The short-term responses of soil quality indicators are important for assessing the effects of new management practices and addressing threats to crop yields in greenhouses. The aim of this study was to assess, during three consecutive cropping seasons, the effect of a sustainable management package (CRTMP)—which includes the on-site reuse of greenhouse crop residues and tillage—in comparison with conventional management, based on fertigation only (CMP), on certain biochemical soil quality indicators and crop yields. CRTMP significantly increased (p < 0.05) the values of total organic carbon (TOC), particulate organic carbon (POC), light fraction (LF), water soluble organic carbon (WSOC), and dehydrogenase (DH) and β-glucosidase (GL) activities at a depth of 0–15 cm, as well as the mean concentration of nitrates in the soil solution. In addition, a significant Pearson’s correlation (p < 0.01) found between the indicators suggested a balanced improvement of soil biological activity and nutritional soil state. Nonetheless, the significant (p < 0.05) increases in the mean concentration of chlorides in the soil solution and electrical conductivity (p < 0.05) increased the risk of salinization, which may have affected the concentration of nitrates in the petiole sap and total production in CRTMP, which were significantly lower than in CMP. Nevertheless, the proportion of premium product was significantly higher in CRTMP, while the proportion of non-commercial production decreased.

We present a method for the rapid determination of methane emissions from landfills based on atmospheric dispersion theory, which suggests that the methane concentration, at a small distance from the soil/atmosphere interface, is proportional to its flux. Thus, after suitable calibration, the determination of methane concentrations close to the ground allows for flux determination in a shorter time than with standard enclosure techniques. This concept was tested using a surface probe in direct contact with the ground. The probe extracts a continuous sample of the air at the probe/ground interface and transports it to a portable methane analyzer. It was observed that stable methane concentrations were measured 30 s after the probe was positioned at the measurement point. These concentrations correlated well with the fluxes measured by standard static chambers. The method was used to determine the fluxes at 217 points within a 90,000 m(2) landfill. These measurements facilitated mapping of the CH4 emissions and the localization of hotspots. We conclude that the method is simple, effective, and relatively quick, compared to existing standard methods.

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Agriculture and mining are the most important economic activities in the province of Almería (SE Spain) and generate large amounts of waste. Almería is one of the driest regions in Europe, and its water resources come mainly from groundwater. The high water consumption of greenhouses (between 5000 and 6000 m³ ha^-1 y^-1) has resulted in a sharp decline of water table levels and a worsening of water quality. Therefore, it is necessary to implement actions that lead to the more efficient use of irrigation water. The objective of this study was to evaluate the effect of two waste types (marble sludge and biochar from greenhouse plant debris) on the soil water holding capacity. Three treatments were performed in pots using two of the most common soils in greenhouses. A lettuce seedling was planted in each pot, and the volumetric water content was periodically controlled. The first treatment contained 600 g of soil, the second treatment contained 200 g of marble sludge at the bottom and 400 g of soil on the surface, and the third treatment contained 150 g of marble sludge at the bottom, 50 g of biochar in the middle and 400 g of soil on the surface. The results showed that the use of marble sludge, biochar and the combination of both waste types increased water holding capacity. The volumetric water content was relatively high for a longer time, allowing for a reduction in watering frequency and enabling more efficient water use. The waste applications<strong> </strong>were most effective in the soil with a thicker texture and lower evaporation rate.