Carbon sequestration in Spanish Mediterranean forests under two management alternatives: a modeling approach

Management implications associated with two different silvicultural strategies in two Spanish pine forests (Scots pine stands in northern Spain and Mediterranean Maritime pine stands in Central Spain) were explored. Whole-stand yield, growth models and individual tree equations were used to estimate carbon stock in forests under different silvicultural alternatives and site indexes. Each alternative was evaluated on the basis of the land expectation value (LEV). Results reveal the appropriateness of implementing carbon payments, because it can clearly complement traditional management objectives in economic terms. Longer rotations on the poorest sites result in a positive economic return by introducing carbon output. The proportion of carbon stock in the final harvest relative to total fixed carbon is always higher in long rotation scenarios. However, short rotation systems produce the highest values of carbon MAI regardless of site index. The impact of carbon price is higher on the Maritime pine stands than on Scots pine stands. For both the species, changes in the discount rate have a minor impact on Carbon LEV. Notwithstanding, the proportion of total LEV due to carbon is greater when the discount rate increases.     

Assessment of nitrogen losses to the environment with a Nitrogen Trading Tool (NTT)

Nitrogen (N) losses from agriculture often contribute to reduced air, groundwater, and surface water quality. The minimization of these N losses is desirable from an environmental standpoint, and a recent interest in discounted reductions of agricultural N losses that might apply to a project downstream from an agricultural area has resulted in the concept of N credits and associated N trading. To help quantify management-induced reductions in N losses at the farm field level (essential components of a Nitrogen Trading Tool), we defined a Nitrogen Trading Tool difference in reactive N losses (NTT-DNL_reac) as the comparison between a baseline and new management scenarios. We used a newly released Windows XP version of the Nitrogen Losses and Environmental Assessment Package (NLEAP) simulation model with Geographic Information System (GIS) capabilities (NLEAP-GIS) to assess no-till systems from a humid North Atlantic US site, manure management from a Midwestern US site, and irrigated cropland from an arid Western US site. The new NTT-DNL_reac can be used to identify the best scenario that shows the greatest potential to maximize field-level savings in reactive N for environmental conservation and potential N credits to trade. A positive NTT-DNL_reac means that the new N management practice increases the savings in reactive N with potential to trade these savings as N credits. A negative number means that there is no savings in reactive N and no N available to trade. The new NLEAP-GIS can be used to quickly identify the best scenario that shows the greatest potential to maximize field-level savings in reactive N for environmental conservation and earning N credits for trade.     

颗粒炭及新型缓释肥对玉米的应用效应研究

对颗粒炭及以炭为基质的两种新型缓释肥SRF1、SRF2在玉米生产上的效应进行了研究.结果表明,添加颗粒炭的普通肥料和新型缓释肥都能有效地改善玉米的农艺性状,使叶面积、根数等有所增加;在产量方面,添加颗粒炭的普通肥料即OF1 C、OF2 C处理和缓释肥SRF1、SRF2处理分别比相应等养分含量普通肥料处理增产3.0%、7.4%、11.4%、21.1%,差异达显著或极显著水平.各处理总体效果表现为缓释肥>普通肥料 炭>普通肥料>不施肥,且普通肥料 炭及缓释肥处理对玉米的效应都表现为总养分含量为30%的处理大于总养分含量为40%的处理.     

CDM-ARP杉木林碳汇监测方法学研究

为满足浙江省重点产杉区造林再造林项目杉木林的碳汇监测需要,利用杉木Cunninghamia lanceolata立地数量化模型、定量间伐技术、生长收获模型和生物量模型等,区分不同立地条件,采用定量方法,并考虑间伐因素,建立了清洁发展机制造林再造林项目（CDM-ARP）杉木林碳汇监测方法学,对杉木林分碳密度、碳储量和二氧化碳净吸存量进行监测。监测方法分为项目规划阶段（造林前）预测和林分生长阶段（造林后）监测。选择易测定的碳库作为监测对象,并用常规测树因子来估测较难测定的各器官生物量和碳汇量。该方法科学准确,省时省力,成本低廉,快速高效。     

干旱区绿洲冬小麦生态系统CO2源/汇关系研究

通过对阜北农场冬小麦土壤生态系统内部的CO2源/汇关系进行长期定位研究.结果表明:典型日变化,从9:00～19:00,绿洲小麦-土壤生态系统均为碳汇,到20:00由于光照有效辐射(PAR)降低,此过程又转变成碳源;从典型月变化来看,对CO2固定最多的是5月,其值达到了36.59 t/hm2,此时小麦进入抽穗期,叶面积指数达到最大;在整个生育期,冬小麦可以净固定CO2 122.60 t/hm2.     

蛹虫草培养基碳源和氮源对菌丝生长量的影响

采用菌丝重量法研究了蛹虫草培养基的碳源与氮源,比较了不同碳、氮源品种间的差异,筛选出较佳的碳源与氮源,并对二者的含量进行了研究。结果表明在0~5%之间,菌丝生长量随碳、氮源含量的增加而增加;同时碳氮比的研究也从另一侧面证实了以上结论。     

海南岛尖峰岭热带雨林土壤固碳微生物群落特征

采集海南岛尖峰岭地区低地雨林次生林、山地雨林次生林和山地雨林原始林土壤,基于绝对定量PCR和高通量测序技术,探讨了热带雨林土壤中固碳微生物群落结构的多样性与组成及其影响因素。结果表明:固碳微生物的Alpha多样性与基因丰度均表现为低地雨林次生林高于山地雨林原始林;尖峰岭热带雨林土壤固碳微生物优势菌门为假单胞菌门(Pseudomonadota,44.28%～70.60%)和放线菌门(Actinomycetota,11.95%～33.73%),优势菌属为慢生根瘤菌属(Bradyrhizobium,11.53%～31.06%)、诺卡氏菌属(Nocardia,4.97%～17.07%)、中慢生根瘤菌属(Mesorhizobium, 4.44%～12.97%)、分枝杆菌属(Mycobacterium, 2.62%～9.20%)、芽绿菌属(Blastochloris,4.34%～10.12%)、固氮弧菌属(Aromatoleum,1.97%～5.39%)、分枝菌酸杆形菌属(Mycolicibacterium,1.71%～3.78%)、固氮螺菌属(Azospirillum,1.97%～2.65%)、...     

基于生命周期评价法对燕麦碳足迹的研究

为明确燕麦的碳足迹特征,采用生命周期评价理论,对河北张家口、内蒙古乌兰察布和呼和浩特燕麦主产区58个农户及16家加工企业进行实地调研,对我国燕麦加工过程中的碳足迹进行了核算。结果表明,在燕麦种植环节,单位面积的碳足迹是800.29±263.77kgCO_2-eq·hm~(-2),单位产量的碳足迹是0.380±0.125tCO_2-eq·t~(-1)。其中,种植大户单位面积碳足迹为801.93±814.05 kg CO_2-eq·hm~(-2),单位产量的碳足迹为0.380±0.386t CO_2-eq·t~(-1),接近于平均水平;种植散户单位面积的碳足迹为648.54±875.31kgCO_2-eq·hm~(-2),比燕麦种植平均水平低19.00%,单位产量碳足迹为0.422±0.570 tCO_2-eq·t~(-1),比燕麦种植平均水平低11.10%。在燕麦加工环节,燕麦加工产品燕麦粉、燕麦片、燕麦米的单位质量碳足迹分别是69.67±5.77、130.62±10.86和50.76±4.81 kgCO_2-eq·t~(-1)。从燕麦食品全生命周期的角度分析,燕麦种植过程中的碳足迹显著低于玉米、水稻、小麦三大主粮作物,可以大面积种植。其中,燕麦种植散户的化肥用量和大户的灌溉电耗是燕麦种植环节碳足迹的主要来源。燕麦加工环节中燕麦片的碳足迹最大,主要因为燕麦片加工中需加热灭酶、汽蒸,涉及天然气的使用,能耗增加。因此,通过农户规模化种植、选择适合当地的节水灌溉技术,引导相关企业就近和适度加工、优化节能减排的技术等方法来减少碳足迹,促进燕麦产业的可持续发展。     

葫芦与西瓜砧穗在不同土壤上根际碳代谢指纹特征与差异

土传病害的发生与微生物关系密切,但砧穗互作下根际微生物活性变化尚不明确。为阐明在不同土壤类型下,砧穗互作对根际微生物活性的影响,采集黑土(吉林)、砖红壤(海南)、黄棕壤(江苏)和灰漠土(新疆)四种类型土壤,并在每种土壤上均种植自根葫芦、自根西瓜、嫁接西瓜(葫芦砧木)以及嫁接葫芦(西瓜砧木),利用Biolog培养技术探究不同处理下根际微生物碳源代谢活性的差异。结果表明,不同土壤类型下微生物代谢活性差异显著(R~2=0.534,p0.001),不同嫁接植物之间根际微生物碳源利用同样存在显著差异(R~2=0.075,p0.001)。不同嫁接处理根际微生物对碳源的综合代谢水平自根西瓜嫁接葫芦(西瓜砧木)嫁接西瓜(葫芦砧木)自根葫芦。聚类推进树(Aggregated boosted tree,ABT)分析显示土壤有效磷、速效钾是影响微生物碳源利用的主要因子。评估不同土壤类型下根际微生物碳代谢活性对砧穗互作的响应,可为防控土传病害提供依据。     

Effect of Phosphorus Additions and Arbuscular Mycorrhizal Fungal Inoculation on the Growth,Physiology, and Phosphorus Uptake of Wheat Under Two Water Regimes

Drought stress greatly affected the growth and development of wheat in the world, while wheat growth could benefit through improvement of water status and nutrient uptake by mycorrhizal symbiosis or addition of phosphorus (P). Experimental treatments were (a) phosphorus addition (0 and 90 kg/ha), (b) soil water condition (40% field capacity and 95% field capacity), and (c) arbuscular mycorrhizal fungi (AMF, Glomus intraradices) (noninoculation and inoculation) which were conducted in a growth chamber. The results showed that addition of phosphorus and AMF inoculation significantly increased the relative water content and specific leaf area of flag leaves especially under 40% field capacity (water deficit (WD)). The leaf gas exchange parameters were all decreased under WD. The water use efficiency (WUE) and instantaneous WUE (WUEi) was enhanced by WD, AMF inoculation, and phosphorus addition. AMF inoculation and WD significantly decreased the carbon isotope discrimination (CID) of leaf. The P concentrations in stem, grain, and leaf were significantly increased by phosphorus addition, WD, and AMF inoculation. Significant correlations were found between WUE and grain P, stem P, and leaf P concentrations. Leaf CID was significantly negatively correlated with WUE and stem P concentrations. Inoculation of AMF or phosphorus addition could improve the growth, physiology, and phosphorus uptake in spring wheat under drought conditions.