精养鱼池施用新型磷肥——“鱼特灵”

本文通过在精养鱼池中施用新型磷肥“鱼特灵”,使池水有效磷由10微克/升以下提高到30微克/升以上,有效氮明显下降,有效N/P保持在35～50:1,浮游植物数量显著增加。试验地浮游植物数量(Y)与总铵(NH_4-N+NH_3-N)(X_1)、NO_3-N(X_2)、PO_4-P(X_4)呈如下关系式:Y=55.94-0.67X_1-11.61X_2-47.95X_4(r=0.73,n=28,P<0.05)达到了增施磷肥,促进氮肥利用和浮游植物增殖,改善水质,提高池塘初级生产力的目的。施用“鱼特灵”后,池塘平均净产增长11.6%,其中鲢、鳙净产增长13.7%。     

烟草叶面积不同测定方法的比较研究

研究了烟草叶面积的6种测定方法，并对其测定结果进行了对比分析。结果表明：叶面积指数法与准确的测定方法间测定结果差异不显著，叶面积指数法可以用于烟草叶面积的实际测定和计算。     

春小麦产量和蛋白质关系研究──干物质积累分配与氮素同化运转

利用产量不同、蛋白质含量不同和加工品质各异的３个春小麦品种，研究了灌浆过程中干物质积累分配和氮素同化运转与产量和蛋白质含量的关系．结果表明，干物质的积累量，品种间存在明显差异，高产低蛋白品种和干物质产量高于低产高蛋白类型，高产高蛋白类型积累量最高；营养体的氮素积累变化动态．因向籽粒中转运量的不同而异．各营养体对籽粒氮的贡献顺序为茎（含叶鞘）＞叶片＞穗轴和颖片；品种间开花前后的氮素同化量不同，高蛋白品种倾向于花前同化量多，高产品种花后同化量比例相对增加，高产高蛋白类型两者兼之，品种间花后氮素同化量占总同化量的变幅为１５．３５％～４８．３５％；生育期干物质产量高是高产高蛋白品种的重要物质基础，氮素总同化量与蛋白质含量关系不大，氮素转运效率与蛋白质含量密切相关．ＮＨＩ：ＧＨＩ比例决定着蛋白质含量．     

Can Landform Stratification Improve Our Understanding of Crop Yield Variability?

Farmers account for yield and soil variability to optimize their production under mainly economic considerations using the technology of precision farming. Therefore, understanding of the spatial variation of crop yield and crop yield development within arable fields is important for spatially variable management. Our aim was to classify landform units based on a digital elevation model, and to identify their impact on biomass development. Yield components were measured by harvesting spring barley (Hordeum vulgare, L.) in 1999, and winter rye (Secale cereale, L.) in 2000 and 2001, respectively, at 192 sampling points in a field in Saxony, Germany. The field was stratified into four landform units, i.e., shoulder, backslope, footslope and level. At each landform unit, a characteristic yield development could be observed. Spring barley grain yields were highest at the level positions with 6.7 t ha⁻¹ and approximately 0.15 t ha⁻¹ below that at shoulder and footslope positions in 1999. In 2000, winter rye harvest exhibited a reduction at backslope positions of around 0.2 t ha⁻¹ as compared to the highest yield obtained again at level positions with 11.1 t ha⁻¹. The distribution of winter rye grain yield across the different landforms was completely different in 2001 from that observed in 2000. Winter rye showed the highest yields at shoulder positions with 11.1 t ha⁻¹, followed by the level position with 0.5 t ha⁻¹ less grain yield. Different developments throughout the years were assumed to be due to soil water and meteorological conditions, as well as management history. Generally, crop yield differences of up to 0.7 t ha⁻¹ were found between landform elements with appropriate consideration of the respective seasonal weather conditions. Landform analysis proved to be helpful in explaining variation in grain yield within the field between different years.     

Management Zones Classified With Respect to Drought and Waterlogging

Within-field variations in potential grain yield may be due to variations in plant available soil water. Different water holding capacities affect yield differently in different years depending on weather. By estimating plant-water availability in different weathers, scenarios could be created of how yield potential and thereby fertilizer demand may vary within fields. To test this, measured cereal grain yields from a dry, a wet and an intermediate year were compared with different soil moisture related variables in a Swedish arable field consisting of clayey and sandy areas. Soil water budget calculations based on weather data and maximum plant available water (PAW), estimated from soil type and rooting data, were used to assess drought. A reasonable correlation between estimated and measured soil moisture was achieved. In the dry year, drought days explained differences in yield between the clayey and the sandy soil, but yield was better explained directly by maximum PAW, elevation, clay content and soil electrical conductivity (SEC). Yield correlated significantly with SEC and elevation within the sandy soil in the dry year and within the clayey soil in the wet year, probably due to water and nitrogen limitation respectively. Dense SEC, elevation and yield data were therefore used to divide the field into management zones representing different risk levels for drought and waterlogging. These could be used as a decision support tool for site-specific N fertilization, since both drought and waterlogging affect N fertilization demand.     

玉米粗缩病发病叶龄与主要为害性状的相关性分析

对玉米粗缩病进行了系统的田间调查,分析了发病叶龄与玉米粗缩病主要为害性状的关系。结果表明：玉米在其生育期内均可感病,发病越早,病情越重,9叶期后发病症状显著减轻。发病叶龄与玉米粗缩病的严重度（r=-0．938,P〈0．01）、株高（r=0．884,P〈0．01）、穗粒重（r=-0．823,P〈0．01）密切相关。     

不同施磷量对油菜新品种产量的影响

通过田间试验,研究磷肥与油菜产量、品质和植株形态之间的关系,确定油菜高产、优质、高效的磷肥施用量。不同油菜品种磷肥用量试验的结果表明:①每公顷施纯磷360kg的处理,中双9号,每公顷产量达3301.65kg,中油杂2号,产量达到最大值,每公顷产量3781.95kg。②一次分枝对产量影响最大,二次分枝、主花序的贡献相对要小得多。③随着施磷量的增加单位面积有效角果数呈增长的趋势。     

烟叶烘烤自控专家系统的研究与应用

根据烟叶三段式烘烤工艺条件要求,采用数字温度传感器,单片微型计算机程序控制,研制了烟叶烘烤自控专家系统.应用结果表明,自控烤房与普通烤房相比较,烤房内通风速度增加1.6~2.4 m.s-1;叶间隙风速增加0.33~0.04 m.s-1;烤房内温度均匀一致;垂直温差和水平温差小;可准确落实三段式烘烤工艺,能显著提高烟叶烘烤质量.     

不同保果处理对贡柑坐果及叶片营养的影响研究

针对广东贡柑自然着果率低及滥用生长调节剂保果等问题进行谢花后不同保果处理研究的结果显示,喷施GA31次 保果素1次的座果率显著高于连续喷施GA32次;喷施保果药剂 环割处理的座果率显著高于未环割处理,其中以喷施GA31次 保果素1次 环割处理的座果率和产量最高。同时指出,各种保果措施均能提高贡柑春梢叶片的氮、钾营养含量,但对贡柑的果实品质没有影响。     

水分胁迫对冬小麦水分生理特性和产量构成三因素的影响

采用盆栽试验研究了水分胁迫对冬小麦水分生理特性和产量的影响。结果表明,光合速率、蒸腾速率、耗水量、耗水系数、地上部生物量、根系生物量、总生物量、穗数、千粒重和穗粒数均随土壤水分的减少而呈降低趋势;水分利用效率则呈增加趋势。通过统计回归,获得了冬小麦主要水分生理指标与土壤水分关系的数学拟合模型。