内蒙古近40年最高、最低温度变化特征

利用内蒙古25个气象站1961—2003年的月平均最高、最低气温和日较差资料,通过计算气候倾向率、小波变换和突变检验,分析了内蒙古近40年气候变暖特征。结果表明:①近40年我区气候变暖明显,最低温度升幅明显高于最高温度的升幅,表现出一种日夜增暖的不对称性,使得日较差变小;②在年温度的变化中冬季变暖的贡献最大,且以东北部寒冷地区更为明显;③平均最高温度有24年左右的准周期,平均最低温度无明显周期震荡,但无论从最高还是最低温度看,目前我区都处于相对暖期中;④我区20世纪60年代以来的气候变暖在70年代中期超过了显著水平,并经历了一次突变过程,突变点在1983年,而最高温度对变暖的响应明显滞后于最低温度。     

冻融作用对大兴安岭多年冻土区泥炭地土壤有机碳矿化的影响研究

冻融循环是影响土壤碳氮生物地球化学过程较为重要的因素。在全球变化背景下,冻融作用对冻土区土壤碳库稳定性及其关键生物地球化学过程影响研究是当前国际热点,尤其是冻融作用影响下多年冻土区泥炭地土壤有机碳矿化研究目前仍未明确。选取我国大兴安岭多年冻土区泥炭地表层（0~15 cm）和深层（15~30 cm）土壤,采用冻融试验及室内培养方法,探索分析了冻融作用影响下泥炭地土壤有机碳矿化特征,并从土壤活性碳和土壤酶活性角度阐述了影响机制。结果表明在短期的培养中,土壤有机碳矿化量在483~2836 mg/kg间波动,而冻融循环均显著降低了表层和深层土壤有机碳矿化量,并且对深层土壤有机碳的矿化抑制作用更为明显,高达76%。值得注意的是,冻融循环却明显促进了CH₄的排放,尤其是表层土壤,高达145%。冻融循环作用也显著增加了土壤可溶性有机碳（DOC）含量,但却降低了土壤微生物量碳（MBC）以及土壤纤维素酶、淀粉酶和蔗糖酶活性。冻融作用下低的土壤酶活性以及相对低质量碳是抑制土壤有机碳矿化的原因。全球变暖背景下,与单纯温度增加所导致的土壤有机碳矿化释放量相比,冻融循环作用能降低大兴安岭泥炭地活动层中土壤有机碳在短期内碳的释放。     

科尔沁沙地气候变暖及对农牧业的影响

利用通辽地区1950—2006年的气温、降水、降水日数、积温、日照、无霜期等资料，分析了科尔沁沙地地区近57年来的气候变化越势、突变和周期波动，探讨了科尔沁沙地气候变暖对当地农牧业的影响。结果表明：该地区1950年代以来气候变暖已成事实，1987年是气候变暖的突变时间点。气候变暖后，低温日数明显减少，高温日数增加；农业积温增加；无霜期延长，曰照时数增加；全年降水日数减少，特别中雨日数明显减少。气候变暖对科尔沁沙地农牧业的影响有利有弊，综合分析是弊多利少。     

黑龙江省农田土壤养分时空变化分析

通过对黑龙江省主要农产区中的27个县(市)2a的农田土壤养分含量数据进行统计分析,结果表明黑龙江省农田土壤肥力状况属中上等水平;2005年与2004年相比,速效氮和有机质增加,速效磷和速效钾减少;空间变异程度上,速效磷>速效钾>有机质>全氮。     

雷竹林立体气候特征及其对出笋的影响

利用3 a小气候观测分析了雷竹生长期不同层次温度、土壤水分变化特点,以及雷笋生长关键期与气象要素的关系。雷竹林中立体气候特征是气温变化较地温变化大,随着土壤深度的增加地温的变化幅度越来越小;从地面到地下40 cm深度,越往下土壤水分含水率越高。自然出笋期平均地温9.6℃左右时,出笋量明显增加;11.4℃左右时出笋量激增。人工覆盖增温使孕笋期时间缩短,出笋的时间提前1~2月。     

Precipitation responses to radiative processes of water- and ice-clouds: an equilibrium cloud-resolving modeling study

云辐射过程对制约天气与气候很重要。本文通过分析二维云分辨模式敏感性试验模拟平衡态平均资料研究降水对水云及冰云辐射过程的响应。模式给定的垂直速度为零。存在冰云辐射过程时去除水云辐射过程,以及去除冰云辐射过程会加强大气长波辐射冷却和降低空气温度及饱和混合比。饱和混合比的减少导致水汽凝结增加及其相关的潜热释放的增加,从而增加降雨。去除水云辐射过程通过减少长波辐射冷却增加对流层上部局地大气变暖。而增强的变暖通过霰的融化增强而增加降水源与降水。     

吉林省土壤养分监测结果初报

选择吉林省具有代表性的9个站点，对吉林省大田土壤的氨态氮、速效单质磷、速效单质钾、PH值和有机质进行了观测。结果表明，我省各地土壤氨态氮和速效单质磷的含量，均是优质地段〉中等地段〉劣质地段；同一地块不同层次表现为从上到下（10—30cm）养分含量逐渐减少，表屡养分含量明显高于底层，即10cm氮、磷含量〉20cm氮、磷舍量〉30cm氮、磷含量，而土壤钾含量与土质优劣无明显关系。不同深度的钾含量变化也不明显；白城、松原土壤呈碱性。永吉呈酸性，其它测站呈中性；同时分析了播种前和收获后土壤养分变化、PH值变化及养分丰缺情况。     

模拟氮沉降对温带阔叶红松林地氮素净矿化量的影响

采用埋置PVC管的树脂芯方法原位测定了不同氮形态及其剂量作用下长白山阔叶红松林地0～7 cm和0～15 cm土壤氮素净氨化、净硝化和净矿化量的季节和年际变化规律.近3年的观测结果表明,对照处理不同土层氮素年净矿化量中以净氨化占主导地位,约占净矿化量的53％～72％,高剂量NO3-N的输入使该比例减少至37％～66％,而NH4-N的输入却使该比例增至86％～92％.随着模拟氮沉降量增加,土壤氮素年净矿化量也随之增加,尤其外源NH+4-N输入对净矿化量的促进作用更为明显,但随着施肥年限的延长,这种促进作用逐渐减弱.与林地0～15 cm土壤相比,氮沉降量增加对0～7 cm土壤氮素净氨化和净矿化量的促进作用更为明显,尤其是NH4Cl处理的促进作用更大.通过将实验结果与前人报道的野外原位观测整合,逐步回归分析后发现土壤氮素年净矿化量随着氮素年沉降量的增加而增大,氮沉降量对不同区域森林土壤氮素年净矿化量的贡献率约为38％;大气氮沉降量、森林有机层pH及其碳/氮比值可解释不同区域森林表层土壤氮素年净矿化量一半的变化.研究结果将利于有效预测区域林地氮素净矿化量特征及其对环境变化的响应.     

大兴安岭地区近3O年气候变化及其对农业的影响

利用统计学方法对近30年来大兴安岭地区的气候变化特点进行了研究，在全球气候变暖的大背景下，从温度、降水、蒸发、冻土等气象要素分析得出：该地区气候有明显的变暖趋势，但存在区域差异，同时分析了气候变化对农业生产所产生的影响，为合理利用大兴安岭地区气候资源提供了依据。     

全球变暖背景下的广东省降水量及旱、涝变化趋势

分析粤港澳7个气象站近100年来降水量变化趋势,并对其与全球气候变暖的关系进行分析.结果表明:广东省全年及前、后汛期的降水量变化存在2～7年、10年和30年左右的周期;广东省雨量的长期变化与全球气候变暖不存在一致性,但近期气候变暖和广东的重旱、重涝事件频率增加有关;目前,广东的年降水量处于长期变化中的峰值下滑趋势,预估2020年处于少雨时期,沿海地区重旱、轻旱出现频率增加.     

Influences of international agricultural trade on the global phosphorus cycle and its associated issues

Industrial phosphorus (P) fertilizer has substantially improved global food production, but has also led to environmental impacts. Intensive global agricultural trade has increased and the impacts of trade on aggravating or alleviating future P scarcity must be examined, especially for the most vulnerable countries. We combined data to estimate the global P trade among countries and its impacts on global P flows, based on global agricultural trade, cropland soil P budgets and crop P fertilizer footprints (the amount of industrial P fertilizer applied for producing one unit of P in the harvested crop). The global agricultural P trade represented a fraction of 16% of P in harvested crops in 2014, half of which was exported from the United States of America, Brazil and the European Union and one fifth imported by China. Virtual P fertilizer flows (about 2.60 Tg P y^-1) referred to industrial P fertilizers applied to traded crops by exporting countries; thus, 1/3 of global virtual P fertilizer flows were associated with the international soybean trade. P use efficiency (PUE), the ratio of the harvested crop-P to the total external P inputs, is a larger problem for tropical than temperate countries. Global crop trade had brought in a net 0.2 Tg P y^-1 savings of industrial P fertilizers globally, compared to crop production in export and import countries. >0.50 Tg y^-1 of the gross global accumulation of soil P and P in freshwater were associated with global agricultural trade. Global PUE, however, could be improved considerably, and thus global cooperation and improving PUE could help to solve the problem of future P scarcity. Vulnerable countries should also propose urgent national plans to address their own situations of P scarcity or low PUE.     

水分和氮肥对冬小麦产量的影响及其调控技术

通过对冬小麦进行不同水分等级和不同施氮量的控制试验,利用数理统计和数学分析方法,从水分利用效率和经济效益角度,分析了水分和氮素对冬小麦产量的影响及其相互作用的关系,提出了河南省冬小麦砂壤土的水肥配置模式,经生产检验,这种模式是可行的。     

CO2气肥固体发生剂在温棚室蔬菜栽培中的应用

温棚室内Ｃ炒足是影响温棚蔬菜生产的重要因素之一。温棚人工增施ＣＯ２的方法很多，但都有一定的局限性，作者根据现在温棚室的实际情况研制出一种新型高效的ＣＯ２发生剂－－固体气肥发生剂，对比试验表明，该发生剂能使蔬菜增产２５％以上，投入产比在１：６以上，并且具有无公害的特点。     

用卫星遥感技术进行化肥市场预测的可行性探析

利用卫星遥感技术，准确掌握一定地域范围的土壤湿润程度（即土壤墒情）、农作物长势、农作物的播种面积，再结合一定时期的降雨量和气象预报信息，比较准确的预测出市场化肥需求量，用来帮助化肥厂家制定出科学的生产和销售方案，尽可能的利用现有资源产生最大的经济效益。     

烤烟栽培中吸水树脂的应用

利用吸水树脂抗旱保肥性能，解决了烟适时移栽。研究了吸水树脂对烤烟生长发育，肥料利用率，烟叶产量，烟叶Ｎ、Ｐ、Ｋ含量及烟叶光合，蒸腾和水利用效率的影响。确定了烤烟栽培中吸水树脂的应用效果。     

春玉米生长发育、产量和籽粒品质对减量施氮的响应

针对当前东北地区过量施氮的问题,研究减量施氮对春玉米生长发育、产量及籽粒品质的影响,对优化氮肥的科学管理技术,促进春玉米生产绿色高效发展具有重要意义.本研究以丹玉405为试验材料,通过大田播种的方式,以农民习惯性施氮量为对照,设置11.1％、55.5％和100％三个水平减量施氮试验,分析春玉米生长发育、产量和籽粒品质对...     

Does smallholder maize intensification reduce deforestation? Evidence from Zambia

Increasing food production to meet growing demand while reducing tropical deforestation is a critical sustainability challenge. This is especially true in sub-Saharan Africa, which faces serious food insecurity issues and where smallholder farming is the main driver of forest conversion. Competing theories imply opposite predictions as to whether deforestation increases or decreases with smallholder agricultural intensification, which can improve food security by increasing crop yields per area cultivated. This research provides new empirical evidence on the association between deforestation and smallholders’ use of modern inputs, in particular inorganic fertilizer on maize and improved maize seeds, using Zambia as a case study. We analyze this association nationwide in a spatially disaggregated manner at the lowest administrative level using machine learning-based small area estimation, which makes use of detailed nationally representative surveys on smallholder farm households for 2011 and 2014, and census data to statistically predict modern inputs use country-wide for 2011, when average maize yields were 1.28 tons/ha. Then, we evaluate the association between improved maize seed and fertilizer inputs and subsequent deforestation, while controlling for key geospatial covariates. The results support the land-sparing hypothesis, finding that smallholder farmers’ use of improved maize seed is negatively associated with deforestation on non-acidic (pH ≥ 5.5) soils, an effect that is enhanced by complementary inorganic fertilizer use. Fertilizer use on its own, however, is weakly associated with increased deforestation. Sustainable intensification via use of improved seeds on adequately fertile soils and improving soil health appears compatible with reducing both deforestation and food insecurity.     

中国小麦和玉米农田N2O减排措施及潜力

旱作农田是N₂O的主要排放源,削减其N₂O排放有助于整体降低农田温室气体排放。运用整合分析(Meta-analysis)的方法,研究了不同农业管理措施对中国小麦和玉米农田N₂O排放的影响,并估算了各减排措施的减排潜力。结果表明：添加抑制剂可显著减少小麦和玉米农田N₂O排放36%~46%,并增加作物产量;施氮量减少30%以内,可削减N₂O排放10%~18%,且对产量无明显影响;施用缓(控)释肥和秸秆还田能显著减少小麦田N₂O排放,但对玉米田的减排效果并不显著。在不同的减排措施下,中国小麦和玉米农田N₂O减排潜力分别为9.29~13.90 Gg N₂O-N/生长季和10.53~23.19 Gg N₂O-N/生长季。河南、山东、河北和安徽省小麦田减排潜力最大,占全国小麦田N₂O减排潜力的53%;黑龙江、吉林、山东、河北和河南省玉米田减排潜力最大,约占全国玉米田N₂O减排潜力的50%。     

Nitrous oxide emissions from fertilized and unfertilized soils in a subtropical region (Andalusia,Spain)

Field measurements of N₂O emission rates were carried out from August until October 1982 in a subtropical region in Europe, i.e. in Andalusia, Spain. The measurements were performed by using an automatic sampling and analysis technique allowing the semi-continuous determination of N₂O emission rates. The N₂O emission rates were positively correlated to the soil surface temperature and exhibited a diurnal rhythm with maximum rates in the afternoon and minimum rates in the early morning with average values of 1 g N₂O–N/m²/h for the grass lawn and 15 g N₂O–N/m²/h for cultivated land. Application of urea and ammonium nitrate resulted in elevated N₂O emission rates when compared to the unfertilized control. The loss of fertilizer-nitrogen as N₂O was 0.18% for urea and 0.04% for NH₄NO₃ which compares very well with data obtained in a temperate climate (Germany). The total source strength of fertilizer-derived N₂O is estimated to be 0.01–2.2 Tg N₂O–N per year. The N₂O flux from unfertilized natural soils may be as high as 4.5 Tg N₂O–N, indicating that the N₂O emission from soils contributes significantly to the global N₂O budget.     

Field measurements of NO and NO2 emissions from fertilized and unfertilized soils

Field measurements of NO and NO₂ emissions from soils have been performed in Finthen near Mainz (F.R.G.) and in Utrera near Seville (Spain). The applied method employed a flow box coupled with a chemiluminescent NO _x detector allowing the determination of minimum flux rates of 2 g N m^-2 h^-1 for NO and 3 g m^-2 h^-1 for NO₂.The NO and NO₂ flux rates were found to be strongly dependent on soil surface temperatures and showed strong daily variations with maximum values during the early afternoon and minimum values during the early morning. Between the daily variation patterns of NO and NO₂, there was a time lag of about 2 h which seem to be due to the different physico-chemical properties of NO and NO₂. The apparent activation energy of NO emission calculated from the Arrhenius equation ranged between 44 and 103 kJ per mole. The NO and NO₂ emission rates were positively correlated with soil moisture in the upper soil layer.The measurements carried out in August in Finthen clearly indicate the establishment of NO and NO₂ equilibrium mixing ratios which appeared to be on the order of 20 ppbv for NO and 10 ppbv for NO₂. The soil acted as a net sink for ambient air NO and NO₂ mixing ratios higher than the equilibrium values and a net source for NO and NO₂ mixing ratios lower than the equilibrium values. This behaviour as well as the observation of equilibrium mixing ratios clearly indicate that NO and NO₂ are formed and destroyed concurrently in the soil.Average flux rates measured on bare unfertilized soils were about 10 g N m^-2 h^-1 for NO₂ and 8 g N m^-2 h^-1 for NO. The NO and NO₂ flux rates were significantly reduced on plant covered soil plots. In some cases, the flux rates of both gases became negative indicating that the vegetation may act as a sink for atmospheric NO and NO₂.Application of mineral fertilizers increased the NO and NO₂ emission rates. Highest emission rates were observed for urea followed by NH₄Cl, NH₄NO₃ and NaNO₃. The fertilizer loss rates ranged from 0.1% for NaNO₃ to 5.4% for urea. Vegetation cover substantially reduced the fertilizer loss rate.The total NO _x emission from soil is estimated to be 11 Tg N yr^-1. This figure is an upper limit and includes the emission of 7 Tg N yr^-1 from natural unfertilized soils, 2 Tg N yr^-1 from fertilized soils as well as 2 Tg N yr^-1 from animal excreta. Despite its speculative character, this estimation indicates that NO _x emission by soil is important for tropospheric chemistry especially in remote areas where the NO _x production by other sources is comparatively small.