Use of Agro-Waste as a Source of Crop Nutrients in Intensive Horticulture System

The inadequate management of agro-waste in intensive agriculture has a severe negative impact on the environment. The valorization of crop residue as a source of crop nutrients is a valid alternative to close the nutrient cycle and reduce the use of external input. In this study, plant material was incorporated into the soil as fresh crop residue, after either composting and vermicomposting processes, to evaluate their effects on tomato yield and nutritional status (petiole sap analysis: NO3 and K+ concentration) over three crop cycles. A control treatment with mineral fertigation and an organic control treatment with goat manure were also included. Enzymatic activity and microbial population in the soil were evaluated. Although no differences between treatments were observed in the first cycle, in the second and third cycles, the yield obtained with the application of organic amendments derived from agro-waste was comparable to the yield obtained with mineral fertilizers. Overall, the sap analysis did not reveal a clear relationship with yield performances. The compost treatment resulted in higher microorganism presence in the soil. Soil dehydrogenase activity (DHA), acid phosphatase activity (ACP), and β-glucosidase activity (β-GLU) were generally more stimulated when organic amendments were used. The study confirms the applicability of soil fertilizers derived from agro-waste as a good alternative to mineral fertilizers

Acondicionamiento de un compost salino para su uso como sustrato de cultivo

Cada vez es más común el uso de compost en la elaboración de sustratos de cultivo, pero uno de los inconvenientes más frecuentes que presentan este tipo de materiales para ser utilizados como sustrato es su elevada salinidad. Este problema puede ser tratado de distintas maneras. En este trabajo se evalúan dos de las técnicas disponibles: el lavado rápido (15 h) con agua previo al cultivo y el lavado gradual (60 días) mediante un riego con solución nutritiva (SN). Se comparan ambos métodos, tanto desde el punto de vista de la eficiencia como desde el punto de vista de la liberación de nutrientes, como técnica más adecuada para el manejo de la salinidad de un compost con alta C.E. (18,7 dS m-1 en extracto de saturación). En ambos ensayos se produjo un rápido e importante descenso de la C.E., y fue suficiente el aporte de 3 veces el volumen de su capacidad de contenedor (CC) para llegar a valores de C.E. en los lixiviados por debajo de 4 dS m-1. El riego con solución nutritiva produjo un lavado más eficiente, especialmente, en el caso de los iones más perjudiciales como son el sodio, los cloruros y los sulfatos. La liberación de iones mediante la lixiviación siguió patrones similares en ambos ensayos, excepto para los fosfatos, el calcio y el magnesioThe use of compost as substrate in soilless systems is increasing quickly, but its high salinity is one of the most common problems of these materials for this use. This problem can be easily treated in different ways. In this paper we evaluate two of these techniques: one is a quick washing (15 h) with tap water prior to cultivation, and the other consist in a gradual washing (60 days) by watering with nutrient solution (NS). The aim of this paper is to compare the two methods, in terms of effectiveness and assess the dynamics of nutrient release, as most appropriate technique for managing salinity of compost with high E.C. (18,7 dS m-1 in saturation extract). In both trials there was a rapid and significant decrease in E.C. Three times the volume of its container capacity (CC) was sufficient to reach values of E.C. in leachate below to 4 dS m-1. The leaching efficiency was higher in the case of watering with SN especially more harmful ions such as Na+, Cl- and SO4 2-. Ion release by leaching followed similar patterns in both cases except for phosphate, calcium and magnesiumLos autores quieren agradecer a la Xunta de Galicia la financiación de este trabajo (Proyectos PGIDT05TAM097E y 09MRU016291PR) así como la beca predoctoral concedida a Marta Illera Vives. A la empresa Pescados Rubén, por el suministro de los subproductos con los que se realizó el compostS

Conditioning of saline compost for use as cultivation substrate

Cada vez es más común el uso de compost en la elaboración de sustratos de cultivo, pero uno de losinconvenientes más frecuentes que presentan este tipo de materiales para ser utilizados como sustrato es su elevada salinidad. Este problema puede ser tratado de distintas maneras. En este trabajo se evalúan dos de las técnicas disponibles: el lavado rápido (15 h) con agua previo al cultivo y el lavado gradual (60 días) mediante un riego con solución nutritiva (SN). Se comparan ambos métodos, tantodesde el punto de vista de la eficiencia como desde el punto de vista de la liberación de nutrientes, como técnica más adecuada para el manejo de la salinidad de un compost con alta C.E. (18,7 dS m-1 en extracto de saturación). En ambos ensayos se produjo un rápido e importante descenso de la C.E., y fue suficiente el aporte de 3 veces el volumen de su capacidad de contenedor (CC) para llegar a valores de C.E. en los lixiviados por debajo de 4 dS m-1. El riego con solución nutritiva produjo un lavado más eficiente, especialmente, en el caso de los iones más perjudiciales como son el sodio, los cloruros y los sulfatos. La liberación de iones mediante la lixiviación siguió patrones similares en ambos ensayos, excepto para los fosfatos, el calcio y el magnesio.The use of compost as substrate in soilless systems is increasing quickly, but its high salinity is one ofthe most common problems of these materials for this use. This problem can be easily treated in different ways. In this paper we evaluate two of these techniques: one is a quick washing (15 h) with tap water prior to cultivation, and the other consist in a gradual washing (60 days) by watering with nutrient solution (NS). The aim of this paper is to compare the two methods, in terms of effectiveness and assess the dynamics of nutrient release, as most appropriate technique for managing salinity of compost with high E.C. (18,7 dS m-1 in saturation extract). In both trials there was a rapid and significant decrease in E.C. Three times the volume of its container capacity (CC) was sufficient to reach values of E.C. in leachate below to 4 dS m-1. The leaching efficiency was higher in the case of watering with SN especially more harmful ions such as Na+, Cl- and SO4 2-. Ion release by leaching followed similar patterns in both cases except for phosphate, calcium and magnesium

Medium-Term Influence of Organic Fertilization on the Quality and Yield of a Celery Crop.

For some years now, part of society has been demanding the implementation of circular economy models and so the use of organic matter as a source of nutrients is once again taking center stage. In this scenario, the aim of this work was to implement an integrated management model for a farm and to study the influence on a celery crop of organic amendments (animal and vegetable) obtained on the farm, as opposed to inorganic fertilization. This influence was evaluated for the yield and the nutritional, organoleptic, and sanitary quality of the resulting crops. The yield and size of the marketable parts of the celery plants were greater with the inorganic treatment; however, the nutritional and sanitary quality was better in the organic treatments, while the chromatic attributes, as well as the total P and Ca, were not affected by the different fertilization treatments applied. It is therefore concluded that the organic management model is environmentally and economically sustainable

Medium-Term Effect of Organic Amendments on the Chemical Properties of a Soil Used for Vegetable Cultivation with Cereal and Legume Rotation in a Semiarid Climate

The response of a Petrocalcic Palexeroll dedicated to the cultivation of vegetables (Apium graveolens L.) with a rotation of a mixture of cereals and legumes when organic amendments are added has been studied; specifically, three fertilization treatments were experimented with: two organic (LSM and COA) and one with chemical fertilizers (I). The LSM and COA plots were managed according to the regulations governing organic production, while in I, conventional agricultural production practices were used. Over a three-year period, monthly samples were taken from the topsoil and analyzed for organic carbon (OC), total nitrogen (TN), C/N ratio, total P (P), electrical conductivity of the saturation extract (ECext) and extract ions, pH in water (pHw) and 1 M KCl (pHKCl), cation exchange capacity (CEC), exchangeable bases (Mg2+, K+, Na+), and assimilable elements (Fe, Cu, Mn, Zn). The results obtained indicated significant differences between the treatments for the OC, TN, C/N, and P; specifically, in the case of OC the mean concentrations were 22.2 > 20.1 > 17.5 g kg−1 for the LSM, COA, and I, respectively. The addition of organic amendments also improved the soil function for food production, evidenced by the higher concentrations of K, Mg, and micronutrients. The ECext and extracted ions were also sensitive to the treatments such that the sequence of ECext in the third year was COA = LSM > I, with values of 5.0, 4.8, and 3.3 dSm−1, which forced a rethink of the doses of the amendments applied. These results suggest that the LSM-based agronomic model had a beneficial effect on the soil properties and contributed to its function as a C sink

Predictive Model to Evaluate Water and Nutrient Uptake in Vertically Grown Lettuce under Mediterranean Greenhouse Conditions

The decrease in arable land, water scarcity, and climate change increase the pressure on natural resources and agricultural production systems. In this context, agriculture must ensure food production for the rapidly growing and increasingly urban population of the world. Efforts must be made to obtain the highest yield from the unit area and promote the transition to more sustainable production systems Hydroponics is a modern growing technology mainly applied in greenhouses, which has developed rapidly over the past 30–40 years. Substrate-free hydroponic vertical crops (VC) can reduce the pressure conventional agriculture exerts on resources, saving water and nutrients, and increasing crop yields per unit area. Therefore, this study aimed to validate a proposed predictive model (PM) to simulate water and nutrient uptake in vertical crops under greenhouse conditions. On the basis of the Penman–Monteith equation, the PM estimates transpiration, while nutrient uptake was estimated using the Carmassi–Sonneveld submodel. The PM was experimentally evaluated for vertically grown lettuce under Mediterranean greenhouse conditions during spring 2023. The irrigation technique was a closed-loop fertigation circuit. The experiment consisted of testing two densities (50 and 80 plants·m−2) and three plant positions (low, medium, and upper). ANOVA (p 2 were used to evaluate the PM performance and crop behavior. The low density and the upper position had significantly higher mass values. The results suggest a high degree of performance for the PM, as the R2 ranged from 0.7 to 0.9 for water and nutrient uptake. Both densities had a yield 17–20 times higher than conventional lettuce production and significant savings in water, about 85–88%. In this sense, the PM has great potential to intelligently manage VC fertigation, saving water and nutrients, which represents an advance toward reaching SDG 6 and SDG 12 within the 2030 Agenda

Predictive Model to Evaluate Water and Nutrient Uptake in Vertically Grown Lettuce under Mediterranean Greenhouse Conditions

Agriculture is the main driver of depletion resources worldwide, and its duty is to ensure food security within a rapidly increasing demographic and urbanization, so it is important to transi-tion to sustainable production systems. Vertical crops (VCs) can reduce the pressure on conven-tional agriculture because they save water and nutrients and increase crop yield. Therefore, this study aimed to validate a proposed predictive model (PM) to simulate water and nutrient uptake in vertical crops under greenhouse conditions. Based on the Penman-Monteith equation, PM es-timates transpiration, while nutrient uptake was estimated using the Carmassi-Sonneveld sub-model. PM was experimentally evaluated for vertically grown lettuce under Mediterranean greenhouse conditions, during spring 2023. The irrigation technique was a closed-loop fertiga-tion circuit. The experimental consisted of testing two densities (50 and 80 plants·m-2), where each unit of the experiment unit was divided into three heights (lower, medium, and upper). It performed ANOVA with a value of p < 0.05 and R2 to assess PM performance. The results sug-gest a high degree of PM, since R2 ranged from 0.6 to 0.8 for the uptake of water and nutrients. Both densities had a yield between 17-20 times higher than conventional lettuce production and significant savings in water, between 85-88%. In this sense, PM has great potential to intelli-gently manage VC fertigation, saving water and nutrients, which represents an advance towards reaching SDG 6 and SDG 12, within the 203