Enrique Agulló

Substitution of peat in horticultural seedlings: suitability of digestate-derived compost from cattle manure and maize silage codigestion.

The increasing demand for soilless media for horticultural crop production and the rising environmental concerns about the use of non-renewable resources such as peat as substrate has led to the search for alternative materials as constituents of growing media, such as waste organic by-products. Also, biogas production through the anaerobic digestion of organic wastes generates a potential fertilizer, the digested substrate (digestate). The aim of this work was to study the feasibility of using the composted solid fraction of a digestate obtained after the codigestion of cattle manure and maize–oat silage as a component in the formulation of growing media for the commercial seedling production of three species: tomato (Lycopersicon esculentum Mill.), muskmelon (Cucumis melo L.), and pepper (Capsicum annuum L.). Four substrates were compared: pure peat (control) and three mixtures containing 25%, 50%, and 75% by volume of compost with the corresponding amount of peat. Physical, physicochemical, and chemical analyses of the different growing media were carried out and the effects of the different mixtures of peat/compost on seed germination and on the nutritional status of the seedlings were also studied. In general, compost addition neither influenced negatively the physical and physicochemical properties nor produced any reduction in the germination rate in the species studied, but it did enhance the seedlings’ nutritional status.

Fe, Cu, Mn, And Zn Input and Availability in Calcareous Soils Amended with the Solid Phase of Pig Slurry

Abstract A number of feed additives, such as As, Co, Cu, Fe, Mn, Zn, and Se are added to enhance pig growth and performance, but most of these micronutrients pass directly through the animal, which leads to elevated levels in the manure. An accumulation of P and trace elements, especially Zn and Cu, typically occurs with repeated swine manure application on soil. The potential environmental hazard associated with the loading of these elements in amended soils could actually be a positive fact in calcareous soils that usually show a high deficiency in available micronutrients. In this experiment, we analyzed the effect of the application of the solid phase of pig slurry to agricultural calcareous soils on the input and availability of Fe, Mn, Cu, and Zn. The experimental design was based on a field experiment using, as fertilizers two manures derived from the solid phase of pig slurry (composted, [C] and noncomposted [NC]). Two application rates were established to supply to the soils 300 and 450 kg N ha−1, respectively, using a nonamended soil as a control. Soil samples were taken at 0, 14, 33, 53, 73, and 103 days. Available Fe, Cu, Mn, and Zn were extracted with DTPA (0.005 M DTPA, 0.01 N CaCl2, and 0.1 N TEA at pH 7) and determined by using atomic absorption spectrophotometry. A significant effect of manure application on available Fe, Cu, Mn, and Zn was observed. Zn and, to a lesser degree, Fe DTPA contents in amended soils were increased by composted and noncomposted pig manure, and Mn was increased by the noncomposted material. Extractable Cu was lower in amended soils, than in the controls. In general, the composted pig manure induced less variation of the studied micronutrient contents in amended soils than the noncomposted manure.

Composition of Oregano Essential Oil (Origanum vulgare) as Affected by the Use of Winery-Distillery Composts

Abstract Three different winery-distillery composts were used as binary components with peat-perlite mix (PP) in growing media for oregano cultivation. These composts were prepared using exhausted grape marc as principal component combined with several co-composting wastes, such as citrus juice waste (C1), tomato soup waste (C2) and cattle manure (C3). Three treatments were established for each compost type, with increasing compost quantities to traditional PP mix (0%, 25% and 50%). Physical and physico-chemical analyses of the different mixtures of winery-distillery composts and PP were carried out. The volatile compounds of oregano samples were extracted by steam-hydrodistillation and analyzed by GC/MS. Twenty-seven compounds were tentatively identified, with terpinen-4-ol, carvacrol, thymol and γ-terpinene being the major compounds. The total yield of volatile compounds (mg plant−1) was always increased by the use of the compost materials as ingredients of the growing media. However, the total volatile concentration of control samples, 16.3 g kg−1, was only increased by the compost-mixtures containing 50% of C1 and 25% of C2 or C3. The final recommendation is to use grape marc together with citrus juice or tomato soup wastes at ratios of 1:1 as growing media for the cultivation of aromatic herbs, including oregano

Use of Composts Derived from Winery Wastes in Tomato Crop

The effects of fertigation levels on parameters related to fruit quality were studied, using compost derived from winery wastes as growing media for a tomato crop. We evaluated five growing substrates: perlite and four composts derived from winery‐distillery residues. Two levels of fertigation were applied: a standard fertigation for tomato crop and a half‐level of fertigation obtained by a 50/50 v/v dilution. Our objective was to evaluate the possibilities of winery waste composts as an alternative to perlite as growing substrate. We tried to measure the effect of these organic substrates on yield and on the parameters more strongly related with fruit quality: tomato solid soluble content and titratable acidity. The commercial F1 hybrid variety of tomato “Boludo” was used. Significant differences among the levels of fertigation were found, but only small differences among the substrates could be observed. These results have been obtained under two different fertigation levels, one of them probably causing a slight level of salinity. The composts evaluated have shown adequate characteristics when used as substrates for a tomato crop, indicating the suitability of winery waste composts as an alternative to the growing media currently used.

Recycling of Agro-food Wastes into Vineyards by Composting: Agronomic Validation in Field Conditions

The objective of this work was to study the agronomic effects produced by the application of agro-food composts in vineyards (Vitis vinifera L.) in organic farming field conditions. To carry out this objective, yield, nutrient contents and quality of fruit, and different physicochemical, chemical, and biological properties of the soil at the beginning and end of the experiment were studied. Four agro-food-derived composts were used. Three of these composts were elaborated mainly using exhausted grape marc and wastes from citrus juice production (C1 and C2) or cattle manure (C3). Compost (C4) was elaborated using the solid fraction of a digestate obtained after the anaerobic digestion of cattle slurry, mixed with vine shoot pruning. Three treatments were used as control treatments: sheep manure (SM), commercial pelletized sheep-derived compost (CC pellet), and a treatment without any organic amendment (B). The study was developed in Fuente Álamo (Albacete, Spain) using Petit Verdot vine variety and organic farming management. The addition into the vineyard soil of the agro-food-derived composts increased soil salinity, the contents in nitrogen and oxidizable organic carbon, and the soil biological activity. Grape yield was also significantly increased with the compost-based treatments compared to control treatment (B), with C1 and C3 showing similar results to the treatment CC pellet. In general, organic amendments did not affect the alcohol production capacity of the fruit but increased the total acidity and the contents of several nutrients, as well as reduced polyphenol levels in grape.

Quality assessment of tomato landraces and virus‐resistant breeding lines: quick estimation by near infrared reflectance spectroscopy

BACKGROUND Several tomato landraces are very popular in south-eastern Spain for their organoleptic fruit quality, but these cultivars are highly susceptible to several viruses. A breeding programme is being carried out for the introduction of virus resistances into these landraces. In the last steps of our breeding programme a high number of breeding lines must be evaluated for agronomic and organoleptic quality parameters. Near infrared reflectance spectroscopy (NIRS) technology shows considerable promise and is ideally suited to the requirements of breeders. RESULTS Significant differences between a set of 35 tomato breeding lines, seven landraces and one commercial hybrid were observed for quality and mineral content parameters, suggesting that there are considerable levels of genetic diversity between the cultivar groups studied. Using NIRS on dry samples of tomato constitutes a feasible technique to estimate the content of several minerals (C, N, P, K, Ca, Na, Mn, Mg and Cu) according to the coefficient of determination for calibration (R(2) > 0.90). NIRS estimations of soluble solids content and titratable acidity obtained were considered useful only for general screening purposes. CONCLUSIONS NIRS technology may be a useful tool in the selection of lines coming out of tomato breeding programs, allowing a quick estimation of mineral content. However, the estimation of soluble solids content and titratable acidity by NIRS must be improved.

Micronutrient Concentration in Horticultural Crops Grown on a Soil Amended with the Solid Phase of Pig Slurry

Abstract Previous studies carried out on metal fractionation have shown that more than 95% of metals are in the solid phase of pig slurries (SPPS), with copper (Cu), and zinc (Zn) being the commonly occurring micronutrients in animal slurries. The input of micronutrients associated with the application of SPPS could be an important pathway for the supply of these essential elements to arable crops in bioavailable forms, especially in calcareous soils, which induce the immobilization of these elements. The aim of this work was to study the effect of application of pig manures (fresh and composted) derived from the SPPS on the micronutrient—iron (Fe), Cu, Magnesium (Mn), and Zn—concentration on amended calcareous soils in horticultural plants (cucumber and Milan cabbage). In addition, the effect of composting and application rates were analyzed. The experiment was conducted in field conditions on a Xerofluvent soil with a clayey‐loam texture. The organic wastes used in this study were uncomposted and composted solid fractions of swine manure slurry (UC‐SPPS and C‐SPPS, respectively) at two different rates (supplying 300 kg N ha−1 and 450 kg N ha−1 respectively). A mineral fertilizer treatment equivalent to 300 kg N ha−1 and a control treatment without fertilization were also included for comparison. The use of SPPS amendment induced a biomass production similar to the mineral fertilizer for cucumber, but higher in Milan cabbage plants, without any yield increment associated with the increased application rate of SPPS or composting. Micronutrient concentration in cucumber and cabbage plants was affected by the SPPS amendment, with an increase of Mn and Zn uptake and a decrease of Cu, compared to the control. The increasing application rate of SPPS did not induce a general increase in the plant uptake of micronutrients; the opposite was true for the crops grown in the C‐SPPS‐amended soils.

Valorization of Mediterranean Livestock Manures: Composting of Rabbit and Goat Manure and Quality Assessment of the Compost Obtained

The purpose of this work was to study the viability of the composting of goat (Capra aegagrus hircus) manure (GM) and rabbit (Oryctolagus cuniculus) manure (RM) and to evaluate the quality of the compost obtained. For this, a mixture of these manures was prepared at a goat/rabbit ratio of 44:56 (fresh-weight basis) and 50:50 (dry-weight basis). The mixture was composted by the Rutgers static pile composting system, with forced aeration and controlled temperature. Throughout the composting process, the temperature was monitored and physicochemical, chemical, and biological parameters were evaluated. The temperature evolution showed the suitable development of the composting process, with thermophilic values (>40 °C) maintained for more than 90 days. The finished compost had stabilized and humified organic matter. However, the pH (9.4) and the salinity (EC of 13.4 dS/m) could limit its potential agricultural use.

Vermicomposting as an Added-Value Post-treatment for Livestock Waste Composts

The aim of this work was to study the effects of vermicomposting on selected properties of composts derived from animal and plant wastes. For this, two different worm beds were established and fed with two composts: C1, made from goat (Capra aegagrus hircus) manure and rosemary (Rosmarinus officinalis) pruning wastes, and C2, made from rabbit (Oryctolagus cuniculus) manure and grass clippings, to study the quality of the final vermicomposts. Physical and chemical properties were determined in the end products. Vermicomposting improved several properties of the composts, increasing their total water-holding capacity (in C1, from 333 to 451 mL/L, and in C2, from 371to 419 mL/L), reducing salinity (in C1, from 6.8 to 2.4 dS/m, and in C2, from 10.3 to 4.6 dS/m), and balancing pH in the final composts obtained, especially in C1 (from 8.57 to 8.02). The type of raw material used in the worm beds significantly influenced the final characteristics of the end products obtained and the development of the process, with more favorable results being obtained with the compost derived from rabbit manure and grass clippings (C2).

Optimization of Medlar Pruning Waste Composting Process by Cattle Manure Addition

In this study, medlar pruning waste (MPW) was composted with and without cattle manure (CM). Two piles were prepared: one contained only MPW (pile 1) and one contained MPW augmented with CM (pile 2). Both piles were composted in an enclosed composting vessel with passive aeration and aeration by turning. During the composting process, temperature, pH, electrical conductivity (EC), organic matter (OM), OM losses, total organic carbon (Corg), total nitrogen (NT), Corg/NT ratio, and germination index (GI) were measured. Pile 2 produced a faster increase of the temperature and had a longer thermophilic phase than pile 1. However, the rate of OM degradation was faster in pile 1 than in the pile containing CM (pile 2). The addition of CM also resulted in an increased pH and salt content. In both piles, C/N ratio decreased throughout the process, presumably as a result of the faster organic carbon degradation compared to N mineralization. However, only pile 2 had a final C/N ratio <20, the limit accepted for compost by the Spanish legislation on fertilizer. Also, both composts had GI > 50 percent, indicating an absence of phytotoxicity.