Foliar application of titanium on potato crop

Although titanium (Ti) is not considered a nutrient, researches demonstrate that Ti leaf application can provide beneficial effects on plants growth. The objective of this study was to evaluate the influence of foliar applications of Ti levels on the metabolism, nutrient uptake and yield of potato crop, Agate cultivar. The experiment was conducted in a randomized complete block design with five treatments and four replications. The treatments were composed of 0, 10.2, 15.3, 20.4 and 22.9 g Ti ha-1, divided into three applications during the growth stage, tuberization stage and tuber filling stage. Foliar applications of Ti increase the chlorophyll content (Spad value) in the tuber filling stage. Ti levels do not interfere with N, Zn and Cu nutrient accumulation. Increasing Ti levels linearly reduce the Mn, lipid peroxidation (PL) and urease content and increase the activity of peroxidase (POD), nitrate reductase (ANR), catalase (CAT), proline and Fe content in the growth stage, with maximum level around 3 to 6 g Ti ha-1. In the tuberization stage, at high levels of Ti, there is an increase in urease activity and CAT while ANR has its lowest value. In the tuber filling stage, high Ti levels are related to high Fe, Mn, high ANR and superoxide dismutase (SOD) activity and low PL activity. The ideal level of titanium applied by leaf for greater yield of tubers is 11.3 g of Ti ha-1

Leaf nutrient status of tomatoes in coconut coir medium – differences in cultivars, impact on yield and quality

Received: January 29th, 2021 ; Accepted: May 12th, 2021 ; Published: June 22nd, 2021 ; Correspondence: [email protected] coir as an alternative to rockwool is increasingly used as a substrate for soilless hydroponic greenhouse production of tomatoes. However, little is known about the nutrient status of tomatoes in coconut coir, especially under intensive production conditions. The aim of this study was to investigate the nutrient status of different tomato cultivars (orange plum ‘Organza F1’, red cherry ‘Daltary RZ F1’, red large fruit-sized ‘Securitas RZ F1’ and pink large fruit-sized ‘Fujimaru F1’) under industrial greenhouse production, using coconut coir as a substrate to reveal nutrient imbalances, their impact on tomato yield and quality, and cultivar differences. Essential nutrient and leaf SPAD value was detected for the youngest fully developed leaves and the old still vital leaves twice per month from April to August 2020. The total yield, marketable and non-marketable yield was regularly determined. During the crop cycle, the content of most of the nutrients in tomato leaves corresponded to the standard range reported for tomatoes. Only some imbalances were found: all cultivars were characterized by low Zn and high S levels in both young and old leaves. The obtained results identified several differences between the cultivars: cherry tomatoes 'Daltary' had significantly higher N, K, Fe and Zn in leaves compared to other cultivars. The lowest N, Fe and Cu were determined for large fruit-sized ‘Securitas’. Regardless of the nutrient status and microclimate conditions, the marketable yield of ‘Daltary’, ‘Organza’ and ‘Securitas’ was almost 100%, indicating on high suitability of these cultivars for hydroponic cultivation in coconut coir

Nitrogen Fertilization Using Drip Fertigation for Cucumber Cultivation Based on Leaf-Count Technique

With the aim of optimizing productivity and reducing soil salinity and production costs in cucumber cultivation, we developed a leaf-count technique based on the positive correlation between leaf increments and nitrogen uptake for spring and summer greenhouse cultivation. In this technique, the amount of nitrogen uptake was determined from leaf increments, and the determined amount of nitrogen was applied in real-time. In the producers’ field test, it was not only possible to significantly reduce the amount of nitrogen fertilization compared to conventional cultivation, but it was also verified that salt accumulation was eliminated. In addition, in the unimproved outdoor farmland that was reconstructed from the tsunami disaster after the Great East Japan Earthquake in 2011, a remarkable increase in yield was observed compared to conventional cultivation using the leaf-count technique developed for spring greenhouse cultivation. Producers can practice this by simply counting leaves and applying nitrogen from a quick reference table

Use of fluorescence indices as predictors of crop N status and yield for greenhouse sweet pepper crops

To increase nitrogen (N) use efficiency and reduce water pollution from vegetable production, it is necessary to optimize N management. Fluorescence-based optical sensors are devices that can improve N fertilization through non-destructive field monitoring of crop variables. The aim of this work was to compare the performance of five fluorescence indices (SFR-R, SFR-G, FLAV, NBI-R, and NBI-G) to predict crop variables, as dry matter production, crop N content, crop N uptake, Nitrogen Nutrition Index (NNI), absolute and relative yield, in sweet pepper (Capsicum annuum) crops grown in greenhouse. Fluorescence measurements were periodically made with the Multiplex® 3.6 sensor throughout three cropping cycles subjected to five N application treatments. The performance of fluorescence indices to predict crop variables considered calibration and validation analyses. In general, the five fluorescence indices were strongly related with NNI, crop N content and relative yield. The best performing indices to predict crop N content and NNI at the early stages of the crops (i.e., vegetative and flowering phenological stages) were the SFR indices, both under red (SFR-R) and green (SFR-G) excitation. However, in the final stage of the crop (i.e., harvest stage), the best performing indices were NBI, both under red (NBI-R) and green (NBI-G) excitation, and FLAV. The two SFR indices best predicted relative yield of sweet pepper at early growth stages. Overall, the fluorescence sensor and the fluorescence indices evaluated were able to predict crop variables related to N status in sweet pepper. They have the capacity to be incorporated into best N management practices

Concentración de nitrógeno y clorofila en hojas de chile dulce hidropónico en invernadero bajo diferentes estrategias de manejo del riego y la nutrición

 Introducción. El nitrógeno (N) es un elemento esencial para el proceso de fotosíntesis, y por tanto, determinante en el rendimiento. El uso de sensores ópticos para determinar índices de transmitancia (SPAD, CCI), reflectancia (NDVI) y fluorescencia (Fv.Fm-1) relacionados con el estado del N foliar, permite un adecuado manejo a partir del monitoreo “in situ” no destructivo. Objetivo. Evaluar el efecto de diferentes estrategias de manejo del fertiriego sobre las concentraciones de nitrógeno y clorofila en hoja; y la relación entre i- concentración de N y de Clorofila (Cl) en hoja, ii- concentración de N y de Cl en hoja con el rendimiento y iii- concentración de N y de Cl en hoja con índices SPAD, CCI, NDVI y Fv.Fm-1. Materiales y métodos. Se evaluaron 6 tratamientos en un diseño irrestricto al azar con arreglo factorial 2 x 3, que combinaron 2 estrategias de riego (E1: bajo volumen y de mayor frecuencia y E2: alto volumen y menor frecuencia) y 3 niveles de nutrición: bajo (NB), medio (NM) y alto (NA). Las medidas directas de N y Cl en hoja se determinaron con el método Kjeldahl y por extracción con etanol, respectivamente. Resultados. El nivel de nutrición afectó el contenido de N, donde los tratamientos NM y NA fueron similares, aunque superiores a NB. El modelo de regresión mostró poca capacidad para estimar N y rendimiento a partir del contenido de Cl en hoja. La estimación de Cl en hoja a partir de los índices CCI (R2: 0,71) y SPAD (R2: 0,75) resultaron prometedores solamente en NB. Para estimar N foliar, la regresión con Fv.Fm-1 mostró valores de R2 de 0,89 en NB y 0,69 en NM; mientras que para NDVI los valores R2 fueron 0,61 en NB y 0,47 en NM. Conclusión. Los índices SPAD, CCI, NDVI y Fv.Fm-1 presentaron potencial para estimar la concentración de clorofila y de N en hoja con aportes bajo y medio de nutrientes, y con limitaciones en los tratamientos con altos aportes de nutrición

Assessing Performance of Vegetation Indices to Estimate Nitrogen Nutrition Index in Pepper

Vegetation indices (VIs) can be useful tools to evaluate crop nitrogen (N) status. To be effective, VIs measurements must be related to crop N status. The nitrogen nutrition index (NNI) is a widely accepted parameter of crop N status. The present work evaluates the performance of several VIs to estimate NNI in sweet pepper (Capsicum annuum). The performance of VIs to estimate NNI was evaluated using parameters of linear regression analysis conducted for calibration and validation. Three different sweet pepper crops were grown with combined irrigation and fertigation, in Almería, Spain. In each crop, five different N concentrations in the nutrient solution were frequently applied by drip irrigation. Proximal crop reflectance was measured with Crop Circle ACS470 and GreenSeeker handheld sensors, approximately every ten days, throughout the crops. The relative performance of VIs differed between phenological stages. Relationships of VIs with NNI were strongest in the early fruit growth and flowering stages, and less strong in the vegetative and harvest stages. The green band-based VIs, GNDVI, and GVI, provided the best results for estimating crop NNI in sweet pepper, for individual phenological stages. GNDVI had the best performance in the vegetative, flowering, and harvest stages, and GVI had the best performance in the early fruit growth stage. Some of the VIs evaluated are promising tools to estimate crop N status in sweet pepper and have the potential to contribute to improving crop N management of sweet pepper crops

Different Responses of Various Chlorophyll Meters to Increasing Nitrogen Supply in Sweet Pepper

Intensive vegetable production is commonly associated with excessive nitrogen (N) fertilization and associated environmental problems. Monitoring of crop N status can enhance crop N management. Chlorophyll meters (CMs) could be used to monitor crop N status because leaf chlorophyll (chl) content is strongly related to crop N status. To monitor crop N status, relationships between CM measurements and leaf chl content require evaluation, particularly when excessive N is supplied. The SPAD-502 meter, atLEAF+ sensor, MC-100 Chlorophyll Concentration Meter, and Multiplex sensor were evaluated in sweet pepper with different N supply, throughout the crop, ranging from very deficient to very excessive. CM measurements of all sensors and indices were strongly and positively related to leaf chlorophyll a + b content with curvilinear relationships over the entire range of chl measured (∼0–80 μg cm-2). Measurements with the SPAD-502, and atLEAF+, and of the Multiplex’s simple fluorescence ratio index (SFR) had asymptotic responses to increasing leaf chl. In contrast, the MC-100’s chlorophyll content index (CCI) had a progressively increasing response. At higher chlorophyll a + b contents (e.g., >40 μg cm-2), SPAD-502, atLEAF+ and SFR measurements tended to saturate, which did not occur with CCI. Leaf chl content was most accurately estimated by CCI (R2 = 0.87), followed by the SPAD-502 meter (R2 = 0.85). The atLEAF+ sensor was the least accurate (R2 = 0.76). For leaf chl estimation, CCI measured with the MC-100 meter was the most effective of the four sensors examined because it: (1) most accurately estimated leaf chl content, and (2) had no saturation response at higher leaf chl content. For non-saturating leaf chl content (∼0–40 μg cm-2), all indices were sensitive indicators. As excessive applications of N are frequent in intensive vegetable crop production, the capacity of measuring high leaf chl contents without a saturation response is an important consideration for the practical use of chlorophyll meters

EFFECT OF N ON FRUIT PRODUCTION AND QUALITY OF GREENHOUSE HORTICULTURAL CROPS, AND PRACTICES TO IMPROVE THE USE OF NUTRIENTS.

Tesis doctoral en período de exposición públicaDoctorado en Agricultura Protegida (RD99/11) (8901

Evaluación del contenido de nitrógeno y clorofila en chile dulce (Capsicum annuum L.) var. Dulcitico, en respuesta al manejo del fertirriego en ambiente protegido

La producción hortícola se caracteriza por el alto consumo de fuentes nutricionales, entre ellos los fertilizantes nitrogenados. El consumo de este tipo de fertilizantes es desmedido, lo que provoca bajas productividades y un aumento en la contaminación ambiental mediante la emisión de gases de efecto invernadero, así como la eutrofización de fuentes de agua debido a un aumento en el contenido de nitrógeno. Debido a esta problemática, los productores realizan monitoreos del N mediante metodologías donde el productor tiene la necesidad de eliminar tejido vegetal y además esperar días o semanas por los resultados, retrasando la corrección de las deficiencias o de los excesos de este nutriente. Se han implementado métodos no destructivos para su determinación, algunos de los cuales se basan en sensores ópticos como los cuantificadores de la transmitancia, reflectancia o fluorescencia del tejido fotosintético, presentando relaciones con el contenido de N foliar. El objetivo de este trabajo fue evaluar el efecto de diferentes concentraciones de nutrientes en solución nutritiva y de agotamientos del contenido de humedad (% V⋅V-1) en el sustrato, sobre el contenido de nitrógeno, de clorofila y el rendimiento en el cultivo de chile dulce hidropónico bajo condiciones de invernadero. Materiales y métodos Se utilizó un sistema hidropónico de chile dulce var. Dulcitico bajo invernadero ubicado en la Estación Experimental Fabio Baudrit Moreno (E.E.F.B.M) de la Universidad de Costa Rica, ubicada en La Garita de Alajuela. El cultivo se estableció en tablas de fibra de coco (FICO®) con un sistema de riego por goteo con goteros autocompensados y antidrenantes. Se estableció un diseño factorial irrestricto al azar, combinando tres niveles de nutrición (alta, media y baja) y dos niveles de agotamiento hídrico (10% y 35%). Se realizaron mediciones mensuales del contenido de clorofila de manera directa mediante un método de extracción con etanol e indirectas con el uso de equipos como el SPAD-502, Apogee (MC-100), Fluorómetro, Espectroradiómetro (Field Spec 4) y Greenseeker. También se determinó el contenido de nitrógeno (N) mediante el método Kjeldahl y el rendimiento del cultivo mediante cosechas semanales. Con los datos, se realizó un análisis para determinar el cumplimiento de supuestos de normalidad y homocedasticidad del análisis de varianza (ANDEVA), para posteriormente realizar un análisis de regresión para cada variable con el contenido de clorofila y de nitrógeno. No hubo interacción entre los factores de nivel de nutrición y porcentaje de agotamiento en las variables directas evaluadas, sólo hubo efecto por parte de la nutrición. La variable de clorofila mg⋅g-1 no presentó diferencias significativas entre tratamientos, en las variables del contenido de nitrógeno (%N) y rendimiento Kg⋅planta-1 el tratamiento de nutrición baja fue estadísticamente distinto al de nutrición media y alta. En cuanto al análisis de regresión, el análisis para las variables del contenido de clorofila (mg⋅g-1) y de nitrógeno (%) mostraron coeficientes de determinación (R2) bajos, siendo el más alto de 0,18 en el tratamiento de nutrición baja. En el análisis realizado entre el contenido de clorofila (mg⋅g-1) y las variables determinadas con los instrumentos, el CCI, SPAD y NDVIG mostraron los mayores de R2, siendo estos 0,71, 0,75 para el CCI y SPAD en el tratamiento de nutrición baja y 0,63 para el NDVIG en el tratamiento de nutrición media. En el análisis de regresión realizado entre las variables y el contenido de N, las variables Fv⋅Fm-1 y NDVI presentaron los mayores coeficientes de determinación con valores de 0,89 y 0,61 respectivamente, esto en el tratamiento de nutrición baja. Por último, el rendimiento mostró mayores valores de R2 cuando este se analizó con el contenido de N con un valor de 0,5 en el tratamiento de nutrición media. Las variables evaluadas son afectadas por las condiciones nutricionales en el cultivo, donde el CCI y SPAD resultan ser las más prometedoras cuando se quiere determinar el contenido de clorofila en el cultivo ante un déficit nutricional. Mientras que, para determinar el estatus del nitrógeno, las variables Fv/Fm y NDVI son las que muestran el mejor comportamiento para dicha determinación, esto ante deficiencias nutricionales. Por último, el rendimiento presentó una mejor relación con el contenido de nitrógeno en comparación con el contenido de clorofila.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Agroalimentarias::Estación Experimental Agrícola Fabio Baudrit Moreno (EEAFBM)UCR::Vicerrectoría de Docencia::Ciencias Agroalimentarias::Facultad de Ciencias Agroalimentarias::Escuela de Agronomí