Tillage system effect on nitrogen rhizodeposited by faba bean and chickpea

• Published in: Field crops research 2011-01, Vol.120 (1), p.189-195
• Main Authors: López-Bellido, Luis, Benítez-Vega, Jorge, García, Purificación, Redondo, Ramón, López-Bellido, Rafael J.
• Format: Article
• Language: English
• Subjects: 15N labelling; belowground biomass; chickpeas; Cicer arietinum; Conventional tillage; crop production; crop rotation; Crops; faba beans; Mediterranean climate; nitrogen; Nitrogen rhizodeposition; No tillage; nutrient content; plant development; rhizodeposition; rhizosphere; roots; soil fertility; soil nutrient balance; soil nutrients; soil-plant interactions; species differences; Vicia faba
• ISSN: 0378-4290; 1872-6852
• DOI: 10.1016/j.fcr.2010.10.001

The quantification of the below-ground N of legumes is a key to understand its effect on soil N fertility and the N economy of subsequent legume-based rotations. Significant amounts of the N fixed by legumes are incorporated into the soil as fallen leaves and stems. However, the N from roots, nodules and root exudates has rarely been quantified under field conditions, nor have the management effects been evaluated. This study measured the effects of tillage system [no-tillage (NT) and conventional tillage (CT)] on N rhizodeposition in faba bean ( Vicia faba L.) and chickpea ( Cicer arietinum L.) during a 3-year period (2003–2004, 2005–2006 and 2006–2007) in a Vertisol under rainfed Mediterranean conditions. Faba bean and chickpea plants were labelled in situ with 15N using stem feeding and leaf feeding, respectively. NT increased the N derived from rhizodeposition (NdfR) with respect to CT (135 vs. 68 kg N ha −1 in faba bean and 115 vs. 97 kg N ha −1 in chickpea). Such differences between tillage methods can be attributed to the more favourable conditions for root growth produced by NT. NdfR was significantly influenced by depth; in faba bean, the greatest amount (70%) was found in the 0–30 cm layer, whereas in chickpea, 41% of the NdfR was concentrated in the 30–60 cm depth. The 54% and 61% of total plant N was NdfR (in faba bean and chickpea, respectively) representing 90% of the below-ground plant N in both crops. Our results show that the N derived from rhizodeposition is an important source for N balance and is a key to soil fertility in rain-fed Mediterranean cropping systems.