刺槐单株生物量动态研究

本文依据420株刺槐生物量及23株树干解析资料,应用灰色Verhulst模型,对太行山坡地刺槐林单株干、枝、叶、根生物量动态进行了研究,分别建立了预测模型,预测了各器官生长的速生期和停止生长林龄,为实现刺槐林的多目标经营提供决策依据。     

土壤生物量-碳和-氮与土壤有机碳、氮及施肥的关系

应用氯仿熏蒸培养法测定不同肥力水平的土壤生物量-C 和-N。结果表明:士壤生物量-C 与土壤有机碳的相关性达到极显著水准;用6mol/L HCl 水解的总氮量与土壤全氮也有很好的相关性,但与生物量-N 则不然;生物量-N 与酸解的氨基酸态氮及未知态氮都有显著相关性。施肥显著提高土壤生物量-C 和-N,有机无机肥料配合施用的大于单施化肥的。     

羊草＋杂类草群落生物量动态模式的研究

对黑龙江肇州县羊草＋杂类草群落地上生物量的季节动态、地下生物量的分布以及地上生物量与降雨量、温度之间的关系进行了分析．结果表明，在生长季内，群落地上生物量动态模式呈单峰型，符合四次多项式模型增长，最大地上生物量出现在８月５日，其值为１９７．３ｍ２而后下降；群落地下生物量分布由上至下呈负幂函数变化，其模型为：Ｂｕ＝Ｙ·（Ｄ＋１０）－ｘ．其中在０－３０ｃｍ土层中，群落地下生物量占总地下生物量的７７％～８２％．     

毛条灌木草场建立方法的研究

通过对毛条灌木林进行平茬，在人工灌溉条件下观测平茬毛条生物产量的变化，认为毛条平茬后具有很强的萌蘖能力，可产生原生枝条数4．1倍的萌生枝条；每年灌溉1次，灌水量1050m^3／hm^2，既可维持平茬毛条林的正常生长；在4株／m^2的密度条件下，平茬毛条的年产草量(干质量)可达538g／m^2，植被盖度可达78％以上，达到了经济效益和生态效益的共同提高；根据平茬毛条的生长变化规律，可初步确定冬春季节和夏季干旱时期为毛条灌木草场适宜的放牧时间。     

The effects of stubble burning and tillage on soil carbon sequestration and crop productivity in southeastern Australia

Abstract. In Australia, stubble burning and tillage are two of the major processes responsible for the decline of soil organic carbon concentration in cropped soils, and the resulting soil degradation. However, the relative importance of these two practices in influencing the soil organic carbon concentration and the long-term impact on soil quality and productivity are not clear. The effects of stubble burning as practised by farmers in southeastern Australia were evaluated in two field trials, one of 19 years duration, the other of 5 years. Conventional tillage (three tillage passes) led to greater loss of soil organic carbon than stubble burning. Loss of total soil organic carbon attributed to stubble burning in the 0–10 cm layer was estimated to be 1.75 t C ha⁻¹ over the period of the 19-year trial, equivalent to 29% of that lost due to tillage. In the 5-year trial, no change in soil organic carbon due to stubble burning was detectable. Changes in soil quality associated with stubble burning detected in the longer trial included a reduction in macro-aggregate stability, and increases in pH and exchangeable K⁺. Only the latter two were detected in the shorter trial. A higher mean wheat yield (average 0.15 t ha⁻¹) following stubble burning was observed in the 19-year trial but not in the 5-year trial. Research to monitor the longer term effects of stubble burning is needed, and to identify conditions where loss of soil organic carbon is minimized.     

松嫩平原羊草草地水淹干扰恢复过程的群落动态

根据随机取样的测定数据，经过幂函数和多元回归分析及相关检验，揭示了草地水淹干扰对羊草 寸草苔、羊草 杂类草群范数量性状的变化规律。水淹干扰对草地植被的物种组成及其比例有明显的影响。水淹后基本恢复到正常草地的种类数量和生产量配置大约需要6—7年。随着生境水分减少和土壤变干，羊草种群的数量和生物量均以幂函数形式增加，而寸草苔和杂类草的数量和生物量则呈先增后降的变化过程。     

铅对草坪植物生物量与叶绿素水平的影响

通过盆载模拟试验研究了铅对植物生物量、叶片叶缘素含量变化的影响，以及植物中毒后的症状。结果表明，铅对植物根系生长发育影响极大，可使根冠细胞有丝分裂减少、根量减少。铅进入叶肉组织后导致叶片失绿，严重时使叶片枯黄死亡。试验早期植物中毒症状表现为根冠膨大变黑，严重时根系腐烂。当营养液中Pb浓度达5.0mol／m^3时，试验后期引起植物死亡且不易恢复。     

Carbon storage by urban tree cultivars, in roots and above-ground

Urban trees can favorably affect factors underlying global warming by storing carbon and by reducing energy needs for cooling and heating buildings. To estimate carbon stored in roots and above-ground portions of trees, data was collected consisting of whole tree sampling of Amelanchier, Malus, Pyrus, and Syringa cultivars. Roots were excavated using an Air-Spade^™. Regression analysis resulted in two equations for predicting total carbon storage based on height and diameter of trees up to 20 cm dbh: Y = 0.05836 (dbh²) for root carbon storage, and Y = 0.0305 (dbh² × h)^0.9499 for above-ground carbon storage, explaining 97% and 96% of the variation, respectively. Average carbon stored in roots of various cultivars ranged from 0.3 to 1.0 kg for smaller trees, those 3.8 to 6.4 cm dbh, to more than 10.4 kg for trees 14.0 cm to 19.7 cm dbh. Average total carbon stored by cultivars ranged from 1.7 to 3.6 kg for trees less than 6.4 cm dbh to 54.5 kg for trees larger than 14.0 cm. The data from these equations apply mainly to trees in nurseries and recently transplanted trees. Comparisons showed that above-ground estimates from previous studies using a sampling technique overestimated values obtained from actual above-ground weights.     

Variation of Parthenium hysterophorus in response to soil quality: implications for invasiveness

Summary The performance of Parthenium hysterophorus , native to the tropical Americas and invasive to several countries, was evaluated for response to soil quality. Phenological (six stages) and quantitative growth variables [relative growth rates in height (R_h) and diameter (R_d)] were measured every fortnight. Based on harvest data, the variables, root:shoot (R:S) ratio, specific leaf area (SLA), relative growth rate in biomass (R_w), net assimilation rate (NAR) and dry matter allocation to plant components, were determined. High clay content in soils prolonged the rosette stage, enhanced R_h and R_d and hampered root growth, but promoted biomass allocation to shoots. The extreme degree of plant mortality was observed, with only 33.3% individuals surviving to reproduce in the soils with highest clay contents. This appears to be one of the most important findings that certainly has a major bearing on the range of adaptation of the weed. Seed mass declined whereas seed production increased in relatively coarser soils with the exception of nearly pure sand. In soils rich in clay, plants produced a smaller number of larger seeds. These data suggest that variation in fundamental functional traits would enable P. hysterophorus to adjust to a variety of habitat conditions.     

有效碳数法研究及其在农药气相色谱分析中的应用

有机化合物结构与其所含有的有效碳数有一定的关系，本文给出了２０类结构化合物及其所含有有效碳数的关系，并对理论计算值和实测值进行了比较，结果十分接近，利用有效碳数法可以设计农药分析实验方案和无标样的情况下测定农药杂质含量。