Non-destructive estimation of potato leaf chlorophyll from canopy hyperspectral reflectance using the inverted PROSAIL model

Optimizing nitrogen (N) fertilization in crop production by in-season measurements of crop N status may improve fertilizer N use efficiency. Hyperspectral measurements may be used to assess crop N status by estimating leaf chlorophyll content. This study evaluated the ability of the PROSAIL canopy-level reflectance model to predict leaf chlorophyll content. Trials were conducted with two potato cultivars under different N fertility rates (0–300 kg N ha⁻¹). Canopy reflectance, leaf area index (LAI) and leaf chlorophyll and N contents were measured. The PROSAIL model was able to predict leaf chlorophyll content with reasonable accuracy later in the growing season. The low estimation accuracy earlier in the growing season could be due to model sensitivity to non-homogenous canopy architecture and soil background interference before full canopy closure. Canopy chlorophyll content (leaf chlorophyll content × LAI) was predicted less accurately than leaf chlrophyll content due to the low estimation accuracy of LAI for values higher than 4.5.     

Effects of nitrogen nutritional stress on the morphological and yield parameters of tomato (Solanum lycopersicum L.)

This investigation was carried out to better understand the effects of nitrogen stress on the growth and yield of tomato(Solanum lycopersicon L.). Seeds of S. lycopersicon(Ife No. 1 variety) were collected from the Osun–State Ministry of Agriculture, Oshogbo, Nigeria and planted in analyzed top soil. The plants were grown for a period of five weeks within which they were supplied with water and kept under optimum environmental conditions that enhanced normal growth. After this period, the plants were subjected to different levels of nitrogen stress which include: plants supplied with distilled water only(n), plants supplied with complete nutrient solution(N), plants supplied with nutrient solution in which nitrogen concentration sources was increased by a factor of 5(N5), and plants supplied with nutrient solution in which nitrogen concentration sources was increased by a factor of 10(N10). Analysis of Variance(ANOVA) results shows that there is no significant effect of stress on the growth and morphological parameters of tomato plants. However, there was a significant effect of nitrogen stress on the yield parameters. Nitrogen stress also caused an increase in the number and size of fruits produced in plants subjected with high nitrogen concentration.     

寿光市蔬菜品质与农业地质背景关系

根据寿光市蔬菜种植区种植特征,采用对部分茄果类蔬菜、水、土的样品抽样测试、数理统计、相关分析等方法,得出蔬菜的品质与农业地质背景存在一定的相关性,以及土壤有选择蔬菜品种性,蔬菜在品质上有选择农业地质条件性的结论。     

喙突斜叶虫的形态学及分类地位的探讨

在对养殖水体病害纤毛虫调查中观察到一侧口目纤毛虫,经鉴定为喙突斜叶虫。借助蛋白银技术对其纤毛图式作了首次揭示,确定了其独立地位,同时还对其生境特征及与相近种的关系做了综合描述和探讨。研究中还进行了杀灭试验。     

寿光市蔬菜品质与农业地质背景关系

根据寿光市蔬菜种植区种植特征,采用对部分茄果类蔬菜、水、土的样品抽样测试、数理统计、相关分析等方法,得出蔬菜的品质与农业地质背景存在一定的相关性,以及土壤有选择蔬菜品种性,蔬菜在品质上有选择农业地质条件性的结论。     

马铃薯不同品种耐盐性差异初步研究

马铃薯是世界上一种重要的粮食作物。本项试验目的是为了就6个马铃薯品种对盐胁迫的生长反应和耐盐性差异进行比较研究。根据试验结果, 马铃薯是一种对盐分很敏感的作物, 高盐分(EC12.0ds/m)处理使植株高度、生物量、产量严重下降, 而低盐分(EC4.0dS/m)和中盐分(EC8.0ds/m)处理则由于品种的不同各显示出差异。由产量和生物量确定6个品种的耐盐顺序为: V-3>Mariva>Piratini>CFC-69.1>CEW-69.1>Muziranzara, V-3和Mariva推荐为进一步实验品种。     

外来植物刺萼龙葵及其在乌鲁木齐出现的生态学意义

刺萼龙葵（ Solanum rostratum ）为茄科茄属有严重危害的有毒植物,原产于北美。在美国被列为有害杂草,在加拿大被列为入侵植物,在俄罗斯和我国被列为境内限制传播的检疫杂草。该植物于1981 进入我国辽宁,继而在北京出现,如今首次在乌鲁木齐被发现,说明它的潜在入侵区包括干旱区。文章阐述了刺萼龙葵的主要形态特征、分布与生境、化学成分及功效、危害、进化生物学、在中国入侵危险性评价等方面的研究进展,分析了其在乌鲁木齐出现的生态学意义,提出了有待研究的科学问题,旨在为防止其在干旱区传播蔓延及其开发利用提供参考。