Does Biochar Addition Influence the Change Points of Soil Phosphorus Leaching?

Phosphorus change point indicating the threshold related to P leaching, largely depends on soil properties. Increasing data have shown that biochar addition can improve soil retention capacity of ions. However, we have known little about weather biochar amendment influence the change point of P leaching. In this study, two soils added with 0, 5, 10, 20, and 50 g biochar kg-1 were incubated at 25℃ for 14 d following adjusting the soil moisture to 50% water-holding capacity （WHC）. The soils with different available P values were then obtained by adding a series of KH2PO4 solution （ranging from 0 to 600 mg P kg-1 soil）, and subjecting to three cycles of drying and rewetting. The results showed that biochar addition significantly lifted the P change points in the tested soils, together with changes in soil pH, organic C, Olen-P and CaC12-P but little on exchangeable Ca and Mg, oxalate-extractable Fe and Al. The Olsen-P at the change points ranged from 48.65 to 185.07 mg kg-1 in the alluvial soil and 71.25 to 98.65 mg kg^-1 in the red soil, corresponding to CaCl2-P of 0.31-6.49 and 0.18-0.45 mg L~, respectively. The change points of the alluvial soil were readily changed by adding biochar compared with that of the red soil. The enhancement of change points was likely to be explained as the improvement of phosphate retention ability in the biochar-added soils.     

有机肥造粒方式及设备传动方式的合理性探讨

该文简介有机肥的应用现状以及制备工艺原理,指出对有机肥造粒是有机肥制备过程中很重要的环节;介绍常用造粒设备的主要技术参数、工作原理、基本组成、传动方式、结构特点、适用范围等,进一步论述了各自的优缺点;重点对造粒的球形度、压实度(强度)、生产效率,以及设备所需的驱动功率、转速、传动链的长短、运动平稳性进行了探讨,进一步指出了有机肥造粒设备的发展方向。     

地中海山地土壤中团聚体的形成和有机质的储存

Soil aggregation and organic matter of soils from the pre-Pyrenean range in Catalonia (NE Spain) were studied, in order to assess their quality as carbon sinks and also to select the best soil management practices to preserve their quality. Aggregate stability, organic carbon and micromorphology were investigated. The highest amount of organic carbon was found in alluvial, deep soils (228 Mg C ha^-1), and the lowest was in a shallow, stony soil with a low plant cover (78 Mg C ha^-1). Subsurface horizons of degraded soils under pastures were the ones with smaller and less-stable aggregates. Fresh residues of organic matter (OM) were found mostly in interaggregate spaces. Within the aggregates there were some organic remains that were beginning to decompose, and also impregnative nodules of amorphous OM. Although OM was evenly distributed among the aggregate fractions, the larger blocky peds had more specific surface, contained less decomposed OM and had a lower organic/mineral interphase than smaller crumb aggregates, which were also more stable. Soil carbon storage was affected primarily by the OM inputs in the surface horizons. In order to store organic carbon over the mid-and long-term periods, the mechanisms favouring structuration through biological activity and creating small aggregates with intrapedal stable microporosities seemed to be the most effective.     

Microbial respiration activities related to sequentially separated, particulate and water-soluble organic matter fractions from arable and forest topsoils

This study aimed to reveal differences in the relevance of particulate as well as water-soluble organic matter (OM) fractions from topsoils to the easily biodegradable soil organic matter (SOM). We selected eight paired sites with quite different soil types and soil properties. For each of these sites, we took samples from adjacent arable and forest topsoils. Physically uncomplexed, macro-, and micro-aggregate-occluded organic particle, as well as water-soluble OM fractions were sequentially separated by a combination of electrostatic attraction, ultrasonic treatment, density separation, sieving, and water extraction. The easily biodegradable SOM of the topsoil samples was determined by measuring microbial respiration during a short-term incubation experiment (OC_R). The organic carbon (OC) contents separated by i) the physically uncomplexed water-soluble OM, ii) the macro-, and iii) the micro-aggregate-occluded organic particle as well as water-soluble OM fractions were significantly correlated with OC_R. The correlation coefficients vary between 0.54 and 0.65 suggesting differences in the relevance of these OM fractions to the easily biodegradable SOM. The strongest correlation to OC_R was detected for the OC content separated by the physically uncomplexed water-soluble OM indicating the most distinct relation to the easily biodegradable SOM. This was found to be independent from land use or soil properties.     

速补钙磷对白唇鹿发病率的影响

对65只白唇鹿在补饲过程中添加速补钙磷,结果表明补饲过程中添加速补钙磷的试验组与对照组相比,对白唇鹿异食癖,提高鹿茸产量、降低鹿软骨病骨质疏松、瘫痪等作用显著。平均每只鹿鹿茸产量增加139.5g。鹿软骨病、瘫痪下降1.48%、异食癖发病率降为零。鹿羔月体重平均增2.5kg。     

Mixtures of organic amendments and biochar promote beneficial soil microbiota and affect Fusarium oxysporum f. sp. lactucae,Rhizoctonia solani and Sclerotinia minor disease suppression

The use of soil fumigants and fungicides to control soilborne pathogens is reduced due to awareness of their negative drawbacks. Long-term application of such agrochemicals negatively affects soil microbiota and reduces natural soil suppressiveness. We investigated long-term impacts of biochar and not-pyrogenic organic amendment (OAs: manure, alfalfa straw and glucose), on disease suppression compared with conventional management in three pathosystems: Fusarium oxysporum f. sp. lactucae (FOL)–lettuce, Rhizoctonia solani–tomato and Sclerotinia sclerotiorum–lettuce, by conditioning soil for 2 years. Soil analyses included pH, electrical conductivity, organic carbon, total nitrogen, C:N ratio, N-NO₃⁻, N-NH₄⁺, cation exchange capacity, available phosphorus, Ca²⁺, Mg²⁺, K⁺, Na⁺, fluorescein diacetate (FDA), and total and active limestone. Soil microbiota was characterized by combining BIOLOG EcoPlates with next-generation sequencing of 16S and 18S rRNA genes. Soil amended with OAs generally suppressed disease by S. sclerotiorum and FOL compared to fumigants and synthetic fertilizers. However, the incidence of R. solani infection was lower in soil treated with synthetic fertilizers than soil amended with OAs. EC, pH, C:N, N-NO₃⁻, N-NH₄⁺, FDA and BIOLOG were significantly correlated with disease, depending on pathosystem. Bacterial richness and diversity, presence of some genera like Acidobacteria, Chloracidobacteria, Solibacteres, Anaerolineae, Nitrospira and Deltaproteobacteria were negatively related to disease incidence of FOL and S. sclerotiorum, whereas damping-off caused by R. solani was negatively affected by the presence of Flavobacterium and Chitinofagha. Therefore, we concluded that long-term application of OAs can effectively improve soil suppressiveness and reduce disease incidence against root pathogens, although the effects vary considerably depending upon pathosystem.     

晾晒时间和青贮时间对青贮玉米发酵品质的影响

目的 探究不同晾晒时间和青贮时间对全株青贮玉米发酵品质的影响。方法 以玉米（Zea mays L.）青贮品种“曲辰9号”为试验材料,将乳熟末期的青贮玉米全株收获粉碎后,在阴凉处分别晾晒0（对照,CK）、1、2、3、4 d,然后在塑料桶（5 L）中分别进行青贮,待青贮60、90、120 d时进行发酵品质的评定。结果 青贮玉米的含水量随着晾晒时间的增加而降低,在晾晒2、3、4 d后含水量显著（P<0.05）低于CK;用晾晒2、3、4 d的全株青贮玉米原料进行青贮,pH值显著（P<0.05）高于CK,晾晒2 d青贮120 d处理除外。晾晒时间对乳酸、丁酸、中性洗涤纤维（NDF）和酸性洗涤纤维（ADF）含量均产生显著（P<0.05）影响,青贮时间仅对乳酸、丁酸产生显著（P<0.05）影响,其中,乳酸含量随着青贮时间的延长而增加,丁酸含量在原料晾晒之后明显增加。CK处理中,青贮90、120 d的NDF含量显著（P<0.05）高于青贮60 d处理。利用氨态氮、乙酸、丙酸、丁酸开展V-Score分析,晾晒导致青贮玉米发酵品质降低,试验中品质较优的青贮为原料粉碎后未经晾晒的处理（CK）。结论 在未经晾晒处理下进行青贮60 d的青贮玉米,综合品质较高。在青贮玉米原料含水量为74%时,不建议粉碎之后通过晾晒降低含水量再青贮。     

有机肥部分替代化肥对春暖式大棚西兰花产量和品质的影响

为实现春暖式大棚西兰花优质高产高效生产,在等氮条件下研究有机肥不同比例（0、15%、30%、45%、60%）替代化肥对春暖式大棚西兰花产量、效益、品质以及土壤养分的影响。结果表明:春暖式大棚有机肥部分替代化肥处理西兰花产量都有所提高,土壤有机质、全氮、有效磷和速效钾含量均有增加趋势。与CK相比较,30%比例替代处理每667 m²增效115.88元;45%和60%比例替代处理的西兰花蛋白质和可溶性糖含量均增加,硝酸盐含量均下降。综合春暖式大棚西兰花产量、效益、品质和土壤养分等因素,有机肥部分替代化肥（氮）以30%为最佳。     

黄土丘陵区不同土地类型下土壤养分特征—基于生态化学计量学

为探讨黄土丘陵区不同土地类型下土壤有机碳（SOC）、全氮（TN）、全磷（TP）含量特征,本研究以黄土丘陵区典型小麦地、云杉林地、苜蓿地为对象,基于实测数据,采用方差、相关统计分析,研究不同土地类型、不同土层深度（0~10 cm、10~20 cm、20~40 cm、40~60 cm、60~80 cm、80~100 cm）土壤SOC、TN、TP含量及其化学计量比。结果表明：3种不同土地类型土壤SOC、TN和TP含量均随土层深度增加而降低,其平均含量分别为12.19、0.33和0.48 g·kg^-1,小麦地和苜蓿地土壤SOC、TN和TP空间变异性较云杉林地偏大。SOC、TN含量为云杉林地>小麦地>苜蓿地,TP含量为云杉林地>苜蓿地>小麦地。土壤SOC、TN和TP间均存在显著正相关关系。小麦地C/P显著（P<0.05）高出苜蓿地41.96%,N/P显著高出云杉林地、苜蓿地28.57%、36.19%。3种不同土地类型土壤化学计量比（C/N、C/P、N/P）均值分别为：39.61、31.53、0.83,且其C/N大于中国平均值（12.3）,C/P、N/P较全国平均值（61.0、5.2）明显偏小,黄土丘陵区C/N较稳定。土地类型对土壤C、N、P含量及其化学计量比存在不同程度的影响,合理调整土地利用结构有助于土壤养分的存留,有利于土壤生态的恢复。