Abstract
The enhancement of the actual low yields is the most important challenge regarding organic farming management. In this view, a valid tool may arise by the improvement of fertilization management and efficiency. In this regard, arbuscular mycorrhizal fungi (AMF) can play an important role, especially in low fertility soils such as calcareous ones, through a better nutrient uptake and by alleviating abiotic stresses. A replicated-space experiment was carried out to investigate the role of mycorrhizal-based inoculants combined with full or halved fertilizer doses on yield and physiological traits of three early potato cultivars organically grown in highly calcareous and alkaline soils. The results indicate that AMF symbiosis ameliorated, in comparison to the not-inoculated plants, the potato tolerance to limestone stress by enhancing the potential quantum efficiency of photosystem II (Fv/F0) and plant gas-exchange parameters (photosynthesis rate and stomatal conductance). Moreover, a significant improvement of marketable yield (+25%) was observed, mainly due to an increase of the number of tubers plant−1 (+21%) and, to a lesser extent, of average tuber weight (+10%). The AMF efficiency was higher applying halved fertilizer doses and in the location where soil conditions were unfavourable for potato growth. Moreover, the qRT-PCR highlighted that AMF colonization was similar in each location, demonstrating their tolerance to limestone, alkalinity and P stresses. These findings outlined that AMF are good candidate to bio-ameliorate calcareous soils and are very useful for improving potato yields under organic farming, limiting external fertilizers supply and environmental pollution.
Highlights
In the latest years, an increasing public interest for environmental safety and food quality has driven a major expansion in the organic farming sector all over the world [1]
analysis of variance (ANOVA) results showed that mycorrhizal colonization was significantly influenced (p ≤ 0.001) by main factors and even their interactions (Table 3)
The changes in terms of yield, including its components, and physiological traits in early potato crop organically grown in relation to mycorrhizal colonization and cultivar were studied in three crop organically grown in relation to mycorrhizal colonization and cultivar were studied in three different locations
Summary
An increasing public interest for environmental safety and food quality has driven a major expansion in the organic farming sector all over the world [1]. In Europe, Spain, Italy and France are the countries with the largest organic agricultural land (2.1, 1.9 and 1.7 Mha, respectively [2]). The entire European Union organic food market is composed of 37% cereal products, 11% dairy products, 11% meat and 41% all other products [3]. Potato (Solanum tuberosum L.) is successfully organically grown both in Italy [4] and elsewhere [5,6]. The production of organic early potato tubers is of particular economic relevance. They can be sold around 200–250 euros
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