Effects of Different LED Light Recipes and NPK Fertilizers on Basil Cultivation for Automated and Integrated Horticulture Methods

Abstract

This study aims to optimize the conditions for “Genovese” basil (Ocimum Basilicum) germination and growth in an indoor environment suitable for horticulture through a synergic effect of light and fertilizers addition. In fact, several studies determined that specific light conditions are capable of enhancing basil growth, but this effect is highly dependent on the environmental conditions. In this study, the effect of different light sources was determined employing a soil with a negligible amount of fertilizer, demonstrating substantial improvement when light-emitting diode (LED) lights (hyper red and deep blue in different combinations) were applied with respect to daylight (Plants height: +30%, Total fresh mass: +50%). Thereafter, a design of experiment approach has been implemented to calculate the specific combination of LED lights and fertilizer useful to optimize the basil growth. A controlled-release fertilizer based on nitrogen, phosphorus, and potassium (NPK) derived from agro-residues was compared with a soil enriched in macronutrients. The results demonstrate significant improvements for the growth parameters with the employment of the controlled-release NPK with respect to enriched soil combined with a ratio of hyper red and deep blue LED light equal to 1:3 (Total fresh mass: +100%, Leaves number: +20%).

Statistical Optimization of a Hyper Red, Deep Blue, and White LEDs Light Combination for Controlled Basil Horticulture

“…R 2 and Pred-R 2 (Table 9) confirms the overall good fit of the data, with only two responses with unacceptable quality, Number of plants and Days for germination having R 2 < 0.45. These two responses are mainly related with the germination phase that according to literature is the more critical to model [28]. However, a particular good fitting of the model is shown by LAI, Dry mass, Stem dry mass and Water responses with values of R 2 equal or above 0.90.…”

“…As burying soil, Floradur B pot coarse universal potting soil (Floragard Vertriebs GmbH, Oldenburg, Germany) was employed. Detailed specifications about this substrate can be found in a previous study, as the same soil was employed to promote the comparison among different soils suitable for basil [28]. This soil respects the limits generally applied to fertilizer compounds necessary to be sold and employed [30].…”

“…On these bases, the main objective of the present study is to evaluate the artificial illumination spectrum that is capable to induce the most significant biomass improvement of "Genovese" basil (Ocimum Basilicum) plants in a controlled environment. Following the results presented in [28] three different light-plants distances and four different LEDs modules have been considered in combination. From a previous study, the effect of different artificial lights was evaluated as negligible, with respect to a fertilizer addition, to promote basil growth [28].…”

“…Following the results presented in [28] three different light-plants distances and four different LEDs modules have been considered in combination. From a previous study, the effect of different artificial lights was evaluated as negligible, with respect to a fertilizer addition, to promote basil growth [28]. A slight favorable effect was estimated for a combination of LEDs light containing hyper red and deep blue light in a proportion of 1:3 (LEDs modules quantity), but further investigation was necessary [28].…”

“…From a previous study, the effect of different artificial lights was evaluated as negligible, with respect to a fertilizer addition, to promote basil growth [28]. A slight favorable effect was estimated for a combination of LEDs light containing hyper red and deep blue light in a proportion of 1:3 (LEDs modules quantity), but further investigation was necessary [28]. A statistical approach (design of experiments) has been applied to reduce the number of possible combinations of the variables, and, consequently, of the experiments needed to obtain statistically reliable correlation among data [29].…”