间作对刺梨园土壤养分的影响

以贵州省龙里县刺梨(Rosa roxburghii Tratt)园间作玉米、辣椒模式为研究对象,以刺梨园自然生草为对照,分析刺梨间作园土壤养分特征,为刺梨园管理提供理论参考。结果表明:1)与刺梨园自然生草相比,间作玉米、辣椒均降低了0~20 cm土壤pH值以及土壤有机质含量、总氮含量、有效氮含量、有效磷含量,提高了土壤总磷含量、总钾含量、有效钾含量;2)间作辣椒的刺梨园土壤pH值以及土壤有机质含量、总氮含量、有效氮含量、总钾含量均高于间作玉米的,而有效钾含量低于间作玉米的。这说明在正常的田间管理条件下刺梨园自然生草对多数土壤养分的维持起到较好作用,间作玉米、辣椒施肥时建议采取有机肥为主、无机肥为辅,从而达到维持刺梨园土壤养分平衡。     

云南河口不同土地利用方式下的土壤养分变化

选取云南河口橡胶园、油梨园和香蕉园的3种热带作物作为研究对象,通过研究其土壤pH、有机质、碱解氮、有效磷和速效钾等指标,分析不同土地利用方式下的土壤养分变化状况。结果显示:3种热带作物中橡胶园有机质、解碱氮最高,pH、有效磷最低,速效钾居中;油梨园土壤pH、有机质、解碱氮、有效磷均为中间水平,速效钾最低;香蕉园土壤pH、有效磷、速效钾含量最高,有机质最低。总体来看,香蕉园土壤养分水平相对较高,橡胶园中等,油梨园中等偏下,这些养分指标中仅有橡胶园和油梨园土壤pH、有效磷之间存在极显著差异,各土壤养分之间为一般正相关关系,差异不显著。     

沙田柚低产原因

广西玉林地区农技推广站陈国平等人选择三个具有代表性的高产、较高产和低产抽园进行调查研究，找出沙田抽低产的主要原因是：1.土壤有效养分和有机质含量：高产抽园有机质含量、速效氮、速效磷、速效钾、钙、镁含量均明显高于低产拍园。有效养分含量低，有机质缺乏，是抽园低产的基本原因。2．花朵质量：单花鲜重1．26士O．27克，最大2．0克，是最小0．4克的5．O倍，大花的座果率极显著高于小花座果率。多数大花子房呈绿色或浅绿色，座果率高，多数小花子房呈黄绿色或黄白色，座果率很低。花朵发育不完全、花质差是沙田抽低产的根本原因。…     

甘肃油橄榄园土壤养分丰缺状况

为了给油橄榄园土壤管理和合理施肥提供参考,通过对陇南白龙江沿岸低山河谷地区有代表性的126个油橄榄园的土壤进行取样测定,在前人研究的基础上,确定了甘肃油橄榄园土壤养分标准,并用该指标评价了果园土壤养分肥力的丰缺情况。结果表明:陇南油橄榄产区土壤肥力普遍存在的问题是有机质含量低,碱解氮、有效磷和速效钾亏缺,且各营养元素之间存在不同程度的差异;土壤p H值对土壤养分有效性影响较大,土壤p H值与有机质、碱解氮、有效磷含量呈显著或极显著负相关。     

凤县花椒园土壤养分特征研究

采取典型样地采样和实验室经典测试方法,对凤县花椒园0~20、20~40cm层土壤有机质及速效氮、磷、钾含量进行了分析研究,结果表明凤县花椒园0~40cm土层有机质、速效氮、磷、钾平均含量分别为12.88g·kg~(-1)、11.12mg·kg~(-1)、7.23mg·kg~(-1)和142.92mg·kg~(-1);有机质及速效氮磷钾含量差异较为明显,整体变异系数偏高,尤其是速效磷,0~20cm土层变异系数高达119.49%。有机质及速效磷含量均属于中等偏低水平,速效氮处于缺乏等级,速效钾含量较高,生产中应提倡增施有机肥和氮磷复合肥,结合花椒生长期针对性地补充钾肥,以提高花椒产量和品质。     

野生栎树群落的土壤环境特征及其在城区成功恢复的土壤改良途径

选取野生栎树群落和城市人工绿地,分别进行了土壤容重、pH值、有机质、碱解氮、速效钾、有效磷含量的研究分析。结果表明:野生栎树群落的土壤有机质、碱解氮、速效钾含量均高于城市人工绿地,只有有效磷含量低于城市人工绿地。野生栎树群落对土壤养分的作用规律总体表现为:土壤有机质、碱解氮、速效钾、有效磷含量向土壤上层富集,而城市人工绿地对土壤养分的影响与之不同。     

江西省方竹林土壤养分有效态含量特征

对江西省方竹林地土壤主要营养元素有效态含量进行检测，分析土壤pH值、有机质含量对土壤营养元素有效态含量的影响。结果表明：江西省方竹林土壤整体上呈弱酸性，不同养分元素间含量差异较大，有效锌、有机质和速效氮含量较丰富，有效磷和速效钾缺乏；土壤pH值与有机质含量之间的相关性较小；土壤元素有效态含量随着pH值的增大而逐步增加，在pH值为7.0左右达到峰值，随后呈下降趋势；有机质和pH值对各元素有效态含量的影响大小基本一致，有效锌和有效磷之间的相关性最大，达到了极显著水平，而速效氮和速效钾之间的相关性最小。     

东营冬枣栽培区土壤养分差异分析

以东营市各县区冬枣栽培区土样为研究对象,测定土样中有机质、氮、磷、钾的含量,研究分析全市冬枣园土壤养分含量情况。结果表明,各县区除优质栽培区外,其他冬枣栽培区土壤有机质含量较低,尤其是河口区和垦利区,应注重土壤有机质的积累,改善各种营养元素的供应能力和有效性;除广饶县冬枣栽培区土壤中钾含量足以供应冬枣正常生长之外,其他冬枣栽培区土壤中的氮、磷养分含量比较缺乏。全市各县区冬枣栽培区需结合各自实际,有针对性地调整氮磷钾用量,合理科学施肥,提高肥料利用率。     

果园覆草好处多

果园覆草,即在果园地面覆盖秸杆或杂草。每亩果园覆草1000～1500公斤,连续覆草3～4年,能加厚活土层10～15厘米,0～40厘米土壤内有机质比清耕园提高61.1%,0～20厘米表土层的有机质含量比清耕园可提高1倍多,氮、磷、钾含量分別比清耕园相对增加54.7%、27.7%和28.9%.覆草还可减少地表水分蒸发,提高土壤对水分的渗透和     

白石山森林土壤有机质及氮,磷,钾养分状况研究

对太行山脉北端白石山不同类型森林土壤中氮、磷、钾养分全量及有效量进行了室内分析。结果表明：土壤有机质平均含量为１８．３７％￣１０６．３４ｇ／ｋｇ，全氮量为１．１１￣３．４３ｇ／ｋｇ，全钾量为２０．６９￣２５．４６ｇ／ｋｇ；碱解氮含量为３８．５￣２４４．３ｍｇ／ｋｇ，速效钾含量为１３３．２￣２１４．４ｍｇ／ｋｇ，有机质及氮、钾全量较高，有效供应较好；全磷量多低于０．８ｇ／ｋｇ，速效磷多低于１０ｍｇ／     

油橄榄根系与土壤物理因子关系的研究

通过对油橄榄根系类型、剖面须根的调查和土壤条件的研究,结果表明土壤物理性质是影响根系生长发育的主导因素。在质地粘重、通气不良与生长期多雨的条件下,油橄榄根系均表现为水平根型。而适宜根系生长发育的土壤条件是,砂粒>40％、粘粒<30％、渗透性80—150 mm/h、非毛管孔隙度>20％、坚实度2.5—4.5 kg/cm~3。     

我国油橄榄中试园土壤条件及其营养指标的研究

1983—1987年对湖北省武昌、宜昌、当阳县和陕西省城固县油橄榄中试园土壤与营养状况进行了研究。结果表明:油橄榄生长较好的(一类树下)土壤条件是pH7—8,CaCO_3>5％,有机质>1.8％,速效N>74.4—87.4mg/kg土,速效P>40mg/kg土,速效K>200mg/kg土,交换性Ca103—181mmol/kg土,交换性Mg24—34mmol/kg土。生长结实好的一类树叶片营养指标为N2.0—2.5％,P_2O_5 0.14％,K_2O 1.5％,CaO 4.0％,MgO 0.8％。通过分析建立了预测产量和施肥控制的回归方程。     

Soil carbon stock in olive groves agroforestry systems under different management and soil characteristics

The atmospheric concentrations of greenhouse gases have increased to unprecedented levels during last decades, raising concerns about their effect on climate change. Agriculture and land use change play an important role in atmospheric CO₂ emission and fixation, especially by affecting the soil carbon (C) storage. In this context, agroforestry systems (AFSs) could play an important role contributing to climate change mitigation. Given the importance of olive cultivation in the Mediterranean region, it is important to investigate soil C stock in olive groves, and to assess which agronomic practices could improve the soil C stock in these systems. For this reason, a study was conducted in different olive groves, including conventional and organic management, and a typical silvopastoral AFS. Furthermore, an abandoned olive grove and nearby forest were examined as a comparison. Soil samples were collected in each farm and analysed for C content and physico-chemical characteristics. This study indicates that, irrespective of the management, olive groves in the Umbria region of Italy are characterised by a high level of soil C stock if compared to those growing in other areas and to forest ecosystems, indicating that the practices adopted in the area are not negatively affecting soil C storage. A slightly lower soil C stock was measured in the silvopastoral AFS in comparison to the other farms, while high soil C stock was associated with the use of pomace, suggesting that this practice can be used to further increase soil C stock in olive orchards.

     

不同施肥处理对黄瓜土壤速效养分变化的影响研究

对黄瓜菜地进行了不同施肥处理,通过测定土壤养分,研究了化肥减量及增施有机肥对土壤养分的影响。结果表明:按当地化肥施用量的处理在成熟期土壤速效磷、铵态氮、速效钾含量均比其他处理高,但养分利用率较低;化肥施用量减少20%的处理次之;化肥施用量减少40%+20%有机肥的处理养分全量较高,并且速效养分不高,其养分流失量少,肥料利用率高;而化肥用量减60%+40%有机肥的处理养分全量及速效养分含量都较低,其肥料利用率比化肥施用量减少40%+20%有机肥的处理差。化肥施用量减少40%+20%有机肥能很好地提高土壤各种养分含量,且供肥平稳,能满足黄瓜生长需要,为最合理施肥处理。     

Active organic carbon pool of coniferous and broad-leaved forest soils in the mountainous areas of Beijing

In order to explore the effects of different forest types on active soil carbon pool, the amounts and density of soil organic carbon (SOC) were studied at different soil horizons under typical coniferous and broad-leaved forests in the mountainous area of Beijing. The results showed that the amount of total SOC, readily oxidizable carbon and particulate organic carbon decreased with increasing depths of soil horizons and the amounts at depths of 0–10 cm and 10–20 cm in broad-leaved forest was clearly higher than that in coniferous forests. The trend of a decrease in SOC density with increasing depth of the soil horizon was similar to that of the amount of SOC. However, no regular trend was found for SOC density at different depths between coniferous forest and broad-leaved forests. The ratio of readily oxidizable carbon to total amount of SOC ranged from 0.36–0.45 and the ratio of particulate organic carbon to total amount of SOC from 0.28–0.73; the ratios decreased with increasing depths of soil horizons. Active SOC was significantly correlated with total SOC; the relationship between readily oxidizable carbon and particulate organic carbon was significant. A broad-leaved forest may produce more SOC than a coniferous forest.     

毛竹林集约经营过程中土壤活性有机碳库的演变

为了探讨不同集约经营历史毛竹林的土壤有机碳库演变规律,在浙江省安吉县分别采集了集约经营5、10、20和40年的毛竹林土壤样品,与粗放经营毛竹林进行比较.结果表明:毛竹林集约经营的前5年里,土壤总有机碳、微生物量碳、水溶性碳和矿化态碳含量均明显下降(P＜0.05);土壤总有机碳持续下降至20年后趋于稳定,土壤水溶碳、矿化态碳含量集约经营5年后一直到第40年无明显变化;随着集约经营措施的实施,土壤活性有机碳占总有机碳的比例变化不大(除矿化态碳在0～5年以及微生物量碳在10～20年明显下降外).集约经营20年后,土壤总有机碳下降了34.70%,微生物量碳下降了49.35%.相关分析表明,各活性碳之间显著或极显著相关.比较不同经营类型的毛竹林发现,集约经营并未改变土壤各类碳含量的剖面特征.集约经营会导致土壤碳的大量损失,并使土壤生物学性质明显下降.     

Gap size effects on above- and below-ground processes in a silver fir stand

Changes in soil properties related to natural regeneration of silver fir (Abies alba, Mill.) in small (185 m²) and medium (410 m²) gaps, in the Calabria Apennines (Southern Italy), were studied 2 years after gap creation. The organic matter within the medium gaps decayed more rapidly than those in the small gaps. Among the microenvironmental variables and soil properties, soil temperature was most strongly positively related to organic matter decomposition rates. Medium gaps had high soil temperature and photosynthetically active radiation (PAR) transmittance, and low soil moisture. Within medium gaps, we found a great amount of phenolic compounds and a low content of organic matter and humic acids. These results indicate that in the medium gaps mineralization of organic matter was more important than humification. In contrast, in small gaps, the great amount of organic matter, the high content of humic acid and the values of humification index suggested that in these gaps the humification process of organic matter prevailed. Within small gaps, we observed more silver fir regeneration than medium gaps. Difference in organic matter content, particularly in the amount of phenolic compounds, may account for differences observed in natural regeneration of silver fir between small and medium gaps.     

Variations in soil chemical properties and microbial biomass in artificial gaps in silver fir stands

Changes in soil chemical and microbiological parameters in small (185 m²) and medium (410 m²) gaps, created in mature silver fir (Abies alba Mill) stands (mean height 30 m) in the Calabrian Apennines (Southern Italy), were studied over 2 years. Medium gaps had high soil temperature and photosynthetically active radiation (PAR) transmittance and low soil moisture. Within small gaps we detected a greater amount of organic matter, with respect to under canopy cover sites and medium gaps. Moreover, a different trend of the organic matter between small and medium gaps was observed. In the medium gaps, with respect to under canopy cover sites and small gaps, we found a relatively low content of organic matter, associated to a lower amount of humic acid, which suggested that the organic substrate undergoes a mineralization rather than a humification process. An opposite trend was observed in small gaps, where the increase of organic matter content, associated to an increase of humic acid and microbial biomass, suggested a better humification process. Moreover, in small gaps the highest level of urease and the greatest fluorescein diacetate (FDA) hydrolysis were observed. The different trend of organic matter observed in small and medium gaps may be related to changes in the environmental conditions. PAR transmittance, significantly higher in medium gaps, contributed to increase soil temperature and decrease soil moisture, affecting soil microbial populations and organic matter trend. These results suggest that the creation of small gaps represents the silvicultural practice with minor environmental impact.     

湖北省板栗林地土壤养分状况调查研究

对湖北省板栗主产区林农习惯施肥调查结果表明：板栗生产中钾肥用量极少,磷肥用量偏低,而氮肥相对较多.应用GPS定位,采集湖北省28个县市板栗产区土壤样品112个;以常规方法分析了各土样pH值、有机质及土壤有效N、有效P、有效K、交换性Ca、交换性Mg、有效Fe、有效Mn、有效Cu和有效Zn含量.结果表明：湖北省板栗产区80％左右以上的土壤pH及土壤有效N含量适宜于板栗生长,但50％以上的土壤有机质低于15 g/kg,生产中应通过施用有机肥和采取抚育管理措施来提高土壤有机质含量;有效P和有效K含量均较低,其低量比率分别为56.3％和73.11％,生产中应多施用P、K肥料.     

Changes in soil carbon during the establishment of a hardwood plantation in subtropical Australia

Soil carbon (C) pools are not only important to governing soil properties and nutrient cycling in forest ecosystems, but also play a critical role in global C cycling. Mulch and weed control treatments may alter soil C pools by changing organic matter inputs to the forest ecosystem. We studied the 12-month mulch and weed control responses on the chemical composition of soil organic C and the seasonal dynamics of water extractable organic C (WEOC), hot water extractable organic C (HWEOC), chloroform-released organic C (CHCl₃-released C), and acid hydrolysed organic C (acid hydrolysable C) in a hardwood plantation of subtropical Australia. The results showed that compared with the non-mulch treatment, the mulch treatment significantly increased soil WEOC, HWEOC, and CHCl₃-released C over the four sampling months. The weed control treatment significantly reduced the amount of HWEOC and CHCl₃-released C compared with the no weed control treatment. Neither the mulch nor weed control treatment significantly affected soil acid hydrolysed organic C. There were no significant seasonal variations in soil WEOC, HWEOC, CHCl₃-released C, and acid hydrolysed organic C in the hardwood plantation. Solid-state ¹³C nuclear magnetic resonance (NMR) spectroscopy was used to study the structural chemistry of soil C pools in hydrofluoric acid (HF) treated soils collected 12 months after the mulch and weed control treatments were applied. Overall, O-alkyl C was the dominant C fraction, accounting for 33–43% of the total NMR signal intensity. The mulch treatment led to higher signal intensity in the alkyl C spectral region and A/O-A ratio (the ratio of alkyl C region intensity to O-alkyl C region intensity), but lower signal intensity in the aryl C and aromaticity. Compared with the no weed control treatment, the weed control treatment reduced signal intensity in the aryl C and aromaticity. Together, shifts in the amount and nature of soil C following the mulch and weed control treatments may be due to the changes in organic matter input and soil physical environment.