Santiago Bonachela

Irrigation scheduling of plastic greenhouse vegetable crops based on historical weather data

Irrigation scheduling based on the daily historical crop evapotranspiration (ETh) data was theoretically and experimentally assessed for the major soil-grown greenhouse horticultural crops on the Almería coast in order to improve irrigation efficiency. Overall, the simulated seasonal ETh values for different crop cycles from 41 greenhouses were not significantly different from the corresponding values of real-time crop evapotranspiration (ETc). Additionally, for the main greenhouse crops on the Almería coast, the simulated values of the maximum cumulative soil water deficit in each of the 15 consecutive growth cycles (1988–2002) were determined using simple soil-water balances comparing daily ETh and ETc values to schedule irrigation. In most cases, no soil-water deficits affecting greenhouse crop productivity were detected, but the few cases found led us to also assess experimentally the use of ETh for irrigation scheduling of greenhouse horticultural crops. The response of five greenhouse crops to water applications scheduled with daily estimates of ETh and ETc was evaluated in a typical enarenado soil. In tomato, fruit yield did not differ statistically between irrigation treatments, but the spring green bean irrigated using the ETh data presented lower yield than that irrigated using the ETc data. In the remaining experiments, the irrigation-management method based on ETh data was modified to consider the standard deviation of the inter-annual greenhouse reference ET. No differences between irrigation treatments were found for productivity of pepper, zucchini and melon crops.

Measurement and simulation of evaporation from soil in olive orchards

Abstract Evaporation from the soil (Es) beneath an olive orchard was characterised in a semi-arid Mediterranean climate (Córdoba, Spain). First, the microlysimeter method was modified to measure accurately Es beneath tree orchards. The variability in irradiance reaching the soil beneath the orchard caused spatial variations in Es during both evaporation stages. In the first days of the drying cycle, Es was higher for high irradiance locations but the opposite occurred the subsequent days, although daily differences in Es between locations progressively declined. For the energy-limiting stage, linear relationships between Es values and incident photosynthetically active radiation were found for different times throughout the season. The slopes of the relationships were similar, but their intercepts differed substantially, showing the importance of a variable aerodynamic component in determining Es. A simple functional model was formulated to estimate Es at daily time steps. During the energy-limiting stage, Es is calculated as the sum of the equilibrium evaporation at the soil surface and an aerodynamic term, derived from the Penman equation. For the falling rate stage, Ritchies (1972) approach is adopted for the Es calculations. The model was successfully tested in an orchard of 6×6 m spacing, typical of intensive olive orchards, under a wide range of evaporative demand conditions. Trees covered around 36% of the soil surface. The model predicted an average seasonal Es of 286 mm, which represents around one third of the estimated olive evapotranspiration and about 50% of the average seasonal rainfall of the area.

Water use and production of a greenhouse pepper crop under optimum and limited water supply

Summary Sweet pepper, grown from Autumn to Spring, is a major crop in greenhouse vegetable production systems of the Mediterranean coast in south-eastern Spain. Irrigation water is limited in this region, yet little information is available to assist in irrigation management at the farm and regional levels. The aim of this work was to determine crop evapo-transpiration, water-use efficiency and the effect of continuous water deficits on crop growth and production of pepper grown in plastic greenhouses in two growing seasons. Three irrigation treatments were applied: T1, watered with 100% of the estimated crop water requirement; and T2 and T3 watered with 50% and 20% of the estimated crop water requirements, respectively. Seasonal crop evapo-transpiration (ETc) in treatment T1 was 346–362 mm. The effect of water deficit on crop growth became apparent approximately 80 d after transplanting. The contributions of soil water uptake to total ETc for treatments T2 and T3 were 20–22% and 43–47%, respectively. The response of ETc to water stress was apparent at a threshold value of 55% of available water content (AWC), suggesting an allowable depletion of soil moisture equivalent to 27 mm. For treatments T2 and T3, reductions in total fruit production (relative to treatment T1) were 33% and 62%, respectively; and reductions in marketable fruit production were 47% and 67%, respectively. Water deficit had little effect on total fruit number, but substantially increased the proportion of unmarketable fruits due to their small fruit size, and to high incidences of sunburn and blossom-end rot. Linear relationships were found between both shoot biomass and marketable fresh fruit production with ETc. Mean water use efficiency values for shoot dry matter (WUEb) were 4.5 – 4.7 g m–2 mm–1; for total fresh fruit production (WUEt) between 24 – 33 g m–2 mm–1; and for marketable fresh fruit production (WUEm) between 16.9 – 25.9 g m–2 mm–1. Water stress did not induce early fruit production, or influence the relative distribution of assimilates within the plant.

Farm Ponds as Potential Complementary Habitats to Natural Wetlands in a Mediterranean Region

We compared morphometric and physico-chemical characteristics of farm ponds and natural wetlands in Andalusia (southern Spain) to determine whether artificial waterbodies might act as alternative and/or complementary habitats for aquatic biodiversity. Farm ponds were much smaller than natural wetlands, making them unsuitable for species requiring large waterbodies. However, we observed high farm pond density in areas lacking natural wetlands, which suggests a prime role for the conservation of species with low dispersal capacities. Natural-substrate ponds were abundant in traditional extensive farming systems and showed shoreline complexity as high as the most complex natural wetlands. Areas with more intensive agriculture were dominated by artificial-substrate ponds and wetlands, with low physical complexity in both. The high copper load in sediments, due to the use of copper sulphate as biocide, differentiated the artificial-substrate ponds from natural-looking ponds and all natural wetland types. Aqueous mineral levels in farm ponds were much lower than in natural wetlands. We can conclude that farm ponds might play a principal role in region-wide habitat complementarity, by providing a relatively high density of small, permanent, oligohaline waterbodies that is not matched by natural wetland. To enhance this role, measures regulating both pond construction and management are needed, particularly for artificial-substrate ponds.

Pond management and water quality for drip irrigation in Mediterranean intensive horticultural systems

The influence of pond management on water quality for drip-irrigated crops was studied throughout a field survey and a mesocosm experiment. Water sources were pooled into two groups: ground or surface water (GW/SW) and recycled wastewater. Pond covering, which was limited to about a quarter of them, improved water quality by reducing phytoplankton biomass. However, biocide applications and pond dredging were ineffective at improving in-pond water quality. Dredging did not reduce the concentrations of planktonic chlorophyll a or total suspended solids (TSS) in GW/SW fed ponds, whereas biocide applications increased both parameters. Field and experimental data proved that the two predominant taxa of submerged aquatic vegetation (SAV) found in ponds (Potamogeton pectinatus and Chara spp.) improved water quality by increasing water oxygenation and decreasing chlorophyll a and TSS concentrations. Preserving SAV (especially Chara spp.) appears to be an environment-friendly, cost-effective and recommendable alternative strategy for irrigation pond management.

Agricultural Practices in the Mediterranean: A Case Study in Southern Spain

Abstract This chapter appraises the evolution of agricultural practices in the Mediterranean region. Since the early domestication of plants and animals over 10,000 years ago in the eastern Mediterranean, farming practices have been pivotal for the transformation of human society and the environment in this region. Such practices have fundamentally evolved to cope with fluctuating environmental conditions, eventually leading to highly resilient traditional socio-agro systems. In recent times, intensified farming has considerably increased productivity but, in turn, has impaired the environment and human welfare, which has threatened farming sustainability in certain areas. Three farming systems producing dietetically valued foods typically related to the Mediterranean diet are characterized in southern Spain: the extensive Iberian pig production system, the olive production system, and the greenhouse vegetable agro industry.This chapter appraises the evolution of agricultural practices in the Mediterranean region. Since the early domestication of plants and animals over 10,000 years ago in the eastern Mediterranean, farming practices have been pivotal for the transformation of human society and the environment in this region. Such practices have fundamentally evolved to cope with fluctuating environmental conditions, eventually leading to highly resilient traditional socio-agro systems. In recent times, intensified farming has considerably increased productivity but, in turn, has impaired the environment and human welfare, which has threatened farming sustainability in certain areas. Three farming systems producing dietetically valued foods typically related to the Mediterranean diet are characterized in southern Spain: the extensive Iberian pig production system, the olive production system, and the greenhouse vegetable agro industry.

Management effects on fungal assemblages in irrigation ponds: are biodiversity conservation and the control of phytopathogens compatible?

The study of fungi and fungus-like organisms in irrigation ponds has applied interest since waterborne phytopathogens can disperse through the irrigation system to the crop roots. We tested the hypothesis that manag- ing irrigation ponds to maintain high levels of biodiversity could entail agronomic benefits through the control of phytopathogens. The structure of assemblages of fungi and fungus-like taxa were characterized and compared us- ing samples taken from two strata depths (superficial and deep). This was done in four management/water source pond groups of southeastern Spain: groundwater-fed ponds with submerged aquatic vegetation stands (untreated SAV ponds); groundwater-fed ponds submitted to low and high doses of copper sulfate, and ponds fed with recy- cled urban wastewater bearing intermediate doses of copper sulfate. Higher density and diversity of fungi, besides a singular assemblage composition, were found in untreated SAV ponds compared to treated ponds, particularly for samples taken in the deep stratum. Phytopathogenicity of the main phytopathogens detected (Pythium isolates) was generally low and rather unaffected by the type of pond management. However, much evidence from poten- tial unsuitable hosts (submerged macrophyte species) and fungal composition (related to the presence of potential pathogen antagonists) suggests that managing ponds to preserve submerged vegetation might prove useful for controlling root rot diseases.