The potential for combining living wall and vertical farming systems with aquaponics with special emphasis on substrates

Aquaponics is a method of food production, growing fish and vegetables in a recirculating aquaculture system. Aquaponics uses the water from the fish to feed the plants in a totally natural way and like hydroponics, aquaponics is considered to be more sustainable as more plants can be grown per square metre compared to normal agriculture. However, as is the case with normal agriculture, in aquaponics plants are grown within horizontally. In aquaponics, using the UVI system, the ratio between fish tanks:filters:plant tanks is 2:1:5 which means that the plant tanks are occupying close to half of the production space. In order to reduce the spatial requirement for plants, which would make production even more sustainable, this research investigates aspects of combining living wall and vertical farming technologies in aquaponics. It is considered that by growing the plants vertically less space would be required. In this research living wall system is investigated but the main focus is on the potentials of using various inert substrates in the living wall systems for vertical aquaponics. The results showed that a pot system performs better in terms of management of the systems. With regard to substrates, horticultural grade coconut fibre and horticultural grade mineral wool outperformed other substrates.     

全膜垄作侧播栽培模式下主要旱作马铃薯品种营养品质综合评价

在定西半干旱黄土丘陵区,通过大田试验研究了全膜垄作侧播模式下甘引1号、甘引2号、黑美人、新大坪、青薯9号、庄薯3号、陇薯6号、定薯1号、青薯168等9个主栽马铃薯品种的营养品质性状差异,并采用模糊数学的隶属函数法和因子分析法综合评价了各品种的营养品质,以期为甘肃马铃薯主产区优质马铃薯品种选择提供科学依据。结果表明,全膜垄作侧播栽培技术模式下,9个马铃薯品种综合营养品质顺序依次是甘引1号甘引2号黑美人新大坪青薯9号庄薯3号陇薯6号=定薯1号青薯168。     

Synthetic fibre as biological support in freshwater recirculating aquaculture systems (RAS)

The aim of this study was to evaluate the use of synthetic fibre as a biological support for the adhesion of nitrifying bacteria in an aquaculture recirculation system (RAS). It was developed from three assays over 120 days. In the first assay, the synthetic fibres used as biological support were introduced in tanks of biological filtration of the system for posterior respirometry analysis and scanning electron microscopy (SEM). Respirometry and SEM were performed 10 days after inoculation with nitrifying microorganisms. Water quality parameters were monitored daily, and the respirometry showed that the bacteria in this assay were consuming the following amounts of ammonium: concentrations [C1]35.369 mg NH₃/L, R² = 0.9912; [C2]51.628 mg NH₃/L, R² = 0.9883; [C3]79.494 mg NH₃/L, R² = 0.986; and [C4]215.225 mg NH₃L, R² = 0.9934. In the second assay, a 1920-L tank was stocked with 120 Nile tilapia, Oreochromis niloticus, with an initial weight 32.11 ± 7.6 g and a biomass of 3.8 kg. After 60 days, the tank and its contents were assessed to evaluate zootechnical parameters and physical–chemical parameters of water quality. From these results, a third assay was developed in which the biomass of fish was increased to challenge the recirculation system. The tank was stocked with 480 jundiá Rhamdia quelen (initial weight 11.34 ± 2.4 g and biomass 5.4 kg) for 60 days. In both the tilapia and jundiá assays, the fish were fed four times per day with a commercial diet of 35% crude protein and 42% crude protein, respectively, at 5% of each individual fish’s body weight. At the end of the zootechnical assays, the synthetic fibres used showed efficient biological support for bacterial growth, as confirmed by scanning electron microscopy. The fibres also demonstrated maintenance of the water quality, which allowed good fish growth in the recirculating aquaculture system, and the maintenance of up to 11.19 kg/m³ of biomass of fish.     

Production of Nile tilapia Oreochromis niloticus grown in BFT using two aeration systems

Aeration systems used in BFT farming need to meet the dissolved oxygen demand from the biota present in the tank, as well as to keep the particulate matter in suspension. In BFT systems, it is common to use blowers, but the choice of an aerator with better efficiency in oxygen transfer and in electric energy consumption is indispensable. The vertical pump model (VPM) aerator is the most used in intensive tilapia production systems in southern Brazil. The objective of this research was to verify if this aerator model can support Nile tilapia farming under BFT system without producing negative impacts on the functionality neither of the biofloc nor in the production indexes. Simultaneous farming on BFT using blowers served as control. Oreochromis niloticus juveniles with an initial density of 7 kg/m³ were used. After 56 days of farming, the VPM aerator obtained significantly better results, both in water quality parameters and in production indexes, when compared to those obtained in the control treatment. The temperature was higher in the treatment of the blowers due to the lower thermal exchange between the atmospheric air and the tank water. Although the VPM caused lower temperatures, it obtained a productivity of 21.2 kg/m³, compared to 20.2 kg/m³ of the blowers. It was concluded that the use of the VPM aerator had no negative influence on both the formation and functionality of the biofloc, obtaining even higher production rates.     

2014-2016年我国种植业化肥施用状况及问题

【目的】种植业化肥施用量的变化不仅影响着我国化肥的供销平衡,还与环境安全密切相关。掌握种植业化肥施用状况是贯彻新发展理念,推进农业供给侧结构性改革的重要前提保障。【方法】本研究利用农业农村部339个国家级基层肥料信息网点调查数据,计算2014—2016年我国种植业化肥施用总量,并对主要农作物和不同区域化肥施用量和化肥施用品种分别进行统计分析。【结果】2014—2016年我国种植业化肥施用量分别为5989.7万t、6052.6万t和6041.4万t,其中三大粮食作物小麦、玉米、水稻年均化肥施用总量分别为728.3万t、1214.2万t和887.1万t,合计占到化肥施用总量的46.9%,华北、华中南和华东三个区域年均化肥施用总量分别为1603.1万t、1156.8万t和978.7万t,合计占到化肥施用总量的62.0%,复合(混)肥和尿素是农民最常购买的两种肥料,年均购买比例分别为76.8%和65.1%。【结论】我国种植业化肥施用量在2016年首次实现了零增长,化肥减量工作取得重要进展,但区域养分供应不平衡现象突出,主要表现为华北、华中南养分盈余较大,西南、西北养分供应不足。不同作物体系也存在施肥不平衡的问题,小麦、水稻基本合理,玉米和花生投入过量,甘蔗和棉花投入不足。建议国家加大力度推进测土配方施肥、机械施肥、有机肥替代化肥等高效施肥模式,促进化肥减量增效,助力乡村振兴战略实施。     

疫病净化对动物后代繁育的影响研究——基于全国297个规模化养鸡场的实证分析

2012年,国务院提出了《国家中长期动物疫病防治规划(2012—2020年)》,要求对16种动物疫病逐步进行控制、净化和消除。基于此,本文利用全国297个规模养鸡场的调查数据,采用随机效应模型,分析疫病净化对养鸡场动物后代繁育的影响。结果表明,已净化养鸡场的日最高产蛋率、种蛋合格率、种蛋受精率、受精蛋孵化率分别比未净化养鸡场高1.091%、1.090%、0.892%、0.528%。相比已净化养鸡场与未净化养鸡场之间后代繁育指标的差异,净化不同病种带来的差异较小。增加疫苗投入、减少兽药使用、合理设置技术人员数量可有效提升鸡群的后代繁育能力,采用封闭式的栏舍、非笼养的饲养方式、非自繁自养的引种方式以及整批的出栏方式可在某种程度上提高养鸡场动物的后代繁育能力。全国7个区域中,华北地区养鸡场的后代繁育能力最强。建议国家加强对疫病净化的宣传,积极组织疫病净化方面的培训和交流。养鸡场在开展疫病净化的同时,重视疫苗免疫工作,尽可能减少兽药的使用,有效地聘用技术人员。     

基于品种熟期和籽粒脱水特性的机收粒玉米适宜播期与收获期分析

【目的】规模化生产条件下,需要兼顾产量和效率的协同提高。通过合理配置不同熟期品种及播期,能够延长播种和收获的机械作业时间,提高机械利用效率和玉米生产效率。【方法】本研究于2015—2017年,选用KWS9384、新玉77和M751 3种不同熟期的主栽玉米品种,观测籽粒含水率变化动态,建立基于授粉后积温(≥0℃)的籽粒含水率预测模型,结合当地气象数据,分析不同品种的播种与收获时期。【结果】结果表明,不同熟期品种的产量和适播期不同。早熟品种KWS9384适宜播期和收获期更长,但产量较晚熟品种低;晚熟品种新玉77和M751产量高,但满足生理成熟及脱水至适宜机械粒收含水率的时间更长。通过早熟品种和晚熟品种的搭配,可以有效延长玉米播种及机械粒收的作业时间;早播晚熟品种、晚播早熟品种的配置方案,能够较好地协调产量和籽粒脱水的关系。【结论】通过分析不同品种适宜播种期及其相应的适宜收获期,提出了高产高效协同生产目标下的品种和播期配置原则,实现特定生态和生产条件下机具利用效率和效益的最大化,为相关技术需求的研究和应用提供思路。     

The impact of supplementation with Rhagodia preissii and Atriplex nummularia on wool production,mineral balance and enteric methane emissions of Merino sheep

The Australian perennial shrubs, oldman saltbush (Atriplex nummularia) and rhagodia (Rhagodia preissii), can complement the diets of sheep grazing moderate‐quality cereal residues. We compared liveweight change, organic matter digestibility, nitrogen and mineral balance, wool growth and methane emissions of Merino wethers offered oaten hay (OMD 622 g kg^?1 DM; N 9.74 g kg^?1 DM) with and without shrub biomass (substituted at 25% of OM). Diets were fed at restricted levels for 1 month. Substituting hay with shrub biomass significantly decreased liveweight loss, increased clean wool growth and increased apparent absorption of phosphorus compared to the hay alone. Substitution of hay with both saltbush and rhagodia led to over 23% greater clean wool growth. Nitrogen balance and apparent digestion of organic matter, calcium and magnesium did not vary significantly between animals on the diets. Wethers on the rhagodia and hay diets had similar enteric methane emissions, while animals offered the saltbush diet had significantly higher emissions (L/OM intake). When methane is expressed in terms of wool growth, animals on the rhagodia diet produced 26% less methane for every gram of wool.     

农耕文化及其产业化发展研究

农耕文化是历经几千年的积累和沉淀而形成的文化资源,是我国文化资源宝库中的重要组成部分,系统、全面地认识农耕文化资源、科学合理地推进农耕文化资源的产业化开发和利用,是弘扬和传承民族文化的需要,也是推进文化创新发展的需要。通过对农耕文化资源的研究,重新认识农耕文化的内涵,明确农耕文化资源的主要类型,针对当前农耕文化产业化发展存在的主要问题,辨析了农耕文化产业化开发的静态模式和动态模式,提出了农耕文化资源产业化开发的核心路径——农民参与主体化、融资渠道多元化、特色开发乡土化、产品设计精品化、产业经营品牌化、环境建设生态化和产业发展国际化。研究为实现农耕文化资源的产业价值提供了重要的理论依据。     

南方规模化奶牛场草基循环农业模式研究

针对奶牛养殖快速发展带来的资源浪费和环境污染问题,探讨了南方规模化奶牛场循环农业模式并提出了相关策略。提出养殖场粪污(包括奶牛粪、尿和养殖废水)是造成环境污染的主要因子,牧草是消纳养殖场粪污,变废为宝,构成循环利用链的主要载体。因此南方规模化奶牛养殖可以就地取材、就近利用,构筑形成草基循环农业模式。草基循环农业模式结合规模化奶牛养殖对鲜草需要量大、杂交狼尾草产量高且对奶牛场污水氨氮吸收率高的三大因素而构建,是低耗高效、安全优质、清洁生态的循环农业模式。