Effect of Integrated Use of Inorganic Fertilizer and Organic Manures on Bacterial Wilt Incidence (BWI) and Tuber Yield in Potato Production Systems on Hill Slopes of Central Kenya

Bacterial wilt (BW) caused by Ralstonia solanacearum is one of the most damaging diseases of potato (Solanum tuberosum L.) in Kenya and worldwide. In Kenya, potato tuber yield losses due to BW infection are estimated at 50 ~ 100%. Low soil fertility is also one of the most important constraints limiting potato production in central Kenya highlands. Farmers tackle this problem through use of inorganic fertilisers and organic manures, both of which amend the soil environment to influence bacterial wilt development. Undecomposed organic manures can also introduce the pathogen into a clean field. Between short rains 1999 and 2000, 10 on-farm extension-researcher- farmer-designed and farmer-managed trials were done at Kianjuki catchment in Embu District. The objective was to use farmers?participatory research approach and select the most suitable organic and inorganic fertiliser combination(s) with lowest BWI and acceptable usable tuber yields, and also to demonstrate use of some components of integrated disease management methods in reduction of disease incidence and spread. Seven treatments were proposed, presented to the farmers for discussion and the most relevant four were selected for evaluation. A newly released potato variety 慉sante?was planted during the short rains 1999 and long rains 2000. BWI didn抰 result in significant differences between treatments but the tuber yields were significantly different in short rains of 1999 and 2000. During short rains 2000, both BWI and tuber yields and unusable tubers differed significantly between treatments. The results confirmed that well- decomposed manures or manures from pathogen-free areas can be used in combination with inorganic fertilisers to improve soil fertility and potato tuber yields in smallholder farms without influencing BWI. Use of certified seed tubers in pathogen free field and following recommended field sanitation measures resulted in apparently bacterial wilt free crop. Considering the high cost of inorganic fertiliser and its negative effects on the environment, reduced usage at half the recommended rates combined with half rates of FYM is feasible option friendly to the farmer, soil and environment. The interviewed farmers also ranked the option as the most appropriate combination for soil fertility improvement for potato production in smallholder farms.

Impact of Organic Soil Amendments on the Physical Characteristics and Yield Components of Potato （Solanum tuberosurn L.） in the Highlands of Cameroon

A field experiment was conducted in the Western Highlands of Cameroon to study the effects of Calliandra calothyrsus, sterilized compost, non-sterilized compost and mineral fertilizers （NPK 11：11：22） on physical characteristics, yield components and late blight disease severity of potato （Solanum tuberosum）. A two factorial treatment combination made up of fertilization schemes and sanitary measures were laid out in a randomized complete block design （RCBD） with four replicates and 10 treatments. Data collected were subjected to a multivariate ANOVA and means separated with the Dunnett t-test with Calliandra calothyrsus considered as the main treatment. Mineral fertilizers and Calliandra calothyrsus significantly augmented stem diameter, plant height and plant vigor, total and marketable yields, despite the fact that late blight severity was high in the two treatments. The correlation matrix showed that total yield had significant and positive correlation with stem diameter （r = 0.74）, plant height （r = 0.61）, plant vigor （r = 0.61） and marketable yield （r = 0.99） and negative correlation （r = -37） with late blight severity. The increase observed is attributed to the nutrient contents of the treatments applied. Leafy prunings of C. calothyrsus increase soil organic matter which probably improves moisture retention and biological activity. The highest late blight severity recorded between the 45 and 60 coincides with active development of plant canopy which influences disease severity and create a canopy microclimate conducive to disease development. This study suggests that Calliandra calothyrsus has the potential of improving potato production provided appropriate fungicide is used.

Effect of Chicken Manure, Compost and Cow Dung on the Growth and Yield of Sweet Potato [Ipomoea batatas (L.) Lam.] under Guinea Savannah Agroecological Zone of Ghana

Twelve percent (12%) of Ghanaians are food insecure, and climate-smart crops like sweet potatoes are required to help end poverty. Small-scale farmers in Ghana who produce low-technology, subsistence crops, such as sweet potatoes, are more food secure than those who do not. This study was initiated to investigate the effect of chicken manure, compost, and cow dung on the growth and yield of “apomuden”, “SARI-Nyoriberigu”, “SARI-Nan” and “kufour” sweet potato under the Guinea Savannah agroecological zone of Ghana. Organic fertilizer increased leaf chlorophyll content and leaf area index. The application of cow dung, chicken manure and compost in 2015 significantly increased total storage root yield by 38%, 55% and 98%, 62%, 45% and 37%, 52%, 61% and 44%, and 33%, 36% and 28% for SARI-Nyoriberigu, Kufour, SARI-Nan and Apomuden, respectively, when compared to the untreated check. In 2016, and in comparison with the untreated check, the application of cow dung, chicken manure and compost increased total storage root yield by 42%, 61% and 93%, 69%, 49% and 41%, 57%, 67% and 48%, and 36%, 39% and 30% for SARI-Nyoriberigu, Kufour, SARI-Nan and Apomuden, respectively. Hence, the application of organic fertilizers will increase sweet potato yield, give higher returns to resource-poor smallholder farmers and contribute to enhancing food and nutrition security.

Effects of Long-Term Winter Planted Green Manure on Distribution and Storage of Organic Carbon and Nitrogen in Water-Stable Aggregates of Reddish Paddy Soil Under a Double-Rice Cropping System

In agricultural systems, maintenance of soil organic matter has long been recognized as a strategy to reduce soil degradation. Manure amendments and green manures are management practices that can increase some nutrient contents and improve soil aggregation. We investigated the effects of 28 yr of winter planted green manure on soil aggregate-size distribution and aggregateassociated carbon（C） and nitrogen（N）. The study was a randomized completed block design with three replicates. The treatments included rice-rice-fallow, rice-rice-rape, rice-rice-Chinese milk vetch and rice-rice-ryegrass. The experiment was established in 1982 on a silty light clayey paddy soil derived from Quaternary red clay（classified as Fe-Accumuli-Stagnic Anthrosols） with continuous early and late rice. In 2009, soil samples were collected（0-15 cm depth） from the field treatment plots and separated into water-stable aggregates of different sizes（i.e., 〉5, 2-5, 1-2, 0.5-1, 0.25-0.5 and 〈0.25 mm） by wet sieving. The long-term winter planted green manure significantly increased total C and N, and the formation of the 2-5-mm water-stable aggregate fraction. Compared with rice-rice-rape, rice-rice-Chinese milk vetch and rice-rice-ryegrass, the rice-rice-fallow significantly reduced 2-5-mm water-stable aggregates, with a significant redistribution of aggregates into micro-aggregates. Long-term winter planted green manure obviously improved C/N ratio and macro-aggregate-associated C and N. The highest contribution to soil fertility was from macro-aggregates of 2-5 mm in most cases.

Applying organic amendment enriches nutrient status of municipal solid waste compost and its application enhances tuber yield and nutrient concentrations of potato

Elevated price of chemical fertilizers and poor nutrient content in conventional organic sources such as municipal solid waste(MSW)compost necessitate the production of nutrient enriched compost which could serve as a potential alternative organic fertilizer option.We studied three types of amended compost that were prepared by mixing 20%mustard oil cake(MOC)and 30%poultry manure(PM)or cow dung or sugarcane press mud(SPM)with 50%MSW compost.Trichoderma viride was inoculated into every type of compost.The rate of amended or unamended MSW compost application was 10 t ha^(−1).The use of different amendments improved the nutrient level of MSW compost,of which the N increment was remarkable,ranging from 1.14%N(unamended compost)to 2.9%–3.22%N depending on the types of amendment.A field experiment was conducted to evaluate performances of the amended MSW composts on the yield and nutrient content of potato(variety BARI Alu25).All compost treatments except the sole MSW compost treatment produced significantly higher tuber yields than the sole fertilizer treatment.The press mud based MSW compost+fertilizer treatment produced the highest tuber yield of 31.6 t ha^(−1)(65%increase over 100%fertilizers and 57%increase over 100%compost treatment).The tuber N concentration varied from 0.128%to 0.594%,P from 0.018%to 0.035%,K from 0.213%to 0.313%and S from 0.020%to 0.053%,with the highest result recorded with press mud+fertilizer treatment.The use of amended composts had residual effects on soil N,P,K and S contents.Thus,the treatment containing 50%fertilizer+50%compost mixture(MSW:MOC:SPM in a ratio of 5:2:3)performed the best followed by PM amended compost.It is concluded that integrated use of 10 t ha^(−1) organic amended MSW compost with chemical fertilizers can ensure higher crop yield,nutrient content and sustained soil fertility in nutrient-deficient sub-tropical soil.

马铃薯整地施肥播种联合作业机的研制与试验

依据现阶段马铃薯播种机械发展现状,结合本地农民对播种机的现实需求,设计了一款马铃薯整地施肥播种联合作业机。对机具进行总体结构设计和主要参数确定,在对关键部件进行详细设计计算的基础上,制作了马铃薯联合作业机的试验样机,并进行大量田间试验。试验结果表明,设计的马铃薯联合作业机各项指标满足国家标准要求。

油菜—富硒水稻—富硒甘薯轮作对土壤养分及甘薯的影响

为掌握油菜—富硒水稻—富硒甘薯轮作种植模式(T)与传统冬闲—水稻—甘薯种植模式(CK)的差异,特开展种植试验,分析甘薯收获后土壤pH值、有机质、全氮、碱解氮、速效钾、交换性钙、有效锌和有效硼的含量,甘薯可溶性糖、维生素C含量,以及大米和甘薯的硒元素含量。结果表明,与CK相比,T处理的土壤肥力和甘薯品质明显提升,其中0~20 cm土壤的有机质、全氮、碱解氮、速效钾、交换性钙、有效锌和有效硼分别提升21.8%、3.2%、5.4%、28.4%、34.6%、42.5%、300.0%,20~40 cm土壤则分别提高22.8%、5.6%、14.0%、32.6%、38.0%、104.4%、325.0%;甘薯总糖、维生素C含量分别提高125.09%、16.34%。另外,通过施用富硒肥,T处理的大米和甘薯硒元素含量分别达到0.14、0.15 mg/kg。因此,油菜—富硒水稻—富硒甘薯轮作种植模式(T)可实现油菜绿肥还田及水稻、甘薯秸秆还田,达到改良土壤、提升甘薯品质的目标。

紫马铃薯皮粉对黑水虻幼虫生长性能、废弃物消减率、虫体营养组分及肠道微生物的影响

本试验旨在研究育成猪粪中添加紫马铃薯皮粉对黑水虻幼虫生长性能、废弃物消减率、虫体营养组分及肠道微生物的影响。选取4日龄黑水虻幼虫3 000只,随机分为5组,每组3个重复,每个重复200只。对照组饲喂育成猪粪,试验组分别饲喂育成猪粪+2%紫马铃薯皮粉(2%添加组)、育成猪粪+4%紫马铃薯皮粉(4%添加组)、育成猪粪+6%紫马铃薯皮粉(6%添加组)和育成猪粪+8%紫马铃薯皮粉(8%添加组)。试验期16 d。结果表明:1)6%、8%添加组的幼虫平均干重显著低于对照组及2%、4%添加组(P<0.05)。各组之间废弃物消减率无显著差异(P>0.05)。2)4%、6%和8%添加组的粗蛋白质含量显著高于对照组(P<0.05),2%、4%、6%和8%添加组的粗脂肪含量显著低于对照组(P<0.05)。3)4%添加组的变形菌门相对丰度显著低于对照组(P<0.05),放线菌门、拟杆菌门、蓝菌门、疣微菌门、酸杆菌门相对丰度显著高于对照组(P<0.05)。4)4%添加组的普罗威登斯菌属、Breznakia和肠球菌属相相对丰度显著低于对照组(P<0.05),狭窄梭菌属、土孢杆菌属、棒状杆菌属、罗姆布茨菌属和苏黎世杆菌属相对丰度显著高于对照组(P<0.05)。5)狭窄梭菌属和土孢杆菌属相对丰度分别与幼虫平均干重、粗蛋白质含量呈显著正相关(P<0.05),而肠球菌属相对丰度与粗蛋白质含量呈显著负相关(P<0.05)。6)4%添加组的肠道微生物网络图连接数为3 138个,节点数为178个,高于其他各组,说明4%马铃薯皮粉添加比例下肠道最为复杂。由此可见,育成猪粪中添加4%紫马铃薯皮粉能在不影响幼虫平均干重和废弃物消减率情况下,提高虫体粗蛋白质含量,降低粗脂肪含量,有益于幼虫肠道健康,有利于提升昆虫蛋白质生产效率。

基于GGE模型的甘薯品系产量性状和试验环境评价

为了综合评价甘薯区域试验品系基因型及基因型与环境互作关系,采用GGE双标图法对2020-2021年福建省甘薯区试2组优质淀粉新品系产量数据进行分析。结果表明:2020年‘泉薯26’丰产性最好,在漳浦、福州、泉州、莆田、三明和南平具有较强区域适应性,‘龙薯39号’丰产性和稳产性较好,是试验理想品系;2021年‘金薯43’丰产和稳产性最好,是试验理想品系,‘红金薯2号’具有较好丰产性,在宁德、龙岩、三明和福州具有较强区域适应性。此外,三明试验点在2年试验中具有较高鉴别力和代表性,是理想的试验点。GGE双标图法能够直观评价参试品系的产量特征和试验点的代表性,为客观评价甘薯新品系的高产性和稳产性提供简便、有效的分析手段。

我国北方一作区马铃薯高产稳产区分布特征

北方一作区马铃薯种植面积和总产量居我国首位,明确其高产稳产区分布,对马铃薯种植合理布局具有重要意义。基于1981—2019年研究区域内234个气象站点逐日气象数据以及作物、土壤数据,利用APSIM-Potato模型,以产量平均值和变异系数为高产性和稳产性评价指标,将研究区域划分为高产高稳、高产低稳、低产高稳和低产低稳4个亚区,分析不同生产水平下我国北方一作区马铃薯高产稳产区分布特征,探讨降水和土壤对马铃薯高产性和稳产性的影响。结果表明:不同生产水平下马铃薯高产区比例呈下降趋势;随着限制因素增加,高产高稳区面积比例逐渐降低,气候-土壤潜在生产水平下高产高稳区面积比例仅占研究区域总面积的13%;高产低稳区是潜在的高产高稳区,及时采取有效措施可提升稳产性。降水对马铃薯高产性和稳产性的影响大于土壤。实际生产中,降水和土壤限制下高产性和稳产性降低的区域,应注意结合当地灌溉条件配合耕作措施,以确保马铃薯高产稳产。

不同栽培方式对马铃薯田间土壤温湿度及产量的影响

为了研究地膜覆盖和绿肥对提高我国西南高寒山区春播马铃薯田间耕层土壤温度和水分的影响,通过2009-2010年设置地膜覆盖和绿肥的不同处理,研究其对马铃薯田间土壤耕层温度、水分及产量的影响。结果表明:与传统栽培方式相比,播种后至封行前,地膜覆盖且施绿肥栽培方式和地膜覆盖栽培方式耕层土壤(0～20cm)日平均温度提高3.6℃和2.9℃。地膜覆盖且施绿肥栽培方式、施绿肥栽培方式和地膜覆盖栽培方式田间土壤(0～21cm)平均含水率提高了12.93%、6.3%和10.88%;封行后,地膜覆盖且施绿肥栽培方式和地膜覆盖栽培方式田间土壤平均含水率低6.35%和6.4%。地膜覆盖且施绿肥栽培方式和施绿肥栽培方式马铃薯的块茎产量增加25.6%和2.3%。因此,地膜覆盖且施绿肥栽培方式能显著地提高苗期耕层土壤温度、含水率和马铃薯的块茎产量。

羊厩肥与氮磷化肥配施对马铃薯干物质积累及产量的影响

本文以加工型马铃薯大西洋为试验材料,系统研究了羊厩肥与氮磷化肥配施对马铃薯干物质积累及产量的影响。结果表明,羊厩肥、NP化肥及两者配合施用均提高了马铃薯全株的干物质积累量,地上茎叶和地下块茎干物质积累量均表现为羊厩肥+NP肥>NP肥>羊厩肥>CK;叶片、地上茎、块茎的干物质日增长速率最大值出现时间均随羊厩肥+NP肥、NP肥、羊厩肥的施用而延后。在无肥和NP肥基础上施用羊厩肥、在无肥和羊厩肥的基础上施用NP肥,均可提高马铃薯各时期植株干物质含量,且具有显著的正累积效应。地上茎干物率和块茎增长期以后的叶片干物率均为施肥处理大于CK,而块茎干物率则为CK大于施肥处理。羊厩肥与NP肥配合施用,对马铃薯具有明显的增产效果。

绿肥和稻草联合还田提高土壤有机质含量并稳定氮素供应

【目的】研究绿肥、稻草不同还田模式对湘南地区水稻产量和土壤肥力的影响,为绿肥、稻草还田技术的推广和土壤培肥提供理论依据。【方法】2013—2018年在湘南红壤地区开展了6年田间小区定位试验,共设置6个处理,分别为冬闲+稻草不还田(CK)、冬种紫云英+稻草不还田(MV)、冬闲+早稻草全部还田(RS1)、冬闲+早、晚稻草全部还田(RS2)、冬种紫云英+早稻草全部还田(RS3)、冬种紫云英+早稻草全部还田+晚稻留高茬还田(RS4),各处理均施等量化肥。每季收获后测产,计算平均产量、产量变异系数和可持续指数。2017年晚稻收获后,取0—20 cm土层土壤样品,测定其养分含量和水稳性团聚体含量。【结果】与CK相比,除R S 1处理外,其余处理早稻、晚稻和周年平均产量均显著提高,增幅分别为6.6%~24.6%、11.9%~28.8%和9.0%~26.5%,以RS4处理增产效果最显著,其晚稻和周年平均产量均显著高于其他还田处理。与CK相比,除RS1处理早稻和MV处理晚稻外,其余处理早、晚稻产量变异系数均下降,且均以RS3处理最低;除晚稻MV处理外,其余处理早、晚稻产量可持续系数保持不变或提高,且早、晚稻均以RS3处理最高。试验开展5年后,各处理土壤有机质含量与初始土壤相比均明显提高,绿肥、稻草还田处理除RS1外均显著高于CK,RS4处理还显著高于RS1处理;各处理土壤全氮含量较2013年均有所降低,但绿肥、稻草还田处理较CK下降幅度小,MV和RS3处理全氮含量显著高于CK。土壤速效钾含量除MV和RS3处理低于CK外,其他处理均有不同程度的增加。粒径>0.25 mm水稳性团聚体以RS2处理最高,达68.9%。【结论】绿肥联合早稻草全部还田和晚稻留高茬还田措施可提高土壤有机质含量,稳定土壤氮素供应的长期效果显著,是湘南红壤地区水稻高产稳产和可持续发展相对较好的耕作制度,能够有效促进水稻增产,改善土壤理化性质,稳定氮素供应。

施肥对土壤及黄瓜中稳定性氮同位素丰度的影响

研究不同肥料配施对土壤、黄瓜及其叶片中稳定性氮同位素丰度(1δ5N‰)及硝酸盐和硝酸还原酶活性的影响。结果表明,随着配施有机肥比例的降低,黄瓜中1δ5N呈现先低后高再低的趋势;各处理单施化肥初期时黄瓜中1δ5N与有机肥60%和40%配施处理间差异显著(P<0.05),中期时与有机肥60%、40%配施处理及对照间的差异显著(P<0.05),末期时与有机肥60%配施处理间有差异(P<0.05),与其他不同配施时差异不显著(P>0.05);相同处理的不同采摘时期黄瓜中1δ5N差异不显著(P>0.05)。不同处理时叶片与黄瓜间的1δ5N呈正相关(r=0.9836),其1δ5N主要受不同肥料配施处理的影响。随着有机肥比例的降低,黄瓜中硝酸盐含量逐渐降低,与黄瓜中1δ5N间的线性相关性差(r=0.6568);而叶片中硝酸还原酶活性逐渐提高,其中对照处理、100%、80%和60%有机肥处理时与叶片中δ15N丰度呈正相关(r=0.9187);60%、40%、20%有机肥和100%化肥处理时与叶片中1δ5N呈负相关(r=-0.9773)。总体来看,可以初步利用1δ5N作为标记来区分有机肥和化肥种植的黄瓜,但需要进一步研究1δ5N在作物中的分馏和分布规律。

施肥对大白菜中氮同位素及硝酸盐含量的影响

研究不同肥料配施处理对土壤和大白菜中稳定性氮同位素丰度(δ15N‰)及硝酸盐含量的影响。结果表明,随着有机肥比例的降低,大白菜中δ15N和硝酸盐含量分别呈现逐渐降低和增加的趋势,对照大白菜中δ15N和硝酸盐含量分别为+9.355‰和1459mg/kg;纯有机肥(100%-O)和纯化肥(100%-C)处理大白菜中δ15 N分别为+6.898‰和+4.098‰(P>0.05),而硝酸盐含量分别为1658和2138mg/kg(P<0.05);不同肥料配施处理时大白菜中δ15 N和硝酸盐含量间存在负相关(R=-0.9064)。土壤中δ15N的变化受不同施肥处理的影响较小,其变化范围为+7.706‰～+9.903‰;而大白菜中δ15N的变化影响较大,其范围为+4.098‰～+9.355‰。研究表明不同肥料配施处理能够影响大白菜中δ15N的变化趋势,可以初步利用δ15N作为标记来判断肥料来源,但需要进一步研究不同肥料配施时δ15N的分布规律。

长期不同施肥下塿土有机碳和全氮在团聚体中的分布

【目的】研究小麦/玉米轮作体系不同施肥方式下土壤有机碳（SOC）和全氮（TN）在（？）土不同水稳性团聚体中的分布特征,以期深入理解不同施肥方式对土壤碳、氮固持的机制。【方法】采集（？）土21年长期肥料定位试验不同施肥处理0-10 cm和10-20 cm土层土样,分析其水稳性团聚体（〉2 mm、2-1 mm、1-0.5 mm、0.5-0.25 mm以及〈0.25 mm）有机碳和全氮的分布特征。试验设不施肥（CK）,化肥氮磷钾配施（N、NP、NK、PK、NPK）和秸秆还田配施氮磷钾（SNPK）以及两个水平有机肥与氮磷钾配施（M1NPK、M2NPK）9个处理。【结果】长期施肥0-10 cm土层土壤团聚体SOC和TN含量明显高于10-20 cm,平均增幅20%以上。2-1 mm或1-0.5mm团聚体中SOC和TN的含量最高,〈0.25 mm团聚体最低。长期不施磷肥处理的土壤团聚体SOC和TN含量均与CK相似。NP、NPK以及SNPK处理,0-10 cm土层SOC较CK分别增加16%-43%、9%-40%和22%-47%;TN增幅分别为28%-48%、39%-61%和39%-91%。10 20 cm土层,NP、NPK以及SNPK处理〉2mm、2-1 mm、1-0.5 mm土壤团聚体SOC较CK增幅分别为35%-49%、17%-40%和45%-46%,TN增幅分别为44%-47%、39%-54%和54%-64%。长期有机肥与氮磷钾配施处理（M1NPK、M2NPK）,0-10 cm土层的团聚体SOC平均较CK分别增加68%-122%和61%-163%,TN平均分别增加84%-133%和97%-175%;10-20 cm土层,SOC较CK平均增幅分别为20%-61%和39%-118%,TN增幅平均分别为43%-86%和107%-136%。SOC和TN主要储存于〈0.25 mm团聚体中（〉40%）2-1 mm团聚体储存最少（〈10%）。长期不施氮或不施磷对SOC和TN在团聚体中的储存比例基本没有影响。长期NP、NPK以及M1NPK、M2NPK均降低了各土层SOC和TN在〉2 mm或2-1 mm的储存比例增加了在1-0.25 mm团聚体储存比例。〉2 mm或2-1 mm团聚体的C/N比值高于微团聚体（〈0.25 mm）,而与CK相比,长期施肥降低了土壤团聚体的C/N比值。【结论】关中地区（？）土长期偏施化肥对有机碳和全氮在团聚体的含量及分布没有显著影响而长期氮磷或氮磷钾化肥配合、氮磷钾与有机物配合均明显增加土壤团聚体的有机碳及全氮含量,特别是长期氮磷钾配合有机肥能显著增加土壤1-0.25 mm团聚体对土壤有机碳和全氮的固存比例,提高土壤有机碳和全氮储量减少温室气体的排放。

黑土团聚体结合碳对不同有机肥施用量的响应

以连续11年化肥配施不同剂量有机肥的黑土为研究对象,采用团聚体分组与闭蓄态微团聚体分离技术,研究土壤团聚体及其内部组分有机碳对不同有机肥施用量的响应,以期从团聚体尺度揭示黑土有机碳的物理稳定性机制。试验设置4个处理:OM0,仅施化肥;OM1,低量有机肥(7.5 Mg hm-2 a-1)+化肥;OM2,中量有机肥(15 Mg hm-2 a-1)+化肥;OM3,高量有机肥(22.5 Mg hm-2 a-1)+化肥,各处理化肥用量相同。结果显示,与单施化肥相比,有机培肥处理土壤有机碳水平均有显著提升,低量、中量和高量有机肥处理分别提高了7.1%、12.4%和15.7%。有机培肥促进了土壤的团聚化作用,随着有机肥施用量的增加,250—2000μm团聚体含量增加,粉粘粒含量降低,土壤团聚体的稳定性增强,但与中量有机肥相比,高量有机肥输入对土壤团聚化的作用并不明显。有机培肥加速了土壤大团聚体的周转,大团聚体周转速率随着有机肥施用量的增加而加快。有机肥输入并未影响粉黏粒结合有机碳浓度,表明在无有机肥投入的传统管理措施下,黑土粉黏粒已接近或达到碳饱和水平。随着有机肥输入的增加,微团聚体有机碳小幅增加,大团聚体有机碳增加趋势明显,而当有机肥用量最大时,微团聚体有机碳无显著变化,仅大团聚体有机碳仍继续增加,表明高量有机肥投入下微团聚体有机碳库已达到饱和,而更多的新增碳流向大团聚体。对大团聚体内部组分解析发现,高量有机肥处理下大团聚体有机碳的增加主要归因于粗颗粒有机质的增加。这些结果表明,黑土团聚体对有机碳的固持存在由小到大的等级饱和机制,随着有机肥输入的增加,粉粘粒最先达到饱和,然后是微团聚体,而更多的新增碳向周转不断加速的大团聚体富集,固持在活性相对较强的有机碳库—粗颗粒有机质之中。

长期施用有机肥对草甸碱土水稳性团聚体及其碳氮分配的影响

试验依托东北农业大学盐碱土长期定位试验站（始建于1995年），研究不同施肥年限下草甸碱土水稳性团聚体含量及其碳、氮分配规律。结果表明，长期施用有机肥可以显著增加〉0．25mm水稳性团聚体的含量52．3％．60．8％，0．5～0．25inm粒级的水稳性团聚体随着种植和有机肥施用年限的提高显著增加。施肥5年后，草甸碱土土壤团聚体中有机碳和全氮含量开始呈现稳中有升的趋势。大团聚体对有机碳和全氮的贡献率分别为47．9％～89．3％和52．9％～82．1％。〉5mm和5～2mm粒级的团聚体中有机碳和全氮含量与该粒级团聚体数量均呈显著性正相关。连续5年高量有机肥的投入，已经对草甸碱土培肥改良起到了显著效果，此后维持正常的施入量即可。

半干旱区减氮增钾、有机肥替代对全膜覆盖垄沟种植马铃薯水肥利用和生物量积累的调控

【目的】减氮增钾和有机肥替代是提高中国作物生产中资源利用效率、改善农田生态环境、提升农产品质量和降低作物生产病害风险的有效途径。研究明确半干旱区全膜覆盖垄沟种植马铃薯减氮追施、有机肥替代和增施钾肥对马铃薯干物质积累和水分利用的影响,为该区域实施水肥高效管理提供依据。【方法】在4年大田定位试验基础上,通过测定全膜覆盖垄沟种植条件下传统施肥(PM)、减氮25%并花期追施和增施钾肥(PMN)和减氮50%与有机肥替代并花期追施(PMO)的土壤贮水量、马铃薯的生物量和产量等指标,计算不同施肥模式的耗水量、生长速率、水分利用效率和肥料偏生产力,以明确不同养分管理模式对马铃薯耗水过程的调控及其对干物质积累和水肥利用效率的影响。【结果】2011—2014年PMN花前耗水量较PM分别降低了17.4、28.7、26.8和34.2 mm,花后耗水量增加了31.1、34.7、36.7和49.2 mm;PMO没有显著降低马铃薯花前耗水,而花后耗水量分别增加了17.8、24.3、11.2和10.3 mm。与PM相比,PMN在盛花期后显著提高马铃薯地上地下生物量和生长速率,使马铃薯产量在2012—2014年平均增加2 595.1 kg·hm-2,并使水分利用效率(WUE)在2013—2014年分别增加了14.4%和6.3%,达到显著差异;PMO显著提高马铃薯各生育期的地上地下生物量和生长速率,4年平均马铃薯块茎产量增加了2 945 kg·hm-2,而且WUE在2012—2014年显著高于PM。PMN和PMO较PM均能显著提高马铃薯肥料偏生产力、化肥偏生产力、氮素偏生产力和化肥氮素偏生产力,表明PMN和PMO能协同提高作物的养分和水分利用效率,实现以肥调水和以水促肥的目标。2011年为严重干旱年份,虽然PMN和PMO能调节马铃薯花前花后耗水,提高地上地下生物量和生长速率,显著提高养分偏生产力,但产量和水分利用效率无显著提高。【结论】PMN和PMO均能显著调节马铃薯花前花后耗水量,增加生物量和提高生长速率,使得马铃薯块茎产量、水分利用效率和养分利用效率增加。与PMN相比,PMO对马铃薯产量、WUE和养分偏生产力的增加幅度更大,是资源更加高效和作物增产的养分管理模式。

以马铃薯渣为原料的沼气发酵体系的建立

单纯以马铃薯渣为原料进行沼气发酵很难成功，本研究建立稳定的以马铃薯渣为原料的沼气发酵体系，研究该体系的产气规律，达到充分利用马铃薯渣、，提高产气效率的目的，为采用马铃薯渣厌氧发酵产生沼气提供技术支持。在发酵容积为20L的牛粪沼气发酵体系的基础上，通过用马铃薯渣逐步替换牛粪的方式，以7d为一个驯化周期，驯化原有沼气发酵体系。驯化到第6代以后，沼气发酵体系逐渐稳定。在驯化过程中，pH从原来的7．5～7．7变化至稳定后的6．4～6．9；产气高峰期逐渐提前，至第6代后产气高峰期为添加薯渣后1d。发酵体系稳定后，各代平均日产气量为10.39L，平均最高日产气量为10．55L，最高日产气体积比达到1．261；COD去除率维持在50％～55％；稳定后木质纤维素分解率为18．9％。