Soil acidity and alkalinity (pH) has a significant impact on plant growth and development. From the process, it is mainly reflected in the impact of climate and elements in soil on plant growth, while climate mainly a...Soil acidity and alkalinity (pH) has a significant impact on plant growth and development. From the process, it is mainly reflected in the impact of climate and elements in soil on plant growth, while climate mainly affects carbon, hydrogen and oxygen, which account for 96% in the atmosphere. The more important elements in the soil are nitrogen, phosphorus and potassium, and the secondary elements are calcium, magnesium, sulfur and so on. This paper selects the conventional economic plant planting land as the development of the experiment, obtains the main components in the soil, and carries out the intervention experiment of different concentrations of soil pH value. The pH value in the soil is divided into four levels: pH 1 (<5.5), pH 2 (5.5 - 6.5), pH 3 (6.5 - 7.5), pH 4 (7.5 - 8.4) as the independent variable, and takes the elements in the soil as the dependent variable for linear regression analysis. The results show that pH 1 (<5.5), pH 2 (5.5 - 6.5), pH 3 (6.5 - 7.5), pH 4 (7.5 - 8.4) can explain the change of elements in soil. The results show that pH 1 (<5.5), pH 2 (5.5 - 6.5), pH 3 (6.5 - 7.5), pH 4 (7.5 - 8.4) can explain the change of elements in soil. Among them, pH 1 (<5.5) and pH 4 (7.5 - 8.4) are the most unstable, while pH 2 (5.5 - 6.5) and pH 3 (6.5 - 7.5) have little impact on plant growth and are relatively stable. Therefore, the acidity and alkalinity of soil has a certain impact on the elements in soil, but it is not a decisive impact. It can be proved that the influence relationship between independent variables and dependent variables.展开更多
在盆栽试验条件下，研究在3个遮阴水平和5个施氮水平处理组合下，水稻分蘖期、孕穗期和抽穗期冠层叶片叶绿素计测定值（soil and plant analyzer development value，SPAD value）的空间分布规律及其差异，为弱光条件下实时进行水稻叶...在盆栽试验条件下，研究在3个遮阴水平和5个施氮水平处理组合下，水稻分蘖期、孕穗期和抽穗期冠层叶片叶绿素计测定值（soil and plant analyzer development value，SPAD value）的空间分布规律及其差异，为弱光条件下实时进行水稻叶片氮素营养诊断及优化提供依据.结果表明，同对照相比，在遮阴条件下水稻冠层 SPAD值波动幅度受到明显抑制.遮光使水稻冠层叶片 SPAD值下降，并抑制施氮水平对水稻叶片向上位叶输送氮素的正向作用.经变异系数分析发现，L4叶对施氮水平变化反应最为敏感.另外，在中度和重度遮阴条件（遮光率分别为65%和85%）下可利用叶片相对叶色差值（relative SPAD value，RSPAD）进行氮素营养状态的诊断.相对叶色差值SPADL3-L2，SPADL4-L3与施氮水平呈显著线性正相关关系（R2L3-L2=0.87~0.97，R2L4-L3=0.85~0.97），这一关系不受生育期和施氮水平的影响.在正常光照条件下，宜选用 SPADL3-L2指示水稻整个生育期氮素营养状况.在日照较弱的季节或受林木遮光影响较大的田块，宜选择 SPADL4-L3作为诊断指标.展开更多
以不同温度胁迫下(35℃/3d、35℃/5d、38℃/3d和38℃/5d)的水稻田间试验为基础,研究抽穗期高温胁迫对两个水稻品种扬稻6号和南粳43的干物质积累和分配、叶片绿色度值(Soil and plant analyzer development,SPAD)和净光合速率的影响。结...以不同温度胁迫下(35℃/3d、35℃/5d、38℃/3d和38℃/5d)的水稻田间试验为基础,研究抽穗期高温胁迫对两个水稻品种扬稻6号和南粳43的干物质积累和分配、叶片绿色度值(Soil and plant analyzer development,SPAD)和净光合速率的影响。结果表明,与常温对照(CK)相比,高温胁迫下,两个水稻品种干物质积累量、SPAD值和净光合速率显著下降(P<0.05),茎鞘物质输出率和转运率显著增加(P<0.05)。随着胁迫温度的升高和胁迫时间的延长,两个水稻品种各指标的变化幅度逐渐增加。不同水稻品种对高温胁迫的反应不同,扬稻6号受高温影响要小于南粳43。展开更多
通过两年的田间试验,利用叶绿素仪(SPAD-502)测定了不同生育时期水稻(南粳44号)冠层叶片的SPAD(soilplant analysed and development)值、叶绿素含量、叶氮含量及净光合速率,在此基础上分析了SPAD值与叶绿素含量、叶氮含量及净光合速率...通过两年的田间试验,利用叶绿素仪(SPAD-502)测定了不同生育时期水稻(南粳44号)冠层叶片的SPAD(soilplant analysed and development)值、叶绿素含量、叶氮含量及净光合速率,在此基础上分析了SPAD值与叶绿素含量、叶氮含量及净光合速率的关系。结果表明:水稻冠层叶片的SPAD值与叶绿素含量、叶氮含量及净光合速率的关系均呈显著相关,但是在不同的生育期内SPAD值与其他三项指标的变化并没有同步,存在一定时间的超前或者滞后。随着叶绿素荧光分析技术的发展,无损伤、快速、灵敏测定叶片光合作用的变化成为可能,因此想要更好地了解叶片光合作用的内在变化,还需要研究SPAD值与各项叶绿素荧光参数的关系。展开更多
Precise estimation of vegetable nitrogen(N)status is critical in optimizing N fertilization management.However,nondestructive and accurate N diagnostic methods for vegetables are relatively scarce.In our two-year fiel...Precise estimation of vegetable nitrogen(N)status is critical in optimizing N fertilization management.However,nondestructive and accurate N diagnostic methods for vegetables are relatively scarce.In our two-year field experiment,we evaluated whether an active canopy sensor(GreenSeeker)could be used to nondestructively predict N status of bok choy(Brassica rapa subsp.chinensis)compared with a chlorophyll meter.Results showed that the normalized difference vegetation index(NDVI)and ratio vegetation index(RVI)generated by the active canopy sensor were well correlated with the aboveground biomass(AGB)(r=0.698–0.967),plant N uptake(PNU)(r=0.642–0.951),and root to shoot ratio(RTS)(r=-0.426 to-0.845).Compared with the chlorophyll meter,the active canopy sensor displayed much higher accuracy(5.0%–177.4%higher)in predicting AGB and PNU and equal or slightly worse(0.54–1.82 times that of the chlorophyll meter)for RTS.The sensor-based NDVI model performed equally well in estimating AGB(R2=0.63)and PNU(R2=0.61),but the meter-based model predicted RTS better(R2=0.50).Inclusion of the days after transplanting(DAT)significantly improved the accuracy of sensor-based AGB(19.0%–56.7%higher)and PNU(24.6%–84.6%higher)estimation models.These findings suggest that the active canopy sensor has a great potential for nondestructively estimating N status of bok choy accurately and thus for better N recommendations,especially with inclusion of DAT,and could be applied to more vegetables with some verification.展开更多
文摘Soil acidity and alkalinity (pH) has a significant impact on plant growth and development. From the process, it is mainly reflected in the impact of climate and elements in soil on plant growth, while climate mainly affects carbon, hydrogen and oxygen, which account for 96% in the atmosphere. The more important elements in the soil are nitrogen, phosphorus and potassium, and the secondary elements are calcium, magnesium, sulfur and so on. This paper selects the conventional economic plant planting land as the development of the experiment, obtains the main components in the soil, and carries out the intervention experiment of different concentrations of soil pH value. The pH value in the soil is divided into four levels: pH 1 (<5.5), pH 2 (5.5 - 6.5), pH 3 (6.5 - 7.5), pH 4 (7.5 - 8.4) as the independent variable, and takes the elements in the soil as the dependent variable for linear regression analysis. The results show that pH 1 (<5.5), pH 2 (5.5 - 6.5), pH 3 (6.5 - 7.5), pH 4 (7.5 - 8.4) can explain the change of elements in soil. The results show that pH 1 (<5.5), pH 2 (5.5 - 6.5), pH 3 (6.5 - 7.5), pH 4 (7.5 - 8.4) can explain the change of elements in soil. Among them, pH 1 (<5.5) and pH 4 (7.5 - 8.4) are the most unstable, while pH 2 (5.5 - 6.5) and pH 3 (6.5 - 7.5) have little impact on plant growth and are relatively stable. Therefore, the acidity and alkalinity of soil has a certain impact on the elements in soil, but it is not a decisive impact. It can be proved that the influence relationship between independent variables and dependent variables.
文摘以不同温度胁迫下(35℃/3d、35℃/5d、38℃/3d和38℃/5d)的水稻田间试验为基础,研究抽穗期高温胁迫对两个水稻品种扬稻6号和南粳43的干物质积累和分配、叶片绿色度值(Soil and plant analyzer development,SPAD)和净光合速率的影响。结果表明,与常温对照(CK)相比,高温胁迫下,两个水稻品种干物质积累量、SPAD值和净光合速率显著下降(P<0.05),茎鞘物质输出率和转运率显著增加(P<0.05)。随着胁迫温度的升高和胁迫时间的延长,两个水稻品种各指标的变化幅度逐渐增加。不同水稻品种对高温胁迫的反应不同,扬稻6号受高温影响要小于南粳43。
文摘通过两年的田间试验,利用叶绿素仪(SPAD-502)测定了不同生育时期水稻(南粳44号)冠层叶片的SPAD(soilplant analysed and development)值、叶绿素含量、叶氮含量及净光合速率,在此基础上分析了SPAD值与叶绿素含量、叶氮含量及净光合速率的关系。结果表明:水稻冠层叶片的SPAD值与叶绿素含量、叶氮含量及净光合速率的关系均呈显著相关,但是在不同的生育期内SPAD值与其他三项指标的变化并没有同步,存在一定时间的超前或者滞后。随着叶绿素荧光分析技术的发展,无损伤、快速、灵敏测定叶片光合作用的变化成为可能,因此想要更好地了解叶片光合作用的内在变化,还需要研究SPAD值与各项叶绿素荧光参数的关系。
基金supported by the National Key Research and Development Program of China(No.2016YFD0201001)the National Natural Science Foundation of China(No.31672236)
文摘Precise estimation of vegetable nitrogen(N)status is critical in optimizing N fertilization management.However,nondestructive and accurate N diagnostic methods for vegetables are relatively scarce.In our two-year field experiment,we evaluated whether an active canopy sensor(GreenSeeker)could be used to nondestructively predict N status of bok choy(Brassica rapa subsp.chinensis)compared with a chlorophyll meter.Results showed that the normalized difference vegetation index(NDVI)and ratio vegetation index(RVI)generated by the active canopy sensor were well correlated with the aboveground biomass(AGB)(r=0.698–0.967),plant N uptake(PNU)(r=0.642–0.951),and root to shoot ratio(RTS)(r=-0.426 to-0.845).Compared with the chlorophyll meter,the active canopy sensor displayed much higher accuracy(5.0%–177.4%higher)in predicting AGB and PNU and equal or slightly worse(0.54–1.82 times that of the chlorophyll meter)for RTS.The sensor-based NDVI model performed equally well in estimating AGB(R2=0.63)and PNU(R2=0.61),but the meter-based model predicted RTS better(R2=0.50).Inclusion of the days after transplanting(DAT)significantly improved the accuracy of sensor-based AGB(19.0%–56.7%higher)and PNU(24.6%–84.6%higher)estimation models.These findings suggest that the active canopy sensor has a great potential for nondestructively estimating N status of bok choy accurately and thus for better N recommendations,especially with inclusion of DAT,and could be applied to more vegetables with some verification.
