Causes of maize density loss in farmers’ fields in Northeast China

Increasing plant density is an effective and important way to reduce maize yield gaps in Northeast China. However, the fact is that a significant plant density gap exists between optimum plant density and actual plant density in farmers’ fields.To quantify the density gap between planned planting density and final harvest plant density(HPD), we studied 60 farmers’ fields on three types of soil for three crop seasons from 2015 to 2017 by measuring their plant-plant distance, actual seedlings density(ASD), final HPD and yield. We also explored the potential causes of density loss by digging the places where the seedlings were missing for two consecutive years in 2016–2017. Results show that the three-year average HPD in farmers’ fields was 59 699 plants ha^–1, which was significantly lower than the planned density, including both the machine setting density(MSD;67 962 plants ha^–1) and theoretical plant density(TPD;67 467 plants ha^–1). No significant difference was found in HPD between years and soil types. However, for MSD and TPD, the average value in 2015 was significantly higher than that in 2016 and 2017. No significant difference between soil types was observed. Furthermore,the results from 2016 till 2017 indicated that a lack of seeds in the soil, a failure to germinate due to low-quality seeds,and a lack of seedlings breaking out of the soil due to environmental problems explained approximately 60.88, 10.33 and 28.80% of density loss, respectively. According to our survey, 63% of farmers did not know their own TPD and HPD, and 54% of farmers did not know the density loss. Therefore, we argue that farmers’ limited knowledge of density and density loss is an urgent problem that needs to be solved in maize production. These observations will be useful for determining best management practices for maize production and for providing helpful suggestions for machine improvement.

Profitability Analysis of Small Scale Irrigation Technology Adoption to Farmers in Nasho Sector, Rwanda

The study aims to assess the effect of small scale irrigation adoption to farmers in Nasho sector, Kirehe District in Rwanda. The average yield was 12,309.73 Kg/2.62 ha or 4698.73 Kg/ha for adopters with the mean difference between adopters and non adopters ranged from 2819.63 Kg to 4766.59 Kg per unit area of production. For food security status, the average mean quantity of maize consumed at home level was 615.54 Kg with the mean difference ranged from 377.29 Kg to 474.68 Kg. For market participation, the average treatment effect of the treated (ATT) of quantity of maize sold was 11,694.24 Kg while the mean difference ranged from 7165.98 Kg to 9015.60 Kg. The Average Treatment Effect of the Treated market price was 213 Frws/Kg while the mean difference ranged from 44.51 Frws/Kg to 48.3053 Frws/Kg. The Average Treatment Effect of the Treated of farmer’s revenues for the users was 938,772 Frws/ha, however, the mean difference between adopters and non adopters ranged from 1,732,942 Frws to 2,007,039 Frws. The Average Treatment Effect of the Treated of farmer’s net farm income was 1,066,393 Frws while mean difference between users and non users ranged from 803,967 Frws to 854,141 Frws. For profitability analysis, the cost benefit ratio (CBR) was taken into account. The total benefit per unit area was 2,434,509 Frws and total average mean cost of 1,382,313 Frws and CBR = 1.761 > 1. The findings of this study will help the policy makers for deeper sector planning and also, it will facilitate other stakeholders to invest in irrigation technology to improve the livelihoods of Rwandan farmers and other surroundings.

Mechanical Harvesting Effects on Seed Yield Loss,Quality Traits and Profitability of Winter Oilseed Rape (Brassica napus L.)

China is one of the most important rapeseed producing countries in the world. Effective mechanical harvesting time for decreasing harvesting loss of winter oilseed rape has been becoming a critical factor. An elite cultivar Zhongshuang 11 （Brassica napus L.） was employed in two rounds of field experiments from 2009 to 2011. Seeds were sown with machine, three combine harvesting times namely combine harvesting A, B, and C （CHA, CHB, and CHC） were designed and manual harvesting （MH） as control was performed at maturity. The harvesting treatments were determined according to color of pod and seed in the field. Seed yield loss and quality in different treatments were evaluated. Results showed that both seed yields and harvesting losses in 2009-2010 were higher than that in 2010-2011, whereas seed oil contents in 2010-2011 were higher than that in 2009-2010. The highest yield appeared in CHB, which was significantly higher than that in MH. Furthermore, harvesting loss in CHB were 50% that in MH. Seed oil content and chlorophyll exhibited no obvious difference between CHB and MH. Economic profit analysis demonstrated that mechanical sowing/combine harvesting （MS/CH） showed an input/output ratio of 1：1.6, and it was 1：1.2 in mechanical sowing/manual harvesting （MS/MH）. Labor-cost accounted for more than 70% of the total cost in MS/MH, which led to low profitability to a great extent. Our results suggested that CHB was the optimum harvesting time for winter oilseed rape along the Yangtze River.

The Current Situation and Development of Grain Storage Technologies and Facilities for Chinese Farmers

In China, the quantity of farmer＇s grain storage covers about 40% of the total grain yield every year. While, the losses of farms＇ grain storage are up to 8%, which is due to the lack of grain storage facility and technology. The losses of farmer＇s grain storage could reach nearly 20 million tons every year. In this paper, the current situation and development of grain storage technology and facility for Chinese farmers were presented. And a series of policy and research work for reducing the losses of farms＇ grain storage was introduced. The large scale farmers are now developing quickly in China, the new storage warehouse and mechanized facility should be developed adaptively. So, the new storage technology and policy to meet the need of large scale farmers were also introduced in this paper.

Welfare effects of rural-urban land conversion on different aged land-lost farmers:exemplified in Wuhan city

Rural-urban land conversion is a universal phenomenon in the rapid process of economic development and urban growth.The welfare of farmers who lost their farmland attracted a widespread concern within the society and academia.However,further research about differentiated policies according to the characteristics of different farmer groups is still need to be conducted.This article divides the land-lost farmers into three age groups:younger than 45,45-65,and more than 65.It proposes a welfare index system including eight functional areas based on different age groups of affected farmers,taking four districts of Wuhan City as case study area.Fuzzy mathematics method is used to derive the aggregated welfare effect index.Our analysis show that the overall welfare levels of land-lost farmers of all age groups declined,but with a varying degree,with the level of welfare in those farmers who are 45-65 years old,younger than 45 years old,and older than 65 years old decreased by 18.7%,16.6%,and 12.7%,respectively.The direction and degree of effects on the functional activity index varies among different groups.Economic conditions,living environment,health,and social participation of all age groups decrease while social security and housing conditions increase.On the other hand,development opportunities,social communication,and leisure have different changing directions in different age stages.These results call for differentiated and tailor-made compensation policies for land-lost farmers,towards improving the welfare levels of all farmers and reduce the disparity among them.

Farmers’ Perception and Impact of Rice Yellow Mottle Disease on Rice Yields in Burkina Faso

Rice improvement for disease resistance has scarcely involved farmers’ knowledge in Sub-Saharan Africa. A participatory rural appraisal was conducted in two main rice cultivation areas in Burkina Faso to assess farmers’ awareness of rice production constraints with emphasis on rice yellow mottle disease (RYMD) and its management. Farmers’ preference for rice varieties to be used in the breeding program was also assessed. Major concerns for rice cultivation as perceived by farmers were water shortage and RYMD. However, relative importance of each constraint depended on the survey areas, RYMD being prominent at Banzon while water shortage predominated at Mogtedo. Mogtedo farmers preferred rice variety FKR19 because of its tolerance to drought. At Banzon, farmers’ first criterion was taste which was reflected in the choice of variety FKR18. Yield was also a major criterion in both areas, positioning NERICA varieties FKR56N, FKR62N, and FKR60N among the top preferred varieties. Farmers mentioned RYMD as the most important rice disease. Most farmers used varietal shifts or pesticide treatments for RYMD management. RYMD incidence reached 28% in average at Banzon over the 2012-2013 main growing seasons. In rice varieties FKR56N, FKR62N and TS2, diseased plants yielded 79.3% less than the healthy ones. Accordingly, based on disease incidence, overall yield loss in the study area was estimated at 22.3%. Altogether, rice production can be significantly increased by taking RYMD into account in a participatory rice breeding strategy.

Evaluation of District-Based Indigenous Farmers’ and Researchers’ Fertilizer Application for Optimal Maize Production

Most research-based fertilizer inputs proposed for small scale farmers to increase their productivity do not achieve the required results and should consider indigenous practices. This study evaluates the practices of nutrient fertilizer input by farmers and researchers and relates them to their corresponding yields and profit so as to establish the appropriateness of the practices in 13 districts of the Northern regions of Ghana. Soil nutrients assessment of Nitrogen (N), Phosphorus (P) and Potassium (K) contents used to evaluate the soil NPK status was based on previous studies. Data on fertilizer application by farmers and researchers were obtained from the Savanna Agricultural Research Institute (SARI). The amount of N, P and K fertilizer input in 13 Districts and its associated maize grain yields by both farmers (89) and researchers were calculated and compared using two-sample t-test. The t-test results indicated that average amount of fertilizer input by researchers was significantly (p < 0.05) higher than the average amount of fertilizer input by the smallholder farmers, but the high fertilizer input did not significantly (p = 0.74) increase researchers’ maize yields and profits in all 13 study districts grouped together, but there was maize increment in only eight districts. On the average, farmers from five districts applied low fertilizer and recorded low yields. However, when researchers increased quantities of fertilizer applied in these five districts, yield significantly (p < 0.05) increased. The outcome showed that smallholder farmers in these five districts could increase maize yields by 36% in the region should they adopt the maize production strategy by the researchers. The study concluded that, for best options, recommended fertilizer doses to enhance maize yields should consider district-specific farmers’ practices and soil NPK status. The study could enable better implementation of location-based nutrient recommendation in the Northern Region of Ghana.

Balance Analysis of Profit and Loss on Exploiting Coal-Bed Gas in China

Models about four aspects according to the balance principle and practice in China were established, which involve the minimum production scale, alert production scale, safe running scale, and the goal production scale for specified profit level. It provides an effective quantitative analyzing method for the investors of coal bed gas exploitation project.

A STUDY ON ECONOMY EVALUATION ON THE PROFIT AND LOSS OF GEOLOGIC ENVIRONMENTAL QUALITY ABOUT GEOLOGIC ENVIRONMENTAL EXPLOITATION PROJECT

The problems of environmental geology refer to the geologic phenomena, incidents or accidents arising from action of environmental geology. The action is mainly the mutual influence between human activity and geologic environment. When human activity is uncoordinated with objective laws of the geologic environment, the problems of environmental geology or economic loss would occur.Therefore,the level and the changing orientation of geologic environmental quality are relative to the types of human activity,particularly relative to human intentional-activities of geologic environmental exploitation project. The geologic environment fitting to mining may not fit to urban construction,and fitting to water conservancy and hydroelectric projects may not fit to communication,and so on.Economy evaluation on the profit and loss of geologic environmental quality is exactly to depict the level of the profit and loss of geologic environmental quality about geologic environmental exploitation projects and the

双重目标下的陕西省稻农农地转入最优价格探讨——基于农地产出和生产利润最大化的视角

基于陕西省汉中、安康两地转入农地的稻农问卷调查数据,采用Translog生产函数构建了投入产出模型和生产利润模型,从产出和利润两个维度对稻农转入农地的价格效应进行了实证研究,分析了农地转入价格对稻农的产出水平和生产利润的影响,确定了农地产出最大化与生产利润最大化双重目标下的稻农农地转入最优价格。结果表明:(1)以农地转入价格0~1500元/hm^(2)为参照,稻农农地转入价格在7500~10500元/hm^(2)时,其产出水平显著上升。(2)稻农农地转入价格在7500~10500元/hm^(2)时,其利润水平显著上升;稻农农地转入价格在10500~13500元/hm^(2)时,其利润水平显著下降。(3)综合权衡产出最大化与利润最大化双重目标,稻农转入农地的最优价格介于7500~10500元/hm^(2)之间。综上,在推进中国农地流转的过程中,应从农民经济效益、国家粮食安全、农村社会稳定和农地流转市场化等多方面考量,把握好农地流转价格的选择标准,以期提高农地流转效率、维护农民权益以及保障我国粮食安全。

印度视角的RCEP贸易损益模拟研究——基于GTAP模型的实证分析

《区域全面经济伙伴关系协定》(RCEP)已于2022年1月1日正式生效,印度是否永久性退出RCEP尚不可知,若在RCEP效果凸显后再度重返,则其国内贸易损益计算依据以及将对成员带来何种宏观经济层面的影响无疑是个值得关注的问题。本文利用GTAP模型对印度是否加入RCEP不同情形之贸易损益进行了模拟验证,结果表明,RCEP生效后各成员的国家总福利水平及总产出水平都将高于生效前,与印度的成员身份并无必然关联,但印度的RCEP局外人身份将对其进出口总额的增长产生负面影响;若印度重返RCEP则不仅对本国进出口贸易额增长发挥正向拉动作用,还会为其他成员带来更大的贸易增长效应;印度加入RCEP也的确存在一定程度的对外贸易逆差增大风险。为此,展望印度加入RCEP的前景,可以做出以下预判和启示:印度可能适时选择重新加入RCEP而非永久退出;印度重返RCEP可为中国经济发展带来新动力;中国应积极运用外交和经济渠道促使印度尽早重返RCEP,为中印双方未来的经济增长创造更好条件。

抽象使用损失:一种应当赔偿的财产损害

我国侵权领域抽象使用损失可赔偿性尚存争议,究其原因为损害的“差额说”导致。“差额说”由莫姆森(Mommsen)于1855年发表《利益说》一文提出,认为损害为受害人在损害事故发生后所有的财产数额与其在假设损害事故不发生的条件下应有的财产数额的差额。因受害人并未支出替代物费用,自然没有产生财产差额,故无损害的发生。莫姆森“差额说”的理论源头为罗马法上的“利益(interest)”概念,对抽象使用损失可赔偿性的否定来源于对罗马法上差额状态的误解。所谓“差额”关注的是物上利益的整体状态,而非简单的财产数额计算,因此“差额说”的真正内涵应当为侵权事件发生前后的利益变化。抽象使用利益的损失应当为一种财产性利益损失,原因有三:第一,抽象使用损失的范围可以凭借主观计算方法确定,物的抽象使用价值可以凭借“商业价值理论”获得财产价值属性,且其确定性要求并非绝对,仅需达到“相对确定”标准即可;第二,应当同等评价营利物的使用损失和自用物的抽象使用损失,加害人的侵权行为阻碍了权利人实现物上的使用利益,造成了受侵害人合理期待的落空,所谓财产的本质与意义不仅在于其本体,更包括利用该财产以达成人生的目的;第三,财产性利益损失的概念更加周延,避免了损害赔偿范围的盲目扩大,对抽象使用损失加以限制更契合中国特色《民法典》权益保护的理念。德国法早已承认抽象使用损失的可赔偿性,并通过司法实务建构出一套完整的规范系统,并以“规范的损害”概念填补传统“差额说”在使用领域赔偿上的不足。“规范的损害”是与“自然的损害”相对的概念,提出损害的定义不拘泥于法律规定,而是根据受损权益在法规范评价上的重要性来决定是否具有可赔偿性。根据《民法典》设立的“获利返还”制度,加害人代受害人实现了物的抽象使用利益,这一利益根据法秩序应归属于受害人,因此这一利益应当返还给受害人,因此抽象使用损失的可赔偿性符合法规范的评价。我国《民法典》亦受德国法影响,采取损害赔偿的一般规定和具体列举损害赔偿项目的结构,因此德国法上“规范的损害”概念对我国有可借鉴意义。与我国损害赔偿体系融合的过程中需要注意规范评价的限制因素,即须满足“受损物为维系个人生活必需之物”和“可感性”要件。本文之目的即在介绍德国法上相关制度构建,并结合中国特色损害赔偿体系,为国内实务与学说提供参考。

基于自然-经济综合视角的碳排放强度与生态盈亏多情景模拟研究——以淮海经济区为例

生态盈亏与碳排放强度是衡量生态环境质量与经济发展水平的重要指标,分析两者时空关联并预测未来演进方向对提升区域生态环境质量健康水平具有指导作用。以淮海经济区为研究对象,以2000年、2010年和2020年3期土地利用数据为基础,运用PLUS模型、双变量自相关、耦合协调度及面板计量回归模型等方法,预测并分析淮海经济区2000—2036年3种情景下碳排放强度、生态盈亏的演化特征及时空关联。结果表明:(1)常规发展情景下,淮海经济区生态性呈下降趋势,强耕地保护情景下生态性微有下降,强生态保护情景下,生态性有所上升,自然要素是主导。(2)常规发展情景下,淮海经济区碳排放量逐渐加大,强耕地保护及强生态保护情景下,则呈下降趋势;三种状态下,碳排放强度均呈下降趋势,时间轴2010—2020年降幅较大,空间序河流水系地区碳排放强度降幅较大。(3)淮海经济区碳排放强度与生态盈亏呈负相关关系,低低和低高聚类主要分布在城镇建设用地周边,高低和高高聚类分布在人类干扰较少的自然区域;高高聚类主要位于河流水系交汇区,表明水域有效降低碳排放强度的功能。(4)淮海经济区的碳排放强度与生态盈亏之间的耦合协调度呈东西高、中部低的态势,高耦合协调度主要分布于低高聚类,即自然地区域,低耦合协调度主要分布于西部平原区;科学技术、经济发展水平及二产占比对耦合协调度呈正影响,城镇化率、道路密度呈负影响。研究认为,淮海经济区当前的土地利用方式,不利于区域环境质量的改善,建议进一步强化建设用地管控、大力推进高标准农田建设和水域保护,以耕地质量提升和水域保护加强提升粮食主产区环境质量健康水平。

违约损害赔偿中的替代交易规则解释论

《司法解释》第60条规定了以替代交易价格为计算基础的损害赔偿计算方法。从替代交易的性质来看,其是一种针对违约的自力救济措施,同时兼具一定的义务属性。从替代交易规则的适用前提来看,替代交易作为自力救济可自由实施,但替代交易规则的适用以合同解除为前提条件。此条件的规范目的在于裁判的确定性与双方当事人利益的平衡。从替代交易实施的适当性要求来看,在替代交易具备商业上替代性时,应推定其符合市场价格,由违约方主张该价格明显偏离交易发生时所在地的市场价格来抗辩。在市场价格本身或偏离程度难以确定时,应综合考虑非违约方实施替代交易的目的和手段来适用替代交易规则。替代交易的高价格导致的过高损害赔偿额可以通过可预见性规则进一步加以限制。

1981—2018年吉林省玉米水分盈亏及旱涝时空分布

吉林省作为我国玉米主产区和重要的商品粮基地,明确吉林省玉米水分盈亏指数及旱涝灾害的时空分布特征,有助于提高农业生产的稳定性和抗灾能力。该文采用吉林省逐日气象站点数据,通过计算月尺度下的潜在蒸散量,构建水分盈亏指数来分析吉林省潜在蒸散量和旱涝灾害的时空分布特征,运用趋势分析法和小波分析法来探究水分盈亏指数的趋势性及周期性变化。结果表明:多年平均潜在蒸散量和各月份平均潜在蒸散量均有由西北至东南逐渐递减的趋势,5—9月潜在蒸散量分别占生长周期内总平均潜在蒸散量的26.3%、24.5%、21.1%、16.8%和11.3%。5月和9月发生中旱及以上频率大于50%的地区主要位于白城市西部,四平市西部和长春市中部地区。8月和9月中涝及以上频率高值区位于吉林省东部及东南部地区。

口粮与利润导向如何影响稻农生物农药施用行为——兼论环境意识的调节作用

本文探讨了农业农村绿色发展背景下,种粮目的对稻农生物农药施用行为的作用机制以及环境意识在其中的调节作用。基于2021年湖北省1103份稻农微观调研数据,从口粮和利润视角分析稻农生物农药施用行为的影响调节机理,并将环境效用纳入了稻农行为理论分析框架,采用Logit模型进一步分析种粮目的和环境意识对稻农生物农药施用行为的影响及其异质性。研究发现:1)口粮导向和利润导向的稻农施用生物农药行为存在显著差异。利润型稻农更倾向于施用生物农药。2)环境意识对稻农生物农药施用行为具有显著正向影响,农药认知能够显著促进利润型稻农的生物农药施用行为,而环保态度对口粮型稻农生物农药施用行为的影响更加显著。3)不同资本禀赋稻农的生物农药施用行为存在显著差异。环保态度对高教育水平稻农生物农药施用行为的影响更显著,而农药认知的正向调节作用存在于低教育水平稻农中;环保态度对低收入水平稻农生物农药施用行为的影响更显著,农药认知和环保态度的调节作用也存在于低收入水平稻农中;环保态度对土地细碎化程度较低的稻农生物农药施用行为的影响更显著,而农药认知的正向调节作用存在于土地细碎化程度较高的稻农中。据此,本文提出要根据稻农种植目的制定相应的生物农药推广措施,制定阶段性生物农药培训内容,提高稻农对生物农药的认知,加强稻农的环保意识,打造农业技术交流平台,进而促进稻农施用生物农药。

SNP遗传力估计方法、影响因素及其在畜禽育种中的应用

遗传力是衡量由遗传因素解释的表型方差的比例,在实际遗传力估计中多只考虑加性遗传效应。由于畜禽传统遗传力估计需要的系谱信息完整性和准确性较难以实现,随着基因组学的发展,以全基因组单核苷酸多态性(SNP)进行遗传力估计的方法得到广泛应用。而对SNP遗传力的准确估计有利于了解遗传变异对表型的作用程度,目前已有不少SNP遗传力估计模型被开发利用。本文主要综述了SNP遗传力的概念、常用估计方法及其影响因素,并与传统遗传力估计进行比较,探究了SNP遗传力在畜禽育种中的应用潜力。

应用盈亏平衡理论指导新疆某奶牛场决策实例分析

为提高奶牛场生产效率,获得最大利润,本研究应用盈亏平衡分析法对新疆某奶牛养殖企业某年度1月份实际的商品奶挤奶牛头数、牛奶产量、牛奶销售价格以及平均奶产量进行分析,预测出该牧场2月份盈亏平衡时的各项生产数据,并对影响养殖企业利润的各因素敏感度进行评估排序。结果发现,在影响该牧场利润的众多因素中,按敏感度由高到低排列依次为商品奶泌乳牛头数、平均奶产量、牛奶销售单价、牛奶产量、变动成本、固定成本、其他收入。以上结果表明,通过优化该养殖场养殖头数等要素,制定出合理的决策方案,可以取得最大利润,并为其运营决策及未来发展规划提供必要的数据支撑和理论指导。

分段批发价下损失厌恶的报童最优订货问题

考虑损失厌恶报童的最优订货量问题.基于量大从优的经济现象,假设商品的批发价根据订购数量分为两段,订购量高于某一数量时价格降低.假设报童是损失厌恶的,其参照点为最大利润和最小利润的凸组合.证明了在最大化期望效用下存在唯一的最优订货量,发现厌恶损失的报童的订货量小于损失中性的报童的订货量.研究参数对最优订货量的一些影响,发现零售商的最优订货量随着批发价和损失厌恶程度的增大而减少,而当参考水平较小时损失厌恶型零售商的最优订货量比经典零售商大,参考水平较大时,损失厌恶型零售商的最优订货量比经典零售商小.通过数值验算给予说明.

昌吉市土地利用时空演变及生态系统服务价值损益分析

通过分析2000-2020年昌吉市的土地利用遥感数据,探究昌吉市经济发展下土地类型与生态价值的相互转移变化。结果表明,昌吉市的草地面积在总区域面积中占比最大,历年占比均超过40.00%;草地和水域面积总体呈减少趋势,其余地类面积总体呈增加态势;草地转为耕地的面积达44 715.71 hm^(2),是转移变化最大的方式。通过灰色预测模型预测未来15年草地和水域的面积依然处于下降趋势但减速放缓,耕地和建设用地的增长也逐步放缓。2000-2020年昌吉市生态系统服务总价值呈下降趋势,由2000年的120.49亿元下降到2020年的113.48亿元;草地的价值最大,约占总价值的60%左右。各项生态系统服务价值变化中,除了食物生产和原材料生产的生态功能的价值略有增加,其他各项生态功能的价值均呈不同程度减少。草地、林地和水域转出造成生态系统服务价值减少,其中草地转为未利用地是价值损失最大的一项土地转移类别。