Early Influence of Wood Ash Application on the Carbohydrate Reserves and Composition in Needles of Scots pine {Pinus sylvestris)

Abstract

Wood ash treatment can probably increase forest productivity on low fertility sites. However, the resulting effect on the carbohydrate concentration as the main carbon and energy reserve in trees is little studied. In 2000, a square of 0.1 ha sandy soil below a 19-year-old Scots pine (Pinus sylvestris) plantation was treated with raw fly ash (0.5 kg.m^-2); untreated square was used as control. One year after the treatment, carbohydrates (glucose, fructose, sucrose, maltodextrins, starch and excess bound fructose) were analyzed enzymatically from current-year and one-year-old needles. The ratio K/N in needles suggested an improved balance between these elements in treated trees, in which the K concentration was higher. The largest relative differences (50% of control) were observed in glucose and fructose in summer. The squares did not differ in the concentration of the accumulated carbohydrate reserves in needles during low temperature stress in winter and before the growth of new shoots in spring. During the vegetation period decreased levels of soluble carbohydrates and starch were observed (max 70% of the control value around 100 mg total carbohydrates g^-1 dry mass). Because the experiment was designed without true replicates, reasons for the observed differences require further study.     

生物土壤添加剂对黄瓜根系分泌物的影响

为收集生物土壤添加剂处理的黄瓜根系分泌物,比较不同处理根系分泌物对种子萌发的影响,利用生长速率法测定不同处理根系分泌物对枯萎病镰刀菌的影响。结果表明,生物土壤添加剂浸提液的处理能够明显促进黄瓜种子萌发,对下胚轴的伸长具有促进作用;生物土壤添加剂浸提液对枯萎病菌抑菌率可达98.1%,与根系分泌物混合后的抑制率仍达87.3%,根系分泌物对枯萎病菌无抑制作用。     

不同改良剂对保护地次生盐渍化土壤改良效果的研究

研究旨在提高保护地次生盐渍化土壤肥力,探索建立适宜当地的次生盐渍化土壤改良模式。选择宿豫区典型保护地次生盐渍化土壤,以不施处理为对照,研究施用有机肥、土壤调理剂、米糠对土壤有机质、碱解氮、有效磷以及水溶性盐的影响。结果表明：各处理均能不同程度对次生盐渍化土壤进行改良,增加土壤养分,降低土壤含盐量。与对照相比,施用有机肥处理较对照土壤有机质、有效磷、速效钾分别提高41.6%、68.3%、121.6%,米糠处理较对照土壤有机质、速效钾显著增加41.4%、48.6%,土壤调理剂处理也有增加土壤有机质、碱解氮和速效钾含量的趋势。此外,各处理还对土壤水溶性盐分有降低效果。其中米糠处理较对照土壤电导率、水溶性盐总量、水溶性钙离子、水溶性镁离子、硫酸根离子含量分别显著降低43.3%、23.5%、28.9%、34.6%、23.2%。米糠、有机肥、土壤调理剂对次生盐渍化土壤改良效果依次递减,其中米糠改良效果较为显著。     

煤矸石—磷石膏—菌渣混合基质与黑麦草根系复合体抗剪性能的差异性

[目的] 探究黑麦草生长对混合基质物理性质与抗剪性能的影响,为煤矸石山植被快速恢复和防治水土流失提供科学依据。[方法] 针对煤矸石物理结构差和养分含量少等特点,通过在煤矸石中添加磷石膏和菌渣形成混合植生基质,在盆栽条件下种植黑麦草,探讨黑麦草生长对混合基质物理性质与抗剪性能的影响。[结果] ①添加不同比例的磷石膏、菌渣改良煤矸石均可以明显促进黑麦草生长,其中在添加20%磷石膏和10%菌渣的煤矸石混合基质上黑麦草株高、地上部干生物量、根重密度和叶绿素含量指标改善效果最好,其次是添加10%磷石膏和10%菌渣的煤矸石。②添加磷石膏和菌渣可明显改善煤矸石混合基质的通气持水能力,其中添加20%磷石膏和10%菌渣处理组相对于只添加10%菌渣处理组煤矸石混合基质的自然含水率、总孔隙度、毛管孔隙度、非毛管孔隙度分别提高了18.88%,14.18%,13.12%和18.08%,而容重降低了24.76%。③添加磷石膏和菌渣的煤矸石混合基质有利于黑麦草根系的发育生长,相对于只添加10%菌渣处理组,添加20%磷石膏和10%菌渣处理组的煤矸石混合基质各级垂直荷载下的抗剪强度平均提高了71.71%,黏聚力和内摩擦角分别提高了102.84%,45.05%。[结论] 添加20%磷石膏和10%菌渣的煤矸石混合基质与黑麦草根系复合体抗剪性能最好,有利于控制煤矸石山水土流失。     

Environmental and Economic Benefits of Saline-Sodic Soil Reclamation Using Low-quality Water and Soil Amendments in Conjunction with a Rice–Wheat Cropping System

A combination of appropriate crop rotation(s) and management interventions has the potential to transform saline‐sodic soil and water resources from an environmental burden into an economic asset. We carried out 2‐year field studies in the Indus Basin of Pakistan to evaluate different irrigation and soil management options of using saline‐sodic waters (SSW) and soils for reclamation and for growing salt‐tolerant cultivars of rice (SSRI‐8) and wheat (SIS‐32). These soils have variable levels of salinity and sodicity (EC_e 9–44 dS m^?1 and SAR 83–319). The treatments on both the sites were the same and consisted of: (1) Irrigation with SSW, (2) Irrigation with freshwater (FW), (3) Soil application of gypsum at 100 % gypsum requirement of soil + SSW (G + SSW), (4) G + one irrigation with SSW and one with FW (G + 1SSW + 1FW), (5) G + two irrigations with SSW and one with FW (G + 2SSW + 1FW), (6) Farm manure at 25 Mg ha^?1 each year before rice + one irrigation with SSW and one with FW (FM + 1SSW + 1FW) and (7) FM + two irrigations with SSW and one with FW (FM + 2SSW + 1FW). Rice was grown as the first crop. After harvesting final wheat crop (fourth in sequence), maximum decrease in bulk density and increase in infiltration rate was observed with G + 1SSW + 1FW while FM + 1SSW + 1FW treatment showed higher decrease in pH_s and EC_e. Significantly the highest decrease in SAR occurred at both sites with G + 1SSW + 1FW. Maximum yields of rice and wheat were generally observed with G + 1SSW + 1FW. The crop yield and economic benefits with treatments showed a positive correlation with that of improvement in soil physical and chemical properties. Overall, the greatest net benefit was obtained from G + 1SSW + 1FW treatment. We also found that the farmers’ management skills were crucial in the overall success in improving crop yields during reclamation of saline‐sodic soils. Based on the results of this study, we propose that SSW could be used to reclaim saline‐sodic soils by using a rice–wheat rotation and a site‐specific combination of soil amendments and water application strategies.     

Philosophy and mechanics of how we arrive at fertilizer and lime recommendationsx

Abstract

Three rates of the synthetic, hydrophylic substance Permabsorb (1.6, 3.2, and 6.4 gm/1) were tested by growing ryegrass, azalea, and impatiens in a greenhouse mix, consisting of 1 part Spagnum peat moss, 1 part vermiculite and 1 part perlite by volume.

The increased water holding capacity furnished by the Permabsorb at 6.4 gm/1 significantly decreased the watering frequency of rye‐grass without affecting yield. All Permabsorb treatments reduced azalea yield because of decreased aeration or toxicity. Impatiens grew poorly in treatments and control.

As the Permabsorb treatments and the control were put through wetting and drying cycles, all held less water unless saturated for long periods of time. Nevertheless, the treatments generally held more water and had lower watering frequencies than the control throughout the 5 to 6 month duration of the experiment.     

Evaluation of extractable elements in artificial substratum made from sewage sludge: Approach to remediation of degraded land in the Arctic

The Arctic (or subarctic) is characterized by a harsh climate and nutrient‐poor soil; what makes it even harsher in Monchegorsk (67°51′N and 32°48′E) is that metal pollution originating from the Ni–Cu smelting industry has severely damaged the soil and ground vegetation, resulting in formation of an industrial desert (barren ground). A pilot‐scale (4 ha) field test was carried out under such conditions to study how to apply municipal sewage sludge for rehabilitation of degraded land. After sewage sludge had been composted, an artificial substratum made from the compost was introduced to the remediation test field, and then willow, birch and grasses were planted on the substratum. The transformation of the artificial substratum was observed in the test field during 3 years. The portion of Cu in residual form was greater than that in other forms, it is hence considered that Cu has low bioavailability in the artificial substratum. Furthermore, the metal distributions statistically increased in fractions of humic acid (insoluble in water under acidic conditions), so the mobile amounts of Ni and Cu became small. The conclusion drawn from the field survey and analysis of extractable metals indicates that the lost vegetation is being restored even while pollution continues to be discharged from the smelter operation. Copyright © 2008 John Wiley & Sons, Ltd.     

第18届CITES缔约方大会木材树种管制变化

2019年8月在瑞士日内瓦召开的濒危野生动植物种国际贸易公约(CITES公约)第18届缔约方大会上,新增附录Ⅱ树种3属共19种,分别为姆兰杰南非柏、染料紫檀和洋椿属所有种(仅限新热带种群);并修订了附录Ⅱ管制的黄檀属、3种古夷苏木和大美木豆的注释。作者针对此次大会有关木材树种议题的分析,及近10年CITES公约附录木材树种名录变化与趋势的评述,为我国CITES木材树种履约策略提出建议。     

硫磺改良盐渍土效果初探

采用田间试验方法,探索了以硫磺为改土材料对渭南盐渍土的初步改良效果。结果表明,硫磺的施用对于土壤及作物(棉花)的养分状况表现出一定的改善作用;并且降低了土壤pH值,相对于施用石膏的处理,硫磺在降低土壤pH上有更明显的作用;另外,虽然硫磺的施用增加了土壤中各离子的含量及EC值,但随着硫磺用量的逐渐增加,土壤中各离子含量及EC值呈现出降低的趋势。因此,硫磺的施用对于该地土壤具有一定的改良作用。但是,虽然结果显示硫磺在该地土壤的改良中起到了一定的作用,但总体效果有限,其主要原因可能是硫磺施用量太低(试验中最高用量为225 kg/hm2),因此,在本试验基础上如果进一步加大硫磺用量将可能会对该地盐碱化土壤具有更为明显的改良作用,但最佳施用量还需要进一步研究。