The effect of different production systems on the content of micronutrients and trace elements in potato tubers

The aim of this study was to determine the effect of different production systems (conventional, integrated and organic) on the content of micronutrients and trace elements in the tubers of very early, early and medium-early maturing potato cultivars. Five Polish potato cultivars were grown in three production systems under field conditions. In plant material selected microelements (chemical elements essential for living organisms) were analysed: boron (B), copper (Cu), iron (Fe), manganese (Mn) and zinc (Zn) as well as some trace elements (not regarded as essential element for living organisms): chromium (Cr), nickel, (Ni) and lead (Pb). The content of micronutrients and trace elements in potato tubers was modified by production system, genotype and weather conditions during the growing season. Organically grown potatoes had a higher content of B (8.6–8.9?mg kg^?1) and Cu (2.8–3.1?mg?kg^?1), and a lower content of Fe (47.0–47.1?mg?kg^?1), Mn (6.0–6.4?mg?kg^?1) and Zn (11.9–12.2?mg?kg^?1), than potatoes grown in conventional and integrated systems. Potatoes grown in the conventional system had the highest Pb content. Organic cultivation can assure better alimentation of potato tubers with B and Cu, which are important microelements often deficient in the soils. On the contrary, when cultivating potato in conventional system, one should supply this element with fertilisers.     

华北地区有机种植和常规种植模式下土壤重金属含量及污染评价

为探讨有机种植与常规种植两种不同种植方式对土壤重金属含量和污染特性的影响,本文在华北5个地区选取典型的有机蔬菜和有机小麦种植基地及附近相似条件的常规种植地块,比较了土壤中Cu、Zn、Pb、Cr、Cd、As共6种重金属含量的差异,并采用不同评价方法对不同种植方式下土壤中重金属的污染程度进行了评价。结果表明:与常规种植相比,有机种植减轻了土壤酸化和盐渍化,提高了土壤有机质含量和阳离子交换量,在一定程度上有利于降低土壤中重金属的生物有效性。与土壤背景值相比,所有调查地区的土壤重金属均有不同程度的增加和积累。与常规种植相比,有机种植模式能有效降低土壤中Cd、Cr含量,有机小麦种植地块因长期施用大量有机肥导致土壤中Cu、Zn、As大量富集;而常规温室菜田同时施用大量的有机肥、化肥及农药,土壤中Cu、Zn、As富集的风险比有机种植模式高;露天蔬菜有机种植地块土壤中Cu、Zn、As含量与常规地块差异不明显。综合污染指数评价结果显示,调查地区土壤均属于轻污染程度,主要贡献因子为Cd、Cu、Zn,有机种植降低了土壤中重金属的综合污染水平;地累积指数法评价结果表明,调查地区处于无污染到中等污染水平,最明显的污染元素是Cd,有机种植降低了土壤中重金属污染的程度和风险;潜在生态危害指数评价结果表明,所调查地块存在轻微潜在生态风险,其中产生较大生态危害的是Cd,表现出轻微生态危害程度。本研究表明,有机种植减轻了土壤中重金属综合污染水平和污染风险,并减轻了土壤重金属的潜在生态危害。     

不同种植密度下有机肥替代氮肥对陇中旱作区马铃薯的影响

为了掌握陇中旱作区不同有机肥替代氮肥量和种植密度组合对马铃薯农艺性状及产量的影响,在等养分替代条件下,以陇薯7号为指示品种,研究了 3个施肥水平(常规施氮、有机肥替代氮肥20％、有机肥替代氮肥40％)与3种种植密度(5.25万、6.00万、6.75万株/hm2)组合对马铃薯生长的影响.结果表明,不同有机肥替代氮肥量和种植密度组合对马铃薯农艺性状、产量及商品薯率有一定的影响;相同替氮量水平下,马铃薯产量及商品薯率随着种植密度的增加均呈先增后减的趋势;相同种植密度下,有机肥替代氮肥20％不仅改善了马铃薯农艺性状,还提高了马铃薯产量构成因素和产量.以有机肥替代氮肥20％(施N 216 kg/hm2、有机肥2 700 kg/hm2)、种植密度为6.00万株/hm2组合处理的马铃薯折合产量最高,为28 333.3 kg/hm2,较对照常规施氮(施N 270 kg/hm2),种植密度为5.25万株/hm2增产12.79％;商品薯率也最高,为79.8％,较对照增加10.1个百分点.综合考虑认为,有机肥替代氮肥20％(施N 216 kg/hm2、有机肥2 700 kg/hm2)+种植密度6.00万株/hm2的组合处理为陇中旱作区马铃薯生产的最佳肥密组合.     

有机农业生产肥料供应

简述了有机农业的基本概念、有机农业生产对肥料的特殊要求和我国肥料资源现状,指出进一步开发肥料资源,推动有机农业生产发展的途径。     

微垄覆膜沟播对阴山丘陵旱作区马铃薯干物质积累及产量的影响

马铃薯产量的形成,是同化产物积累的结果。研究了微垄覆膜沟播条件下马铃薯干物质累积量的变化及产量。结果表明,微垄覆膜沟播可明显提高马铃薯地上部、块茎及全株干物质累积速度和积累量,且地上部干物质的累积量与马铃薯产量呈极显著正相关,因此,微垄覆膜沟播模式的马铃薯产量,比平地覆膜增加了14.6%,比露地平作增加了27.9%。基于微垄覆膜沟播模式可明显提高马铃薯干物质累积量及块茎产量,可以将其作为雨养区马铃薯栽培的重要技术加以推广。     

微垄覆膜沟播对阴山丘陵地区旱作马铃薯土壤水分及产量的影响

阴山丘陵地区土壤水分状况是限制该地区马铃薯发展的主要因素,如何对天然降雨进行高效、永续利用,提高马铃薯对自然降水的利用率,是该地区马铃薯生产发展的战略考虑。本研究提出了微垄覆膜沟播的种植模式,结果表明:(1)微垄覆膜沟播种植模式明显提高土壤0~60 cm土层贮水量,在马铃薯需水关键时期,出苗后35 d和55 d,微垄覆膜沟播土壤贮水量分别比平作覆膜和露地平作提高25.68%、14.26%和28.92%、18.47%。(2)微垄覆膜沟播种植模式可明显提高马铃薯产量及对降雨的利用效率。(3)微垄覆膜沟播种植模式下的马铃薯每公顷吸收的水分数量比平作覆膜和露地平作分别高25.70%和33.52%。因此,微垄覆膜沟播种植模式可以明显提高马铃薯产量及对自然降水的利用效率,可作为发展内蒙古阴山丘陵地区旱作马铃薯的有效途径。     

Soil microbial biomass and activity in organic tomato farming systems: Effects of organic inputs and straw mulching

Organic farming is rapidly expanding worldwide. Plant growth in organic systems greatly depends on the functions performed by soil microbes, particularly in nutrient supply. However, the linkages between soil microbes and nutrient availability in organically managed soils are not well understood. We conducted a long-term field experiment to examine microbial biomass and activity, and nutrient availability under four management regimes with different organic inputs. The experiment was initiated in 1997 by employing different practices of organic farming in a coastal sandy soil in Clinton, NC, USA. Organic practices were designed by applying organic substrates with different C and N availability, either in the presence or absence of wheat-straw mulch. The organic substrates used included composted cotton gin trash (CGT), animal manure (AM) and rye/vetch green manure (RV). A commercial synthetic fertilizer (SF) was used as a conventional control. Results obtained in both 2001 and 2002 showed that microbial biomass and microbial activity were generally higher in organically than conventionally managed soils with CGT being most effective. The CGT additions increased soil microbial biomass C and activity by 103-151% and 88-170% over a period of two years, respectively, leading to a 182-285% increase in potentially mineralizable N, compared to the SF control. Straw mulching further enhanced microbial biomass, activity, and potential N availability by 42, 64, and 30%, respectively, relative to non-mulched soils, likely via improving C and water availability for soil microbes. The findings that microbial properties and N availability for plants differed under different organic input regimes suggest the need for effective residue managements in organic tomato farming systems.     

微生物菌剂对张北冷凉坝上地区马铃薯产量、品质及活化土壤磷钾的效果

采用田间小区试验,以溶磷解钾微生物菌剂(功能菌为巨大芽孢杆菌和胶质芽孢杆菌)和\"冀张薯12\"\"紫色马铃薯\"\"大西洋\"3个品种马铃薯为研究对象,探讨了在张北冷凉坝上地区施用微生物菌剂对不同品种马铃薯产量、品质、土壤速效磷钾以及土壤磷酸酶活性的影响。结果表明:施用微生物菌剂可以显著增加3个品种马铃薯的产量(P0.05),其中\"冀张薯12\"产量增幅最大为24.54%,其他2个品种产量平均增幅仅为6.96%;可以改善马铃薯的品质,尤其是紫色马铃薯,其Vc、可溶性蛋白质和可溶性糖含量均显著提高,增幅分别为320.21%,29.40%,7.12%(P0.05)。此外,菌剂施用调控着整个生育期土壤速效磷钾的含量和相关土壤酶活性,种植\"大西洋\"和\"冀张薯12\"的土壤施用菌剂后速效磷钾含量高于对照且在中后期达到显著水平,同时提高了土壤酸性和碱性磷酸酶的活性,平均增幅为37.52%和32.30%。总之,溶磷解钾微生物菌剂适用于冷凉张北坝上地区马铃薯种植,且对\"冀张薯12\"的促生效果最为明显。     

有机、特别与常规栽培对八种蔬菜土壤养分和酶活性的影响

通过田间试验比较了有机、特别与常规栽培对8种蔬菜土壤基本养分和土壤酶活性的影响。结果表明,与常规栽培相比,有机栽培和特别栽培能够提高土壤有机质、全氮、速效磷和速效钾含量,改良酸性土壤,并显著提高了土壤酶活性。有机栽培蔬菜土壤过氧化氢酶、脲酶、转化酶和酸性磷酸酶活性均显著高于常规栽培。特别栽培的各项土壤指标基本介于有机和常规之间。研究表明有机栽培能够提高土壤养分和土壤酶活性。     

Glycine,nitrate, and ammonium uptake by classic and modern wheat varieties in a short-term microcosm study

Plants take up nitrogen principally in the form of nitrate and ammonium; however, evidence is growing that they can also use organic N in the form of amino acids. Selecting varieties that better use organic N could be important in maximizing productivity in organic and low-input systems because these varieties may access a wider pool of available nutrients. We tested amino acid-N uptake by wheat (Triticum aestivum L.) seedlings over 24 h over a range of soil glycine concentrations. Wheat was grown in 5 ml pipette tips for 10 days prior to labeling with ¹⁴C-labeled glycine. In a second experiment, uptake of amino acid-N relative to nitrate and ammonium was tested in three pre-1940 wheat varieties (Arco, Idaed, and Red Fife), three modern varieties (Alpowa, Madsen, and Zak), and one perennial wheat variety (unreleased). Glycine-N was detected in all shoots (with the exception of the lowest soil concentration) and increased with increasing soil concentration. There were few differences in uptake between individual varieties tested but seedlings of modern varieties were more efficient at capturing organic N than classic varieties. Glycine-N constituted between 3.9% and 8.1% of total N uptake over 24 h and constituted a significantly greater proportion of total N in perennial wheat than annual wheat varieties. These results show that there may be sufficient varietal differences in organic N uptake in wheat to warrant selection for this trait in breeding programs targeted to improving N use efficiency.     

生态农业和有机农业的创新

现代农业系统在明显提高产量、保证粮食安全的同时,也对人类健康和地球的可持续性产生了影响。在持续不断的严重环境破坏和自然资源毁坏的背景下,建立可持续的农业生产方式至关重要。生态农业和有机农业是减少生态可持续性和生产力及社会可持续之间权衡关系的重要方法。这两种农业方法都属生态集约化范畴,均具有减少环境污染的巨大潜力;然而,生态农业和有机农业常导致产量降低。虽然产量降低带来的损失可以通过改变人们的饮食习惯来弥补（如减少食物浪费、减少食用精饲料喂养的肉类）,但是,由于全球的发展趋势与之相反,因此本文探讨了通过科学研究寻求新的解决方案前景来提高低投入农业系统作物产量的可能性。为权衡生产力与可持续发展的关系,使生态农业和有机农业有助于粮食安全,我们对未来研究提出5点建议：1）农场和田地的景观设计与复合种植模式、2）数字化技术的应用、3）以农田低投入为目标的作物育种、4）农业废弃物的高质量循环利用和5）非化学作物保护。     

Effects of soil mesofauna and farming management on decomposition of clover litter: a microcosm experiment

The effects of soil mesofauna and different farming systems on decomposition of clover (Trifolium repens) litter were investigated in a laboratory experiment. Microcosms were incubated for 16 weeks with fine and coarse litterbags in soils from three types of management systems: fallow, integrated farming and organic farming, the latter two cropped with wheat. The effects were studied by analysing litter mass loss, C and N content, DOC, nitrate and pH in soil leachate, and CO₂ production, as well as mesofauna. Mesofauna significantly accelerated mass loss and C and N release from clover litter in all three soils. With mesofauna access, at the end of the experiment average clover mass loss was almost twice as high and clover C and N content were 60% lower than without mesofauna. Farming systems influenced the decomposition through affecting both element turnover and mesofauna. Although in the first weeks less N was leached from organic farming than from integrated farming soil, cumulative N leaching did not differ between these soils. However, more than 20% less N was leached from the fallow soil than from the field soils. CO₂ production was highest in fallow soil. Here, mesofauna had no effect on this variable. In soil with integrated farming, mesofauna reduced cumulative CO₂ production by 10% whereas in soil from organic farming it increased CO₂ production by 20%. Our data suggest that differences in C and N turnover in different management systems are strongly mediated by soil mesofauna.     

Tillage effects on physical properties of agricultural organic soils of north central Ohio

Drainage, tillage, and intensive land use lead to drastic alterations in physical characteristics of organic soils. As decomposition and soil formation progress, bulk density (ρ_b) increases and total porosity (f_t) decreases due to subsidence, shrinkage, and mineralization of soil organic matter (SOM). However, the rate of subsidence and the changes in soil properties differ among management systems. Thus, the objectives of this study were to determine the effects of different tillage practices on ρ_b and f_t of cultivated peat soils. These experiments were conducted during 2004–2005, on Histosols in north central Ohio. Soil core samples were obtained from experimental plots managed with moldboard plow (MB), no-till (NT), or left bare (B). Conversion of plow tillage to NT increased ρ_b from 0.52 to 0.57 Mg m⁻³, and decreased f_t from 0.72 to 0.70 m³ m⁻³.