不同栽培基质对番茄植株长势、果实品质及产量的影响

试验以土壤、菇渣:砂=3:1和菇渣:砂:鸡粪=4:2:1为栽培基质,采用定期浇灌营养液的方式来栽培番茄,研究了不同栽培基质对其植株长势、果实品质及产量的影响。结果表明:与土壤相比,菇渣:砂=3:1和菇渣:砂:鸡粪=4:2:1基质栽培有利于株高生长和茎的增粗,但对叶绿素含量影响不大;菇渣:砂=3:1的植株地上部和地下部全氮和全磷含量均显著高于其它处理;土壤的植株地上部和地下部全钾含量均显著高于其它处理;单果重和单株平均产量以菇渣:砂:鸡粪=4:2:1最高;糖酸比由高到低的顺序为:菇渣:砂:鸡粪=4:2:1>菇渣:砂=3:1>土壤,VC含量由大到小的顺序为:菇渣:砂=3:1>菇渣:砂:鸡粪=4:2:1>土壤。综合3种栽培基质对番茄植株生长、果实品质和产量等指标的影响,菇渣:砂:鸡粪=4:2:1为番茄基质栽培的最优组合。     

The effect of growing soybean (Glycine max. L.) on N2O emission from soil

A pot experiment was conducted to investigate the effect of growing soybean on N₂O emission from soil. When soybean was growing in pots, the cumulative N₂O emission during the growing season was 2.26 mg N pot⁻¹, which was 5.9 times greater than that from the identical but unplanted pots (CK). However, the difference in N₂O fluxes between the two treatments was not significant until the grain-filling stage. Of the total N₂O emission, 94% took place during the period from grain-filling to ripening. Premature harvesting of the aerial parts of the plants at various growth stages substantially stimulated N₂O emission from the soil. These results implied that the process of symbiotic N fixation per se does not stimulate N₂O production or emission, but rather senescence and decomposition of the roots and nodules in the late growth stage. Therefore, additional N₂O would be emitted from the soil after harvesting of soybean with roots, litter, and residues left in situ.     

南方红豆杉扦插繁殖技术研究——Ⅰ.基质、季节与生物措 施对扦插繁殖的影响

试验研究基质、季节和生物措施对南方红豆杉扦插生根、扦插苗生长和叶绿素含量的影响结果表明,以河沙和珍珠岩按8∶2混配苗床基质最佳,其绿苗率、生根率及成苗率分别为86 .0 %、84 .3%和81.7% ,显著高于其他3种苗床基质;其次为河沙和火烧土混配苗床基质>黄土>单一河沙苗床基质。季节和生物措施效应显示第4季度为扦插最佳时期,扦插效果显著优于其他季节,且扦插后拌种黄豆显著优于未拌种黄豆对照组     

1980 tephra from Mount St. Helens: Spatial and temporal variation beneath forest canopies

Summary Tephra and underlying litter and soil were sampled in 1980, 1982, and 1987 beneath subalpine forests where 4.5 and 15 cm of tephra fell during the 1980 eruption of Mount St. Helens, Washington State, USA. Coarse pumice had a higher initial pH and less total N, less exchangeable K, Ca, and Mg, and less extractable B and S than finer textured layers. Tephra pH and concentrations of cations and S decreased rapidly with time, especially during the first 2 years in the finer layers. Total N, Bray-Kurtz P, and organic C concentrations in the tephra increased with time. Changes within a site in total N, pH, organic C, P, Ca, Mg, and S from 1980 to 1987 exceeded the differences among sites at any one time. By 1987 a forest floor covered much of the tephra surface, and differences in Ca associated with site vegetation and seepage had developed in tephra layers of a similar depth. In 15 cm deep tephra at one site in 1987, the tephra crust beneath the forest canopy was thicker and had higher concentrations of coarse particles, organic C, total N, and cations than beneath forest openings. In concave microsites the crust was thicker, with higher pH, organic C, and total N but lower S than in adjacent convex microsites. Spatial and temporal chemical differences are sufficient to affect patterns of vegetation recovery.     

Atmospheric nitrate deposition and the microbial degradation of cellobiose and vanillin in a northern hardwood forest

Human activity has increased the amount of N entering terrestrial ecosystems from atmospheric NO₃⁻ deposition. High levels of inorganic N are known to suppress the expression of phenol oxidase, an important lignin-degrading enzyme produced by white-rot fungi. We hypothesized that chronic NO₃⁻ additions would decrease the flow of C through the heterotrophic soil food web by inhibiting phenol oxidase and the depolymerization of lignocellulose. This would likely reduce the availability of C from lignocellulose for metabolism by the microbial community. We tested this hypothesis in a mature northern hardwood forest in northern Michigan, which has received experimental atmospheric N deposition (30 kg NO₃⁻-N ha⁻¹ y⁻¹) for nine years. In a laboratory study, we amended soils with ¹³C-labeled vanillin, a monophenolic product of lignin depolymerization, and ¹³C-labeled cellobiose, a disaccharide product of cellulose degradation. We then traced the flow of ¹³C through the microbial community and into soil organic carbon (SOC), dissolved organic carbon (DOC), and microbial respiration. We simultaneously measured the activity of enzymes responsible for lignin (phenol oxidase and peroxidase) and cellobiose (β-glucosidase) degradation. Nitrogen deposition reduced phenol oxidase activity by 83% and peroxidase activity by 74% when compared to control soils. In addition, soil C increased by 76%, whereas microbial biomass decreased by 68% in NO₃⁻ amended soils. ¹³C cellobiose in bacterial or fungal PLFAs was unaffected by NO₃⁻ deposition; however, the incorporation of ¹³C vanillin in fungal PLFAs extracted from NO₃⁻ amended soil was 82% higher than in the control treatment. The recovery of ¹³C vanillin and ¹³C cellobiose in SOC, DOC, microbial biomass, and respiration was not different between control and NO₃⁻ amended treatments. Chronic NO₃⁻ deposition has stemmed the flow of C through the heterotrophic soil food web by inhibiting the activity of ligninolytic enzymes, but it increased the assimilation of vanillin into fungal PLFAs.     

沙棘硬枝扦插生根情况研究

[目的]提高沙棘硬枝扦插成活率,培育优质沙棘苗木.[方法]以俄罗斯大果沙棘硬枝为材料,设计不同采条部位、插穗年龄、插穗长度、下切口方式、扦插基质、药剂等处理进行沙棘硬枝扦插试验,测定和分析了不同处理的硬枝插穗生根天数、生根率、不定根长度、不定根数量4个指标.[结果]采自树冠上部的插穗生长明显劣于来自树冠中、下部插穗,3年生插穗明显优于1、2年生插穗,枝条下部不及枝条上部插穗,插穗基部斜切口优于平切口,20～ 25 cm插穗较优,用50 mg/L NAA速蘸,插穗生根率最高,达80.67％.[结论]该研究为大果沙棘人工栽培提供理论依据.     

余氏植物营养液扦插美丽异木棉生根试验初报

美丽异木棉是一种很难扦插生根的多年生高大乔木,用植物营养液进行系列处理,在全光喷雾条件下,扦插生根率达86%。     

The effect of cutting operation on higher plants diversity

Investigation of higher plant diversity in different age cutovers indicated those diversity indices of herb, xylophyta and advanced plants increased gradually in the cutovers from 1984 to 1994, and diversity indices had obviously positive correlation with richness and evenness.     

DYNAMIC THINNING SYSTEM FOR LARCH PLANTATION

Now,thereisagreatlargeareaoflarchplantationinNortheastofChina.Withtheincreasingofthestandage,competitionsamongtreeindividualschangefromexploitationcompetitiontointerferencecompetitions-Inordertofullyutilizetheresourceofsoilandclimate,effectivetechniquesshou1dbetakentoregulatetherelationshipoftreeindividuals,So,thestabilityandbioproductivityaswellaseconomicbenefitcanbeincaersed.CHARACTERSOFSTANDThestandisdahurianlarchplantati-onthatwasplantedinthespringofl958.Thesiteisabandonedfarmlandw…     

香菇生料栽培技术研究

本文报道了利用棉籽壳、木屑、麸皮为主料，不经湿热灭菌而栽培香菇的方法。提出培养料经55℃以上7天发酵，翻堆两次，装袋接种培菌。最佳培菌气温恒定于12℃以下，无光低温。试验结果，生料与熟料产量接近。