Costa Bárbara Nogueira Souza, Tucker Daniel A, Khoddamzadeh Amir Ali
Agroecology Program, Department of Earth and Environment, Institute of Environment, Florida International University, Miami, FL 33199, USA.
Plants (Basel). 2023 Feb 8;12(4):760. doi: 10.3390/plants12040760.
Cocoplum () is an ecologically significant native species to Southern Florida. Application of precision agriculture technologies such as optical sensors reduces the cost of over-fertilization and nutrient runoff. The aim of this work was to establish a base line sensor value for fertilizer treatment in cocoplum by monitoring chlorophyll content using the Soil Plant Analytical Development (SPAD), atLEAF, and Normalized Difference Vegetation Index (NDVI) sensors. Initial slow-released fertilizer treatment 8N-3P-9K was used at 15 g (control), 15 g (supplemented with +15 g × 2; T1), 15 g (+15 g; T2), 30 g (+15 g × 2; T3), 30 g (+15 g; T4), and 45 g (+15 g × 2; T5). Evaluations were conducted at 0 (base reading), 30, 60, 90, 120, 150, and 180 days after treatment. Growth parameters, optical non-destructive chlorophyll meters, leaf and soil total nitrogen and total carbon, and total nitrogen of leachate were analyzed. The results demonstrated that the treatment using 30 g slow-released fertilizer (8N-3P-9K) supplemented twice with 15 g in November and March after the first fertilization in October provided the least contamination through runoff while still providing adequate nutrients for plant growth compared to higher fertilizer concentrations. These results demonstrate that the highest treatment of nitrogen can cause considerable losses of N, causing extra costs to producers and environmental damage due to the flow of nutrients. Thus, techniques that help in N monitoring to avoid the excessive use of nitrogen fertilization are necessary. This study can serve as a basis for future research and for nurseries and farms, since it demonstrated from the monitoring of the chlorophyll content by optical sensors and by foliar and substrate analysis that lower treatments of nitrogen fertilization are sufficient to provide nutrients suitable for the growth of cocoplum plants.
可可李（）是佛罗里达州南部具有重要生态意义的本土物种。应用光学传感器等精准农业技术可降低过度施肥成本和养分径流。这项工作的目的是通过使用土壤植物分析发展（SPAD）、atLEAF和归一化植被指数（NDVI）传感器监测叶绿素含量，为可可李施肥处理建立基线传感器值。最初使用的缓释肥料处理为8N - 3P - 9K，用量分别为15克（对照）、15克（补充 + 15克×2；T1）、15克（+ 15克；T2）、30克（+ 15克×2；T3）、30克（+ 15克；T4）和45克（+ 15克×2；T5）。在处理后的0（基础读数）、30、60、90、120、150和180天进行评估。分析了生长参数、光学无损叶绿素仪、叶片和土壤总氮及总碳以及渗滤液总氮。结果表明，在10月首次施肥后，11月和3月分两次补充15克的30克缓释肥料（8N - 3P - 9K）处理，与较高肥料浓度相比，通过径流造成的污染最少，同时仍为植物生长提供了充足的养分。这些结果表明，最高的氮肥处理会导致大量氮素损失，给生产者带来额外成本，并因养分流失造成环境破坏。因此，有助于监测氮素以避免过度使用氮肥的技术是必要的。这项研究可为未来的研究以及苗圃和农场提供依据，因为通过光学传感器监测叶绿素含量以及进行叶面和基质分析表明，较低的氮肥处理足以提供适合可可李植物生长的养分。
