玉米秸秆生物炭对秸秆腐熟进程、养分含量和CO2排放量的影响

生物炭具有良好的理化特性(富碳、呈碱性、孔隙丰富),能够有效调节其所在系统的理化性质.通过室内培养试验研究了玉米秸秆生物炭对玉米秸秆腐熟进程以及腐熟产物的理化性质、养分含量和CO₂气体排放的影响.试验设置4个处理:对照(CK);生物炭添加量5%(B₁,生物炭干基质量占玉米秸秆腐熟体系的干基质量分数);生物炭添加量10%(B₂);生物炭添加量20%(B₃).结果表明: 生物炭能够提高秸秆腐熟体系的升温速率和温度峰值,加快秸秆腐熟进程;生物炭能够提高秸秆腐熟过程中微生物活跃时期的pH值,提高秸秆腐熟体系的电导率(EC),为微生物降解有机物提供更适宜的环境;生物炭能够促进秸秆腐熟体系有机质的降解,增加秸秆腐熟体系的总养分含量,提高秸秆腐熟产物的品质.另外,随着生物炭添加量的提高,氮(N)含量没有显著变化,磷(P₂O₅)含量和钾(K₂O)含量都显著提高.其中,B₃处理的P₂O₅和K₂O含量较CK分别提高了0.2%和0.9%.生物炭添加能够提高秸秆腐熟体系CO₂的排放通量,且CO₂排放通量与温度的变化趋势一致,进一步说明生物炭能够提高微生物降解有机物的强度.     

玉米秸秆生物炭对秸秆腐熟进程、养分含量和CO2排放量的影响

生物炭具有良好的理化特性(富碳、呈碱性、孔隙丰富),能够有效调节其所在系统的理化性质.通过室内培养试验研究了玉米秸秆生物炭对玉米秸秆腐熟进程以及腐熟产物的理化性质、养分含量和CO₂气体排放的影响.试验设置4个处理:对照(CK);生物炭添加量5%(B₁,生物炭干基质量占玉米秸秆腐熟体系的干基质量分数);生物炭添加量10%(B₂);生物炭添加量20%(B₃).结果表明: 生物炭能够提高秸秆腐熟体系的升温速率和温度峰值,加快秸秆腐熟进程;生物炭能够提高秸秆腐熟过程中微生物活跃时期的pH值,提高秸秆腐熟体系的电导率(EC),为微生物降解有机物提供更适宜的环境;生物炭能够促进秸秆腐熟体系有机质的降解,增加秸秆腐熟体系的总养分含量,提高秸秆腐熟产物的品质.另外,随着生物炭添加量的提高,氮(N)含量没有显著变化,磷(P₂O₅)含量和钾(K₂O)含量都显著提高.其中,B₃处理的P₂O₅和K₂O含量较CK分别提高了0.2%和0.9%.生物炭添加能够提高秸秆腐熟体系CO₂的排放通量,且CO₂排放通量与温度的变化趋势一致,进一步说明生物炭能够提高微生物降解有机物的强度.     

鸡粪改良铜尾矿对3种豆科植物生长及基质微生物量和酶活性的影响

基质改良和耐性植物种选择是重金属矿业废弃地人工生态恢复的关键。通过室内盆栽试验研究不同比例腐熟鸡粪改良铜尾矿后对3种豆科植物决明(Cassia tora)、田菁(Sesbania cannabina)、菽麻(Crotalaria juncea)生长和尾矿基质中土壤微生物量C、N及过氧化氢酶、碱性磷酸酶、脲酶和脱氢酶活性的影响。结果表明:添加鸡粪改良处理后3种植物茎叶生物量、根系生物量和体内总磷含量均有提高,植物体内总氮含量则只有菽麻明显增加。添加鸡粪可提高尾矿基质中微生物量C以及脲酶和脱氢酶活性,其中菽麻生长的尾矿基质中微生物量C含量增加最显著。尾矿基质中微生物量C与基质中总氮、有效磷呈显著正相关,菽麻生长的尾矿基质中微生物量C与基质中有效态Cu、Zn呈显著负相关。田菁、菽麻生长的尾矿基质中脲酶、脱氢酶与基质中总氮、有效磷呈显著正相关,决明、菽麻生长的尾矿基质中脱氢酶与基质中微生物量C呈显著正相关,决明生长的尾矿基质中脲酶、脱氢酶与基质中有效态Zn呈显著负相关。综合分析表明,铜尾矿∶鸡粪=250∶1的处理方式可作为鸡粪改良铜尾矿基质较好的一种比例模式,该处理方式下菽麻可作为铜尾矿生态修复优选植物种。     

利用废弃菌袋鸡粪堆肥发酵制备微生物菌肥的探索

为探索食用菌栽培废弃物资源的回收利用,以废弃菌袋和鸡粪为基质,按1:1(W/W)充分混匀,添加1%(W/W)的腐熟菌剂初发酵3周后,添加0.5%(W/W)的功能菌剂进行复发酵。结果表明废弃菌袋和鸡粪腐熟充分,其种子发芽指数(GI)符合有机固体废弃物腐熟情况的公认指标。堆肥成品的酸碱度、有机质含量、全氮、全磷、全钾、重金属(总砷,总汞,铅,镉)含量等指标均符合行业标准NY525-2012,可用于农田、果园等作物的肥料,为后续废弃菌袋和鸡粪的资源化利用提供参考。     

微生物菌剂对干旱区城市防护绿地凋落物分解的影响

为探寻促进干旱区城市防护绿地凋落物分解的途径,2007年10月下旬,分别采用青贮复合菌剂、秸秆腐熟剂和速腐增效剂3种微生物菌剂,对克拉玛依市区北郊防护绿地内的凋落物进行为期198 d的堆腐试验.结果表明： 堆腐前期(0～30 d),微生物菌剂处理能够加快堆腐凋落物的分解,其中速腐增效剂处理与对照差异显著;随堆腐时间的延长,堆腐凋落物中N、P和Ca浓度均持续上升;试验结束时,各营养元素浓度均比初始值高14.2%～252.9%;在整个堆腐过程中,堆腐凋落物有机碳分解率持续升高,C/N值逐渐下降.添加微生物菌剂加快了堆腐凋落物的腐熟速度,提高了堆腐凋落物养分浓度,其中以秸秆腐熟剂处理效果最佳.     

玉米秸秆堆肥的田间积制和原位还田肥效

针对我国西南丘陵山区玉米秸秆随处堆放或就地焚烧,既浪费资源又污染空气的情况,研究一种适合当地有机肥就地积制利用的方法.试验将玉米秸秆直接堆放于田边地角,接种菌剂,添加增氮和保氮剂,覆盖薄膜,腐熟后的堆肥配施化肥原位施入烟地.结果表明: 与对照(自然堆肥,CK)相比,生物堆肥(玉米秸秆+菌剂+增氮剂+保氮剂+覆盖薄膜)的物料升温快(2～3 d,>35 ℃),高温期(≥50 ℃)持续时间长(约15 d),降温慢;微生物种群在高温期减少,但细菌数量比CK高2～3个数量级;经90 d的积制,玉米秸秆呈深褐色或黑色,为碎屑或粉末状态,完全腐熟,含水量低于25%, pH 6.14,活性有机质和氮磷钾养分含量显著高于CK.在烤烟栽培中,生物堆肥配施50%的化肥可显著提高烟叶产量、均价、产值,改善烟叶品质.说明这种生物堆肥方式实现了玉米秸秆资源化利用,消除了由此引起的空气污染,适合于丘陵山区.     

秸秆还田方式对东北水稻土理化性质及微生物群落的影响

【目的】研究秸秆还田方式对东北黑土理化性质及微生物群落的影响。【方法】试验周期为2019年12月至2021年10月,秸秆还田采用2种方式： 秸秆直接还田+微生物菌剂WJ(strawdirect return+microbial agent WJ;MD),秸秆堆肥还田+微生物菌剂WJ(straw compost return +microbial agent WJ;MC)。分析土壤肥力、酶活和微生物群落。【结果】分析两种方式土壤有机质(SOM)、腐殖酸(HS)和富里酸有机碳(FA-C)含量,发现秸秆直接还田+微生物菌剂WJ比秸秆堆肥还田+微生物菌剂WJ分别增加2.28g/kg、7.82g/kg和5.26g/kg。土壤铵态氮(NH4⁺-N)、速效磷(AP)略高于秸秆堆肥还田+微生物菌剂WJ,均在6月份达到峰值。胡敏酸有机碳(HA-C)含量下降。此外,土壤脲酶、转化酶、纤维素酶活性和碱性磷酸酶活性对比发现,秸秆直接还田+微生物菌剂WJ比秸秆堆肥还田+微生物菌剂WJ分别高8.55%、15.46%、4.35%和6.19%。高通量测序结果显示,秸秆直接还田+微生物菌剂WJ中细菌和真菌的多样性均比秸秆堆肥还田+微生物菌剂WJ丰富。其中Anaerolinea、Bacteroidetes、Pseudomonas为优势细菌,Tausonia、Mrakia、Mrakiella为优势真菌。【结论】秸秆直接还田+微生物菌剂WJ比秸秆堆肥还田+微生物菌剂WJ更有利于土壤有机质、腐殖酸、土壤酶活性和微生物多样性的增加,这说明秸秆添加WJ菌剂直接还田可以减少有机养分的流失,保持田间土壤肥力。     

水分对有机基质栽培番茄生理特性、品质及产量的影响

以"齐粉"番茄品种为试材,研究了不同相对含水量对有机基质栽培番茄生长、生理特性、产量、品质和水分利用率的影响.结果表明:随着有机基质相对含水量的升高,番茄株高、茎粗、节间长和单株叶面积极显著增加,叶片色素含量、水势、渗透势及根系活力和果实产量显著增加,而番茄果实品质和水分利用率显著降低.从果实产量、品质和水分利用率方面综合考虑,80%基质相对含水量处理的果实产量达26 kg.m-2以上,可作为番茄有机基质栽培水分管理的量化指标;如果仅考虑果实品质,则50%基质相对含水量可以作为水分管理指标.     

秸秆还田土壤改良培肥基质和复合菌剂配施对土壤生态的影响

通过田间试验,研究水旱轮作（冬小麦-夏水稻）中水稻秸秆全量还田条件下土壤改良培肥基质和复合菌剂配施对小麦土壤养分、土壤物理结构和土壤生物学性质及土壤微生物区系的影响,为快速土壤培肥、提高中低产农田产量提供实践基础和技术支持。试验于江苏省盐城市滨海县黄河湾项目基地进行,共设置五个处理：①土壤改良培肥基质+复合菌剂+常规化肥（MOS+CMA+CF）;②复合菌剂+常规化肥（CMA+CF）;③土壤改良培肥基质+常规化肥（MOS+CF）;④常规化肥（CF）;⑤不施肥对照（CK）。对小麦返青期（S1）、拔节孕穗期（S2）和成熟期（S3）分别进行土壤理化性质、土壤酶活性、微生物量碳氮和微生物区系分析。结果表明,与CK相比,MOS+CMA+CF处理能够在短时期内提高土壤速效养分含量（其中速效氮提高了23.59%、速效磷提高了40.74%、速效钾提高了43.78%）,降低土壤容重,提高土壤孔隙度,显著提高土壤微生物量氮含量和土壤脲酶活性;同时,该处理还能在小麦返青期和拔节孕穗期增加土壤细菌和真菌多样性,提高微生物丰度,最终提高了小麦产量（与CK和CF相比,产量分别提高了149.29%和24.93%）。CMA+CF能够显著提高土壤纤维素酶活及土壤微生物量碳含量,表现出有较好的秸秆降解能力;并且在提高土壤理化指标含量、提高脲酶酶活、提高微生物量氮含量和小麦产量方面仅次于联合处理。由于MOS富含有机质,MOS+CF处理能够维持并提高土壤有机质含量、改善土壤物理环境。总之,短期内,MOS+CMA+CF处理提升土壤肥力,提高小麦产量的效果是最显著的;但CMA+CF处理在加速秸秆养分还田、改善土壤理化状况,增强微生物活性和丰富以及提高小麦产量方面也表现出优势,且复合菌剂经济方便有效,具有很好的田间技术推广价值。     

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。     

缓释砂硒对绿甘蓝富硒作用及生长的影响

砂硒因沙子具有透气保水的特性,同时硒释放相对缓慢,能提供稳定的硒来源,是比较理想的富硒蔬果培养基质。为了探讨缓释砂硒对绿甘蓝富硒作用和生长的影响,该研究设置对照组(CK),实验组缓释砂硒(CT)、鸡粪和砂硒1∶1混合(CT1)、鸡粪和砂硒1∶2混合(CT2)和鸡粪(CT3) 5个处理。结果表明:CT、CT1和CT2处理的绿甘蓝硒含量比CK分别增加45%、61%和64%,逐步回归分析表明绿甘蓝硒含量和土壤硒含量呈显著正相关(P<0.05); CT2处理的效果最好,绿甘蓝的产量增加45%,叶片厚度增加22.78%,水分利用效率提高56.66%。土壤锰含量和硒含量共同解释了绿甘蓝生物量变化的72%,而土壤锌含量解释绿甘蓝水分利用效率变化的66%。这表明砂硒添加后,通过增加土壤硒含量提高绿甘蓝硒含量,砂硒和鸡粪配比更有效地提高了绿甘蓝硒含量并促进其生长。     

不同培养料和发酵次数栽培巴氏菇比较

分别以玉米秸秆和稻草为培养料栽培巴氏菇,对菌丝生长性状进行对比;同时,在我国传统发酵栽培方法的基础上,将三次发酵法与二次发酵法进行了对比。试验结果表明:利用玉米秸秆栽培的巴氏菇在发菌速度及子实体质量和产量上均优于稻草;培养料经过3次发酵更适宜巴氏菇生长。经过3次发酵的玉米秸秆培养料栽培的巴氏菇产量和生物学效率分别为7.7 kg/m2和27.5%,子实体粗蛋白含量44.89%,可溶性糖含量44.01%,18种氨基酸总量31.70%,明显高于2次发酵的玉米秸秆培养料及2次、3次发酵的稻草培养料。     

不同有机肥对砂田西瓜产量、品质和养分吸收的影响

探讨不同有机肥对西北砂田西瓜生长、产量、品质和养分吸收利用的影响,为砂田西瓜合理施肥、优质高效生产提供理论依据.本试验以单施化肥为对照,在氮、磷、钾等养分条件下,设置了牛粪、鸡粪、羊粪、猪粪4个处理,测定了西瓜不同生育时期生长指标、产量、品质及养分吸收积累量.结果表明: 施用牛粪、鸡粪和猪粪有机肥较单施化肥可促进西瓜营养生长和氮、钾养分的运转,显著提高西瓜产量和养分的吸收积累量,其中西瓜产量较化肥处理分别显著提高了27.4%、31.6%和30.2%,氮素积累量分别提高了26.3%、39.8%和47.4%,磷素积累量分别提高了49.3%、48.3%和55.9%,钾素积累量分别提高了35.8%、41.6%和51.9%.猪粪处理的西瓜品质最优,中心、边缘可溶性固形物含量较化肥处理分别显著提高了5.5%和11.6%,Vc含量提高了19.9%.羊粪处理各指标与化肥处理间差异不显著,甚至略低于化肥处理.综上,砂田西瓜种植应优先选用猪粪和鸡粪有机肥,避免或减少施用羊粪有机肥.     

Changes in microbial biomass indices after 10 years of farmyard manure and vegetal fertilizer application to a sandy soil under organic management

The main objective of the second Darmstadt trial was to investigate the effects of vegetal fertilizers on soil properties and crop yield in comparison with farmyard manure. The experiment consisted of seven treatments: (i) inorganic fertilizers, (ii) vegetal organic fertilizers, (iii) vegetal organic fertilizers equivalent to biodynamic preparations, (iv) cattle farmyard manure, (v) cattle farmyard manure with addition of biodynamic preparations, (vi) high level of cattle farmyard manure, and (vii) high level of cattle farmyard manure with biodynamic preparations. The soil properties analyzed were pH, soil organic C, N, P, and S, soil microbial biomass C, N, and P, basal respiration and fungal ergosterol. The application of vegetal fertilizers had slightly negative effects on soil organic C, no effects on crop yield (potato, winter rye) and microbial biomass, but positive effects on ergosterol in comparison with farmyard manure. The increase in ergosterol was caused by straw return in the vegetal, but also in the inorganic fertilizer treatments. The biodynamic preparations did not affect the contents of soil organic C and total N. The low effectiveness of vegetal fertiliser in maintaining soil organic C levels is of particular importance for organic cropping systems and should be examined further under different site conditions.     

生物质炭配施有机物料对贫瘠红壤酶活性和微生物碳源代谢功能的影响

为进一步促进红壤固碳培肥,于2017和2018年通过田间试验研究了两种有机物料(玉米秸秆和羊粪)单施以及与生物质炭配施对贫瘠红壤养分含量、碳转化相关酶活性和微生物底物利用速率的影响。试验设置6个处理,即不施有机物料(对照)、玉米秸秆、羊粪、单施生物质炭、玉米秸秆与生物质炭配施、羊粪与生物质炭配施。结果表明:与对照相比,有机物料施用显著增加了土壤pH值、有机碳、全氮、有效磷和速效钾含量;与单施秸秆和羊粪相比,生物质炭与秸秆或羊粪配施显著增加了土壤有机碳、速效钾和碱解氮含量,但两者无交互效应。与对照相比,有机物料施用显著提高了β-葡萄糖苷酶(BG)、纤维二糖水解酶(CB)、β-木聚糖苷酶(XYL)和过氧化物酶(PERO)活性;与单施秸秆相比,生物质炭与秸秆配施处理酚氧化酶、过氧化物酶活性分别显著降低了28.6%、22.2%;与单施羊粪相比,生物质炭与羊粪配施处理α-葡萄糖苷酶(AG)、BG、XYL和PERO活性分别显著降低了46.1%、50.9%、41.6%和31.3%。与对照相比,有机物料施用显著提高了土壤基础呼吸和微生物对碳水化合物的利用速率,而生物质炭配施处理对碳水化合物、羧酸类底物的利用速率存在显著抑制作用。微生物碳源利用速率与BG和PERO活性呈显著正相关。因此,有机物料与生物质炭配施更有利于提高土壤养分含量,降低有机碳分解酶和微生物碳源代谢活性,从而促进红壤固碳培肥,有利于贫瘠红壤的地力提升。     

Effect of Three Plant Residues and Chicken Manure used as Biofumigants at Three Temperatures on Meloidogyne incognita Infestation of Tomato in Greenhouse Experiments

Plant residues of broccoli, melon, and tomato with or without addition of chicken manure were used as biofumigants in two pot experiments with Meloidogyne incognita-infested soils. The efficacy of these biofumigants in controlling M. incognita infestation in susceptible tomato bio-assay plants was studied at soil temperatures of 20º, 25º, and 30 ºC. None of the plant residues was effective at 20 ºC, and broccoli was more effective than tomato or melon at 25 ºC. At 30 ºC all three plant residues reduced M. incognita infestation of tomato to very low levels. Chicken manure was effective in one of two experiments at 20 ºC, and at 25 ºC enhanced the efficacy of tomato and melon residue in one of two experiments. At 30 ºC chicken manure was equally effective as the three plant residues but did not further decrease infestation levels in plant residue amended soils. It is concluded that biofumigation to control M. incognita is unlikely to be effective under cool conditions, that at soil temperatures around 25 ºC broccoli is more effective than melon and tomato, and that the addition of chicken manure at this soil temperature may enhance the efficacy. At high soil temperatures, of approximately 30 ºC, the biofumigant source seems of minor importance as strong reductions in tomato infestation by M. incognita were achieved by addition of each of the three plant residues as well as by addition of chicken manure.     

Microbial community structure and dynamics during anaerobic digestion of various agricultural waste materials

The influence of the feedstock type on the microbial communities involved in anaerobic digestion was investigated in laboratory-scale biogas reactors fed with different agricultural waste materials. Community composition and dynamics over 2 months of reactors’ operation were investigated by amplicon sequencing and profiling terminal restriction fragment length polymorphisms of 16S rRNA genes. Major bacterial taxa belonged to the Clostridia and Bacteroidetes, whereas the archaeal community was dominated by methanogenic archaea of the orders Methanomicrobiales and Methanosarcinales. Correlation analysis revealed that the community composition was mainly influenced by the feedstock type with the exception of a temperature shift from 38 to 55 °C which caused the most pronounced community shifts. Bacterial communities involved in the anaerobic digestion of conventional substrates such as maize silage combined with cattle manure were relatively stable and similar to each other. In contrast, special waste materials such as chicken manure or Jatropha press cake were digested by very distinct and less diverse communities, indicating partial ammonia inhibition or the influence of other inhibiting factors. Anaerobic digestion of chicken manure relied on syntrophic acetate oxidation as the dominant acetate-consuming process due to the inhibition of aceticlastic methanogenesis. Jatropha as substrate led to the enrichment of fiber-degrading specialists belonging to the genera Actinomyces and Fibrobacter.     

Fluctuations in sugar content are not determinant in explaining variations in vitamin C in tomato fruit

The present study aimed to clarify the relationship between sugars and vitamin C in fruit. The objective was to determine whether vitamin C content was regulated by sugar content due to the role of sugar as a precursor for vitamin C. During summer, maximal content in sugar and vitamin C were found in both genotypes tested Solanum lycopersicon ‘Cervil’ and ‘Levovil’. During autumn, fruit pruning increased fruit size and hexose content but fruit vitamin C content did not increase. Therefore sugar substrate was not limiting for vitamin C synthesis during autumn. We demonstrated for two cultivars, ‘Cervil’ and ‘Levovil’, with different sugar accumulation profiles during ripening, that sugar content was not determinant in the regulation of vitamin C content. The strong correlation observed between sugars and vitamin C in ‘Cervil’ was due to their concomitant increase during fruit ripening.     

畜禽粪便堆肥的理化腐熟指标及其红外光谱

选择新鲜的牛粪、猪粪和鸡粪为堆肥原料,通过室内模拟直接堆肥试验,研究堆肥过程理化参数变化、种子发芽指数以及腐熟物红外光谱特征.结果表明: 堆肥过程温度变化明显,牛粪出现一次堆肥高温阶段,鸡粪和猪粪各两次,堆肥温度超过50 ℃以上时间均大于10 d,温度可以最直观地表征堆肥的腐熟程度.堆肥过程中pH值变化幅度较大,其中猪粪的pH值从6.63上升至7.74,鸡粪从7.73上升至8.66,牛粪则先从7.86上升至8.36再下降至7.52;有机碳含量逐渐降低,牛粪、猪粪和鸡粪分别下降23.3%、28.2%和31.7%;堆肥过程中,牛粪、猪粪和鸡粪的铵态氮含量分别下降87.8%、73.6%和79.7%,硝态氮含量分别增加至堆肥前的56.81、6.49和4.85倍,铵态氮/硝态氮均下降至2以下.温度、pH值、有机碳含量和铵态氮/硝态氮能较好地反映3种粪便高温堆肥的腐熟程度,且与种子发芽率相关性较高(P≤0.05).红外光谱分析表明,在堆肥过程中,牛粪和猪粪的脂肪族、多糖类物质减少,芳香结构化增强,腐殖化程度增加;鸡粪则相反.在建立理化指标体系的同时,应兼顾物质结构的稳定性.     

Seven years of repeated cattle manure addition to eroded Chinese Mollisols increase low-molecular-weight organic acids in soil solution

Background and aims

Organic amendments are an option in enhancing soil biological productivity. Limited research exists on the effects of long-term cattle manure addition on low-molecular-weight organic acids (LMWOAs) concentrations in corn (Zea mays L) and soybean (Glycine max L.) fields in the region of soil erosion. The purpose of this study was to investigate the potential influence of cattle manure on the LMWOAs concentration in erosion soil.

Methods

A field experiment was established in Hailun city, Northeast China to determine the impact of long-term cattle manure addition on the total amounts of main LMWOAs in eroded Mollisol fields. There were three levels of simulated-erosion, which removed 0, 10 and 30 cm of topsoil. Two soil amendments were: (1) chemical fertilizer at the rate normally used by farmers in the region and (2) chemical fertilizer plus 15,000 kg?ha^?1 (dry weight basis) of cattle manure. Main LMWOAs in soil were assessed at the flowering stage of soybean and the jointing stage of corn.

Principle results

Compared to chemical fertilizer alone, 7-years of repeated cattle manure addition significantly increased total amounts of main LMWOAs in rhizosphere about 9–70 times and bulk soil about 6–62 times. The magnitude of increase by cattle manure was in the order of oxalate>malate>malonate>lactate>maleate in corn plots, and oxalate>malate>malonate>lactate in soybean plots. In comparison, cattle manure and topsoil removal had larger effect on LMWOAs concentrations in corn plot than soybean plot. The addition of cattle manure application and top soil removal had significant independent influence on main LMWOAs concentration in soil solution.

Conclusion

This study suggested that addition of cattle manure would be an effective approach in modifying soil biological properties through the increases in low-molecular-weight organic acids to eroded Chinese Mollisols.