The Use of Municipal and Pulp and Paper Sludges to Increase Production in Forestry

Because of their high nutritional content and soil conditioning properties,. municipal and pulp and paper (P&P) sludges-biosolids-can serve as soil amendments for nutritionally deurived or organically soils on forest sites. Studies conducted over the past 20 years at an experimental forest site in Western Washington, USA, have largely confined the potential of biosolids to increase the productivity of many forest lands. These studies clearly demonstrated that application of biosolids at environmentally acceptable rates will result in growth responses for both young seedlings as well as established stands. Municipal biosolids have been applied to a number of different Douglas-fir stands. Young stands applied at 47 Mg ha-1 showed an average of 72%, 14% and 2% height responses for Site Class IV, III and 11, respectively, over a 10 year period. Thinned versus unthinned 55-yeardd Douglas-fir applied with 142 dry Mg ha-l averaged 43% and 48%, respectively, for the 12 year period greater than controls. Average growth responses of 65% and 40% occurred in the 65-year-old stand for the Site Class IV and 11, respectively, from a 47 dry Mg ha1 application. Growth response resulting from application of P&P biosolids to a number of tree species has also been excellent. When properly applied, biosolids can provide an excellent alternaLive to chemical fertilizers as a means of enhancing forest production. Growth response is typically greater and lasts longer when compared to chemical fertilization. Careful consideration has to be made of the site conditions to be certain that environmental risks are minimal and losses through leaching and overland flow will not occur.     

山西省朔州市冬季气温变化特征与暖冬的气象成因及对农林业的影响

为了揭示朔州市冬季的气候变化规律,特别是近年冬季的气候变化特点,运用气候倾向率、相关分析等统计方法,根据山西省朔州市6个气象观测站1988-2005年冬季平均气温、平均最高气温、平均最低气温资料,对朔州市近18年来冬季气温变化做了分析。结果表明,自20世纪70年代,朔州市冬季气温总体呈逐年上升趋势,1988年后的18年,朔州市出现15个暖冬年,冬季平均气温变化趋势不太明显,平均最高气温呈下降趋势,平均最低气温呈上升趋势,但与20世纪后30年相比,升温速率明显下降。冬季平均气温、平均最高气温、平均最低气温的最大增温率均出现在1月,1月变暖趋势最为明显。结论认为,这种经常出现的气候异常,有一定的气象成因,对农林业的生产产生了很大的影响,本文对此进行了分析和讨论,并提出了降低暖冬对农林业危害的建议。     

Changes in soil fauna and soil conditions under Pinus radiata agroforestry regimes during a 25-year tree rotation

 Pinus radiata was planted in a grazed pasture at Tikitere, New Zealand in 1973; final tree stocking rates were 0, 50, 100, 200 and 400 stems ha^–1; trees were harvested in 1999. We sampled the loamy sand for chemistry, earthworms, enchytraeids and nematodes during crop growth. There were no visible changes in the soil profile between years 2 and 25 of the P. radiata rotation, but marked changes in soil chemistry with pH declining at all depths. Topsoil pH declined but plant-available P and the soil C : N ratio increased. That similar trends occurred in pasture may have reflected reduced inputs. Lumbricid earthworms declined with increasing time and tree stocking rate; significant populations were found only in pasture at 25 years; no related changes in soil bulk density were detected. Enchytraeids were abundant but declined in the plots with 200 and 400 stems ha^–1. The composition of the nematode fauna at a soil depth of 0–10 cm varied, and there were changes in the “control” pasture. Pratylenchus sp. and Pungentus sp. were characteristic of pasture;Diphtherophora sp. appeared at higher tree stocking rates. In addition to changes related to the change in landuse there were temporal changes that affected faunal composition across tree stocking rates: Heterodera sp. and Paratylenchus sp. were rare after year 6;Prismatolaimus sp. was most abundant in years 2, 13 and 25;Axonchium sp. occurred in year 6 and Alaimus sp. mainly in year 25. Overall, the changes in soil chemistry reflected the change from pasture to forest. Parallel changes in soil microfauna and macrofauna also reflected the change in landuse, from fertilised pasture to coniferous forest, and are considered reversible. Received: 5 July 1999     

How do AMF-inoculation and supplemental irrigation affect the productivity of rainfed yellow sweet clover in agrisilviculture systems?

ABSTRACT

Yellow sweet clover (Melilotus officinalis L.) was assessed for its yield in an agri-silvicultural model of the plum (Prunus domestica (L.) cv. Opal). The treatments included two sun light exposures (morning light and afternoon light) as main plots and species of arbuscular mycorrhizal fungi (AMF) (Funneliformis mosseae, Rhizophagus irregularis and no-AMF-inoculated control) as subplots. The treatments were separately arranged for two irrigations (rainfed and supplemental irrigation) during 2016–2017. In irrigated and AMF-inoculated plants, a significant increase was observed in the performance of yellow sweet clover (dry weight and biological yield), seed nutrients (phosphorus and potassium) and weight of aerial parts in morning light conditions as much as rainfed conditions, identically for two species of fungi. In both rainfed and supplemental irrigations, the biological yield of F. mosseae inoculated plants increased by up to 23%. In supplemental irrigation, the maximum growth of plant height and relative water content were obtained from AMF-inoculated plants (R. irregularis) in afternoon light area as much as rainfed condition. In conclusion, the identical beneficial effects of mycorrhizal fungi species were enhanced by single supplemental irrigation. However, plant performance, including the quality and quantity of yield, was superior in the morning light part of each treatment.     

Phosphorus and Suspended Sediment Loads in Base-Flow and Runoff Events: A Case Study of a Small Stream in NW Spain

This study focuses on the role of runoff events in influencing concentrations and export of suspended sediments and phosphorus in a headwater stream draining an agroforestry catchment in northwestern Spain. Large differences exist between suspended sediment and phosphorus (P) concentrations measured during base-flow conditions and runoff events, with a higher delivery during runoff events. Suspended sediment and phosphorus exports were 29.44 and 0.08 kg ha^?1 y^?1 respectively, with more than 50% delivered during runoff events (12% of the year). The relative contributions of phosphorus forms to the total annual export were 75% and 25% as particulate and dissolved phosphorus, respectively. Soil erosion is the main source of suspended sediment and phosphorus in the stream.     

Geochemical Behavior of Dissolved Organic Carbon under Baseflow Conditions at the Corbeira Stream Water,Spain

Geochemical processes related to dissolved organic carbon (DOC) under baseflow are studied in Corbeira Stream (northwestern Spain). The stream drains a catchment occupied by forest and agricultural fields. Dissolved organic carbon and other chemical parameters were analyzed. Seasonally, DOC values show a gradual rising background beginning in late spring to summer, finishing with major anomalies in the early to middle autumn. Suspended solids (SS) values exhibit a steady to falling background. The greatest DOC peaks seem be a function of rising temperatures and degradation of organic matter in wet soils. Divergent DOC and SS backgrounds in dry season and synchronicity between DOC-SS peaks associated with negative correlation of SS to pH in autumn seem be conspicuous geochemical signatures in perennial streams under temperate climates. The first one indicates the predominance of subsurface flows in streams, and the second one indicates the predominance of overland runoff.     

Agronomic Potentials of Rarely Used Agroforestry Species for Smallholder Agriculture in Sub-Saharan Africa: An Exploratory Study

Despite significant evidence that green manures from agroforestry species can improve soil fertility, green biomasses from many agroforestry species have not been sufficiently explored. In this study, we determined the suitability of green manures of Tithonia diversifolia, Gliricidia sepium, and Senna spectabilis for smallholder agriculture in Africa. Field trials were established to compare them with mineral fertilizer. The results showed that green manures of the three species were of high quality based on their macronutrient compositions. The effect of the green manures (particularly Tithonia) on both the biomass and fruit yield of okro were comparable and in some cases greater than fertilizer treatments. Total yield response in Tithonia treatment was 61% and 20% greater than the control and fertilizer treatments, respectively. In addition, the okro plants recovered a greater percentage of the nitrogen (N), phosphorus (P), and potassium (K) added as green manure compared to fertilizer-treated plots, which received the greatest N, P, and K inputs.     

Fine-scale spatial and temporal variation in earthworm surface casting activity in agroforestry fields, western Honduras

Quantification of the spatial and temporal distribution patterns of soil fauna is a relatively new area of research, and has been proposed as the key to understanding the high diversity typical of soil fauna communities. Field research on the relationships among the spatial distribution patterns of trees, litter and earthworm surface casting was carried out in two agroforestry fields in a rugged area of western Honduras. Grid-based sampling at a scale of 2-20 m was employed to determine whether any spatial relationships existed among these variables at this fine scale. Each field was sampled twice at either 2 or 3 week intervals, to determine the short-term stability of spatial relationships. The spatial distribution of litter showed a strong pattern of aggregation, whereas earthworm cast distribution did not exhibit strong spatial autocorrelation. However, the spatial distribution patterns of each of these variables were well explained by the spatial arrangement of trees in both sites. Fitted model cross-semivariograms explained between 70% and 90% of the total variation in cross-semivariance between tree density and litter cover, and between tree density and earthworm cast weight. The results of the study suggest that farmers may be able to manipulate populations of earthworms indirectly by managing the spatial arrangement of trees within their crop fields. Planning the distribution of trees could allow farmers to create ‘patches’ of organic resources within fields, while minimising the negative effects of trees on crop growth due to competition for light, water and nutrients. Over the short time scale of the study, unusually heavy rainfall led to substantial changes in spatial distribution patterns of earthworm cast activity and litter cover, which may otherwise not have occurred. This result emphasises the need to take into account short-term temporal change during ecological studies at fine spatial scales.     

等高植物篱技术研究进展

简述了等高植物篱的基本概念,国内外学者对空间结构如最大带间距、最小带间距以及带内结构研究概况、布设与管理,分析了植物篱的综合效益,并指出该技术存在的问题及其发展趋势。     

银杏混农林间作模式栽培技术研究

对银杏为主的混农林系统改良试验示范研究结果表明,银杏与低秆农作物间作平均高生长和粗生长值均高于单一种植的20％左右,银杏-烤烟模式生长最佳,其树种平均高生长和粗生长值分别比对照增加25％左右。