■对菠菜来说,氮的平衡供应是必不可少的,支持最佳生长和适当的硝酸盐(NO3-)水平,以提高储存质量。因此,选择正确的氮肥种类和施用量是菠菜种植成功的关键。本研究研究了不同氮肥类型和施用量对生长的影响。硝酸盐含量,和菠菜植物的储存质量。
■将四种肥料以5种N剂量(25、50、200和400mgNkg-1)施用于温室塑料盆中生长的植物。实验中使用的肥料类型为硫酸铵(AS),缓释硫酸铵(SRAS),硝酸钙(CN),和酵母残留物(YR)。菠菜参数,如土壤植物分析开发(SPAD)值(叶绿素含量),植物高度,和新鲜重量进行测量。在模拟收获后处理的储存期(0、5和10天)之后分析叶片中的硝酸盐含量。
■氮肥的施用显著影响菠菜的生长参数和硝酸盐含量。YRx400处理产生最大的叶子(10.3±0.5厘米长,5.3±0.2cm宽)。对于AS,SPAD值随着N剂量的增加而增加,SRAS,和CN肥料,AS×400(58.1±0.8)和SRAS×400(62.0±5.8)达到最高值。YR处理显示适度的SPAD增加。鲜重响应取决于肥料类型,N剂量,和储存期。当所有肥料的鲜重增加到200mgkg-1剂量时,在AS和CN的最高剂量下观察到下降。随着氮剂量的增加,SRAS的鲜重逐渐增加,在AS和CN中没有最高剂量的负面影响。菠菜叶片中的硝酸盐含量因肥料类型而异,剂量,存储日CNx400在收获(第0天)时导致最高的NO3-含量(4,395mgkg-1),超过欧盟的安全限制。该水平在储存的10天内降低,但在第0天和第5天保持高于CN的限制。SRAS和YR肥料在整个实验中通常具有较低的NO3-浓度。在+4°C下储存显著影响NO3-含量。虽然水平在前5天保持相对稳定,到第10天,所有肥料和剂量都大幅下降,在10天的储存期内提供对菠菜硝酸盐含量的见解。
■对于快速的早期生长和潜在的更高的产量,AS在中等剂量(200mgkg-1)下可能是合适的。SRAS提供了一种更平衡的方法,与AS相比,促进持续增长,同时可能减少NO3-积累。酵母残渣,氮释放缓慢,NO3-水平一直很低,可能是有机菠菜生产的可行选择。
UNASSIGNED: A balanced supply of nitrogen is essential for spinach, supporting both optimal growth and appropriate nitrate (NO3 -) levels for improved storage quality. Thus, choosing the correct nitrogen fertilizer type and application rate is key for successful spinach cultivation. This study investigated the effects of different nitrogen (N) fertilizer type and application rates on the growth, nitrate content, and storage quality of spinach plants.
UNASSIGNED: Four fertilizer types were applied at five N doses (25, 50, 200, and 400 mg N kg-1) to plants grown in plastic pots at a greenhouse. The fertilizer types used in the experiment were ammonium sulphate (AS), slow-release ammonium sulphate (SRAS), calcium nitrate (CN), and yeast residue (YR). Spinach parameters like Soil Plant Analysis Development (SPAD) values (chlorophyll content), plant height, and fresh weight were measured. Nitrate content in leaves was analyzed after storage periods simulating post-harvest handling (0, 5, and 10 days).
UNASSIGNED: The application of nitrogen fertilizer significantly influenced spinach growth parameters and nitrate content. The YRx400 treatment yielded the largest leaves (10.3 ± 0.5 cm long, 5.3 ± 0.2 cm wide). SPAD values increased with higher N doses for AS, SRAS, and CN fertilizers, with AS×400 (58.1 ± 0.8) and SRAS×400 (62.0 ± 5.8) reaching the highest values. YR treatments showed a moderate SPAD increase. Fresh weight response depended on fertilizer type, N dose, and storage period. While fresh weight increased in all fertilizers till 200 mg kg-1 dose, a decrease was observed at the highest dose for AS and CN. SRAS exhibited a more gradual increase in fresh weight with increasing nitrogen dose, without the negative impact seen at the highest dose in AS and CN. Nitrate content in spinach leaves varied by fertilizer type, dose, and storage day. CNx400 resulted in the highest NO3 - content (4,395 mg kg-1) at harvest (Day 0), exceeding the European Union\'s safety limit. This level decreased over 10 days of storage but remained above the limit for CN on Days 0 and 5. SRAS and YR fertilizers generally had lower NO3 - concentrations throughout the experiment. Storage at +4 °C significantly affected NO3 - content. While levels remained relatively stable during the first 5 days, a substantial decrease was observed by Day 10 for all fertilizers and doses, providing insights into the spinach\'s nitrate content over a 10-day storage period.
UNASSIGNED: For rapid early growth and potentially higher yields, AS may be suitable at moderate doses (200 mg kg-1). SRAS offers a more balanced approach, promoting sustained growth while potentially reducing NO3 - accumulation compared to AS. Yeast residue, with its slow nitrogen release and consistently low NO3 - levels, could be a viable option for organic spinach production.