Economics of simulated beef-forage rotational grazing under weather uncertainty

A biophysical model GRAZE is used to simulate pasture growth and animal weight gain for steers pastured on Bermudagrass. Economic performance is simulated for a continuously grazed pasture and compared to the performance of nine systems in which a rotational grazing schedule is strictly adhered to. Sensitivity of the performance of each strategy to weather risk is assessed for ten alternative weather scenarios, and each pasture management system is ranked for trade-offs between risk and returns using stochastic dominance ordering. Results indicate that expected net returns are highest with a continuous grazing system, but that risk considerations may influence some producers to select one of the rotational systems.     

Economics of rainwater harvesting for crop enterprises in semi-arid areas of East Africa

This paper presents an analysis of economics of rainwater harvesting by poor farmers in Tanzania. A questionnaire was used to survey 120 households to obtain information on the performance of their enterprises over 6 years (1998–2003). The information was mainly based on recollection as few farmers kept detailed records. Actual monitoring and measurements of yield and inputs was done in the farmers’ enterprises over 2 years during 2002/2003 and 2003/2004 production seasons. The analysis was done for four categories of rainwater harvesting systems differentiated by the size of catchments from which water is collected and the intensity of concentration and/or storage of the collected rainwater. These categories are: micro-catchments, macro-catchments, macro-catchments linked to road drainage and micro or macro-catchments with a storage pond. Results show that rainwater harvesting for production of paddy rice paid most with returns to labor of more than 12 US$ per person-day invested. These benefits are very high due to the fact that without rainwater harvesting it is not possible to produce paddy in the study area and rainfed sorghum crop realizes a return to labor of only US$ 3.7 per person-day during above-average seasons. For the rainwater harvesting systems, those designed to collect water from macro-catchments linked to road drainage, performed best during both categories of seasons. The results also show that contrary to expectations, improving rainwater harvesting systems by adding a storage pond may not lead to increased productivity. Another finding that goes against the widely held belief is that rainwater harvesting results in more benefits during the above-average seasons compared to below-average seasons. It is therefore, concluded that there is a potential for combining rainwater harvesting with improved drainage of roads. The construction of rural roads in semi-arid areas can beneficially be integrated with efforts to increase water availability for agricultural needs.     

Optimal site-specific fertilization and harvesting strategies with respect to crop yield and quality response to nitrogen

Incorrect fertilizer decisions can be costly if quality of the output, in addition to yield, is influenced by the application rate, which contrasts the flat payoff function estimated for fertilizer by previous studies focusing only on quantity. This study aims at modelling economic potentials of the combination of site-specific fertilization and quality specific harvesting at the example of wheat (Triticum aestivum L.), in Germany. Crop yield and protein response data to different nitrogen fertilizer applications were used from 15 locations to simulate site-specific wheat management. Four different management strategies were compared using a step wise price function for wheat qualities: uniform management, completely separate management, site-specific fertilization with uniform harvest, uniform fertilization with quality-specific harvest. It was found that opportunity costs (>50 €/ha) may apply, if threshold values for crop qualities are missed. Separation of different qualities can reduce this risk and create incentives for producing higher qualities on heterogeneous fields. Completely separate management had an economic advantage of up to 30 €/ha for the gross revenue, while site-specific fertilization alone had only marginal economic effects. However, these advantages have to cover costs for the use of technologies used, to be economically preferable.     

A review of rainwater harvesting

This article reviews recent literature on rainwater harvesting and its potential application for crop production. Some 170 articles published between 1970 and 1980 were found, all of them revealing an awareness of the increasing need for rainwater harvesting and a recognition of its potential.A definition of rainwater harvesting is presented on the basis of three characteristics common to it: arid to semi-arid climate, local water, and small-scale operation. The following elements are considered:runoff inducement — vegetation management, surface treatment, chemical treatment;runoff collection — Micro-Catchment Water Harvesting (MCWH) and Runoff Farming Water Harvesting (RFWH);storage and conservation.Design aspects of MCWH are reviewed: MC size, ratio of contributing area to collecting area, and layout. MCWH is especially suitable to non-irrigated areas. The Kinematic Wave Equation and Dynamic Equations have been used in modelling MCWH.RFWH can be useful in improving irrigation water availability in surface reservoirs. For modelling RFWH, the Unit Hydrograph Method is suitable. More research is required to determine the potential of runoff farming without surface reservoirs.     

果实采摘机器人的研究综述

分析了果实采摘机器人工作对象特点,从采摘机器人机械手的设计、末端执行器的设计、行走装置的设计、果实的识别和定位方面分析了果实采摘机器人的国内外发展现状,并探讨了采摘机器人存在的关键技术问题。     

油菜籽收获机械化

油菜收获机械化是农业机械化发展的必然,但由于油菜品种、种植方式、种植规模不一以及油菜自身的特点,使得油菜收获机械化在我国远远落后于稻麦收获机械化.文章对我国油菜收获机械化的现状、发展趋势及影响因素进行了分析,并对油菜收获机械化的发展提出了建议.     

甘蔗机械化收获技术现状分析

现阶段我国甘蔗收割仍以传统的人工收割和不全面的小型化机械收割方式为主,机械化收割水平较低.为研发能够适应要求的收割机,从甘蔗机械化收割现状和特点出发,对甘蔗机械化收割机技术现状进行综合分析,重点阐述甘蔗收割机扶蔗装置、物流通道和剥叶装置技术的研究现状和发展动态,并归纳制约我国甘蔗实现全面机械化收割所存在的问题及解决措施...     

A simulation study of sugar cane harvesting

Before being harvested sugar cane is burnt in the fields and then cut and carried to the processing plant. After burning, the cane must be processed within 15 days, otherwise the saccharose in it transforms into ethanol and the cane has to be discarded. In this paper we present a simulation algorithm for scheduling the operations and planning the resources, in such a way that the lapse of time between end of burning and processing is minimized. This algorithm can be used as a basis for a decision support system. It calculates the maximum size of a field that can have all its cane processed within 15 days. Alternatively, it can give the quantity of cane in a field that cannot be processed in time and hence will be spoilt.     

加快玉米机械化发展步伐

玉米是山西省第一大粮食作物,年种植面积稳定在160多万hm2,占全省粮食作物播种面积53%以上,在保障山西粮食安全和社会稳定中发挥着重要作用.伴随着社会经济的全面发展,从客观上对玉米生产提出了规模化、集约化、机械化的更高要求.     

苹果采摘机器人无线数据传输系统

针对解决苹果采摘机器人众多传感器数据采用有线传输,数据线纷繁杂乱、检修不便等问题,以及其直动关节在伸缩过程中对末端执行器传感器数据线容易扯断纠结等具体情况,设计了传感器无线数据传输系统。首先对苹果采摘机器人无线数据传输进行了整体设计,对无线通信模块电路、USB通信电路进行了选型设计,同时设计了部分传感器的信号调理电路;其次为了无线数据实时、可靠的传输,在方法上采取了质效控制措施,并制定了数据传输协议,然后进行了无线数据传输的程序设计,最后通过测试结果验证了传输协议的健壮性,数据传输的高效性,并根据测试结果与系统开销之间进行协调,选取了最优设置参数。该研究为采摘机器人及其他农产品生产机器人数据传输提供了一种无线实现方式和新的实现方案。     

Micro-catchment water harvesting potential of an arid environment

Micro-catchment water harvesting (MCWH) requires development of small structures across mild land slopes, which capture overland flow and store it in soil profile for subsequent plant uses. Water availability to plants depends on the micro-catchment runoff yield and water storage capacity of both the plant basin and the soil profile in the plant root zone. This study assessed the MCWH potential of a Mediterranean arid environment by using runoff micro-catchment and soil water balance approaches. Average annual rainfall and evapotranspiration of the studied environment were estimated as 111 and 1671 mm, respectively. This environment hardly supports vegetation without supplementary water. During the study period, the annual rain was 158 mm in year 2004/2005, 45 mm in year 2005/2006 and 127 mm in year 2006/2007. About 5000 MCWH basins were developed for shrub raising on a land slope between 2 and 5% by using three different techniques. Runoff at the outlets of 26 micro-catchments with catchment areas between 13 and 50 m² was measured. Also the runoff was indirectly assessed for another 40 micro-catchments by using soil water balance in the micro-catchments and the plant basins. Results show that runoff yield varied between 5 and 187 m³ ha⁻¹ for various rainfall events. It was between 5 and 85% of the incidental rainfall with an average value of 30%. The rainfall threshold for runoff generation was estimated about 4 mm. Overall; the soil water balance approach predicted 38-57% less water than micro-catchment runoff approach. This difference was due to the reason that the micro-catchment runoff approach accounted for entire event runoff in the tanks; thus showed a maximum water harvesting potential of the micro-catchments. Soil water balance approach estimated water storage in soil profile and did not incorporate water losses through spillage from plant basins and deep percolation. Therefore, this method depicted water storage capacity of the plant basins and the root zone soil profile. The different between maximum water harvesting potential and soil-water storage capacity is surplus runoff that can be better utilized through appropriate MCWH planning.     

广西甘蔗收获机械推广模式研究

国内各科研院所和生产厂家正在积极进行甘蔗收获机械的研制,并已经达到了一定的水平,有些机型已取得了重大突破,但距离批量化生产还有较长的路要走.我国目前农业生产力相对落后,蔗农收入普遍较低,以分段式中、小型机具作业为主体,大中型联合收获机为辅助的模式将会持续一段时间.甘蔗收获机械化的未来将会向以高效率、适应性强的切段式甘蔗联合收获机为主体,其他机型为辅助的模式不断发展.     

土下果实收获挖掘自动限深系统设计

花生、马铃薯等土下果实收获过程中,实时控制挖掘深度是保证作业质量的重要前提.本文总结了国内外农机自动限深相关技术概况,提出了一套基于SensComp公司的6 500超声波测距模块的自动限深测量和控制系统,介绍了该系统的硬件设计和软件设计,本自动限深技术对于土下果实收获减阻降耗、提高作业质量具有重要意义.     

Field evaluation of sand-ditch water harvesting technique in Jordan

Water harvesting is viable alternatives for rainfed agricultural production in semiarid lands. A field experiment was conducted to evaluate the efficiency of a relatively new water harvesting technique, called sand ditch, for moisture and soil conservation. Twelve field plots of 10 m × 2 m were constructed in two adjacent fields having silt loam soils but varied in soil depth, 0.75 m and 2 m, and slope of 10% and 12%. A 130 L barrel was installed at the downslope end of the plots to collect water and sediments at the end of each rainstorm along the rainy season. Three types of treatments were used in duplicates (12 plots in total); sand-ditch plots in which a ditch of 2-m long, 1 m wide and 0.8 m deep was constructed in the middle of plots across the slope (2 in each field), two compacted plots and two plots covered with plastic mulch in addition to four control plots, 2 in each field. The total amount of runoff, sediment concentration, total infiltration and sediment loss for the experimental plots were measured or calculated after each storm during the winter season 2004/2005. Experimental results showed that sand-ditch technique significantly reduced runoff and sediment loss and increased infiltration and soil moisture compared to control or compacted plots. The overall average runoff and sediment reductions in the sand-ditch plots were 46% and 61% compared to control plots. Sediment losses from compacted plots were about 2.2 and 6 folds higher than control and sand-ditch plots, respectively making soil compaction unsuitable technique for rainfall harvesting under the current experimental and climatic conditions. Construction of sand ditch also increased the dry matter yield of native grass by an average of 62% and 40% in the two experimental fields compared to control.     

我国山药机械化收获技术研究进展

我国山药种植历史悠久,种植范围广泛,因受其自身生长特点、地理环境和种植模式的影响,山药收获机械化程度较低,大多采用人工收获。随着产业结构的发展,山药收获机械化的发展程度直接影响农户的经济效益。分析我国几种山药的种植特点,概述我国山药收获的主要方式,阐述行走系统、传动系统、开沟系统、土壤翻振机构、定位系统等山药主要收获装备和技术的研究现状和进展,简单论述国外山药收获机的研究,在此基础上指出我国山药收获机械化面临农机与种植环境融合不够、种植模式不统一、收获机具质量差、缺乏核心技术创新、收获功能不完善等问题,并对山药机械化收获装备面临的问题提出相关建议：因地制宜研制山药机械化收获设备、推进种植规程建设、学习借鉴发达的国家发展经验、提高核心部件的创新能力、研制联合收获机。     

兵团机采棉技术推广的新进展

2009年兵团加快了机采棉技术推广步伐,机采棉种植模式播种面积超过23.3万hm~2,采棉机总数突破500台;机采棉清理加工线达到83条。计划完成机采棉花10.6万hm~2以上。     

蒜薹机械化收获技术现状分析

蒜薹收获是大蒜生产的重要环节,收获时既要保证蒜薹质量又不能伤害植株影响其继续生长,实现机械化收获比较困难,蒜薹收获仍以人工为主,为研发能达到推广应用要求的蒜薹收获机,对蒜薹收获机械化技术现状进行分析。从大蒜的收获模式和蒜薹收获的方法对蒜薹、蒜头产量的影响出发,综合分析现有蒜薹收获机械的类型、关键部件和工作原理,通过现有蒜薹收获机械性能比较分析,针对现有蒜薹收获机械普遍存在对蒜薹假茎破坏、影响蒜头后期生长的问题,提出采用夹薹原理机械化收获蒜薹,蒜薹长且对假茎损伤小,蒜薹收获机械化应向智能化方向发展才能提高收获部件工作的准确性、减少对植株和蒜薹的损害乃至无损。为我国蒜薹收获机械进一步发展提供借鉴和参考,推动大蒜生产机械化的发展进程。     

草坪草根茎采集机改进与试验研究

根茎采集机是高效采集草坪草根茎的专用设备。国内某公司在CSO1A-36B型梳草机基础上改进设计了一款根茎采集机,针对该机存在的问题,重新设计出新刀片并合理排列,刀片材料改用65Mn,配备动力选用美国B&S公司生产的4.8kW四冲程汽油机。试验证明,新设计出来的采集机生产率高、性能稳定,可适用于采集根茎繁茂的草坪草。