Soil Fungi-Plant Interaction

Computer modelling & simulatio

Integration of the regulated deficit irrigation strategy in a sustainable orchard management system

Irrigation in arid regions requires special attention to optimize the management of all components of the orchard system in order to increase water use efficiency and reduce environmental impacts (e.g. soil salinization, degradation of ground and surface waters). This six-year study reports the comparison of some orchard practices (soil and irrigation management, plant nutrition) routinely adopted by local farmers (conventional, C) with those interventions having the potential to save water and maximize water use efficiency in a peach orchard and therefore defined as sustainable (S). Due to the relative approach (C versus S) used in this study, classical statistical comparison of results could not be made. The S system included the application of regulated deficit irrigation (RDI) with specific crop coefficients to calculate the plant water requirement. The S system on average saved 1450 m3 ha-1 of water per year without affecting yield or fruit quality. The concept of economic water productivity (EWP) is discussed. We conclude that addressing some practices currently adopted by farmers could increase sustainability of irrigation and enhance (EWP) in peach tree orchards

Sustainable apricot orchard management to improve soil fertility and water use efficiency

This 4-year on-farm study reports the effects of different agricultural practices on yield and carbon input in an apricot orchard grown in Mediterranean area. Groups of plants under local orchard management (LOM) practices (i.e., soil tillage, removing of pruning residues, mineral fertilisers) were compared with plots under sustainable orchard management (SOM) actions (i.e., cover crop, no-tillage, compost application, mulching of pruning residues). In the SOM blocks, fertilization was based on plant demand and soil availability and irrigation volumes were calculated on the evapotranspiration values basis, while in the LOM plots fertilization and irrigation were empirically managed. Results show that yield was enhanced by 28% by SOM. In comparison with LOM plots, changed practices increased the amount of N, P, K annually incorporated into soil thus increasing their reservoir in the soil. The study demonstrates that appropriate crop management can increase the mean annual carbon soil inputs from about 1.5 t ha-1 to 9.0 t ha-1 per year

Sustainable irrigation in fruit trees

Water management in fruit growing, particularly in areas with high water deficit, low rainfall and limited availability of water for irrigation should aid to save water by: i) the choice of high efficiency irrigation methods and their correct management; ii) the proper choice of the specie, cultivar and rootstock to optimise plant water use; iii) the proper choice of the architecture of the canopy and it's correct management in order to improve water use efficiency; iv) the application of regulated deficit irrigation at growth stages less sensitive to water deficit; v) strengthening the role of technical assistance for a rapid transfer of knowledge to the growers on the sustainable use of water in fruit growing

Soil water availability and relationship between canopy and roots in young olive trees (cv Coratina).

Trials were carried out in the Basilicata region (41°03’ N, 15°42’ E, Southern Italy) using ownrooted plants of the cultivar Coratina planted in 1992 at distances of 6 x 3 m. During 1992, the whole plot (about 7000 m2) was irrigated. From 1993 onwards, irrigation was suspended in part of the plot. A representative number of plants during 1992, 1993, 1994 and 1998 was destroyed in order to carry out dry weight measurements on roots and canopy. The ratio between root and leaf dry weight was always greater in nonirrigated plants compared to irrigated ones. Roots explored a soil volume ranged from 0.5 m3 in the first year to 16.8 m3 in the seventh year for irrigated plants and from 0.5 m3 to 13.4 m3 for non-irrigated ones. The study showed that in deep soil, with a greater capacity for water storage during the rainfall season, limited water supply (220-1350 m3 ha-1) during the first seven years from planting increased canopy growth by 79% compared to nonirrigated plants, but made little difference to root growth. In non-irrigated plants, canopy growth (but not root growth) was drastically reduced, as a defence strategy against water deficit, making for a better root/leaf ratio and consequently greater water availability for leaves

Sustainable management for increasing soil microbial diversity in a Mediterranean agro-ecosystem

Olive can be considered a paradigm species for Mediterranean agro-ecosystems. In conventional olive growing, adopted by the majority of the farmers, frequent soil tillage has reduced soil microbial diversity and microbiota complexity that strongly contribute to the overall soil fertility. Therefore, the conventional agronomic practices should evolve in a more sustainable olive management addressed to improve soil microbial diversity. A better understanding of the ecology of soil microorganisms could lead to identify agricultural management practices that stimulate and select the soil microorganisms having beneficial purposes in agriculture, such those interested in nitrogen cycle. The aim of this study was to evaluate the effects of sustainable practices (grass cover and pruning residues recycling) on soil microbioligical quality in a Mediterranean olive orchard. The trials were carried out in a mature olive grove (Olea europaea L. – cv Maiatica) located in Basilicata Region (Southern Italy.) and managed for 13 years (medium-term) according to two different soil management systems: the sustainable treatment (ST) and the conventional treatment (CT). Soil microorganisms in the two systems were monitored by both microbiological cultural-dependent and molecular methods, and by microscopy. In the ST olive orchard, soil microbiota showed a higher complexity and metabolic diversity. The adoption of ‘innovative’, sustainable, agricultural practices had positive effects on soil microbiota and its biodiversity, which in turn can influence soil fertility and plant growth by increasing nutrients availability and turnover. The results of this study encourage the use of sustainable agricultural practices able to enhance physico-chemical and microbial soil fertility and promote good-quality fruit production without detrimental effects on water and soil resources. The role of the identified microorganisms in the soil microbial netwo rk is discussed, in order to provide a detailed view of the impact that man-made selection had on soil microorganisms of agricultural relevance in a typical Mediterranean agronomic biosystem