水分对微水溶性胶结包膜肥料氮素释放的影响及其生物学效果研究

采用水基成膜法研制出低成本、易降解的微水溶性胶结包膜缓释肥料.应用性能测试、不同田间持水量下土壤培养及小白菜盆栽试验研究了其养分释放规律与生物学效应,试验表明:微水溶性包膜材料致密、整体厚薄较均一,其吸水性、透水性能优良,且具一定的生物降解性能.在田间持水量50%、60%、70%条件下,微水溶性胶结包膜缓释肥料土壤铵态氮含量变化与水分呈正相关关系,24 d后硝态氮含量呈高于尿素处理趋势.在田间持水量50%、60%、70%三种水分条件下,微水溶性胶结包膜肥料处理油菜产量均高于尿素处理,在70%田间持水量下达到了显著差异(P<0.05);微水溶性胶结包膜肥料处理增加了Vc含量,但没有显著增加油菜含氮量、硝酸盐含量和叶绿素含量.     

禁牧对祁连山冰沟流域高山草甸土有机碳及理化性质和酶活性的影响

在青海省祁连山冰沟流域的高山草甸土上,选择放牧与禁牧2个样品采集区,研究了禁牧对祁连山冰沟流域高山草甸土有机碳及理化性质和酶活性的影响。结果表明:高山草甸土遭到放牧牲畜连续3年的啃食和践踏后,植被覆盖度明显降低,归还到土壤中的生物量和枯落物积累量减少,0~20 cm土层有机质含量、有机碳密度、总孔隙度、团聚体、田间持水量、氮磷钾和酶活性降低,容重、CaCO_3和可溶性盐增加,但20 cm以下土层这些性质变化不大。放牧与禁牧比较,0~20 cm土层土壤容重、可溶性盐和CaCO_3分别增加14.15%、6.35%和1.27%;有机碳含量、有机碳密度、总孔隙度、团聚体和田间持水量分别降低29.76%、22.82%、9.45%、6.49%和7.69%;全氮、全磷、全钾、脲酶、蔗糖酶、磷酸酶和过氧化氢酶分别降低25.97%、15.56%、12.17%、33.77%、26.11%、42.00%、29.31%。放牧对有机碳、容重、孔隙度、田间持水量、可溶性盐、氮磷钾和酶活性影响深度为20 cm,对团聚体影响深度为40 cm。     

黄土高原水蚀风蚀交错带不同土地利用方式坡面土壤水分特性研究

为分析不同土地利用方式下坡面土壤水分特性的差异和规律,对黄土高原水蚀风蚀交错带典型坡面上农地、林地和草地的土壤水分特性进行了分析.结果表明:(1) 苜蓿地土壤的持水能力和供水能力最强,其次是杏树林和长芒草地,谷子地最差;(2) 通过土壤水分有效性分析发现,水蚀风蚀交错带田间持水量相当于-0.2×105 Pa土壤基质势时的土壤含水量,永久凋萎点则低于-2.0×106 Pa土壤基质势对应的土壤含水量;(3) 苜蓿地有效水含量最高,谷子地有效水含量最低,而且苜蓿地土壤有效水含量的提高主要是提高了迟效水部分;(4) 对不同土地利用方式下的土壤比水容量变化曲线研究表明,土壤比水容量在田间持水量附近随土壤含水量的降低减小的很快,而当土壤水分降低到田间持水量的50%～60%以下时,土壤比水容量基本不变.     

油页岩栽培基质脱盐技术及其效果研究

油页岩有机矿藏含有大量有机质和作物生长所需的矿质养分,但因较高水溶性盐分含量成为它在农业或园艺作物生产中作为栽培基质利用的重要限制因素.试验对油页岩进行了不同洗盐处理,以获得最佳脱盐措施,达到脱盐标准.通过用不同水量冲洗(水样比0:1,1:1,2:1,3:1,4:1,5:1,6:1,7:1,8:1,9:1和10:1)及在不同水温(40℃,50℃,60℃,70℃,80℃,90℃和100℃)下进行脱盐处理后,测定油页岩的酸碱度、电导率、水溶性盐总量和离子(Cl~-、SO_4~(2-)、CO_3~(2-)、HCO_3~-、Ca~(2+)、Mg~(2+)、K~+、Na~+)组成等变化情况,确定出合理的冲水定额及处理措施,探明了各离子淋失规律.试验结果表明:采用5:1的水样比处理,即每千克油页岩冲水定额为5 L水时脱盐效率高,用水量经济;油页岩经过洗盐处理后,pH从5.2可升高到6.58,其盐分含量从7.69 g/kg降低为1.18 g/kg,脱盐率为84.66%,其盐分含量以及酸碱度均达到了大部分栽培作物生长的要求;对洗盐用水适当加温可以取得更好的脱盐效果.     

土壤含水量对温室樱桃番茄生长发育及果实品质的影响

以樱桃番茄红宝石为研究材料,以5个梯度的土壤含水量(分别为田间持水量的40%~50%、50%~60%、60%~70%、70%~80%和80%~90%)进行处理后,测定并分析植株生长状况、果实品质、产量和水分利用效率的变化规律。结果表明:在土壤含水量为田间持水量的70%~80%时,同化物在樱桃番茄上积累的最多,产量最高,为6.25 kg/m2;在土壤含水量为田间持水量的60%~70%时,樱桃番茄果实品质的各项指标均达到最大值,其中Vc、可溶性糖和干物质的含量分别为652.2 mg/kg,72.8 g/kg,71.8 g/kg,可溶性固形物占总质量的9.8%,水分利用率也最大,为13.9 kg/m3。综合分析水分对植株生长发育、果实品质、水分利用效率和产量的影响,认为土壤含水量为田间持水量的60%~70%,可以作为樱桃番茄生长期间理想的土壤水分控制指标。     

伊犁地区5个引种白蜡对干旱胁迫的响应

为探讨伊犁地区5个引种白蜡的抗旱性差异,为区域化推广栽培提供理论依据,以5个3a生引种白蜡苗木为材料,采用盆栽控水试验方法,设置4个水分梯度(CK、T1、T2、T3,田间持水量分别为80％～85％、55％～60％、40％～45％、30％～35％),测定其SOD活性、POD活性、MDA含量、脯氨酸含量、可溶性蛋白含量、叶...     

生物炭对■土持水能力的影响

通过连续6年定位试验,探究较长时间施用生物炭对土壤保水作用的影响,以期为■土区水土保持和土壤改良提供理论参考。田间试验于2011年开始,设4个生物炭施用梯度:对照,不施生物炭(B0);5 t·hm~(-2)(B5);10 t·hm~(-2)(B10);20 t·hm~(-2)(B20)。在2017年测定了土壤含水量、土壤基础理化性质和水分累积蒸发量等。结果表明:生物炭能够显著减小土壤容重、增加土壤孔隙度、饱和含水量和田间持水量,且随着生物炭施入量的增加,各指标变化幅度也增大,B20与B0处理相比,土壤容重减少了8.28%,毛管孔隙度增加了20.17%,饱和含水量与田间持水量分别增加了22.17%和14.86%;生物炭显著增加了土壤团聚体稳定性,B20与B0处理相比,土壤水稳性团聚体含量增加了19.00%,团聚体破坏率和不稳定团粒指数分别降低了11.34%和9.61%;生物炭还可有效抑制土壤水分的蒸发,B10和B20处理的土壤累积蒸发量分别比B0处理减少了7.45%和10.18%。结合逐步回归分析与通径分析发现,生物炭对土壤结构的改良是其促进土壤持水能力的主要原因。土壤孔隙度和有机碳含量是影响土壤饱和含水量的主要因子,影响土壤毛管持水量的主要因子为有机碳含量和土壤毛管孔隙度,而毛管孔隙度与水稳性团聚体含量则解释了绝大部分土壤田间持水量的变化。研究表明生物炭施用可以显著改良土壤结构,提升■土持水性能,增加干旱半干旱地区土壤的蓄水保墒能力。     

水分胁迫下肥料配比对葡萄光合速率与氮代谢的影响

以无核白鸡心葡萄为试材,设置3个水平的水分处理和3个肥料配比,研究水分胁迫下肥料配比对无核白鸡心葡萄叶片叶面积、叶绿素含量、光合速率及氮代谢相关酶活性的影响。结果表明:萌芽期和坐果期土壤水分含量为田间持水量的55%~60%、施肥配比为N∶P∶K=2∶5∶3的水肥处理能有效促进叶面积增加,提高光合速率,是较好的水肥处理组合;转色期和采收后需维持正常含水量和适当增施钾肥可提高光合速率;土壤水分含量为田间持水量的55%~60%、施肥配比为N∶P∶K=2∶5∶3的水肥处理无核白鸡心葡萄硝酸还原酶活性较高,能有效促进氮肥的吸收利用;水分胁迫处理使谷氨酰胺合成酶活性先升高后降低,且使谷丙转氨酶活性升高。在生长期中轻度水分胁迫、适当增施钾肥能明显提高硝酸还原酶、谷氨酰胺合成酶与谷丙转氨酶活性,提高氮肥的转化利用。     

陕北中部黄土区不同种植年限水稻田有机碳矿化对温度的响应

为了探讨陕北中部黄土区不同种植年限水稻田有机碳矿化对温度的响应,以陕北南泥湾水稻种植基地不同种植年限(3、30、78 a)的稻田土壤为研究对象,基于室内35 d培养试验与矿化动态模型研究方法,解析温度对土壤有机碳矿化的影响。结果表明：土壤有机碳累积矿化量和矿化速率均表现为78 a水稻田>30 a水稻田>3 a水稻田>玉米田。土壤累积矿化量、矿化速率、潜在可矿化有机碳含量(C₀)和潜在可矿化有机碳占总有机碳的比值(C₀/SOC)均表现为30℃处理>20℃处理>10℃处理。水稻田矿化累积量均表现为10℃处理(2 015.14 mg·kg^-1)显著低于20℃(2 799.20 mg·kg^-1)和30℃处理(3 078.47 mg·kg^-1)(P<0.05),但20℃与30℃处理之间无显著差异。玉米田累积矿化量在不同培养温度间没有达到显著差异水平。0～20 cm土层累积矿化量是20～40 cm土层的1.18倍。供试土壤在温度从10℃升高到20℃时的温...     

日光温室不同水分条件下盆栽黄瓜产量和土壤微生物数量

在日光温室内盆栽条件下,研究土壤水分对黄瓜产量和土壤微生物数量的影响,结果表明(1)土壤水分含量初花期和初瓜期为田间持水量的80%～90%、盛瓜期90%～100%、生育后期70%～80%的处理黄瓜产量最高,为389.65g/株;其次为初花期土壤水分为田间持水量的90%～100%、初瓜期80%～90%、盛瓜期70%～80%、生育后期90%～100%的处理,产量为351.49g/株;初花期土壤水分为田间持水量的80%～90%、初瓜期90%～100%、盛瓜期70%～80%、生育后期80%～90%的处理产量最低,为257.54g/株。(2)不同水分处理土壤微生物的数量变化不同黄瓜初花期,土壤水分为田间持水量80%～90%的处理土壤细菌数量最多,土壤水分为田间持水量70%～80%的处理和90%～100%的处理土壤细菌数量少,且二者差异不大。黄瓜初瓜期和盛瓜期当土壤水分由低变高时细菌数量增加,相反细菌数量减少,黄瓜生育后期当土壤水分从高变低时细菌数量增加,水分稳定不变或从高变为中等水平或从低变为中等水平时细菌数量减少。土壤真菌数量在土壤水分含量低时和土壤水分相对稳定的情况下增加,否则减少。各处理土壤放线菌在黄瓜初花期和初瓜期数量差异不大,盛瓜期各处理土壤放线菌的数量增加,生育后期多数处理土壤放线菌的数量有所下降。     

长期定位施肥对旱作农田土壤有机碳及其组分的影响

基于田间定位试验,研究了长期施肥对旱作冬小麦农田土壤有机碳及其组分的影响,试验包括4个处理:不施肥(CK)、氮磷配施(NP)、化肥与有机肥配施(NPM)以及长期休闲地(BL)。结果表明:长期持续施肥30年后,在0~30 cm土层,NPM处理土壤有机碳、微生物量碳、潜在矿化碳以及碳库管理指数分别较CK提高了42.2%、55.9%、40.9%和40.0%(P0.05),NP处理土壤有机碳和微生物量碳与CK差异不显著,潜在矿化碳和碳库管理指数分别提高了29.1%和20.0%(P0.05),施肥对两种活性有机碳含量的影响在15~30 cm土层表现更加显著;与种植作物相比,长期休闲显著降低了土壤潜在矿化碳含量,BL处理较CK降低了20.5%(P0.05)。相关性分析表明,土壤有机碳、潜在矿化碳、微生物量碳以及碳库管理指数两两之间存在着显著的相关性,且有机碳组分含量与土壤有机碳含量在处理间变化具有一致性(除NP处理外),两种活性有机碳相对含量在各处理间差异均不显著。总的来说,长期持续施入有机肥能够有效地增加旱作农田土壤有机碳同时增加其活性组分,有助于培肥地力和土壤固碳。     

Effect of crude oil pollution on organic carbon and humus content in grey-brown soils in Mangyshlak, Pre-Caspian Sea Region

The organic carbon and humus content in oil polluted brown and grey-brown soils in Mangyshlak,Pre-Caspian Sea Region,was analyzed from 2000 to 2008.The results indicated that bitumen substances from crude oil pollution deteriorated the soil property,however,the organic carbon content increased significantly.The products of oil pollution changed the composition of car-bonaceous substances which formed soil humus,and changed the ratios of the humus components.Residual insoluble carbon increased with the rise of oil organic carbon.The mobility of humus components was significantly increased because of the high oxidation-reduction process in the topsoil,and the humus content and microorganism activity increased.The organic carbon content increased significantly,while it decreased with the distance away from the oil well.The rearrangement of physical,physical-chemical and chemical properties of the polluted soils was significant.     

The effect of herbicides on respiration and transformation of nitrogen in two soils I. Metribuzin and glyphosate

The effects of metribuzin and glyphosate at 100 ppm on carbon dioxide evolution and nitrogen transformation in two soils have been investigated in the laboratory. Both herbicides reduced CO2 evolution from Boddington Barn soil (organic carbon content 1.5%, pH 6.6) at some dates, but neither gave any consistent effects on Triangle soil (organic carbon content 4.0%, pH 5.1). Both metribuzin and glyphosate stimulated mineralization of nitrogen for at least 9 weeks. Only metribuzin on Triangle soil gave any indication of inhibition of nitrification. Metribuzin degraded more rapidly in Triangle soil than in Boddington Barn.     

沙地樟子松人工林土壤氮矿化特征

土壤氮(N)的有效性是沙地林生态系统生产力和稳定性的关键限制因子。本研究以科尔沁沙地樟子松人工林为研究对象，分析测定了10~60 a林龄土壤NH₄⁺-N、NO₃^--N和矿质N含量、氨化速率、硝化速率和N矿化速率的变化规律。结果表明：樟子松人工林土壤NH₄⁺-N、NO₃^--N和矿质N含量，随着不同林龄在10~60 a内表现出增加的趋势，其中10~30 a增幅较小，40~60 a显著提高；随着土层深度增加而减小，主要集中在0~20 cm，呈现出表聚性。不同林龄樟子松人工林土壤氨化速率、硝化速率和矿化速率均随林龄增加而增加，随土层深度的增加而降低，其中0~40 cm土层明显大于40~100 cm。通过双因素方差分析，得出林龄与土层对各矿化指标影响显著。土壤矿化指标与人工林地上樟子松株高、胸径、冠幅以及土壤有机碳、全氮、碱解氮有显著的正相关关系。通过冗余分析(RDA)表明，影响不同林龄土壤矿化指标的主要环境因子为全氮、全磷、有机碳；影响不同土层土壤矿化指标的主要环境因子为全氮、碱解氮、有机碳。因此，樟子松人工林能够改善沙地土壤N的有效性，幼龄林和中龄林改善效果较小，近成熟林和成熟林改善效果明显；对表层土的改善效果优于深层土；土壤肥力是影响土壤矿化指标的主要环境因子。     

陕西省泥炭油页岩草炭三种有机矿藏资源基本性状及农业利用的可行性分析

对陕西蕴藏的泥炭、油页岩和草炭3种主要有机矿藏所含的有机物质、矿质养分、水溶性盐分含量和重金属组成进行了系统测定分析，结果表明：在农业应用中，3种有机矿藏资源的最大优势是有机质含量高；限制性因素是沥青含量高、水溶性盐分含量高（尤其是硫酸盐含量高）、重金属砷含量高。在农业利用中可以作为混合基质的配料使用，不宜直接作为栽培基质。     

The effect of herbicides on respiration and transformation of nitrogen in two soils III. Lenacil, terbacil, chlorthiamid and 2,4,5-T

The effects of lenacil, terbacil, chlorthiamid and 2,4,5-T at 100 ppm on carbon dioxide evolution, oxygen uptake and nitrogen transformation in two soils have been investigated for several months in the laboratory. The herbicides had no effect on CO₂ output from either Boddington Barn soil (organic carbon content 1.6%, pH 6.1) or Triangle soil (organic carbon content 3.7%, pH 4.8) apart from 2,4,5-T which reduced it sometimes. All the herbicides caused temporary reductions in O₂. uptake, but in Triangle soil treated with 2,4,5-T a significant reduction was observed during the second half of the incubation. 2,4,5-T and to a lesser extent chlorthiamid, reduced nitrification in Triangle soil. All the herbicides slightly increased mineralization of nitrogen except 2,4,5-T which had variable effects in Triangle soil.     

贝加尔针茅草原土壤原位矿化过程中碳氮转化耦合特征

依托在贝加尔针茅草原建立的长期模拟氮沉降试验平台(始于2010年),运用PVC顶盖埋管法进行原位培养试验,研究不同氮添加下贝加尔针茅草原土壤碳氮组分、净硝化速率、净氨化速率、有机碳转化速率的变化特征及碳氮耦合关系。试验处理包括:对照N0,低氮添加(15、30、50 kg·hm~(-2)·a~(-1))记为N15、N30和N50,高氮添加(100、150、200、300 kg·hm~(-2)·a~(-1))记为N100、N150、N200和N300。结果表明:培养期间,N15、N30、N50和N100处理的净硝化速率显著高于对照N0(P0.05),分别增加了40.80%、110.31%、206.83%和202.04%;N30、N50和N100净氨化速率显著低于对照N0(P0.05),分别降低了16.88%、169.60%和150.67%;N15和N30处理的净矿化速率高于对照N0,分别增加了150%和50%;N50、N100、N150和N200处理的净矿化速率低于对照N0,分别降低了254.52%、161.50%、33.90%和79.85%。土壤有机碳与土壤全氮呈极显著正相关,土壤可溶性有机碳与土壤可溶性有机氮呈极显著正相关,土壤微生物生物量碳与土壤微生物生物量氮呈极显著负相关。有机碳转化速率显著影响微生物生物量氮转化速率,且符合一元线性回归方程。连续高氮沉降会降低土壤净氮矿化速率和有机碳转化速率,对土壤碳氮循环产生负面影响。     

Atrazine behaviour in the different pedological horizons of two Argentinean non-till soil profiles

Atrazine behaviour was investigated in the different pedological horizons from profiles of two non-tilled soils, a Typic Argiustoll and an Entic Haplustoll from the Argentinean pampas. As atrazine use in field conditions was associated with maize cropping, only one type of soil received atrazine every other year. Atrazine behaviour was characterized through the balance of ¹⁴C-U-ring atrazine radioactivity among the mineralized fraction, the extractable fraction and the non-extractable bound residues. The composition of the extractable fraction was characterized. Atrazine mineralization was the main dissipation mechanism in the superficial horizon of the Argiustoll because of microbial adaptation after repeated atrazine applications. In contrast, little atrazine mineralization was found in the Haplustoll profile, and it decreased with depth. The capacity of the soil organic matter to form bound residues was characterized using soil-size fractionation. Atrazine-bound residues depended on the soil organic matter content and the size of the fraction. Organic matter in the largest size fractions had a higher capacity to form atrazine-bound residues. In the Argiustoll profile, the atrazine degradation capacity decreased in the subsurface horizons (Bt₁ and Bt₂), where a large part of bound residues were formed. The deepest horizon (BC) of this profile had a high capacity to degrade atrazine reaching this horizon after a lag period. In the Haplustoll profile, atrazine mineralization and bound residue formation followed the organic carbon mineralization pattern.     

Einfluss von herbizidem Citronella-Öl und Neem (Azadirachtin) auf mikrobielle Aktivitäten im Boden

Within plant protection the products from citronella oil and neem mostly were used against pests. Their application for weed control is still at the beginning. This special application, however, needs higher dosages. The possible soil contamination and the missing microbiological-ecotoxicological information initiated our laboratory trial. The dosages used were relatively high as was necessary for weed control. They allowed the investigation of dose-effect relationships. In a loamy sand soil the biomass-related dehydrogenase activities as well as the carbon mineralization (actual and cumulative CO₂ formation) were measured. Because a soil with and without lucerne meal amendment was used the specific activity increase (=?LIA) could be calculated for both microbial parameters. Mostly both microbial activities were dose-dependently stimulated by the neem compound. Citronella oil at the beginning inhibited with the higher dosages and later on stimulated these activities. Most of the stimulations may be caused by the microbial decomposition of the organic compounds amended to the soil, which overlie some expected biocidal effects. This allows a preliminary estimation of the microbiological-ecotoxicological effects as less critical. Depending on the very high amounts needed for weed control, however, a final evaluation should consider additional investigations with further microbial activities and other soil organisms.