采后蔬菜保鲜技术研究进展

蔬菜是人们日常饮食中必不可少的食物之一,但是其组织结构和生理特性使其容易发生腐败变质,因此采后蔬菜的保鲜效果对后期的贮藏加工十分重要.结合国内外研究进展,从物理保鲜技术、化学保鲜技术、生物保鲜技术3个方面对采后蔬菜的保鲜方法进行综述,同时指出目前国内蔬菜保鲜中存在的一些问题,并对未来采后蔬菜的保鲜技术进行展望.     

Organic matter fractions within macroaggregates in response to long-term fertilization in calcareous soil after reclamation

Soil organic carbon(SOC) plays a key role in improving soil quality and optimizing crop yield. Yet little is known about the fate of macroaggregates(0.25 mm) under long-term fertilization and their relative importance in SOC sequestration in reclaimed calcareous soil. Therefore, the effects of mineral fertilizers and organic manure on the mechanisms of organic carbon(OC) stabilization in macroaggregates were investigated in this study. Four treatments were used: unfertilized control(CK), mineral fertilizer(NPK), compost chicken manure alone(M), and mineral fertilizers plus manure(MNPK). Samples from the 0–20 cm layer of soil receiving 11-year-long fertilization were separated into four fractions based on the macroaggregates present(unprotected coarse and fine particulate organic matter, cPOM and fPOM; physically protected intra-microaggregate POM, i POM; and biochemically protected mineral associated OM, MOM) by the physical fractionation method. Compared with the control, the long-term application of NPK had little effect on SOC content, total nitrogen(TN) content, and OC and TN contents of macroaggregate fractions. In contrast, incorporation of organic manure(MNPK) significantly increased SOC(45.7%) and TN(24.3%) contents. Application of MNPK increased OC contents within macroaggregate-extracted fractions of cPOM(292.2%), fPOM(136.0%) and iPOM(124.0%), and TN contents within cPOM(607.1%), fPOM(242.5%) and iPOM(127.6%), but not the mineral associated organic carbon(MOM-C) and nitrogen(MOM-N) contents. Unprotected C fractions were more strongly and positively correlated with SOC increase than protected C fractions, especially for cPOM-C, indicating that SOC sequestration mainly occurred via cPOM-C in the studied calcareous soil. In conclusion, MNPK increased the quantity and stability of SOC by increasing the contents of cPOM-C and cPOM-N, suggesting that this management practice(MNPK) is an effective strategy to develop sustainable agriculture.     

无土栽培基质理化性状测定方法及其应用研究

[目的]准确测定基质理化性状是进行基质配方研究的基础,根据不同基质材料理化性质及栽培作物生物学特性研究无土栽培基质配比.[方法]选取新疆可用于进行无土基质栽培研发的有机材料、无机材料及各种生产上普遍应用的基质等材料,在不同条件下测定其各项指标.[结果]得出了基质各理化指标的便捷、精确测定方法.[结论]该方法的应用将提高无土栽培基质筛选的进程,能对作物生长基质环境的水分状况、通气性、肥力等进行实时诊断,为实现无土基质栽培精确灌溉和精量施肥提供技术支撑.     

毛竹原状和粉状叶片分解特征对施氮和温度的响应

[目的]毛竹(Phyllostachys edulis)叶片分解与竹林碳循环和养分周转关系密切,通过室内模拟氮沉降和温度升高试验,为预测未来气候变暖和氮沉降条件对凋落竹叶分解的调控提供参考,为科学管理毛竹林提供科学依据。[方法]以毛竹原状叶片及粉状叶片(粉碎过2 mm)为研究对象,布设3因素2水平试验,即施氮(添加氮5 mg·g-1)和不加氮对照,12℃和28℃培养温度,原状和粉状叶片,恒温箱中培养78 d,采用密闭碱液吸收法定期测定CO2释放量,并计算分解速率。[结果]表明:施氮处理、培养温度和叶片形态及其交互作用对凋落竹叶分解速率的影响因培养阶段不同而存在差异,总体上表现为培养前期(0—23 d)和培养中期(24—48 d)的分解速率高于培养后期(49—78 d)。从均值来看,施氮处理抑制原状叶片在12℃培养下的分解速率,而对两种形态叶片在28℃培养条件的分解速率影响不显著;施氮处理可增加原状凋落竹叶分解速率的温度敏感性(Q10),但对粉状凋落竹叶分解速率的Q10值影响不显著,且原状凋落竹叶分解速率的Q10值高于粉状凋落叶。凋落竹叶C/N在培养后期显著升高,且氮添加显著促进粉状竹叶C/N增加。[结论]氮沉降对毛竹凋落叶分解的影响效应与培养温度和叶片形态有关。凋落物分解的影响因素众多,凋落物分解对全球环境变化的响应不仅应该深入研究其化学和生物学机制,还要关注物理过程及其调控潜能。     

冻融对河北省深州市盐碱地土壤理化性质的影响

随着全球气候变暖,冻融对土壤性质的影响日益受到重视。以河北省深州市盐碱土为研究对象,通过分析土壤含水率、全持水量、容重、饱和导水率、电导率、pH和有机质的变化,探讨冻融对0—20cm深度盐碱地土壤理化性质的影响。结果表明:0—20cm土层深度,冻融增加土壤的含水率,而对全持水量的影响较小;0—10cm土层深度,冻融增加了土壤容重与pH,降低了土壤的电导率和渗透性,该层土壤水盐运移呈特殊规律,土壤含水率与电导率呈相反变化趋势;对于10—20cm土层深度,冻融增加了土壤的渗透性和有机质的含量。在相关性分析中,0—20cm土层深度土壤容重与全持水量呈极显著负相关(P0.01),与含水率呈显著负相关(P0.05),其有机质含量和导水率与其他性质无显著相关;0—10cm土层深度土壤pH与容重和含水率呈极显著相关,与全持水量呈显著相关;10—20cm土层深度土壤电导率与容重呈显著负相关,与全持水量呈显著正相关。研究结果为冻融对盐碱土影响的研究及盐碱土的改良提供科学依据。     

Effect of soil physical properties on soybean nodulation and N2 fixation at the early growth stage in heavy soil field in Hachirougata Polder,Japan

We studied the effect of the soil physical properties on soybean nodulation and N₂ fixation in the heavy soil of an upland field (UF) and an upland field converted from a paddy field (UCPF) in the Hachirougata polder, Japan. Seeds of the soybean cultivar Ryuho were sown in each field with or without inoculation of Bradyrhizobium japonicum A1017. The soybean plants were sampled at 35 (V3) and 65 (Rl) d after sowing (DAS), and then nodulation and the percentage of N derived from N₂ fixation in the xylem sap were determined. The soil physical properties were different between UF and UCPF, especially the air permeability and soil water regime. Nodule growth was restricted in UCPF irrespective of rhizobial inoculation, though rhizobial infection was not inhibited by the unfavorable soil physical conditions. Soybean plant growth was closely related to the nodule mass and N₂ fixation activity, and the inoculation of a superior rhizobium strain was effective only at 35 DAS. These results indicate that soybean nodulation and N₂ fixation was considerably affected by the physical properties of heavy soil, and that it is important to maintain the N₂ fixation activity and inoculate the soybean plants with a superior rhizobium strain at a later growth stage in order to increase soybean production in heavy soil fields.     

间伐对杉木人工林土壤理化性质的季节影响

以南京市溧水林场实施了4种间伐强度（CK:0%、LIT:30%、MIT:50%、HIT:70%）的25 a生杉木人工林为研究对象,探讨了间伐7 a后0—20 cm土层的土壤温度、含水率、土壤全C、全N、全P,C/N和N/P的季节变化。结果表明,间伐对土壤理化性质的影响存在明显的季节差异性。春季,间伐对土壤温度、含水率和全C均无显著影响,MIT显著降低了土壤全N和全P的22%和26%,HIT显著降低了土壤全N的11%。夏季,间伐对土壤温度、全N、全P和N/P无显著影响,但3种间伐强度均显著提高了土壤含水率,平均为22%,MIT和HIT均显著降低了土壤全C和C/N。秋季,间伐对土壤理化性质的各个指标均有不同程度的显著影响。其中,3种间伐强度均显著提高了土壤温度、含水率、N/P,但显著降低了全P。冬季,间伐对土壤理化性质影响较小,除MIT显著降低了土壤温度而提高了土壤C/N及HIT显著提高了土壤全P外,间伐对其余指标均无显著影响。这些结果表明,在评价间伐对土壤理化性质影响时应考虑季节差异。间伐7 a后林内土壤全N和全P在一定程度上有所降低,尤其是土壤全P,建议在春季对LIT施适量的氮肥,对MIT施适量的氮肥和磷肥,在秋季对3种间伐处理施适量的磷肥,以提高土壤肥力促进林木生长。从土壤N和P年平均值来看,HIT最有利于保持林地的氮磷养分,LIT次之,MIT最差。     

10种杀菌剂对马铃薯晚疫病的防治效果与经济效益评价

选择72%霜脲·锰锌(克露)可湿性粉剂(WP)、50%烯酰吗啉(安克)WP、25%嘧菌酯(阿米西达)悬浮剂(SC)、64%恶霜·锰锌(杀毒矾)WP、68%精甲霜灵·锰锌(金雷)水分散粒剂(WG)、70%丙森锌(安泰生)WP、68.75%氟吡菌胺·霜霉威(银法利)SC、18.7%烯酰·吡唑酯(凯特)WG、25%双炔酰菌胺(瑞凡)SC和50%多菌灵WP等10种药剂进行了田间马铃薯晚疫病防治试验。结果表明:除50%多菌灵WP之外,其他9种药剂对马铃薯晚疫病均具有明显的防治效果和增产效果,防效均达90%以上,增产10.90%～20.30%,净收入增加500～1000元·(667m2)-1。根据药剂的防效和增产效果,提出广东省马铃薯晚疫病防治的参考药剂,首先是72%霜脲·锰锌WP和50%烯酰吗啉WP,其次是68%精甲霜灵·锰锌WG、18.7%烯酰·吡唑酯WG、25%嘧菌酯SC、70%丙森锌WP和64%恶霜·锰锌WP。     

无公害防治技术在林业病虫害防治中的应用研究

病虫害的发生对于林业生产会造成较大影响,加强林业病虫害的防治,运用无公害防治技术,体现了先进的病虫害防治思想,具有较高的应用和推广价值,有利于减少病虫害对苗木的侵袭,确保苗木的健康茁壮生长,创造更为可观的经济效益和生态效益,人与自然和谐共生的理念也能由此得以实现。本文将探讨无公害防治技术的应用意义及林业病虫害发生的主要原因,并阐述无公害防治技术在林业病虫害防治中的有效应用策略,旨在充分发挥出无公害防治林业病虫害的价值,维持林业生态平衡,从而推动我国林业的可持续健康发展。     

牧民定居的生态、经济和社会效益分析——以新疆昌吉市阿什里哈萨克乡为例

牧民定居工程的实施对改善牧区生态环境,加快区域经济发展、改善牧民生活发挥了一定的作用.本研究以新疆昌吉市阿什里哈萨克乡为例,运用可持续发展理论,通过理论与实证相结合的方法,对牧民定居工程的生态、经济和社会效益进行分析,阐述了牧民定居工程实施过程中存在的问题及其解决对策.