The concept of circular economy, whose model is based on three main pillars: (i) design out waste and pollution; (ii) keep products and materials in use; and (iii) regenerate natural systems, has recently been applied to different sectors. This concept is directly related to bioeconomy. Spain implemented its own strategy in bioeconomy in 2016, affecting all economic activities, agriculture included. In line with this, one of the most important agricultural sectors is the greenhouse horticulture of Almería (SE Spain). This region has experienced deep changes in the last 40 years, and has become one of the most efficient agro-industrial complexes in the world. This rapid growth has brought sustainability problems such as pollution, water overuse, or inadequate waste management. Several studies have undertaken organic waste reuse or minimization, but an important lack of knowledge exists regarding the inorganic fraction. One of the goals of the REINWASTE project is to find solutions for this problem. Therefore, an extensive legal framework has been consulted and an in-depth study of the steps in greenhouse production with the associated residues has been carried out. Additionally, information from experts and stakeholders has been registered, resulting a list of Best Available Technologies (BATs) to prevent and minimize inorganic waste generation. This article highlights the intensive greenhouse horticulture from Almería efforts to reach circularity by closing the loop with inorganic waste.

A rapid method to quantify the total phenolic content (TPC) and total carotenoid content (TCC) in blackberries using near infrared spectroscopy (NIRS) was carried out aiming to provide reductions in analysis time and cost for the food industry. A total of 106 samples were analysed using the Folin-Ciocalteu method for TPC and a method based on Ultraviolet-Visible Spectrometer for TCC. The average contents found for TPC and TCC were 24.27 mg·g⁻¹ dw and 8.30 µg·g⁻¹ dw, respectively. Modified partial least squares (MPLS) regression was used for obtaining the calibration models of these compounds. The RPD (ratio of the standard deviation of the reference data to the standard error of prediction (SEP)) values from external validation for both TPC and TCC were between 1.5 < RPDp < 2.5 and RER values (ratio of the range in the reference data to SEP) were 5.92 for TPC and 8.63 for TCC. These values showed that both equations were suitable for screening purposes. MPLS loading plots showed a high contribution of sugars, chlorophyll, lipids and cellulose in the modelling of prediction equations.

Soil mulching has advantages for horticultural crops, from both agronomic and phytosanitary points of view. The most common material used is polyethylene (PE); however, promising alternatives from the circular economy exist, such as straw (ST) and biodegradable biopolymers (BBs). The effect of the three aforementioned mulches was evaluated and compared to non-mulched soil in a Mediterranean greenhouse for two years of an organic tomato crop. Physical (moisture and temperature) and physicochemical properties of the soil, in addition to crop yield and the effect of the mulches on weed control, were assessed. Additionally, the deterioration of plastic mulches was assessed. The temperature was higher in the mulched soils, but few differences were found between soil and BB at the end of the second cycle. Evaporation was lower in mulched soil, in general, without big differences among the types of mulch. Crop yield did not show differences. At the end of the trials, of the 16 physicochemical variables evaluated, only a slight increase in pH was detected in the ST-mulched plots. BB film degradation reached 5.6% and 6.7% of the total surface at the end of the first and second cycles, respectively. Weeds were equally limited for PE, BB, and ST mulches, but cereal seeds contained within the straw germinated randomly all over the crop cycle. In summary, straw and biodegradable plastic mulches offered the same benefits as conventional PE mulch. Therefore, they can be considered a feasible and more sustainable option, in addition to being consistent with the principles of the bioeconomy.

Pisum sativum L. ssp. arvense, is colloquially called tirabeque or mangetout because it is eaten whole; its pods are recognized as a delicatessen in cooking due to its crunch on the palate and high sweetness. Furthermore, this legume is an important source of protein and antioxidant compounds. Quality control in this species requires the analysis of a large number of samples using costly and laborious conventional methods. For this reason, a non-chemical and rapid technique as near-infrared reflectance spectroscopy (NIRS) was explored to determine its physicochemical quality (color, firmness, total soluble solids, pH, total polyphenols, ascorbic acid and protein content). Pod samples from different cultivars and grown under different fertigation treatments were added to the NIRS analysis to increase spectral and chemical variability in the calibration set. Modified partial least squares regression was used for obtaining the calibration models of these parameters. The coefficients of determination in the external validation ranged from 0.50 to 0.88. The RPD (standard deviation to standard error of prediction ratio) and RER (standard deviation to range) were variable for quality parameters and showed values that were characteristic of equations suitable for quantitative prediction and screening purposes, except for the total soluble solid calibration model.

There is currently a limited understanding of the complex response of fungal microbiota diversity to organic fertigation. In this work, a 2-year field trial with organic tomato crops in a soil previously amended with fresh sheep manure was conducted. Two hypotheses were compared: (i) fertigation with organic liquid fertilizers versus (ii) irrigation with water. At the end of both years, soils were analyzed for physical–chemical parameters and mycobiome variables. Plate culture and DNA metabarcoding methods were performed in order to obtain a detailed understanding of soil fungal communities. Fertigation did not increase any of the physical–chemical parameters. Concerning soil fungal communities, differences were only found regarding the identification of biomarkers. The class Leotiomycetes and the family Myxotrichaceae were identified as biomarkers in the soil fungal community analyzed by means of DNA metabarcoding of the “fertigation” treatment at the end of Year 1. The Mortierella genus was detected as a biomarker in the “water” treatment, and Mucor was identified in the “fertigation” treatment in the cultivable soil fungi at the end of Year 2. In both years, tomato yield and fruit quality did not consistently differ between treatments, despite the high cost of the fertilizers added through fertigation.

Appropriate fertigation management plays an important role in increasing crop quality and economizing water. The objective of the study was to determine the effects of two fertigation treatments, normal (T100) and 50% sustained deficit (T50), on the physico-chemical quality of legumes. The determinations were performed on the edible parts of peas, French beans and mangetout. The trials were conducted in a protected cultivation certified organic farm. The response of legumes to the treatments varied between the cultivars tested. The fertigation treatments had a significant effect on the morphometric traits (width for mangetout and French bean; fresh weight for French bean; seed height for Pea cv. Lincoln). The total soluble solids and citric acid content have been shown to be increased by low soil water availability (T50) for mangetout. Fertigation treatments did not significantly affect the antioxidant compounds (total phenolic and ascorbic acid), minerals and protein fraction contents of legumes studied. Regarding legume health benefits, the most prominent cultivars were BC-033620 pea and French bean because of their high total phenolic (65 mg gallic acid equivalent 100 g⁻¹ fresh weight) and ascorbic acid content (55 mg ascorbic acid 100 g⁻¹ fresh weight), respectively. The results expand our knowledge concerning the nutraceutical quality and appropriate cultivation methods of legumes in order to make the system more sustainable and to encourage their consumption.