中国农业硫信息系统探讨

在中文WINDOWS98平台上 ,以MAPGIS为基础操作平台 ,利用VisualBasic编程语言和MAPGIS提供的控件和API函数结合Access数据库软件开发了中国农业硫信息系统。根据已有数据材料和生产实践需要 ,系统开发了五个应用模块 ,分为土壤硫状况、作物硫营养、硫肥效应、土壤硫平衡、更新与设置。该系统能为农业技术推广、化肥生产销售部门以及农业科研部门提供一个土壤硫、植物硫营养和硫肥有效使用等信息管理工具     

国外水果制干过程中的熏硫护色工艺

熏硫护色方法简单、实用、有效,许多国家在水果制干生产中仍然普遍采用,介绍了国外水果制干的熏硫护色工艺、熏硫时间、方法及用量,并对熏硫过程中,影响二氧化硫效用的因素进行了叙述.为中国生产干果的企业提供参考.     

闽东南耕地土壤硫素平衡及有效硫丰缺状况研究

通过田间试验、土样和雨水、灌溉水采集测定,以及大气硫沉降和土壤硫淋溶流失有关数据收集,研究了闽东南耕地土壤硫素平衡与土壤有效硫丰缺状况。结果表明,早稻-晚稻轮作制和花生-甘薯轮作制每年分别需要91.86,128.67 kg/hm2硫素来满足生长需求,考虑到土壤硫的淋溶和流失以及扣除施肥带入的硫素、大气沉降和灌溉水硫的给源外,早稻-晚稻轮作制需补充22.35 kgS/hm2硫素,花生-甘薯轮作制需补充64.89 kg/hm2硫素,才能维持土壤硫素输入与输出的平衡。178个土壤样品有效硫含量测定结果表明,当前闽东南耕地土壤有效硫平均为26.2mg/kg,其中水田为22.35 mg/kg,旱地则为28.31 mg/kg,低于有效硫临界指标的土样数占总数的69.0%,有效硫含量属于中等级别的只占16.3%,说明硫已成为闽东南耕作土壤的养分限制因子之一。     

Nitrogen:sulphur ratio alters competition between Trifolium repens and Lolium perenne under cutting: Production and competitive abilities

Grasslands species, like others crops, no longer benefit from high atmospheric sulphur deposition. This may cause sulphur limitation and in turn may induce a shift in plant communities by altering species performance and competitive abilities. To test this hypothesis, a greenhouse pot experiment was designed to investigate the interacting effects of sulphur (S) and nitrogen (N) availability on production, morphology and competitive abilities of white clover (Trifolium repens L.) and perennial ryegrass (Lolium perenne L.). Plants were grown in monocultures and mixtures during 4 months. They were supplied with combinations of three levels of S and three levels of N and subjected to three defoliation events. Both S and N gradients altered plants performance and modulated competitive interactions. In L. perenne, above- and below-ground dry matter production, leaf and tiller number and contribution to mixture DM production were little affected by S, but highly by N. For T. repens, these traits were significantly increased by S, but only slightly by N. At establishment, T. repens was subjected to a significant interspecific competition at low N–low S and high N–high S. But at regrowth (cuts 2 and 3), T. repens was much more affected by intra- than interspecific competition. L. perenne was only sensitive to competition (intraspecific) when N supply was combined with no or moderate S supply. We conclude that N:S ratio of soil appears to drive species production, morphology and competitive abilities, which in turn affect leguminous–gramineous species ratio and grassland plant community structure. Since the growth of T. repens was significantly reduced in low S treatments, our results suggest that the drastic fall in atmospheric sulphur deposition could restrict leguminous species in high N soil conditions.     

Critical sulphur concentration and sulphur requirement of microbial biomass in a glucose and cellulose-amended regosol

 The critical S concentration and S requirement of the soil microbial biomass of a granitic regosol was examined. S was applied at the rate of 0, 5, 10, 20, 30 and 50 μg S as MgSO₄·7H₂O, together with either 3000 μg glucose-C or 3333 μg cellulose-C, 400 μg N, and 200 μg P g ^–1 soil and 200 μg K g^–1 soil. Microbial biomass, inorganic SO₄ ^2–-S, and CO₂ emission were monitored over 30 days during incubation at 25  °C. Both glucose and cellulose decomposition rates responded positively to the S made available for microbial cell synthesis. The amounts of microbial biomass C and S increased with the level of applied S up to 10 μg S g^–1 soil and 30 μg S g^–1 soil in the glucose- and cellulose-amended soil, respectively, and then declined. Incorporated S was found to be concentrated within the microbial biomass or partially transformed into soil organic matter. The concentration of S in the microbial biomass was higher in the cellulose- (4.8–14.2 mg g^–1) than in the glucose-amended soil (3.7–10.9 mg g^–1). The microbial biomass C:S ratio was higher in the glucose- (46–142 : 1) than in the cellulose-amended soil (36–115 : 1). The critical S concentration in the microbial biomass (defined as that required to achieve 80% of the maximum synthesis of microbial biomass C) was estimated to be 5.1 mg g^–1 in the glucose- and 10.9 mg g^–1 in the cellulose-amended soil. The minimum requirement of SO₄ ^2–-S for microbial biomass formation was estimated to be 11 μg S g^–1 soil and 21 μg S g^–1 soil for glucose- and cellulose-amended soil, respectively. The highest levels of activity of the microbial biomass were observed at the SO₄ ^2–-S concentrations of 14 μg S g^–1 soil and 17 μg S g^–1 soil, for the glucose and cellulose amendments, respectively, and were approximately 31–54% higher during glucose than cellulose decomposition. Received: 20 October 1999     

SO2对龙眼果实的氧化作用与衰老的影响

以‘石硖’龙眼（Ｄｉｍ ｏｃａｒｐｕｓｌｏｎｇａｎ Ｌｏｕｒ．ｃｖ．Ｓｈｉｘｉａ）为试材,研究了冷藏（４ ℃）条件下,适当的ＳＯ２ 熏蒸预处理对果实氧化作用与衰老的影响。结果表明：硫处理果实,呼吸速率比对照显著降低（Ｐ＜ ０．０１）,使果实受到不可逆抑制;果皮膜透性和丙二醛（ＭＤＡ）含量比对照明显增加（Ｐ＜ ０．０１）,超氧物歧化酶（ＳＯＤ）活性成倍提高,并出现新的ＳＯＤ同工酶带。贮藏效果表明：合理的ＳＯ２ 处理能够延缓果实的衰老进程,延长贮藏寿命     

硫和白云石对皖中黄褐土铅形态分布的影响

通过室内土壤培养试验,应用连续浸提分组方法,研究了S与白云石用量对黄褐土中重金属Pb形态分布的影响.结果表明,高S处理条件下,土壤pH下降,可交换态Pb有升高的趋势:白云石处理条件下,土壤pH升高,显著促进了可交换态Pb向碳酸盐结合态和铁锰氧化态转化,这种形态分布与白云石用量无明显关联,S的添加不足以改变白云石粉对黄褐土中Pb形态的影响.     

硫对春小麦籽粒直链淀粉积累的效应

以3个不同品质类型春小麦为材料,在不同氮水平下,研究施硫对籽粒直链淀粉积累的效应。结果表明:籽粒直链淀粉开始积累比较晚,开花后5~10 d,直链淀粉才开始积累,但最终积累量不高。相同氮素水平不同施硫量处理,直链淀粉动态积累趋势相似,各品种开花后直链淀粉动态积累总体上都呈增加的趋势。硫对籽粒直链淀粉的最终积累量影响是以一定氮素水平为基础的,在高氮(N128)水平下,增施硫肥可降低小麦籽粒直链淀粉含量,对改善小麦品质有一定的积极作用。     

Effect of Sulphur and Foliar-applied Chemicals on Cold Tolerance in Chickpea (Cicer arietinum L.)

In a field study it was observed that sulphur fertilization of chickpea at 100 kg S ha⁻¹ imparted cold tolerance under low temperature stress conditions. Further, foliar sprays of DMSO, H₂SO⁴, KCl and H³BO³ proved effective in alleviating cold injury. Glucose spray also showed efficacy in this regard. The effects of sulphur fertilization and foliar applied DMSO and H²SO⁴ were largely associated with improved sulphur nutrition of plants, while improvement in K content under KCl treatment and B content under H₃BO₃ treatment was responsible for cold tolerance effects. Improvement in overall soluble carbohydrate and protein status of plants was held responsible for glucose effects possibly associated with osmoregulation.     

Partitioning of Biomass, N and S in Sunflower (Helianthus Annuus L.) by Nitrogen and Sulphur Nutrition

Response of sunflower ( Helianthus annuus L.) to sulphur applied ca. 0, 30, 90 and 150 mg kg^-1 and nitrogen applied ca. 0, 100 and 200 mg kg^-1 soil were studied on a Typic Camborthids in greenhouse. Nitrogen and S application had a significant (P < 0.01) main and interactive effect on seed yield and dry weight of leaves and stem. Cumulative N and S contents of sunflower seeds, stem and leaves were significantly (P < 0.01) affected by N and S application. Sulphur transport and accumulation in sunflower seeds was increased with S application. There were significant (P < 0.01) correlations between seed yield and N and S content of sunflower plants. Critical S concentration (%) in 60 days old plants was 0.36 for 95 % relative yield of the maximum. Application of 90 mg S kg^-1 with 200 mg N kg^-1 resulted in the highest seed yield and maximum total S and N contents in sunflower leaves, stem and seeds. Relative increase in sunflower seeds yield at higher levels of N and S was more than that of dry weight of stem and leaves.