From Leguminosae/Gramineae Intercropping Systems to See Benefits of Intercropping on Iron Nutrition

Abstract

To achieve sustainable development with a growing population while sustaining natural resources, a sustainable intensification of agriculture is necessary. Intercropping is useful for low-input/resource-limited agricultural systems. Iron (Fe) deficiency is a worldwide agricultural problem owing to the low solubility and bioavailability of Fe in alkaline and calcareous soils. Here, we summarize the effects of intercropping systems on Fe nutrition. Several cases showed that intercropping with graminaceous plants could be used to correct Fe nutrition of Leguminosae such as peanut and soybean or fruits such as Psidium guajava L., Citrus, grape and pear in calcareous soils. Intercropping systems have strong positive effects on the physicochemical and biochemical characteristics of soil and the microbial community due to interspecific differences and interactions in the rhizosphere. Rhizosphere interactions can increase the bioavailability of Fe with the help of phytosiderophores. Enriched microorganisms may also facilitate the Fe nutrition of crops. A peanut/maize intercropping system could help us understand the dynamics in rhizosphere and molecular mechanism. However, the role of microbiome in regulating Fe acquisition of root and the mechanisms underlying these phenomena in other intercropping system except peanut/maize need further work, which will help better utilize intercropping to increase the efficiency of Fe foraging.

Intercropping—A Low Input Agricultural Strategy for Food and Environmental Security

“…The soil microbiome plays a vital role in making soil nutrients available to crops and it happens more prominently in a cereal-legume intercropping system. Dai et al [139] mentioned greater Fe foraging in maize + groundnut intercropping system in calcareous soil. In an intercropping system, the competition for nutrients among the crop species can be reduced by selecting appropriate crops with dissimilarity in nutrient needs, root morphology and time of peak requirements.…”

Root exudate signals in plant–plant interactions

“…Chemical cues from neighbouring roots also modify sunflower nitrogen foraging and maize phosphorus foraging (Ljubotina & Cahill, 2019; Zhang et al, 2020). In calcareous soil, intercropping with graminaceous plants improves Fe nutrition of legume crops such as peanut and soybean or fruits such as citrus, grape and pear (Dai et al, 2019). Roots of Graminoid plants secrete more phytosiderophores to bind insoluble Fe (III), enhancing Fe availability (Dai et al, 2019; Xiong et al, 2013) and ameliorating interspecific nutrient competition.…”

“…In calcareous soil, intercropping with graminaceous plants improves Fe nutrition of legume crops such as peanut and soybean or fruits such as citrus, grape and pear (Dai et al, 2019). Roots of Graminoid plants secrete more phytosiderophores to bind insoluble Fe (III), enhancing Fe availability (Dai et al, 2019; Xiong et al, 2013) and ameliorating interspecific nutrient competition. These results reveal that root exudate‐mediated belowground interactions play a vital role in the productivity and efficiency of intercropping systems.…”

Assessment of economic and environmental performance in citrus-based intercropping systems

“…Citrus intercropping systems have been studied in several countries, involving a diversity of forest species (COELHO, 2017;HARRISON AND HARRISON, 2016;MVONDO et al, 2019;PAULUS et al, 2019) and other fruit trees (OUMA AND JERUTO, 2010; ANDO-MENSAH AND OFOSU-BUDU, 2012;SINGHA et al, 2018;GILL et al, 2018), as well as intercropping with vegetables (SINGH et al, 2018), cover crops and grain plants (MARTINELLI et al, 2017;MULINGE et al, 2018), grasses (BELLOTE et al, 2013) and legumes (SELIM et al, 2020;LINARES et al, 2008;DAI et al, 2019). Although very valuable for providing management recommendations for these alternative cropping systems, these studies do not offer critical assessments of the differential performances of those varied crop associations, as compared to conventional monocrop citrus orchards; or quantitative bases for explaining and ranking the economic and environmental performances of those alternatives, as to facilitating technical decision on intercropping options and selection of appropriate indicators for such decisions.…”