY

Agriculture, Ecosystems & Environment

Pub Date : 2024-11-11 DOI: 10.1016/j.agee.2024.109375

Jonas Depecker , Filip Vandelook , Kurt Jordaens , Achik Dorchin , Benjamin Ntumba Katshela , Ieben Broeckhoven , Benoit Dhed’a , Arne Devriese , Lien Deckers , Piet Stoffelen , Olivier Honnay

Animal-pollination is crucial in the reproduction of many crops grown in the tropics, including the self-incompatible Robusta coffee. Coffea canephora Pierre ex A. Froehner. is indigenous to the Congo basin where it is naturally growing in the rainforest understorey. Coffee cultivation mainly occurs in either unshaded monocultures or in agroforestry systems. Here we used pan traps to survey the Diptera (true flies) and Hymenoptera (bees) communities as the putative coffee pollinating organisms in the Yangambi region in DR Congo, and we assessed the comparative benefits of a coffee agroforestry system and coffee monoculture to the coffee pollinator community. To assess the pollinator conservation potential of the agroforestry system, we also compared its Diptera and Hymenoptera communities with natural rainforest as a benchmark. Natural rainforest harboured a higher number of individuals, as well as a higher number of species than both agroforestry and coffee monoculture systems, with no differences between the latter two land-uses. Furthermore, we observed different responses in species richness and diversity to land-use between Diptera and Hymenoptera. Our analyses further showed a high species dissimilarity between natural rainforest and the two cultivation systems, without significant differences between the latter. Specifically, the community composition of the agroforestry and coffee monoculture systems were totally different, rather than a subset of the community composition of the natural rainforest. Our study indicates that rehabilitation of agricultural land through intercropping fruit trees may not always enhance pollinator communities and that the studied agroforestry system falls short of matching the bee and fly conservation potential of natural rainforests.

动物授粉对热带地区许多作物的繁殖至关重要，包括自交不亲和的罗布斯塔咖啡。Coffea canephora Pierre ex A. Froehner.Froehner. 是刚果盆地的原生植物，自然生长在热带雨林林下。咖啡种植主要在无遮蔽的单一种植园或农林系统中进行。在此，我们使用盘式诱捕器调查了刚果民主共和国扬甘比地区的双翅目（真蝇）和膜翅目（蜜蜂）咖啡授粉生物群落，并评估了咖啡农林系统和咖啡单一种植对咖啡授粉生物群落的比较效益。为了评估农林系统保护授粉生物的潜力，我们还将其双翅目和膜翅目群落与作为基准的天然雨林进行了比较。与农林系统和咖啡单一种植系统相比，天然雨林中的个体数量和物种数量都更多，后两种土地利用方式之间没有差异。此外，我们还观察到双翅目和膜翅目的物种丰富度和多样性对土地利用的不同反应。我们的分析进一步表明，天然雨林与两种栽培系统之间的物种差异很大，但后者之间没有显著差异。具体来说，农林业系统和咖啡单一种植系统的群落组成完全不同，而不是天然雨林群落组成的子集。我们的研究表明，通过间作果树来恢复农田并不总能提高传粉昆虫群落的数量，所研究的农林系统与天然雨林的蜜蜂和苍蝇保护潜力不相匹配。

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引用次数: 0

Opposite effect on soil organic carbon between grain and non-grain crops: Evidence from Main Grain Land, China 粮食作物和非粮食作物对土壤有机碳的影响截然相反：中国主要粮田的证据

IF 6 1区农林科学 Q1 AGRICULTURE, MULTIDISCIPLINARY

Agriculture, Ecosystems & Environment

Pub Date : 2024-11-09 DOI: 10.1016/j.agee.2024.109364

Shidong Liu , Li Wang , Jie Zhang , Shengping Ding

The soil organic carbon (SOC) content of cropland affects global food production and is crucial for agricultural carbon reduction. The SOC response to long-term changes in main grain land (MGL) likely differs from non-MGL cropland. We constructed a quantitative indicator system for the MGL planting pattern to reveal the relationship between MGL use change and SOC. We produced an MGL dataset for China from 1985 to 2020 based on the existing MGL distribution data and available Landsat images and analyzed the heterogeneity of SOC under different MGLs using two SOC datasets. Time series change detection explained the interaction between planting patterns and SOC. Different MGLs exhibited considerable heterogeneity in SOC. The single rice area with the highest SOC was twice (31.62 g/kg) that of the wheat and maize areas. SOC showed an opposite trend in MGL and non-MGL with increased planting intensity. Soil SOC content affected the expansion decisions of farmers in cropland and MGL. Areas with a high SOC were developed into MGL by farmers early. MGL consumed more SOC and had a stronger urgency for fallow cultivation than non-MGL. The planting intensity of MGL more than the inflection threshold (about 15 years) decreased shallow SOC (0–15 cm), decreasing below the initial value after more than 30 years. Currently, 62.08 % of MGL in China causes a decrease in SOC, with an urgent need for a fallow MGL of 27.38 Mha. Theoretical guidance for optimizing crop planting patterns to ensure food security and reduce agricultural carbon emissions was provided.

耕地的土壤有机碳（SOC）含量影响着全球粮食产量，对农业碳减排至关重要。主要粮田（MGL）的土壤有机碳对长期变化的响应可能不同于非主要粮田耕地。我们为主要粮田种植模式构建了一个定量指标体系，以揭示主要粮田用途变化与 SOC 之间的关系。我们基于现有的耕地分布数据和现有的大地遥感卫星图像，建立了中国从 1985 年到 2020 年的耕地数据集，并利用两个 SOC 数据集分析了不同耕地下 SOC 的异质性。时间序列变化检测解释了种植模式与 SOC 之间的相互作用。不同的地方政府土地在 SOC 方面表现出相当大的异质性。SOC 最高的单一水稻区是小麦和玉米区的两倍（31.62 克/千克）。随着种植强度的增加，主要种植区和非主要种植区的 SOC 呈相反趋势。土壤 SOC 含量影响了农民扩大耕地和套作的决定。SOC 含量高的地区很早就被农民开发成了 MGL。与非套作地相比，套作地消耗的 SOC 更多，休耕的紧迫性也更强。多元土地的种植强度超过拐点临界值（约 15 年）后，浅层 SOC（0-15 厘米）下降，30 多年后降至初始值以下。目前，中国 62.08% 的间作套种导致 SOC 下降，急需 2 738 万公顷的间作套种休耕。这为优化作物种植模式以确保粮食安全和减少农业碳排放提供了理论指导。

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引用次数: 0

Soil metagenomics reveals reduced tillage improves soil functional profiles of carbon, nitrogen, and phosphorus cycling in bulk and rhizosphere soils 土壤元基因组学揭示了减少耕作可改善大体积土壤和根圈土壤中碳、氮和磷循环的土壤功能特征

IF 6 1区农林科学 Q1 AGRICULTURE, MULTIDISCIPLINARY

Agriculture, Ecosystems & Environment

Pub Date : 2024-11-08 DOI: 10.1016/j.agee.2024.109371

Xiaojing Hu, Junjie Liu, Aizhen Liang, Haidong Gu, Zhuxiu Liu, Jian Jin, Guanghua Wang

Conservation tillage practices (CAT) are known to benefit soil health and soil ecosystem functions relative to conventional tillage (CVT); however, much uncertainty remains concerning microbial functional traits and their subsequent effects on soil nutrients under different tillage practices. We analyzed the functional profiles of the C, N, and P cycles in response to CAT of no-tillage (NT), reduced tillage (RT), and CVT of moldboard plowing (MP) in bulk and rhizosphere soils using shotgun sequencing. CAT induced distinct microbial functional patterns relative to CVT, and these differences were generally more evident in rhizosphere soils than in bulk soils. CAT promotes multiple metabolic pathways such as C and N decomposition, fermentation, CO oxidation, N fixation, nitrate reduction and inorganic-P and organic-P transformations in bulk and/or rhizosphere soils. Variations in these metabolic pathways were mainly driven by Bradyrhizobium, Mesorhizobium, Nitrososphaera, Phenylobacterium, Rhizobium which are affiliated with Proteobacteria, Actinobacteria, Acidobacteria, Bacteroidota and Thaumarchaeota. Furthermore, 24 high-quality metagenome-assembled genomes (MAGs) were reconstructed, of which three novel MAGs (TL100, TL46, and TL57) harbored functional genes regulating all metabolic pathways. In particular, NT-enriched MAGs (such as Sphingomonas) promote fermentation, resulting in the reduction of soil total carbon (TC) relative to MP in bulk soils. RT retained the contents of soil TC and total nitrogen (TN) well and up-regulated the phoR gene carried by Streptomyces, which promoted the regulation of P-starvation concomitantly with the increase in the contents of total phosphorous (TP) and available phosphorous (AP) in bulk soil. Additionally, assimilatory nitrate reduction coupled with organic-P mineralization was facilitated by CAT in rhizosphere soil, leading to the mitigation of N loss and the activation of soil organic-P for crop uptake. Overall, our results revealed that CAT significantly accelerated multiple metabolic potentials, and RT could sustain soil nutrient contents better than NT.

众所周知，相对于传统耕作（CVT），保护性耕作方法（CAT）有利于土壤健康和土壤生态系统功能；然而，在不同耕作方法下，微生物功能特征及其对土壤养分的后续影响仍存在很多不确定性。我们利用霰弹枪测序技术分析了免耕（NT）、减耕（RT）和模板犁（MP）等传统耕作法对大块土壤和根瘤土壤中 C、N 和 P 循环的功能特征。相对于 CVT，CAT 诱导了不同的微生物功能模式，这些差异在根瘤土壤中比在大面积土壤中更为明显。CAT 可促进多种代谢途径，如块状和/或根圈土壤中的碳和氮分解、发酵、一氧化碳氧化、氮固定、硝酸盐还原以及无机-磷和有机-磷转化。这些代谢途径的变化主要是由隶属于蛋白细菌、放线菌、酸性细菌、类杆菌科和潮气菌科的布拉迪根瘤菌、中生代根瘤菌、硝化细菌、苯基杆菌、根瘤菌所驱动的。此外，还重建了 24 个高质量的元基因组组装基因组（MAGs），其中 3 个新型 MAGs（TL100、TL46 和 TL57）含有调控所有代谢途径的功能基因。特别是，富含 NT 的 MAG（如鞘氨醇单胞菌）能促进发酵，导致土壤总碳（TC）相对于大体积土壤中的 MP 而减少。RT 很好地保留了土壤总碳和全氮的含量，并上调了链霉菌携带的 phoR 基因，这促进了对磷饥饿的调节，同时增加了大体积土壤中的全磷（TP）和可利用磷（AP）的含量。此外，CAT 还促进了根瘤菌土壤中硝酸盐的同化还原和有机磷的矿化，从而减少了氮的流失，并激活了土壤中的有机磷供作物吸收。总之，我们的研究结果表明，CAT 显著加速了多种代谢潜能，RT 比 NT 更能维持土壤养分含量。

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引用次数: 0

Grazing disturbance reduces biocrust-related cyanobacteria and N-fixer abundance but increases bacterial diversity: Implications for biocrust restoration in degraded drylands 放牧干扰减少了生物簇相关蓝藻和固氮菌的数量，但增加了细菌的多样性：对退化旱地生物群落恢复的影响

IF 6 1区农林科学 Q1 AGRICULTURE, MULTIDISCIPLINARY

Agriculture, Ecosystems & Environment

Pub Date : 2024-11-07 DOI: 10.1016/j.agee.2024.109367

Yue Li , Yuqi Sun , Longkat Ayuba Gufwan , Li Wu , Shubin Lan

Overgrazing is a major driver of dryland degradation, however, so far, there is limited understanding on how this process affects biocrust-related microbial community, and especially how the key groups respond to grazing disturbance. In this study, quantitative polymerase chain reaction (qPCR) and high throughout sequencing technologies were used to investigate the bacterial community abundance and diversity in the Horqin Sandland (China) experiencing different livestock grazing disturbances, in order to examine whether a shift in bacterial community (in particular the key biocrust components, cyanobacteria) was involved, and how this was related to biocrust development and altered soil carbon and nitrogen level. Our results revealed that a clear heterogeneous soil bacterial community was associated with grazing disturbance, which inhibited biocrust development. The decreased photosynthetic cyanobacterial abundance (81.81 % in relative abundance and 98.83 % in absolute abundance) and nitrogen-fixing genes (87.72 %), associated with the lower total carbon and nitrogen content (P<0.05), illustrated a low soil carbon and nitrogen-fixing capability and nutrient level in the grazing-disturbed soils. In particular, a switch of nitrogen-fixing dominance from cyanobacteria to proteobacteria was induced by the grazing disturbance. Compared to the grazing-disturbed soils, higher dominant cyanobacterial operational taxonomic units (OTUs) (especially the species of Nostoc and Scytonema) and lower bacterial diversity (e.g., Shannon, Ace, and Chao index) were observed in the undisturbed biocrust soils, highlighting that the dominants rather than diversity played more important roles in biocrust development. Collectively, our results demonstrate that cyanobacteria are very sensitive (even more than others, e.g., proteobacteria and actinobacteria) to grazing disturbance, therefore, we propose that cyanobacterial inoculation is likely an effective approach to supplement soil cyanobacterial abundance, which is expected to induce biocrust development and increase carbon and nitrogen level in the disturbed drylands.

过度放牧是旱地退化的一个主要驱动因素，但迄今为止，人们对这一过程如何影响与生物壳相关的微生物群落，尤其是关键群落如何应对放牧干扰的了解还很有限。本研究采用定量聚合酶链式反应（qPCR）和高通量测序技术，对遭受不同放牧干扰的科尔沁沙地（中国）的细菌群落丰度和多样性进行了研究，以探讨细菌群落（尤其是生物簇的关键成分蓝藻）是否发生了变化，以及这种变化与生物簇的发展和土壤碳氮水平的改变有何关系。我们的研究结果表明，明显的异质性土壤细菌群落与放牧干扰有关，放牧干扰抑制了生物簇的发展。光合蓝藻丰度（相对丰度为 81.81%，绝对丰度为 98.83%）和固氮基因（87.72%）的降低与土壤总碳氮含量的降低（P<0.05）有关，说明放牧干扰土壤的固碳、固氮能力和养分水平较低。特别是，放牧干扰诱导了固氮优势菌从蓝藻向蛋白菌的转变。与放牧干扰土壤相比，未受干扰的生物簇土壤中蓝藻优势分类单元（OTUs）较高（尤其是Nostoc和Scytonema物种），细菌多样性（如Shannon指数、Ace指数和Chao指数）较低，这表明在生物簇发育过程中，优势菌比多样性发挥着更重要的作用。总之，我们的研究结果表明，蓝藻对放牧干扰非常敏感（甚至比蛋白细菌和放线菌等其他细菌更敏感），因此，我们建议蓝藻接种可能是补充土壤蓝藻丰度的一种有效方法，有望诱导生物簇发育并提高受干扰旱地的碳氮水平。

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引用次数: 0

Enhancing soil ecosystem multifunctionality through combined conservation tillage and legume-based crop rotation in the North China Plain 在华北平原通过保护性耕作和豆科轮作相结合的方式提高土壤生态系统的多功能性

IF 6 1区农林科学 Q1 AGRICULTURE, MULTIDISCIPLINARY

Agriculture, Ecosystems & Environment

Pub Date : 2024-11-07 DOI: 10.1016/j.agee.2024.109355

Wenxuan Liu , Cong He , Shouwei Han , Baijian Lin , Wensheng Liu , Yash Pal Dang , Xin Zhao , Hailin Zhang

Conservation agriculture (CA), based on principles of conservation tillage (CT) and crop rotations, has been adopted as a solution to global climate change. However, interactions between these principles and their cumulative effects on soil functions and crop productivity are not yet fully understood. Herein, a 4-year filed experiment was conducted to assess the impact of CA on soil ecosystem multifunctionality (EMF) in the North China Plain (NCP). The results showed that CA improved EMF by up to 532 % compared to traditional agriculture (rotary tillage under wheat and maize rotation system). This enhancement is mainly driven by a 12.3 % increase in soil organic carbon (SOC) storage, an 8.3 % reduction in soil carbon to nitrogen ratio (C: N), a 68.3 % boost in soil enzyme activities index (SEI), and a 59.7 % increase in available phosphorus (AP) under legume-based crop rotations (LBCR) compared to maize-wheat-maize-wheat (MWMW). The principle of CT improved soil physical structure, enhancing soil aggregate stability by up to 38.1 % compared to rotary tillage (RT). Although, the benefits of CT on crop yield were not always observed, positive interactions on crop yield occurred under LBCR combined with CT. For instance, the soybean-wheat-soybean-wheat (SWSW) rotation produced 40.8 % higher yields than the MWMW rotation under CT. Overall, benefits of CT in improving soil structure, along with the increased diversity crop residues, adjustments in soil nutrient stoichiometric ratios, and enhanced soil enzyme activity under LBCR, led to improved SOC sequestration, crop yield and EMF under CA. The positive interactions between the principles of CA demonstrate its ability to enhance ecosystem multifunctionality. As a result, the combination of CT and LBCR within CA is recommended to sustain the productivity in NCP and other regions with similar conditions.

基于保护性耕作（CT）和作物轮作原则的保护性农业（CA）已被采纳为应对全球气候变化的一种解决方案。然而，这些原则之间的相互作用及其对土壤功能和作物生产力的累积效应尚未得到充分了解。在此，我们进行了一项为期 4 年的试验，以评估 CA 对华北平原土壤生态系统多功能性（EMF）的影响。结果表明，与传统农业（小麦和玉米轮作系统下的旋耕）相比，CA 对土壤生态系统多功能性的改善高达 532%。与玉米-小麦-玉米-小麦（MWMW）相比，在豆科轮作（LBCR）下，土壤有机碳（SOC）储存量增加了 12.3%，土壤碳氮比（C：N）降低了 8.3%，土壤酶活性指数（SEI）提高了 68.3%，可利用磷（AP）增加了 59.7%。与旋耕（RT）相比，CT 的原理改善了土壤物理结构，提高了土壤团聚稳定性达 38.1%。虽然旋耕技术对作物产量的益处并不总是显而易见，但在 LBCR 与旋耕技术相结合的情况下，旋耕技术对作物产量产生了积极的相互作用。例如，大豆-小麦-大豆-小麦（SWSW）轮作的产量比 CT 下的 MWMW 轮作高 40.8%。总体而言，CT 在改善土壤结构方面的益处，加上 LBCR 中作物残留物多样性的增加、土壤养分化学计量比的调整和土壤酶活性的增强，使得 CA 下的 SOC 固存、作物产量和 EMF 均有所提高。CA 原理之间的良性互动表明，CA 能够增强生态系统的多功能性。因此，建议在 CA 中结合 CT 和 LBCR，以维持 NCP 和其他条件类似地区的生产力。

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引用次数: 0

Effects of mound building and caching by steppe mouse (Mus spicilegus Petényi) on the vegetation in agroecosystems 草原鼠（Mus spicilegus Petényi）筑冢和穴居对农业生态系统植被的影响

IF 6 1区农林科学 Q1 AGRICULTURE, MULTIDISCIPLINARY

Agriculture, Ecosystems & Environment

Pub Date : 2024-11-06 DOI: 10.1016/j.agee.2024.109359

Laura Godó , Orsolya Valkó , Sándor Borza , Attila Ferenc , Réka Kiss , Katalin Lukács , Balázs Deák

Several rodent species are considered ecosystem engineers. They exert profound changes in agroecosystems by disturbing the soil during their activities. The steppe mouse (Mus spicilegus) inhabits various agroecosystems and constructs conspicuous mounds for overwintering using piled up plant material and soil. These mounds are widespread in many agroecosystems and may significantly affect the vegetation. In our study, we evaluated the effect of mound building activity of the steppe mouse on the vegetation of agroecosystems in Hungary. We sampled the cache content of 90 mounds in total located in old fields, alfalfa fields, and annual crop fields, and surveyed the aboveground vegetation of the mounds and their surrounding undisturbed matrix in 39 paired plots. Mice cached large amounts of seeds belonging mostly to weeds. In total we found 50,413 germinable seeds of 30 species in the cache content samples. However, the mound vegetation and the cache shared only a few species, suggesting that seeds cached by the mice do not contribute to the regenerating vegetation on the mounds. Soil disturbance by mice created distinct vegetation patches with species composition and structure different from the neighbouring undisturbed matrix. Early secondary successional vegetation patches on mounds introduced small-scale heterogeneity into the homogenous agricultural landscape, increased plant diversity and provided distinct flower resources for pollinators. The detected differences in the aboveground vegetation between the mound and the matrix in the studied habitats suggest that the steppe mouse acts as a facultative engineer species in agroecosystems.

一些啮齿类物种被认为是生态系统工程师。它们在活动中扰动土壤，使农业生态系统发生深刻变化。草原鼠（Mus spicilegus）栖息在各种农业生态系统中，利用堆积的植物材料和土壤建造明显的土丘越冬。这些土堆在许多农业生态系统中广泛存在，可能会对植被产生重大影响。在我们的研究中，我们评估了草原鼠的土丘建造活动对匈牙利农业生态系统植被的影响。我们对位于老田、紫花苜蓿田和一年生作物田中的共 90 个土丘的贮藏内容进行了取样，并在 39 个成对地块中调查了土丘及其周围未受干扰基质的地上植被。小鼠藏匿了大量种子，其中大部分是杂草种子。我们在储藏样本中总共发现了 30 个物种的 50,413 粒可发芽种子。然而，土丘植被和贮藏地仅有少数几个物种是相同的，这表明老鼠贮藏的种子并没有促进土丘植被的再生。老鼠对土壤的扰动形成了独特的植被斑块，其物种组成和结构与邻近未受扰动的基质不同。土丘上的早期次生植被斑块为同质的农业景观引入了小尺度的异质性，增加了植物多样性，并为传粉昆虫提供了独特的花卉资源。在所研究的栖息地中，发现土丘与基质之间的地上植被存在差异，这表明草原鼠是农业生态系统中的一种表面工程师物种。

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引用次数: 0

Effects of exogenous nitrogen addition on soil organic nitrogen fractions in different fertility soils: Result from a 15N cross-labeling experiment 外源氮添加对不同肥力土壤中有机氮组分的影响：15N 交叉标记实验的结果

IF 6 1区农林科学 Q1 AGRICULTURE, MULTIDISCIPLINARY

Agriculture, Ecosystems & Environment

Pub Date : 2024-11-05 DOI: 10.1016/j.agee.2024.109366

Yu Ning , Shuailin Li , Chuanchuan Ning , Jinfeng Ren , Zhuqing Xia , Mengmeng Zhu , Yun Gao , Xinhui Zhang , Qiang Ma , Wantai Yu

Exogenous nitrogen (N) addition serves as a pivotal nutrient management strategy, significantly enhancing agricultural production by regulating soil N availability and retention. However, the dynamics of soil organic nitrogen (SON) fractions in response to various forms of exogenous N addition across differing soil fertility levels remain inadequately understood. This study utilized data from a 25-year fertilization experiment and a ¹⁵N cross-labeling experiment in Northeast China to assess and quantify the effects of mineral N fertilizers and organic materials (manure and straw) on SON fractions in NPK (mineral fertilizer addition) and NPKM (NPK combined with composted pig manure) treatments. Our findings indicate that long-term incorporation of manure substantially elevates soil fertility compared to the exclusive use of mineral fertilizers. Notably, exogenous N primarily boosts soil N availability by enhancing acid-soluble organic N fractions, particularly ammonium nitrogen (AN) and amino acid nitrogen (AAN). Organic materials, particularly straw, significantly enhanced the retention of mineral fertilizer N in both NPK and NPKM treatments (9.54 % vs 10.70 %). Moreover, over 70 % of the N from straw or manure remained in the soil as stable SON fractions. While straw rapidly improves low-fertility soils, manure contributes to enhanced soil N reserves and increased crop yields. Therefore, incorporating organic matter may bolster soil N sequestration in Northeast China, which is contingent upon soil fertility and tailored fertilizer management strategies. This research elucidates the distribution and conversion of exogenous N within SON pools, facilitating optimized N management, sustaining yields, reducing farmland N pollution, and promoting agricultural sustainability.

外源氮（N）添加作为一种关键的养分管理策略，通过调节土壤氮的供应和保持，显著提高了农业产量。然而，人们对不同土壤肥力水平下土壤有机氮（SON）组分对各种外源氮添加形式的响应动态仍然了解不足。本研究利用在中国东北地区进行的一项为期 25 年的施肥试验和一项 15N 交叉标记试验的数据，评估并量化了矿物氮肥和有机材料（粪肥和秸秆）对 NPK（添加矿物肥料）和 NPKM（NPK 与堆肥猪粪相结合）处理中有机氮组分的影响。我们的研究结果表明，与只使用矿物肥料相比，长期施用粪肥可大幅提高土壤肥力。值得注意的是，外源氮主要通过提高酸溶性有机氮组分，尤其是铵态氮（AN）和氨基酸态氮（AAN）来提高土壤氮的可用性。在 NPK 和 NPKM 处理中，有机材料（尤其是秸秆）都能显著提高矿物肥料氮的保留率（9.54% 对 10.70%）。此外，秸秆或粪肥中超过 70% 的氮以稳定的 SON 分馏物形式留在土壤中。秸秆能迅速改善低肥力土壤，而粪肥则有助于增加土壤氮储备和提高作物产量。因此，在中国东北地区，施用有机质可促进土壤固氮，但这取决于土壤肥力和有针对性的肥料管理策略。这项研究阐明了外源氮在SON池中的分布和转化，有助于优化氮管理、维持产量、减少农田氮污染和促进农业可持续发展。

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引用次数: 0

Functional groups of leaf phenology are key to build climate-resilience in cocoa agroforestry systems 叶片物候功能组是可可农林系统建立气候适应能力的关键

IF 6 1区农林科学 Q1 AGRICULTURE, MULTIDISCIPLINARY

Agriculture, Ecosystems & Environment

Pub Date : 2024-11-04 DOI: 10.1016/j.agee.2024.109363

Issaka Abdulai , Munir Hoffmann , Helena Kahiluoto , Michaela A. Dippold , Mutez A. Ahmed , Richard Asare , Winston Asante , Reimund P. Rötter

Agroforestry has the potential to enhance climate change adaptation. While benefits from agroforestry systems consisting of cash crops and shade trees are usually attributed to the (shade) trees, the trees can also have negative impacts due to resource competition with crops. Our hypothesis is that leaf phenology and height of shade trees determine their seasonal effect on crops. We test this hypothesis by categorizing shade tree species into functional groups based on leaf phenology, shade tree canopy height and shade tree light (wet and dry season) interception as well as the effects. To this end, leaf phenology and the effects on microclimate (temperature, air humidity, intercepted photoactive radiation (PAR)), soil water, stomatal conductance and cocoa yield were monitored monthly during wet and dry seasons over a two-year period on smallholder cocoa plantations in the northern cocoa belt of Ghana. Seven leaf phenological groups were identified. In the wet season, highest buffering effect of microclimate was recorded under the trees brevi-deciduous before dry season. During dry season, high PAR and lowest reduction in soil moisture were observed under the trees in the group of completely deciduous during dry season. The evergreen groups also showed less reduction in soil water than the brevi-deciduous groups. In the wet season, shade tree effects on cocoa tree yields in their sub canopy compared to the respective control of outer canopy with full sun ranged from positive (+10 %) to negative (-15 %) for the deciduous groups, while yield reductions for the evergreen groups ranged from −20 % to −33 %. While there were negative yield impacts for all phenological groups in the dry season, the trees in completely deciduous during dry season group recorded least penalties (-12 %) and the trees with evergreen upper canopy the highest (-35 %). The function of shade trees in enhancing climate resilience is therefore strongly dependent on their leaf phenological characteristics. Our study demonstrates how the key trait leaf phenology can be applied to successful design of climate-resilient agroforestry systems.

农林业具有增强气候变化适应能力的潜力。虽然由经济作物和遮荫树组成的农林系统的效益通常归功于（遮荫）树，但树木也可能因与作物争夺资源而产生负面影响。我们的假设是，遮荫树的叶片物候和高度决定了它们对农作物的季节性影响。我们根据叶片物候学、遮荫树冠高和遮荫树（雨季和旱季）截光率以及影响，将遮荫树种分为功能组，以此来验证这一假设。为此，在加纳北部可可带的小农可可种植园中，在为期两年的雨季和旱季期间，每月监测叶片物候及其对小气候（温度、空气湿度、截获的光辐射（PAR））、土壤水分、气孔导度和可可产量的影响。确定了七个叶片物候组。在雨季，干季之前的落叶乔木对小气候的缓冲作用最大。在旱季，完全落叶树种的 PAR 值高，土壤水分减少最少。常绿树种组的土壤水分减少率也低于半落叶树种组。在湿季，与外层树冠阳光充足的对照组相比，遮荫树对可可树下层树冠的产量影响从落叶组的正影响（+10%）到负影响（-15%）不等，而常绿组的减产幅度则从-20%到-33%不等。虽然旱季对所有物候组的产量都有负面影响，但旱季完全落叶组树木的减产幅度最小（-12%），而上部树冠为常绿植物的树木的减产幅度最大（-35%）。因此，遮荫树在提高气候适应能力方面的功能在很大程度上取决于其叶片物候特征。我们的研究证明了如何将叶片物候这一关键特征应用于成功设计气候适应性农林系统。

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引用次数: 0

Nutrient enrichment weakens community temporal stability via asynchrony and species dominance in a subalpine grassland 在亚高山草地上，营养富集会通过异步性和物种优势削弱群落的时间稳定性

IF 6 1区农林科学 Q1 AGRICULTURE, MULTIDISCIPLINARY

Agriculture, Ecosystems & Environment

Pub Date : 2024-11-04 DOI: 10.1016/j.agee.2024.109358

Xiaoling Gan , Weibin Li , Xiaoshuang Ye , Yuan Jiang , Chuanyan Zhao

Rapid and frequent nitrogen (N) and phosphorus (P) inputs have seriously disrupted the stability of many ecosystems, prompting us to find the main mechanisms driving these changes across various ecological systems, which is crucial for predicting ecosystem responses to reactive nutrient inputs. While the mechanisms underlying N-induced stability have been extensively studied, the effects of P and simultaneous N and P enrichment on ecological stability and their driving mechanisms are less understood, particularly in alpine ecosystems. To address this gap, we conducted a short-term (2019–2023) simulation experiment of N and P enrichment in a subalpine grassland of Qilian Mountain to evaluate the effects of nutrient enrichment on ecosystem stability and to identify its potential mechanisms. Our findings demonstrated that five-year nutrient enrichment did not obviously affect species richness/dominance, but N+P enrichment significantly decreased both community aboveground biomass (AGB) and the AGB of dominant species. In addition, community temporal stability was strongly reduced with both N and N+P enrichment. This negative impact was directly driven by the stability of dominant species, species dominance, and compensatory effects, which together explained 77 % of the variation in stability according to structural equation modeling (SEM). Moreover, species richness indirectly influenced community stability through species asynchrony. Our findings provide a theoretical basis for understanding the roles of compensatory effects and dominant species in driving changes in ecosystem stability under nutrient enrichment.

快速而频繁的氮（N）和磷（P）输入严重破坏了许多生态系统的稳定性，这促使我们寻找驱动各种生态系统发生这些变化的主要机制，这对于预测生态系统对活性营养物质输入的反应至关重要。虽然对氮引起稳定性的机制进行了广泛的研究，但对磷以及同时富集氮和磷对生态稳定性的影响及其驱动机制却了解较少，尤其是在高寒生态系统中。为了弥补这一空白，我们在祁连山亚高山草地进行了氮磷富集的短期（2019-2023 年）模拟实验，以评估养分富集对生态系统稳定性的影响并确定其潜在机制。我们的研究结果表明，五年的养分富集对物种丰富度/优势度没有明显影响，但N+P的富集显著降低了群落的地上生物量（AGB）和优势物种的AGB。此外，群落的时间稳定性在氮和氮+磷富集的情况下都大大降低。这种负面影响是由优势物种的稳定性、物种优势度和补偿效应直接驱动的，根据结构方程建模（SEM），它们共同解释了稳定性变化的 77%。此外，物种丰富度通过物种异步性间接影响群落稳定性。我们的研究结果为理解营养富集条件下补偿效应和优势物种在驱动生态系统稳定性变化中的作用提供了理论依据。

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引用次数: 0

Response of grassland greenhouse gas emissions to different human disturbances – A global Meta-analysis 草地温室气体排放对不同人类干扰的响应--全球元分析

IF 6 1区农林科学 Q1 AGRICULTURE, MULTIDISCIPLINARY

Agriculture, Ecosystems & Environment

Pub Date : 2024-11-02 DOI: 10.1016/j.agee.2024.109362

Yong Cao , Zemin Ai , Xiaohu Dang , Huan Liu , Qingqing Li , Mengjia Hou , Yuyan Yao , Yi Deng , Lie Xiao , Shuaimeng Zhu

Human disturbances have increased greenhouse gas (GHG) emissions from grassland, worsening global warming. However, the response of grassland GHG (CO₂, N₂O, and CH₄) to human disturbances across various climatic zones requires further elucidation, as does the intricate relationship between GHG emissions and temperature and precipitation. A Meta-analysis of the effects of human disturbances on GHG in grassland over the past 40 years revealed that grazing, fertilization, mowing, and burning significantly influenced the total emissions of N₂O, CH₄, CO₂, and GHG from grassland. However, the light and moderate grazing exerted no substantial impact on CO₂ emission flux. In frigid zone grassland, the N₂O emission flux was most significantly affected by grazing, the CH₄ emission flux affected by fertilization was higher than grazing, and the CO₂ emission flux was more sensitive to heavy grazing than severe fertilization. In temperate grassland and savanna, GHG emission flux was most sensitive to fertilization, with CO₂ emission flux in savanna being particularly responsive to burning. The effect of increased temperature and precipitation on CO_2e in fertilized grassland was approximately double that of grazed grassland and quadruple that of mowed grassland. This study emphasizes the increased effect of human disturbances on GHG emissions in the grassland, especially with the most significant impact of fertilization disturbances on GHG emissions in most grassland areas. Lowering the level of fertilization during grassland management could serve as a crucial step in mitigating GHG emissions from grassland. In summary, rigorous control of disturbance intensity represented an effective strategy for mitigating greenhouse gas emissions, albeit potentially impacting grassland productivity. Future endeavors should focus on determining the optimal disturbance intensity to strike a balance amidst these complex effects.

人类活动增加了草原的温室气体排放，加剧了全球变暖。然而，草原温室气体（二氧化碳、一氧化二氮和甲烷）在不同气候区对人类干扰的反应，以及温室气体排放与气温和降水之间错综复杂的关系，都需要进一步阐明。一项关于过去 40 年人类干扰对草地温室气体影响的 Meta 分析显示，放牧、施肥、除草和焚烧对草地的 N2O、CH4、CO2 和温室气体排放总量有显著影响。然而，轻度和中度放牧对二氧化碳排放通量没有实质性影响。在寒带草原，放牧对 N2O 排放通量的影响最大，施肥对 CH4 排放通量的影响高于放牧，而 CO2 排放通量对重度放牧的敏感性高于重度施肥。在温带草原和热带稀树草原，温室气体排放通量对施肥最为敏感，热带稀树草原的二氧化碳排放通量对焚烧尤其敏感。温度和降水的增加对施肥草地 CO2e 的影响大约是放牧草地的两倍，是刈割草地的四倍。这项研究强调了人为干扰对草地温室气体排放的更大影响，尤其是施肥干扰对大多数草地地区温室气体排放的影响最为显著。在草地管理过程中降低施肥水平是减少草地温室气体排放的关键一步。总之，严格控制干扰强度是减少温室气体排放的有效策略，尽管可能会影响草原生产力。未来的工作重点应该是确定最佳干扰强度，以便在这些复杂的影响中取得平衡。

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引用次数: 0