不同尿素配施处理下土壤氨挥发特性

采用室内恒温模拟培养方法,以单施尿素处理为对照,研究了减量尿素配施玉米秸秆、配施脲酶抑制剂NBPT和硝化抑制剂DMPP组合、配施玉米秸秆+抑制剂组合等处理对棕壤氨挥发特性的影响,分析了不同处理土壤的p H、铵态氮、硝态氮含量与氨挥发速率的相关性。结果表明:单施尿素处理氨挥发速率在第3天即达到峰值;减量尿素配施玉米秸秆处理的氨挥发速率峰值出现时间延迟至施肥后第5天;在配施玉米秸秆的土壤中添加抑制剂组合后,氨挥发速率峰值延迟至第11天出现。与单施尿素相比,减量尿素配施玉米秸秆并添加抑制剂组合可显著降低氨挥发速率峰值74.27%,培养18 d可减少氨挥发累积损失量43.96%。不同处理的氨挥发速率与土壤的铵态氮浓度、p H呈正相关,与土壤的硝态氮浓度呈负相关。配施玉米秸秆并添加抑制剂组合的土壤中铵态氮浓度达到高峰后可长时间保持较高水平(350 mg·kg-1),并可有效减少硝态氮的浓度。     

白星花金龟幼虫对酵化玉米秸秆取食效果的研究

为探寻玉米秸秆资源化利用新途径、提高玉米秸秆利用效益,本研究利用白星花金龟Protaetia brevitaris Lewis幼虫的腐食性行为,选择其3龄幼虫,用EM菌液发酵玉米秸秆,以每5 d取食量为评价指标,选出幼虫取食的玉米秸秆最佳发酵时间及取食温度;以玉米秸秆发酵饲料为对照,以筛选出牛粪添加量分别为20%、60%的两组发酵饲料为处理,研究了白星花金龟幼虫对发酵饲料的利用率、转化率、消化率以及发酵饲料对白星花金龟幼虫死亡率、生物量增长率的影响。结果表明玉米秸秆发酵时间为25 d,温度为28℃时白星花金龟幼虫取食量最大;白星花金龟幼对玉米秸秆的转化率达到63.82%±30.90%,消化率为22.75%±3.07%,利用率为17.51%±8.50%,显著高于添加的组合;取食玉米秸秆发酵料的白星花金龟幼虫死亡率为5.75%±5.75%,生物量增长率达到11.01%±5.25%,均显著优于牛粪添加的玉米秸秆发酵料;添加牛粪可显著提高白星花金龟幼虫对玉米秸秆发酵饲料的取食量及虫粪产量,可利用白星花金龟3龄幼虫对玉米秸秆进行资源化利用,具有较好的应用前景。     

基于GET技术的混合厌氧发酵产甲烷研究

GET是一种国外新研发的在田间利用秸秆进行甲烷生产的技术。为了推动该技术在我国的实际应用,本研究以稻草与牛粪为发酵原料,水稻田土壤作为基底,采用正交试验法,测试了温度、发酵基质配比（稻草∶牛粪）和秸秆腐熟剂浓度对混合厌氧发酵产气量的影响。结果表明：各处理因子的产气动态呈“S”型增长模式,但在快速增长时间和增长幅度上有一定区别。30 ℃和40 ℃处理的累积产气量显著高于10 ℃和20 ℃处理的累积产气量;发酵基质配比以1∶1处理的累积产气量最大,分别比1∶0（对照）、1∶2和1∶3配比高34.12%、20.39%和21.78%;秸秆腐熟剂浓度的产气效果在实验范围内随着浓度的增加而增加。厌氧发酵过程中各实验因子下挥发性脂肪酸（VFAs）含量和pH在20 d左右分别有一个高峰和低谷值且都有较大差异,各因子主要是通过在这个时期对厌氧发酵进程的影响而对整个产气量产生影响。综合分析显示稻草厌氧发酵产生物甲烷的最优组合为：温度30 ℃、发酵基质配比1∶1、秸秆腐熟剂浓度8%。     

酵母发酵玉米秸秆水解液产麦角甾醇应用研究

生物质是一种可再生资源,生物质发酵可产生高端化工产品.本文主要探讨蒸汽爆破处理玉米秸秆及水解可发酵单糖,考察酵母发酵玉米秸秆糖化液产麦角甾醇的应用研究.实验结果表明:当固液比10%,盐酸浓度1.5%,90℃水解反应3 h,还原糖含量达到53.3%,纤维素转化率79%.发酵工艺参数为玉米秸秆糖化液6.0°Bx,玉米浆4%,pH 7.5,接种量10%,28℃摇床振荡培养32 h,细胞生物量达8.5 g/L,麦角甾醇含量可达2.35%.同时对玉米秸秆发酵产麦角甾醇晶体进行结构表征.     

温度和化学预处理对玉米秸厌氧消化产气量的影响

提出通过中温消化和化学预处理相结合的方法提高玉米秸的厌氧消化产气量。研究了中温和常温条件下,不同负荷率对玉米秸产气量的影响,以及经氢氧化钠、氨水与尿素处理后玉米秸主要成份的变化规律及其对产气量的影响。结果显示,中温消化产气量比常温提高了139．2％～281.8％,消化时间减少了8～16d;除尿素外,氢氧化钠和氨处理都可不同程度地提高玉米秸的产气量;中温消化时,氢氧化钠处理玉米秸的产气量比未处理玉米秸提高了77．0％,比常温消化的未处理玉米秸提高了263．6％。把中温消化和化学处理结合起来是提高玉米秸厌氧消化效率和产气量的有效方法。     

碳氮比对模拟水稻秸秆田间厌氧发酵系统甲烷生产和秸秆降解的影响

利用自制的厌氧发酵装置模拟田间厌氧发酵产生物甲烷的条件,通过添加不同量的尿素,研究C/N对水稻秸秆厌氧发酵产生物甲烷和秸秆降解的影响。设置了C/N为15∶1、20∶1、25∶1、30∶1和对照(53∶1)等五个处理,测定各处理的产气量、甲烷含量和秸秆木质纤维素含量。结果表明C/N对厌氧发酵产气进程有一定影响,峰值出现的时间、峰值的大小在不同处理之间均有差异:以C/N为25∶1的处理峰值出现的最早,较对照早5 d出现;以C/N为20∶1的峰值最高,较对照提高了27. 55%。C/N对厌氧发酵累积产气量和累积甲烷产量有显著影响,以C/N为20∶1的处理累积产气量(4 235. 00 mL)和累积甲烷产量(1526. 34mL)最高,相比对照组的累积产气量和累积甲烷产量分别提高了30. 78%和51. 31%。C/N对水稻秸秆降解也有显著影响。以20∶1和25∶1处理对秸秆降解的效果最好,其中20∶1处理的总降解率、纤维素降解率和半纤维素降解率分别达到了51. 33%、55. 31%和53. 05%,25∶1处理分别为50. 00%、53. 08%和49. 42%。上述结果表明通过添加尿素调节C/N能够提高水稻秸秆厌氧发酵的产生物甲烷效率和促进秸秆降解,以C/N为(20～25)∶1处理的促进效果最好。     

体外添加不同水平的亚麻籽油对气体产量、瘤胃发酵及脂肪酸组分的影响

利用瘤胃体外产气法研究在羊草底物条件下添加不同水平的亚麻籽油(LSO)对气体产量、瘤胃发酵和脂肪酸组分的影响。LSO添加水平分别为底物干物质的5%和10%,体外培养持续48 h。在12、24和48 h时测量总气体产量、甲烷及氢气产量,培养结束后测定发酵指标和发酵液中脂肪酸成分。结果表明,LSO显著降低了产气量和甲烷产量,提高了氢气产量;添加LSO显著提高了总挥发性脂肪酸含量、丙酸和丁酸的比例,还显著降低了发酵液pH和氨氮浓度;同时,添加LSO提高了发酵液中对人体健康有益的共轭亚油酸以及其他不饱和脂肪酸的比例。这些结果表明,富含十八碳不饱和脂肪酸的LSO可以在粗饲料条件下抑制甲烷生成,改善瘤胃发酵,增加了多不饱和脂肪酸的含量,而且抑制甲烷生成及改善瘤胃发酵的效果与添加剂量有关。     

玉米秸秆青贮过程中优势细菌多样性分析

通过从发酵0、1、3、5、15、30和60d自然发酵的青贮玉米(CK)和采用菌剂处理的青贮玉米(处理1)上取样,分别进行pH值测定和菌群总DNA的提取。总DNA经纯化后采用引物341F-GC和518R进行细菌16S rDNA V3区PCR扩增,扩增产物进行变性梯度凝胶电泳(DGGE)分离并回收优势条带和变化明显的条带进行测序分析,了解秸秆饲料发酵过程中的优势细菌多样性及动态变化规律,从而为现有青贮接种菌的改良奠定理论基础。研究结果表明:采用菌剂处理的青贮玉米pH值下降更快,其优势细菌种类更丰富,且各优势菌的丰度比对照组中相应菌的丰度更强。     

添加剂对水稻秸秆实地混合厌氧发酵产甲烷系统的作用

为提高水稻秸秆利用效率,改进水稻秸秆实地混合厌氧发酵产甲烷技术,本研究开展了添加剂在混合厌氧发酵系统的应用研究。试验选取水稻秸秆和猪粪作为发酵原料,通过分别添加不同的浓度的吐温20和腐植酸,测定甲烷的产气量和浓度、秸秆的降解和土壤肥力的变化,以揭示添加剂类型及其浓度对水稻田实地甲烷生产系统的影响。结果表明:添加剂的掺入并未影响产气的动态变化趋势,但显著地促进产气和提高产气浓度,整体效果由高到低为腐植酸吐温20对照,其中经腐植酸处理的产气量和产气浓度对照相比分别提高了50. 73%和24. 55%。添加剂的掺入有利于水稻秸秆纤维素和半纤维素的降解,但对木质素没有显著影响;其中以0. 15 g/L腐植酸和0. 30 g/L吐温20的降解率最高,相较于对照其纤维素降解率均提高了22. 11%,半纤维素降解率分别提高了107. 13%和98. 39%。添加剂的掺入能显著增加土壤肥力,以0. 15 g/L腐植酸和0. 30 g/L吐温20处理水平的效果最优,相较于对照,其土壤有机质分别增加了29. 63%和23. 72%,全氮分别增加了52. 32%和42. 38%,全磷分别增加了83. 33%和57. 14%。     

基于极端顶点混料设计优化黄粉虫秸秆饲料配方

【目的】每年产生的秸秆大部分没有被有效利用,造成大量的资源浪费。虽有部分秸秆发酵后制成畜禽动物饲料,但研究秸秆饲料用于饲养昆虫的少见。本研究旨在拓展秸秆的资源化利用途径,利用发酵秸秆饲养黄粉虫Tenebrio molitor,进而降低黄粉虫饲养中的饲料成本。【方法】以饲养黄粉虫的常规饲料、发酵的玉米秸秆、发酵的红薯秸秆为原料,用极端顶点混料设计法,研究三者不同混合比例对黄粉虫幼虫生长指标(生物量增率、死亡率、体长、饲料利用率和转化率)以及生理指标[含水量、灰分含量、粗脂肪含量、粗蛋白含量、超氧化物歧化酶(SOD)活性、总糖含量、磷含量、中微量元素含量和重金属含量]的影响,筛选出黄粉虫的最佳混料配方。【结果】结果表明,在常规饲料中添加一定量发酵的玉米秸秆和红薯秸秆更有利于黄粉虫幼虫的生长。生物量增率较大的实验组,其饲料利用率和转化率较高。混料配方中红薯秸秆所占比例越大,黄粉虫幼虫的死亡率趋势越大。而不同的混料配方对黄粉虫幼虫的体长和各生理指标无明显影响。最佳的混料配方为:常规饲料∶发酵玉米秸秆∶发酵红薯秸秆=37.24∶20.72∶42.04。此配方饲料成本低,相比于常规饲料配方成本降低了56.94%。此配方下饲养的黄粉虫幼虫,其生物量增率可达32.52%,高于常规饲料饲喂的对照组(25.17%),且黄粉虫幼虫的死亡率低、饲料利用率高。【结论】秸秆饲料经过科学配方既降低了黄粉虫的饲养成本,又提高了秸秆的利用率,具有较好的推广前景。     

The intake of steers and heifers fed on mixtures of alkali-treated or untreated straw with grass silage

Two experiments were made to investigate the intake of cattle when offered straw and silage mixtures.In a trial of changeover design 12 Friesian castrates (steers) were offered five diets. These were grass silage alone or mixed with untreated or NaOH treated straw supplying 20 or 40% of the total dry matter. The addition of 20% straw to the diet significantly reduced dry matter intake, and a further reduction occurred at 40%. Treating the straw with NaOh did not increase dry matter intake but led to an associated increase in digestible organic matter intake.Twelve Ayrshire heifers were given four diets in a trial of changeover design. The diets were silage only and three straw : silage mixtures in which straw provided 40% of the dry matter. The straws were untreated, NaOH treated or KOH treated. Untreated straw markedly depressed dry matter intake; NaOH raised the digestibility of straw and thus increased digestible organic matter intake significantly. The dry matter intake of the heifers was much greater than anticipated with the KOH treated straw : silage mixture and was similar to that achieved with silage only.     

Biomethanation of rice and wheat straw

When rice or wheat straw was added to cattle dung slurry and digested anaerobically, daily gas production increased from 176 to 331 l/kg total solids with 100% rice straw and to 194 l/kg total solids with 40% wheat straw. Not only was methane production enhanced by adding chopped crop residues but a greater biodegradability of organic matter in the straws was achieved.The authors are with the Microbiology and Molecular Genetics Unit, Tata Energy Research Institute, 158 Jor Bagh, New Delhi 110 003, India     

Modeling Water Quality Impacts of Cellulosic Biofuel Production from Corn Silage

The growing interest in the use of alternative biomass products for fuel production requires a thorough understanding of the environmental impacts associated with the production of these bioenergy crops. Corn silage is a potential bioenergy feedstock; however, water quality implications for its utilization as a biofeedstock are not understood. The objective of this work was to evaluate water quality impacts associated with corn silage production. The GLEAMS-NAPRA model was used to quantify runoff, percolation, erosion, nitrate-nitrogen, total phosphorus, and pesticide losses attributed to the production of corn silage with and without winter cover crops for two tillage options (conventional tillage and no till) on three Indiana soils. Results revealed that corn silage would generate greater annual surface runoff (1 to 6 mm) and percolation (1 to 20 mm) compared with corn grain and grain plus stover cropping systems. Silage/winter cereal rye cover crop reduced annual surface runoff and percolation and was strongly influenced by increases in evapotranspiration, when compared with continuous silage production. Silage managed with winter cereal rye cover crop influenced water quality by reducing annual nitrate losses with runoff from a low of 14 % to a high of 27 %, with relatively no effect because of tillage management. No-till practice on silage system produced significantly greater phosphorus losses (7.46 to 18.07 kg/ha) in comparison to silage/cereal rye, corn grain, and grain plus stover harvest (p?<?0.05). For every 1,000 l of ethanol produced from corn silage, erosion losses ranged from 0.07 to 0.95 t/ha for conventional tillage practices and from 0.06 to 0.83 t/ha for no-till practices. The feasibility of cropping systems such as corn silage/cereal rye could contribute to large-scale biomass production but should be further investigated.     

Microbial inoculant effects on silage and in vitro ruminal fermentation, and microbial biomass estimation for alfalfa, bmr corn, and corn silages

Whole crop third cut alfalfa, brown mid-rib (bmr) corn, and corn were chopped and inoculated with one of four microbial inoculants used. Uninoculated silage was the control treatment. Each crop was ensiled in four mini-silos (1 L glass jars) per treatment. All silos were fermented for 60 days at room temperature (22 °C), and then they were opened and analyzed for fermentation products, fiber constituents and N fractions. A fraction of wet silage was ground with a blender for 30 s. In vitro gas production was measured in 160 ml sealed serum vials at 3, 6, 9, 24, and 48 h using the wet ground silage. At 9 and 48 h, rumen fluid was analyzed for volatile fatty acids (VFA) and microbial biomass yield (MBY). In all the three crops, the four inoculants produced only minor changes in pH and fermentation products during ensiling. Of the variables measured, soluble nonprotein N fractions were the characteristics most often affected by some inoculants. At 9 h incubation, in vitro gas production and VFA did not differ between control and inoculated silages, but MBY did. Among crops, alfalfa and corn silages had higher MBY than did bmr corn silage. Among inoculants, three of the four inoculated silages produced more MBY than did control. At 48 h, alfalfa silage produced higher MBY than did corn or bmr silage, and two of the inoculated silages had more MBY than did the control. There was no inoculant by crop interaction. Results suggest that some silage inoculants are capable of altering rumen fermentation, even in cases where effects on silage fermentation are small, and that this effect may be linked to better preservation of crop protein during ensiling.     

Effects of pressed beet pulp silage inclusion in maize-based rations on performance of high-yielding dairy cows and parameters of rumen fermentation

Beet pulp contains high amounts of pectins that can reduce the risk of rumen disorders compared to using feedstuffs high in starch. The objective was to study the effects of inclusion of ensiled pressed beet pulp in total mixed rations (TMR) for high-yielding dairy cows. Two TMR containing no or about 20% (on dry matter (DM) basis) beet pulp silage were used. The beet pulp silage mainly replaced maize silage and corn cob silage. The TMR were intentionally equal in the concentrations of energy and utilisable crude protein (CP) at the duodenum. TMR were fed to 39 and 40 dairy cows, respectively, for 118 days. The average daily milk yield was about 43 kg/day. No significant differences in milk yield and milk fat or milk protein content were detected. DM intake of cows was significantly reduced by the inclusion of beet pulp silage (23.0 v. 24.5 kg/day). However, a digestibility study, separately conducted with sheep, showed a significantly higher organic matter digestibility and metabolisable energy concentration for the TMR that contained beet pulp silage. In vitro gas production kinetics indicated that the intensity of fermentation was lower in the TMR that contained beet pulp silage. In vitro production of short-chain fatty acids, studied using a Rusitec, did not differ between the TMR. However, the inclusion of beet pulp silage in the ration caused a significant reduction in the efficiency of microbial CP synthesis in vitro. The amino acid profile of microbial protein remained unchanged. It was concluded that beet pulp silage has specific effects on ruminal fermentation that may depress feed intake of cows but improve digestibility. An inclusion of beet pulp silage of up to 20% of DM in rations for high-yielding dairy cows is possible without significant effects on milk yield and milk protein or milk fat.     

饲料乳酸菌的分离鉴定及优良菌株筛选

对从饲料玉米、高粱、麦秆及棉花中筛选出的乳酸菌进行分类鉴定和综合性分析。用MRS+CaCO3固体培养基从棉花中分离出乳酸菌18株、高粱中30株、饲料玉米中18株、麦秆中18株。经形态学、生理生化试验进行初步鉴定并按产酸试验,耐盐及耐酸试验挑选出32株产酸率强的乳酸菌对其进行16S rDNA分子鉴定。结果显示,32株菌都具有良好的耐盐、耐酸能力;经生理生化和16S rDNA基因序列鉴定可知32株乳酸菌分属于两个属,即乳杆菌属、肠球菌属,4个种,即干酪乳杆菌(Lactobacilluscasei)、肠道球菌(Entercoccus faecium)、植物乳杆菌(Lactobacillus plantarum)、海氏肠球菌(Entercoccus hirae)。4种饲料原料中肠道球菌普遍存在。除了这种乳酸菌以外,棉花有干酪乳杆菌、植物乳杆菌、海氏肠球菌,玉米和麦秆内有植物乳杆菌。从饲料中筛选出4株具有较强产酸能力的乳酸菌,可进一步研发成青贮饲料添加剂。     

NO formation during agricultural straw combustion

NO formation during combustion of four typical kinds of straw (wheat straw, rice straw, cotton stalk and corn stalk) which belong to soft straw and hard straw was studied in a tubular quartz fixed bed reactor under conditions relevant to grate boiler combustion. Regarding the real situation in biomass fired power plants in China, NO formation from blended straw combustion was also investigated. Nitrogen transfer during blended straw pyrolysis was performed using a thermogravimetric analyzer (TGA) coupled with a Fourier transform infrared (FTIR) spectrometer. The results show that NO conversion for the four straws during combustion is distinctive. Over 70% fuel-N converts into NO for cotton stalk, while only 37% for wheat straw under the same condition. When wheat straw and cotton stalk were mixed, N-NO conversion increases. The limestone addition promotes NO emission during cotton stalk combustion. The presence of SO₂ in atmosphere suppresses NO formation from straw combustion.     

促分解菌剂对还田玉米秸秆的分解效果及土壤微生物的影响

为了探明促分解菌剂的应用对还田玉米秸秆的促分解效果及对土壤微生物群落结构的影响,选用3组促分解菌剂,编号依次为ND、NK和NS,于2009年10月至2010年4月期间,在河北省农林科学院辛集实验站冬小麦-玉米轮作田对玉米秸秆还田地进行了接种试验。在接种后的15、25、145和160 d分别测定秸秆残重率和秸秆残渣中C/N,结果表明与未施菌剂对照(CK)相比,3组菌剂均在一定程度上加快了玉米秸秆的分解,其中以菌剂ND促分解效果最好,NK次之,NS较差,三者的最高促分解效果分别比CK提高了14.3%、7.7%和1.6%,主要促分解效果都出现在早期(前25 d),且菌剂促进秸秆残渣中C/N降低的效果也在早期明显。采用变性梯度凝胶电泳技术(DGGE)检测菌剂对玉米秸秆降解过程中土壤细菌和真菌群落结构的影响,结果表明,与不接种CK相比,接种菌剂主要在早期对土壤细菌和真菌的群落结构产生较大的影响,而后期对土壤微生物群的影响不明显。秸秆还田后接种促分解菌剂,能在接种早期有效加快秸秆分解,而随接种后时间的推进,其促进效果逐渐减弱,与之对应,土壤微生物群落结构早期差异明显,其后差异逐渐减小。     

The effect of eyespot (Cercosporella herpotrichoides Fron.) on wheat and the influence of nitrogen on the disease

The effect of eyespot throughout the season on wheat receiving different amounts of nitrogen was studied in pot experiments. Plants inoculated in December showed chlorosis of outer leaves in February. Among plants with high nitrogen, eyespot killed 11%, caused straggling of 31% and whiteheads in 14% of the surviving ear-bearing straws, reduced yield of straw by 8% and of grain by 16%. The loss in straw yield was due to reduction in plant number, that of grain was about half due to reduction in number of ears and half to production of lighter grains. Among plants with low nitrogen the disease killed 23% of the plants, caused straggling of 86% and whiteheads in 18% of the surviving ear-bearing straws, and reduced yield of straw by 23% and of grain by 44%. The loss in straw yield was due to death of plants, that of grain was about two-thirds due to the production of fewer ears and one-third to that of lighter grains. In the high-nitrogen series the number of shoots at the time of maximum tillering was reduced by 29%; in the low-nitrogen series the disease caused reduction in height, a very uneven crop, delay in ear and anther emergence, and an increase in tail corn from 4% in the controls to 30% in the inoculated plants.
All inoculated plants became infected, but those receiving high nitrogen had only 49% of the ear-bearing straws with severe lesions at harvest, while those receiving low nitrogen had 86%. The larger number of tillers produced when nitrogen was applied may have enabled the less severely diseased shoots to survive and bear ears while the most severely infected died.