不同施肥处理对果蔗产量、外观品质及经济效益的影响

在广州市番禺区以当地习惯施肥为对照,探讨了不同施肥处理对果蔗产量、外观品质以及经济效益的影响,结果表明:与对照相比,采用氮磷钾配比为1:0.3～0.4:0.8～0.9、每667 m2施氮约46 kg的施肥方法,果蔗的株高、茎粗、有效茎数、单茎重、节数、平均节长以及商品蔗长均有不同程度的增加,果蔗的外观品质得到明显改善,且肥料用量减少、用肥成本降低,经济效益增加。     

牧草Pace Setter的栽培技术和经济效益初探

从施肥和密度水平方面对引进牧草PaceSetter的栽培技术进行了研究,并对其经济效益进行了分析,结果表明:替代玉米种植该牧草可较大程度地提高农民的收入,施肥水平为1200kg/hm2、密度水平为15.0kg/hm2时经济效益最高。     

商品猪场确定种猪及精液配种价值的生物经济学方法

商品猪场选购种猪或精液时 ,需要考虑其配种的综合效果 ,这些包括配种后母猪受胎率、窝产活仔数及商品猪的日增重、饲料转化率及瘦肉率等。本文通过建立生物经济学模型模拟商品猪群生产过程 ,利用差额法计算这些指标对出栏猪利润的影响 ,确定其边际效益 ,在此基础上提出“相对配种价值”指数的概念 ,用来估计种猪及精液的综合利用价值 ,为商品猪场选择适当的种猪、精液及配种方法提供参考     

两种不同更新方式巨尾桉生长及效益研究

采用随机区组设计对巨尾桉植苗林与萌芽林进行研究.结果表明:4~6 a龄植苗林保存密度、出材量及造林、采运、销售成本均大于萌芽林,而树高、胸径、单株蓄积、利润、年均利润及净现值小于萌芽林,两种更新方式林木的年均利润、净现值均先增大后减小,峰值出现在第5年,分别达7299.1元·hm-2·a-1、18166.5元·hm-2和7139.4元·hm-2·a-1、16073.4元·hm-2;6 a龄后植苗林连年生长量及经济效益逐渐大于萌芽林,且植苗林年均利润及净现值逐渐趋于平稳增长,而萌芽林生长后劲不足,其最佳主伐时间为5 a.     

几种木本蔬菜的食用价值和经济效益分析

针对天津市最具发展潜力的栾树、刺楸、柳树3种木本蔬菜,对其食用、药用价值和食用方法进行了论述,并初步分析了这3种木本蔬菜发展的经济潜力,为农业种植结构的调整和地方经济的发展提供理论依据。     

Annual crop rotation of tropical pastures with no-till soil as affected by lime surface application

Soil acidity and low natural fertility are the main limiting factors for grain production in tropical regions such as the Brazilian Cerrado. The application of lime to the surface of no-till soil can improve plant nutrition, dry matter production, crop yields and revenue. The present study, conducted at the Lageado Experimental Farm in Botucatu, State of São Paulo, Brazil, is part of an ongoing research project initiated in 2002 to evaluate the long-term effects of the surface application of lime on the soil’s chemical attributes, nutrition and kernel/grain yield of peanut (Arachis hypogaea), white oat (Avena sativa L.) and maize (Zea mays L.) intercropped with palisade grass (Urochloa brizantha cv. Marandu), as well as the forage dry matter yield of palisade grass in winter/spring, its crude protein concentration, estimated meat production, and revenue in a tropical region with a dry winter during four growing seasons. The experiment was designed in randomized blocks with four replications. The treatments consisted of four rates of lime application (0, 1000, 2000 and 4000 kg ha⁻¹), performed in November 2004. The surface application of limestone to the studied tropical no-till soil was efficient in reducing soil acidity from the surface down to a depth of 0.60 m and resulted in greater availability of P and K at the soil surface. Ca and Mg availability in the soil also increased with the lime application rate, up to a depth of 0.60 m. Nutrient absorption was enhanced with liming, especially regarding the nutrient uptake of K, Ca and Mg by plants. Significant increases in the yield components and kernel/grain yields of peanut, white oat and maize were obtained through the surface application of limestone. The lime rates estimated to achieve the maximum grain yield, especially in white oat and maize, were very close to the rates necessary to increase the base saturation of a soil sample collected at a depth of 0–0.20 m to 70%, indicating that the surface liming of 2000 kg ha⁻¹ is effective for the studied tropical no-till soil. This lime rate also increases the forage dry matter yield, crude protein concentration and estimated meat production during winter/spring in the maize-palisade grass intercropping, provides the highest total and mean net profit during the four growing seasons, and can improve the long-term sustainability of tropical agriculture in the Brazilian Cerrado.     

汽车运材成本预测模型及盈亏平衡数据分析

本文根据具有代表性意义的实际数据,建立了能表征运材企业成本性能的数学模型,求算预测方程与预测值,利用成本、利润、运量与运价等盈亏数据进行定量分析、为提高运材企业运输生产率,降低成本,强化运材企业目标管理,提供了高质量的决策依据;亦可对固定成本、变动成本进行管理。     

北京地区猪生长和繁殖性状边际效益的研究

本研究旨在估计北京地区猪生长和繁殖性状的边际效益.以差额法和系统分析法为基础建立农场模型,模拟商品猪群的生产过程,采集了北京地区多个具有代表性的猪场的数据,确定北京地区猪6个生长和繁殖性状的边际效益为:窝产活仔数(头)20.5元、达100kg体质量日龄(d)-0.3元、肥育期日增体质量(g·d-1)0.04元、饲料转化效率(kg·kg-1)-186.4元、胴体背膘厚(mm) 15元、母猪繁殖寿命(胎)1.8元.结果表明,市场价格的变化对性状边际效益的影响很大.     

测土配方施肥对玉溪油菜生长与效益的影响

为了指导当前生产条件下玉溪市红塔区研和镇油菜测土配方施肥技术的推广,于2010-2011年进行了常规施肥和配方施肥的对比试验,以研究氮、磷、钾和硼肥施用对油菜产量及其相关性状的影响。结果表明:油菜栽培以配方施肥效益最好,对油菜增产、增收效果显著,是保证高效生产的技术关键;配方施肥中,施尿素522.0kg/hm2,普钙450.0kg/hm2,硫酸钾120.0kg/hm2,硼砂15.0kg/hm2,可获得3 433.5kg/hm2的产量和20 601.00元/hm2的产值。