Variation of chickpea nodulation in a Mediterranean agroecosystem: relationship with soil characteristics and thresholds for significant contribution to plant growth

Y. Chenene¹*, D. Blavet², M. Belalmi¹, G. Kaci¹³, M. Teffahi¹ and S.M. Ounane¹

¹High National School of Agronomy, Plant Production Department, Laboratory for Vegetal Production, El Harrach, Algiers, Algeria
²Research Institute for Development-IRD, UMR Eco&Sols, Functional Ecology and Biogeochemistry of Soils and Agro-Ecosystems, INRA-IRD-CIRAD-SupAgro, University of Montpellier, Montpellier, France
³University M’Hamed Bougara of Boumerdes, Department of Agronomic Sciences, Avenue de l’indépendance, Boumerdes, Algeria
*Correspondence: cheneneyacine@gmail.com

Abstract:

This study was designed to investigate the influence of some environmental constraints on chickpea (Cicer arietinum L.) growth and nodulation in a reference agroecosystem. This multi-local field experiment, realized in the agroecosystem of Chlef in northern Algeria, involved 24 sites where the local well-adapted genotype Ain temouchent is grown. Determination of soil properties allowed the identification of three clusters of sites. Plant biomass (SDW) varied significantly among sites from 6.7 to 39.4 g SDW plant^-1 and was highly correlated with nodule biomass (NDW). The slope of the regression function between NDW and SDW, defined as the efficiency in use of the rhizobial symbiosis (EURS) inside clusters ranged from 67 to 200 g SDW g^-1 NDW. Analysis of the EURS highlighted the existence of a low nodulation threshold of 0.1 g NDW plant^-1 below which the contribution of nodulation to the host plant growth was not significant and a high threshold above which the nodule biomass increase was not linked with an increase in shoot biomass. Thus, the significant regression of shoot growth as a function of nodulation ranged from 0.10 to 0.35 g NDW plant^-1 (R² = 0.54, P < 0.001). Moreover, nodule biomass was positively correlated with soil Olsen-P, more particularly in cluster A (R² = 0.50, P < 0.05) and B (R² = 0.61, P < 0.01). This approach proved to be a rapid and efficient way to identify the major factors affecting nodulation in order to develop strategies to optimize nodule contribution to chickpea growth and yield.

Key words:

chickpea, efficiency in use of the rhizobial symbiosis, nodulation, Phosphorus, plant-soil interaction, symbiotic nitrogen fixation

Effect of presowing treatment of seeds with insecticides on nodulating ability, nitrate reductase activity and plastid pigments content of lucerne (Medicago sativa L.)

V. Vasileva and A. Ilieva

Institute of Forage Crops, Gen. Vl. Vazov Str. 89, Pleven 5800, Bulgaria;e-mail: viliana.vasileva@gmail.com

Abstract:

To determine the effect of presowing treatment of seeds on the nodulation ability, nitrate reductase activity and plastid pigments content of lucerne (cv. Obnova), a pot trial was carried out at the Institute of Forage Crops – Pleven, Bulgaria. The insecticides Promet 400 SK (furathiocarb) at the dose of 3 L, and Carbodan 35 ST (carbofuran) at the dose of 1, 2 and 3 L 100 kg-1 seeds were used. It was found that the insecticides tested did not depress the nodulation. Nodule number and specific nodulation ability when treated with Carbodan 35 ST at the dose of 3 L 100 kg-1 seeds exceeded that of the control by 23% and 7%, respectively. The root length for the variants with presowing treatment of seeds was higher as compared to the control by 7 to 26%. The variant with Carbodan at the doses of 2 and 3 L 100 kg-1 seeds and Promet increased nitrate reductase activity in roots, and that with Carbodan at the dose of 1 L 100 kg-1 seeds- in the leaves. Total content of plastid pigments increased in all variants with Carbodan and was lower than the untreated control in the variant with Promet.

Key words: