Management of Iron and Manganese Toxicities of Lentil Crops Grown in Central Chile

Abstract

Iron (Fe) and manganese (Mn) toxicity is a widespread problem in lentil production in the coastal dryland of Chile. Increasing the soil pH by liming with CaCO3 or incrementing grain yields through nitrogen fertilization can help the plants to reduce metal concentration. Thus, the main objective of this work was to evaluate two different fertilization strategies (lime (CaCO3) and nitrogen (N) additions) to reduce Fe and Mn toxicities in lentils. Lentils grown under field conditions with the highest Fe and Mn concentrations showed toxicity symptoms, but without grain yield reductions. In a pot experiment using the same soil as in the field with toxicity symptoms, the dry matter (DM) produced at the end of the trial was higher in the plants that received N while the lowest DM production was recorded in those plants treated with lime. In particular, higher root DM sustained the growth of the N-fertilized shoots, which also positively affected the grain yields being 33% higher than the control treatment (no fertilization addition). In the plants fertilized with N, the Fe and Mn levels in the shoots were lower than the control plants and those grown in soils treated with lime, but showed higher concentrations of Fe and Mn in roots. In parallel, roots exhibited high concentrations of Fe and Mn that were 13- and 9-fold higher than in the shoots. Additionally, a significant decrease of 29% in Mn concentration in the grains of plants treated with N was reported. Overall, our results suggest that an increase in DM of lentils by the addition of N can reduce the Mn concentration on leaves to a level that is likely under the threshold that causes toxicity in plant tissues. Finally, we conclude that the increase of Fe and Mn in the roots may be connected to the reduction of these metals on leaves.

Nitrogen fertilizer promoting salt tolerance of two sorghum varieties under different salt compositions

“…These findings were in agreement with those of Ibrahim et al (2019), who indicated that N application in salty soils is indicated as improving plant growth parameters. Also, similar result was reported by Amigo et al (2021), who noticed that N fertilization increased DM production of lentils and reduce Fe and Mn concentrations on leaves to a level that is possibly under the threshold that causes toxicity in plant tissues. Furthermore, saline soil can change the role of N in plants metabolism.…”

Field pea/spring triticale mixtures influenced iron and manganese concentrations in soil and forage plant uptake

“…In addition, due to the possible symbiotic binding of N 2 by legumes and the resulting release of H + into the rhizosphere, acidification of the rhizosphere occurs (Amigo et al., 2021). Combining these processes, it can be assumed that the cultivation of legumes may result in an increased availability of Fe and Mn in the soil.…”

“…However, not all forms of Fe and Mn are available to crop plants. According to Amigo et al (2021), in particular, soil redox potential and pH determine the availability of Fe and Mn to plants. The authors also point out that by changing the redox potential by replacing soil oxygen with nitrogen gas, there was an increase in Fe and Mn soil solubility of several folds.…”