高光谱技术在烟草中的应用研究进展

随着遥感技术的快速发展,以光谱技术为核心的无损监测技术成为国内外研究的热点,并在农业领域得到了广泛应用。综述了水肥因素、品种差异、不同时期和叶位对烟叶冠层和叶片光谱的影响,以及高光谱技术在烟草叶面积指数、病虫害、产量和品质监测中的应用,以期为高光谱技术指导烟草生产提供一定的参考。     

马铃薯紫花851不同种植密度对群体结构的影响试验

以马铃薯新品种紫花851为试验材料,研究不同种植密度对其群体结构的影响。结果表明,紫花851种植密度为52500株/ha时商品薯产量最高,达29850 kg/ha;种植密度为75000株/ha时单位面积结薯数最多,达62.4个/m^2;最佳生理质量指标为：出苗后65 d叶面积指数2.40～2.55、出苗后80 d干物质积累量5373 kg/ha。因此,紫花851作商品薯生产时,最适种植密度为52500株/ha;作种薯生产时,最适种植密度为75000株/ha。     

肥料与密度对玉米农艺性状和产量的影响

此试验通过研究N、P、K、有机肥的配合施用和种植密度对玉米农艺性状和产量的影响,为玉米高效高产提供理论依据和指导。试验采用二因素裂区设计,设主区肥料因子为A共4个水平,即A1（N：150 kg/hm2、P2O5：90 kg/hm2、K2O：45 kg/hm2）;A2（N：300 kg/hm2、P2O5：180 kg/hm2、K2O：90 kg/hm2）;A3（N：450 kg/hm2、P2O5：270 kg/hm2、K2O：135 kg/hm2）;A4（N：450 kg/hm2、P2O5：270 kg/hm2、K2O：135 kg/hm2、有机肥7200kg/hm2）。设副区密度因子为B共6个水平,即B1：108000株/hm2、B2：96000株/hm2、B3：84000株/hm2、B4：72000株/hm2、B5：60000株/hm2、B6：48000株/hm2。共24个处理,3次重复。结果表明：肥料和密度对玉米农艺性状和产量有显著影响。在4个肥料处理中,A4处理在穗长、穗粗、穗粒数、百粒重、产量都是最高值。密度对穗长、穗粗、穗行数、百粒重及产量都有显著和极显著影响,基本上都是随着密度的增高穗长、穗粗、穗粒数、百粒重在降低,但产量却是逐渐增加,在密度为96000株/hm2时产量最高,随后密度进一步增加产量下降。综合考虑肥料和密度因子,A4B2组合产量最高（12513.0 kg/hm2）。     

覆盖对夏玉米产量及水分利用效率的影响

研究不同土壤水分状况下秸秆覆盖对夏玉米生长发育指标、产量和水分利用效率的影响。试验在防雨棚下的测坑中进行,设计了秸秆覆盖和土壤水分控制下限（占田间持水率的75%,65%和55%）两个因素,分析夏玉米生长指标、产量及水分利用效率的变化规律。结果表明,秸秆覆盖对夏玉米生长发育有促进作用,在不同的水分状况下,覆盖处理的夏玉米叶面积指数、产量和水分利用效率均优于不覆盖处理。中水分条件覆盖处理下的夏玉米产量较对照条件下的高水分夏玉米产量无显著降低,而且其水分利用效率最高。建议在夏玉米覆盖生产方式中采用中水分灌溉方式,可以达到节水高产的目的。     

基于环境产量模型和生物产量模型的禹城市夏玉米遥感估产研究

指出了夏玉米是我国重要的粮食作物之一,及时高效地获取夏玉米产量对于我国政府制定农业决策、优化粮食产业结构发展具有重要参考价值。以山东省禹城市为研究区,探讨了基于卫星遥感数据的夏玉米估产技术方法。通过采用高分一号遥感卫星影像和MODIS NDVI产品,经大气校正、几何校正、相对辐射校正、掩膜等预处理,基于环境产量模型和生物量模型的两种估产方法,结合所获取的各项影响因子参数,对禹城市2016年夏玉米产量进行了估算,同时对估产结果进行了精度验证与评价。结果显示:基于环境产量模型的遥感估产平均值为10060 kg/hm^2,估产精度为95.60%;基于生物量模型的遥感估产平均值为9270 kg/hm^2,估产精度为96.20%。以上两种估产模型的估产精度均达到了95%以上,符合估产的精度要求。     

基于生态效益下城镇(郊)陡坡及人工立面不同坡度景观林评价——以干旱半干旱区为例

通过对不同坡度景观林的叶面积指数及净光合速率和蒸腾速率等生理指标的测定,换算得到不同坡度景观林固碳释氧、吸热释水等生态效益指标。结果表明,若注重绿化覆盖度及三维绿量,则以叶面积指数为主导,在台地及0°～20°坡地选择侧柏(LAI∶0.648)为骨干树种;在20°～40°坡地选择山桃(LAI∶0.488)为骨干树种;在40°以上坡面,选择胶东卫矛(LAI∶0.743)和火棘(LAI∶0.589)为骨干树种。若注重生态效益,则以固碳释氧量为主导,在台地及0°～20°坡地选择侧柏(17.587、12.791g·m^-2·d^-1)为骨干树种;在20°～40°坡地选择山桃(18.662、13.572g·m^-2·d^-1)为骨干树种;在40°以上坡面,选择火棘(14.218、10.340g·m^-2·d^-1)为骨干树种。若注重城市或城镇热岛效应,则以吸热释氧量为主导,在台地及0°～20°坡地选择酸枣(1 149.524kJ·m^-2·d^-1,1 990.498g·m^-2·d^-1)为骨干树种;在20°～40°坡地选择山桃(929.407kJ·m^-2·d^-1,1 609.346g·m^-2·d^-1)为骨干树种;在40°以上坡面,选择火棘(1481.387kJ·m^-2·d^-1,2 565.145g·m^-2·d^-1)为骨干树种。针对不同生态需求选择不同景观林是完成干旱半干旱城镇(郊)陡坡及人工立面景观林配置的关键。     

基于无人机多光谱遥感的冬小麦叶面积指数反演

以获取的冬小麦无人机多光谱影像为数据源,充分利用多光谱传感器的红边通道对传统植被指数进行改进,通过灰色关联度分析后基于多个植被指数建模的方法对冬小麦的叶面积指数(leaf area index,LAI)进行反演精度对比。结果显示:使用基于多植被指数的随机森林(RF)比赤池信息量准则-偏最小二乘法(AIC-PLS)反演精度高。得到的LAI反演值和真实值之间的R~2=0.822,RMSE=1.218。研究证明通过随机森林预测具有更好的拟合效果,对冬小麦的LAI反演有较好的适用性。     

融合无人机多光谱和纹理特征的马铃薯LAI估算

目的 研究融合无人机遥感影像多光谱信息和纹理特征估算马铃薯Solanum tuberosum叶面积指数(Leaf area index,LAI)方法,提高马铃薯LAI反演精度。方法 利用大疆P4M无人机采集2021年2－4月南方冬种马铃薯幼苗期、现蕾期、块茎膨大期多光谱影像,用LAI-2000冠层分析仪实测LAI数据。提取影像光谱、纹理等信息,分析植被指数、纹理特征与LAI的相关性,基于R²_adj的全子集分析优选特征变量。采用主成分分析,融合光谱和纹理特征,用PCA-MLR(Principal component analysis-multiple linear regression)模型估算马铃薯LAI。结果 从幼苗期到块茎膨大期,PCA-MLR估算模型优于T-MLR(Texture multiple linear regression)和VI-MLR(Vegetation index multiple linear regression)模型,R²分别为0.73、0.59和0.66。结论 本研究提出一种估算马铃薯LAI的PCA-MLR方法,为马铃薯的长势监测和田间管理提供数据支持。     

The high yield of irrigated rice in Yunnan,China: ‘A cross-location analysis’

A number of field trials on rice productivity have demonstrated very high yield, but reported limited information on environmental factors. The objective of this study was to reveal the environmental factors associated with high rice productivity in the subtropical environment of Yunnan, China. We conducted cross-locational field experiments using widely different rice varieties in Yunnan and in temperate environments of Kyoto, Japan in 2002 and 2003. The average daily radiation throughout the growing season was greater at Yunnan (17.1 MJ m⁻² day⁻¹ average over 2 years) relative to Kyoto (13.2 MJ m⁻² day⁻¹). The average daily temperature throughout the growing season was 24.7 °C at Yunnan, and 23.8 °C at Kyoto. The highest yield (16.5 tonnes ha⁻¹) was achieved by the F1 variety Liangyoupeijiu at Yunnan in 2003, and average yield of all varieties was 33% and 39% higher at Yunnan relative to Kyoto in 2002 and 2003, respectively. There was a close correlation between grain yield and aboveground biomass at maturity, while there was little variation in the harvest index among environments. Large biomass accumulation was mainly caused by intense incident radiation at Yunnan, as there was little difference in crop radiation use efficiency (RUE) between locations. Large leaf area index (LAI) was also suggested to be an important factor. Average nitrogen (N) accumulation over 2 years was 49% higher at Yunnan than at Kyoto, and also contributed to the large biomass accumulation at Yunnan. The treatments of varied N application for Takanari revealed that the ratio of N accumulated at maturity to the amount of fertilized N was significantly higher at Yunnan than at Kyoto, even though there was no great difference in soil fertility. The Takanari plot with high N application showed a N saturation in plant growth at Kyoto, which might be related to low radiation and relatively high temperatures during the mid-growth stage. These results indicate that the high potential yield of irrigated rice in Yunnan is achieved mainly by intense incident solar radiation, which caused the large biomass and the N accumulation. The low nighttime temperature during the mid-growth stage was also suggested to be an important factor for large biomass accumulation and high grain yield at Yunnan.     

Light interception and utilization in relay intercrops of wheat and cotton

In China, a large acreage of cultivated land is devoted to relay intercropping of winter wheat and cotton. Wheat is sown in strips with interspersed bare soil in October and harvested in June of the next year, while cotton is sown in the interspersed paths in the wheat crop in April and harvested before the next wheat sowing in October. This paper addresses the question how strip width and number of plant rows per strip of wheat or cotton affect light interception (LI) and light use efficiency (LUE) of both component crops.