Intercropping with grasses helps to reduce iron chlorosis in olive

Abstract

Grasses are more efficient than dicots in acquiring Fe from calcareous soils. We studied whether intercropping with grasses alleviates Fe chlorosis in olive and whether the effect persists in succeeding dicot crops. Three different pot experiments were conducted. In the first, olive plants were intercropped with 6 different grass species (purple false brome, annual ryegrass, compact brome, goatgrass, barley and red fescue); in the second, the two species best performing in the previous experiment were studied in various calcareous soils and; in the third, chickpea and peanut were grown in pots previously used to cultivate the two grasses. Intercropping with purple false brome and barley increased leaf chlorophyll concentrations and/or boosted growth of olive trees on three different calcareous soils. Olive growth was adversely affected by intercropping in one soil as a result of competition for water. Intercropping increased Fe, Mn, Cu and Zn leaf contents in olive. Also, grass cropping generally raised available levels of soil Fe, Mn, Cu and Zn; this effect, however, resulted in no substantial alleviation of Fe chlorosis in succeeding chickpea or peanut crops. Intercropping with purple false brome and barley appears to be a promising remedy for Fe chlorosis in olive orchards affected by Fe chlorosis.

Evaluation of FE-heme Applications or Intercropping for Preventing Iron Deficiency in Blueberry

“…2). This effect has been noted in other studies on intercropping systems (Cañasveras et al 2014;Covarrubias et al 2014), and it has been attributed to the strong competition for water and nutrients between some grasses and the main crop. In fact, our results show lower leaf N, P, and K concentrations in blueberries associated with Festuca rubra than with the other treatments, whereas this effect was not observed in blueberries associated with Poa pratensis (Table 2).…”

“…On the other hand, several studies have shown that the intercropping of kiwifruit, citrus, grapevine, and olive with graminaceous species contributes to preventing Fe chlorosis with similar effectiveness to synthetic Fe chelates (Ammari and Rombolà 2010;Cañasveras et al 2014;Covarrubias et al 2014). The improvement of Fe nutrition in intercropped fruit tree crops induced by intercropping with grasses as Festuca rubra, Poa pratensis, Hordeum vulgare, and Brachypodium distachyon, is partially due to their abilities to exudate mugineic acid family phytosiderophores (MAs), which are chelating compounds characterized by a high affinity with Fe +3 , promoting Fe solubility in alkaline soil pH conditions (≥ 7.0) (Ma et al 2003;Xiong et al 2013).…”

Environmental isolation explains Iberian genetic diversity in the highly homozygous model grass Brachypodium distachyon

“…This species and B. hybridum can protect the soil from being eroded [81] and are therefore suitable grass cover crops to olive grooves, vineyards and dry fruit croplands [81, 82]. Due to the high degree of homozygosity, obtaining inbreeding lines of B. distachyon can be easily done even under laboratory conditions allowing the rapid generation of reference and cultivated lines.…”

The detection of endogenous 2’-deoxymugineic acid in olives (Olea europaea L.) indicates the biosynthesis of mugineic acid family phytosiderophores in non-graminaceous plants

“…Olive trees originate from the Mediterranean region, where calcareous soils are predominant, but they rarely exhibit Fe-deficiency-induced chlorosis under normal conditions (Sanz et al 1992). Alcántara et al (2003) selected Fe deficiency-tolerant varieties, and Cañasveras et al (2014) showed that intercropping with grasses helped to reduce Fe chlorosis in olive; however, the mechanisms underlying their tolerance to Fe deficiency have yet to be clarified.…”