Contribution of Garcinia kola to the Productivity and Economic Profitability of the Community Agricultural Area of Kedougou: Financial and Comparative Analysis of Production Factors

Inland fishing predominates in the Kedougou region, which has no coastline. This type of fishing does not yet meet the local population’s demand for fish products. In response to this concern, a Community Agricultural Estate housing an integrated fish farm was set up in the commune of Bandafassi, in the village of Itato. Since its creation, this production unit has been faced with the problem of sourcing high-quality, low-cost, monosex male Oreochromis niloticus fry. In order to overcome this constraint, the present research focuses on the contribution of Garcinia kola to the productivity and economic profitability of the Itato farm. The aim of the research is to assess fish production in the experimental set-up and the production costs of tilapia in a controlled environment. The comparative study of the various production factors shows disparities only in the input factor, where scenarios 2 and 3 use additional products. These are 17-α-methytestosterone for scenario 2 and Garcinia kola for scenario 3. These products significantly interfere with fish production, with a fairly high mortality rate for scenario 2 (25% for two production cycles/ cohort2 (B5, B6, B7 and B8) treated with 17-α-methytestosterone). As for scenarios 1 and 3, mortalities are 5% with or without recourse to additional products (G. kola). In addition, average fish production for the three (03) scenarios is estimated at 28687.5 kg/2 cycles. It varies from one scenario to another, i.e. 30937.5 kg/2 cycles for scenarios 1 and 3 and 24187.5 kg/2 cycles for scenario 2. It is therefore higher in scenarios 1 and 3 than in scenario 2. This difference is due to the fairly large losses of individuals in scenario 2. Furthermore, the analysis of the profit and loss accounts for tilapia production varies from one scenario to another depending on the type of farm: 476 Franc CFA for scenario 1, 610 Franc CFA for scenario 2 and 472 Franc CFA for scenario 3 (F CFA = franc of the French Colonies of Africa). The Average operating income for all the fish farming units is 34,726,142 Franc CFA. The highest (41,638,075 Franc CFA) and lowest (29,281,075 Franc CFA) ERs were observed in scenarios 3 and 2 respectively. It was 33,259,275 Franc CFA for scenario 1. The difference between the NERs of the three scenarios is more or less significant in terms of results. The operating result (OR) is positive in all 3 scenarios in our study. However, the scenario 3 system generates a higher rate of return (the ratio between an income and the capital employed to obtain that income) (74%) than that generated by the scenario 1 system (69%). As for the scenario 2 system, it generates a lower financial return than the two previous systems (67%). Above all, this work made it possible to construct an approach that would make it possible to answer such a question by relying successively on various methods: a typology, according to the production factors involved in the operation of the Community Agricultural Estate fish farm.

An Algorithm of 0-1 Knapsack Problem Based on Economic Model

In order to optimize the knapsack problem further, this paper proposes an innovative model based on dynamic expectation efficiency, and establishes a new optimization algorithm of 0-1 knapsack problem after analysis and research. Through analyzing the study of 30 groups of 0-1 knapsack problem from discrete coefficient of the data, we can find that dynamic expectation model can solve the following two types of knapsack problem. Compared to artificial glowworm swam algorithm, the convergence speed of this algorithm is ten times as fast as that of artificial glowworm swam algorithm, and the storage space of this algorithm is one quarter that of artificial glowworm swam algorithm. To sum up, it can be widely used in practical problems.

Net Present Value Method: A Method Recommended by ISO 15686-5 for Economic Evaluation of Building Life Cycle Costs

The publication of ISO 15686-5 is significant for studies related to the life-cycle costs of buildings. Among the many economic evaluation methods, the NPV method is recommended for use by this standard. This study explains the concept and method of PV, and then provides an explanation of the concept and method of NPV, and points out the limitations in the practical application of the method.

不同缓/控释肥对玉米产量·经济效益及肥料利用率的影响

[目的]探究冀南平原玉米种植的缓/控释肥的应用效果。[方法]以邯玉398为材料,选取3种常见的玉米缓/控释复合肥进行田间试验,分析了不同类型缓/控释肥对玉米产量、经济效益及肥料利用率的影响。[结果]施用硫包衣缓/控释复合肥的玉米产量、利润及农学利用效率较常规复合肥分别降低1.95%、3.27%、8.27%~31.21%;施用树脂包衣缓/控释复合肥的玉米产量提高0.65%,但利润、总养分量、磷、钾偏生产力和总养分量农学利用效率分别降低了1.45%、22.59%、49.67%、49.67%、20.09%;施用脲甲醛缓/控释复合肥的玉米产量、利润及总养分量偏生产力和农学利用效率较常规复合肥分别提高5.98%、5.50%、5.99%、25.22%,且产量、利润显著提高。[结论]综合分析,脲甲醛缓/控释复合肥可作为冀南平原玉米种植中的优先推荐。

基于“慢”+时尚的设计走向与市场发展的服务设计研究

从新经济浪潮的背景出发,发现“慢”+时尚的设计走向与市场发展,最终用于指导当代的服务设计研究。结合文献研究、桌面调研,明确了慢与时尚的结合逐渐走入人们的视野。基于对时尚领域的形式化思考,主流性变革以及正向与反向的逻辑体系思考,并以“慢”+时尚的露营服务设计为例进行实证研究。本文进行了对慢+时尚在设计走向与市场发展两个方面的深度论述,同时立足于两个论点阐述了慢+时尚这一视角下设计与市场的架接关系以及所产生的未知效应。本文所产出的理论研究及实例结果对于慢+时尚未来发展走向的系统化思考具有重要的借鉴意义。

缓释肥类型及其运筹方式对弱筋小麦产量及品质的影响

为探究缓释肥类型及施用模式对小麦产量和品质的调控作用及机制,以弱筋小麦扬麦33为供试材料,选取3种类型(8种品牌)的缓释肥[包膜型缓释肥(S1~S5)、合成型微溶性缓释肥(S6)、化学抑制剂型缓释肥(S7、S8)]作为供试氮源,设置缓释肥一次性基施(M1)和基施60%+返青期追施40%(M2)两种施肥模式,常规尿素施肥(基肥∶壮蘖肥∶拔节肥∶孕穗肥为5∶1∶2∶2)为对照(CK),分析了相同施氮水平下缓释肥类型及其运筹方式对小麦产量、氮素积累转运、氮效率、品质和效益的影响。结果表明,与CK相比,同一品牌缓释肥在不同施肥模式下小麦产量、开花期和成熟期氮素积累、籽粒氮素积累、花前氮素转运量及转运效率、花后氮素积累及其对籽粒的贡献率和氮利用效率均表现为M2>CK>M1。其中,M2模式下小麦显著增产的缓释肥依次为S6>S1>S2>S3>S8。M1模式下各处理小麦籽粒品质指标均符合弱筋小麦国家标准;M2模式下除S2、S6外,其余缓释肥的小麦籽粒品质指标均符合弱筋品质要求。除M2S5外,其余处理产值及净效益均表现为M2>CK>M1。综合认为,本试验条件下,S1(硫包膜型)、S3(树脂包膜型)、S8(抑制型)缓释肥基施60%+返青期追施40%可实现弱筋小麦产量、品质、氮效率和经济效益的协同提升。

水稻机插侧深施肥减氮增效效应研究

本研究采用水稻机插侧深施缓释肥技术,探究不同施肥量和施肥方式对南粳5055的产量构成因素、茎蘖动态和经济效益的影响,以探索适合本地种植大户的施肥方式。结果表明:与常规施肥方式对比,侧深施肥能有效提高肥料的利用率、结实率、穗粒数、经济效益,但是降低了成穗率;在总施氮量相同,缓释肥侧深施肥量不同的情况下,一次性施肥的成本最高,产量最低,随着缓释肥用量减少,成本降低,缓释肥侧深施420 kg·hm^(-2),分蘖肥追施速效氮肥,穗期施用复合肥的施肥模式,效益能达最大。

Differences of yield and nitrogen use efficiency under different applications of slow release fertilizer in spring maize

Excessive or insufficient application of fertilizer has raised broader concerns regarding soil and environmental degradation.One-time application of slow release fertilizer (SF) has been widely used to reduce yield gap with potential maize yield and improve nitrogen use efficiency (NUE).A 2-year field experiment (2018–2019) was conducted to evaluate the effects of SF rates from 0 to 405 kg N ha^(–1) (named F0,SF225,SF270,SF315,SF360,and SF405) and 405 kg N ha^(–1) of common fertilizer(CF405) on the grain yield,biomass and N accumulation,enzymatic activities related with carbon–nitrogen metabolism,NUE and economic analysis.Results indicated that the highest grain yields,NUEs and economic returns were achieved at SF360in both varieties.The enzymatic activities related with carbon–nitrogen metabolism,pre-and post-silking accumulation of biomass and N increased with increasing SF rate,and they were the highest at SF360 and SF405.The grain yield at SF360had no significant difference with that at SF405.However,the N partial factor productivity,N agronomic efficiency and N recovery efficiency at SF360 were 9.8,6.6 and 8.9% higher than that at SF405.The results also indicated that the average grain yields,NUE and economic benefit at SF405 were 5.2,12.3 and 18.1% higher than that at CF405.In conclusion,decreasing N rate from 405 kg ha^(–1)(CF) to 360 kg ha^(–1)(SF) could effectively reduce the yield gap between realized and potential maize yields.The N decreased by 11.1%,but the yield,NUE and economic benefit increased by 3.2,22.2 and 17.5%,which created a simple,efficient and business-friendly system for spring maize production in Jiangsu Province,China.

On the feasibility of re-stimulation of shale wells

As a result of advances in horizontal comple- tions and multi-stage hydraulic fracturing, the U.S. has been able to economically develop several decades of worth of natural gas. However, a considerable concern has risen on the economic viability of shale gas development for reasons associated with the fast production declines as well as recent down-turns of natural gas prices besides rises in the costs of new technologies. Therefore, an economic analysis is required to investigate the profitability of the re- fracturing treatment of unconventional gas resources. Net present value of cash flows and internal rate of return are calculated for a range of gas prices considering 20 years of natural gas production from a typical unconventional shale gas reservoir. A systematic comparison is then accom- plished for three scenarios： （1） re-fracturing versus no re- fracturing, （2） combination of re-fracturing and drilling new wells, and （3） time-dependent re-fracturing treatment. Further, this paper incorporates the cost of re-fracturing treatment, the cost of drilling a new horizontal well, the water treatment cost, as well as the current and future price of natural gas in the model. The findings of this work would help the future re-stimulation development plans of the emerging unconventional shale gas plays.

出口下降、经济增速下行与双循环新发展格局

本文利用城市层面的数据建立简约式的差分模型,识别出口下降对中国经济增长的影响。为了解决模型中可能存在的内生性问题,本文利用Bartik方法构造工具变量。研究发现,出口下降是中国近年来经济增速下行的一个原因,与其他地区相比,出口下降较多的地区其经济增长率降幅更大。为了捕捉地区间商品贸易和劳动力流动对外部冲击经济效应的影响,本文还建立了一个多区域量化空间均衡模型。结果表明,出口下降对东部地区特别是与国际市场联系紧密的省市如广东、上海、天津、福建、江苏的影响较为明显;若出口下降10%,则全国实际GDP会下降0.17个百分点,福利水平会下降0.15个百分点;提高国内各地区的生产率以及降低地区间的贸易成本可以抵消外部冲击对中国经济的消极影响。

缓控释肥对春玉米干物质积累、产量和经济效益的影响

以桂单162为供试品种,采用大田试验,研究常规施肥(CK)、“一炮轰”和一次性缓控释肥(2种)共4个处理对春玉米农艺性状、干物质积累与分配、产量和经济效益的影响。结果表明:与常规施肥(CK)相比,一次性缓控释肥处理下玉米株高、穗位高、茎粗、叶面积和单株干物质积累量均较高;一次性缓控释肥处理下前期干物质在叶片和茎鞘中的分配比例均较低,后期在籽粒中的分配比例较高;一次性缓控释肥有助于增加玉米吐丝阶段穗的干物质积累量,提高成熟期玉米籽粒产量;一次性缓控释肥处理不仅能提高玉米百粒重,同时也能提高玉米穗行数和行粒数,穗长、穗粗和秃尖长均有不同程度的改善。T3处理条件下,百粒重较CK提高7.36%,秃尖长减少28.8%,产量提高3.96%,农民收益增长25.20%。综之,与常规施肥相比,选用茂施牌一次性缓控释肥进行一次性底施,不仅可以为植株生长过程提供充足肥料,同时还可以合理调配干物质分布,增加籽粒中干物质分配比例,最终提高产量和收益。

油菜缓释配方肥施用效果研究

为探究缓释配方肥在油菜上的施用效果,2021—2022年在江西省赣州市定南县以常规肥、缓释配方肥和6个不同甘蓝型油菜品种为试验材料,开展不同肥料对油菜产量和效益的影响研究,以期为当地油菜轻简化高产高效栽培提供参考。研究结果表明,施用缓释配方肥可延长油菜生育期,提高菌核病抗性与肥料利用率,增加单株角果数与千粒质量,从而获得更高产量。与常规肥处理相比,施用缓释配方肥的油菜生育期延长1~2 d,菌核病发病率降低14.95%,肥料偏生产力提高22.73%,株高增加2.64%,单株角果数增加3.37%,千粒质量增加3.87%,产量为1893.63 kg/hm^(2),增产6.68%。缓释配方肥处理比常规肥处理增收1722.56元/hm^(2),增幅为31.42%。缓释配方肥在实现肥料一次性施用的同时,保证了丰产,节省了肥料、人工成本,显著提高了经济效益,达到了油菜生产节本、增产、增效的目标。

不同硫包膜缓释肥施用模式对红皮小麦产量及效益的影响

为了探究在减施增效的施肥目标下,不同硫包膜缓释肥施用模式对淮南麦区红皮小麦产量及效益的影响,选用镇麦15为试验材料,将硫包膜掺混肥(SCU)和普通尿素进行配施,设置1个不施肥对照(CK)和6种施肥模式(U、SR1、M1、SR2、M2和SR3),研究小麦产量及其构成因素、干物质积累、经济系数和经济效益对不同施肥模式的响应。结果表明:1)相同施氮量下,采用2次施肥的M1和SR2的产量较常规施肥U模式增幅分别达到13.00%和12.00%,而减氮条件下M2、SR3模式的增幅达到15.56%和10.09%,这主要得益于缓释肥促进小麦穗粒数的增加;2)M1、SR2和M2模式都具有相对较高的茎质量、叶质量、穗质量,但只有M2的经济系数最高,其经济效益也最高,达968.62元/667 m^(2),比常规施肥模式提高28.14%。总体上,M2模式在总施氮量减少15%的基础上增产增效显著。

缓释复合肥料对玉米产量及土壤养分含量的影响

缓释复合肥料具有养分释放速率慢、释放周期长的特点,可以满足农作物整个生育期对养分的需求,近年来应用愈加广泛。本文通过田间试验,研究了缓释复合肥料对玉米农艺性状、产量、经济效益及土壤养分含量的影响。结果表明:缓释复合肥料处理玉米的穗长、穗粗、穗粒数均优于等养分混合肥及常规复合肥处理;产量分别增加2 460、1 365 kg/hm~2,增幅分别为40.3%、19.0%;节本增收分别达到4 770、5 445元/hm~2;土壤中有机质、碱解氮、有效磷、速效钾含量均有所提高。建议在玉米生产中根据实际情况推广应用缓释复合肥料。

一种包膜缓释钾肥的制备及性能试验

针对目前市售包膜缓释钾肥售价昂贵的问题,提出一种低成本缓释钾肥的制备。试验首先优化了自制包膜缓释钾肥的包膜厚度和包膜中硅藻土含量,然后对优化后包膜缓释钾肥的耐水性、水和土壤溶出性、田间缓释性,以及经济效益性进行研究。试验结果表明,当包膜厚度为20%,硅藻土含量为60%时,包膜缓释钾肥的综合性能较优。此时,钾肥最大破坏力为32.2 N,水中缓释周期为7 d,土壤中缓释周期为80 d。包膜缓释钾肥作用于田间时,养分释放速度较慢,大部分钾肥被作物吸收,只有少量钾肥养分流失,对作物生长和减少资源浪费都产生了积极的影响。通过与市售包膜缓释钾肥成本比较发现,自制聚乙烯醇/硅藻土包膜缓释钾肥成本仅为市售包膜缓释钾肥的一半,表现出良好的缓释性能和经济效益。

新型缓释氮肥肥效及经济效益分析研究

采用盆栽试验的方法研究了自制的缓释氮肥在菠菜和樱桃萝卜上的应用效果。通过对蔬菜产量、氮素利用率和硝酸盐含量的分析测定得出:缓释氮肥Ⅰ的肥效最好,经济效益最高。在不同的氮素水平下蔬菜的产量随着施肥量的增加,呈现先增加后减少的趋势,当施肥量达到每盆(2.5 kg土)0.33 g时,产量达到最高,符合肥料的报酬递减率。比较不同氮肥品种可以看出,施用缓释氮肥的蔬菜产量均高于尿素,并且缓释氮肥Ⅰ高于缓释氮肥Ⅱ;氮素利用率随着施肥量的增加而逐渐降低,自制的缓释氮肥的实际效果表现较好,其氮素利用率也高于尿素,并且在第二茬作物中氮素利用率仍然很高;硝酸盐含量随着施肥量的增加而增加;经济效益为缓释氮肥Ⅰ在0.33 g/盆的水平下达到最高。

缓释肥料对月季产量及养分利用率的影响

以月季（Chinese rose）为研究对象,采用田间小区试验探讨缓释肥料在月季上的施用效果。结果表明,施用缓释肥料可改善月季主要的农艺性状;与Conv-F相比,缓释肥处理增加月季产量7%~14%,经济效益增加874.18元/667m2,产投比提高达24.46%;在等NPK比例和等养分量条件下,缓释肥处理增加月季产量1.7%~8.33%,经济效益增加522.66元/667m2,产投比提高达11.6%;提高了氮、磷、钾当季养分利用率,其中Opt-F-8‰处理的氮、磷和钾养分利用率较Opt-F处理分别提高了7.96、1.31和3.9个百分点。

脲醛缓释肥不同配比对小麦生长及土壤氮素养分的影响

在黄淮海地区冬小麦中高产田采用小区试验,以普通尿素基施、普通尿素基施加追施作对比,研究脲醛氮占总氮30%,40%,50%,60%,70%的不同脲醛缓释掺混肥在田间的氮素养分释放特征,以及对土壤氮素养分、小麦产量、氮素利用率及经济效益的影响,探明合理施用脲醛缓释肥最优氮素配比,以达到增加产量、节约资源、增加经济效益的目的。结果表明:脲醛掺混肥氮素释放量在小麦生育进程中呈现高低再高低的变化过程,脲醛氮占总氮40%或50%最有利于土壤氮素供应,脲醛氮所占比例过大或过小,都不利于小麦整个生长期氮素供应。脲醛氮占总氮40%和50%的处理小麦穗数和穗粒数表现较好,每公顷比普通施肥增产11.36%~13.67%,而脲醛氮占总氮30%,60%和70%的处理增产效果不显著。与普通尿素基肥、基肥加追肥处理相比,脲醛氮占总氮40%,50%的处理氮素利用效率提高24.80%~103.87%,而脲醛氮占总氮30%,70%的氮素利用率没有显著变化,甚至会降低氮素利用率。脲醛氮占总氮40%,50%的处理比普通施肥处理增收1 350~1 591元/hm^2。综合考虑资源节约、增产效果及增收等因素,建议在黄淮海地区冬小麦中高产田施肥管理中以脲醛氮占总氮40%~50%进行配比施用。

缓控释肥施用方式对夏玉米产量、肥料利用率及经济效益的影响

在不同类型土壤上,研究缓控释肥全层混施和种肥同播两种施用方式对夏玉米产量、肥料利用率及经济效益的影响。结果表明:在氮肥减施10%条件下,施用缓控释肥料在棕壤和砂姜黑土上采用种肥同播的方式均能获得较高产量,与习惯施肥相比,分别增产1.55%和1.77%;两种施肥方式均可大幅提高氮肥利用率,增幅为28.13%~37.45%;磷肥、钾肥利用率除了砂姜黑土试验区全层混施处理略有降低外,其他施肥处理均有所提高,磷肥利用率提高18.77%~35.78%,钾肥利用率提高22.12%~26.91%。与习惯施肥相比,棕壤试验区,两种施肥方式均能提高收益,其中种肥同播施肥方式收益较高,增收312.11元/hm^(2),砂姜黑土试验区,种肥同播施肥方式增收416.45元/hm^(2),全层混施处理略低,减少138.39元/hm^(2)。可见缓控释肥采用种肥同播施肥方式在不同类型土壤上均能提高夏玉米产量,大幅提高肥料利用率,最终获得较好的经济效益。