The Effect of Nitrogen Supply on Water and Nitrogen Use Efficiency by Wheat–Chickpea Intercropping System under Rain-Fed Mediterranean Conditions

Abstract

It is well known that legume–cereal intercropping systems are more efficient in terms of resources use, in particular nitrogen (N) and water. However, the response of this cropping system to water and N co-limitation was poorly studied in most of the recent field researches. The present study aims to assess the relationship between N and water use efficiency (NUE and WUE) by chickpea–durum wheat intercropping under contrasted climate and N supply conditions. Field experiments were carried out during the 2021/2022 growing season, in three sites located at both sub-humid and semi-arid regions. WUE, NUE, aboveground biomass, grain yield and crop physiological parameters for either intercropped chickpea or durum wheat were assessed and compared to the respective measurements in monocultures among all N-fertilizer level × site treatments. The results showed that WUE relative to grain yield (WUEGY) and biomass (WUEYB) were significantly higher in sole cropped wheat under the conditions of the three studied sites, except for WUEYB in S2, in which intercropping increased WUEYB by +0.46 and +1.03 kg m−3, as compared respectively, to monoculture under low application of N fertilizer. As compared to chickpea monoculture, intercropping increased WUEGY by more than 0.30 and 0.57 kg m−3 under semi-arid conditions (S1 and S3) over three N-application doses, and by more than 0.18 kg m−3 under sub-humid conditions (S2). Simultaneously, NUE was significantly increased by intercropping, where in the mixed crop the highest values were noted as compared to sole-cropped durum wheat and chickpea. However, reducing the N-application dose leads to a gradual increase in NUE by more than 4.44 kg kg−1. As a consequence, intercropping enhanced protein accumulation in the grain yield of mixed crops by more than 30 kg ha−1 as compared to sole-cropped durum wheat, in particular under moderate N-application and sub-humid climate. Indeed, average chlorophyll content was increased (7.8%) in intercropped durum wheat under all applied N-doses in sub-humid conditions. Rain-fed chickpea–wheat intercropping promotes an improvement in growth and yield quality thanks to simultaneous optimization of water and N use under low and moderate N-application in both semi-arid and sub-humid climates.

Impact of Cereal–Legume Intercropping on Changes in Soil Nutrients Contents under Semi–Arid Conditions

“…One potential avenue in this regard is the adoption of intercropping systems. Intercropping involves cultivating multiple crop species simultaneously on a single plot of land, aiming to enhance the land utilization efficiency and ultimately achieve higher productivity levels [9,10]. This agricultural practice is grounded in ecological principles, specifically facilitation and complementarity [6,8].…”

“…This agricultural practice is grounded in ecological principles, specifically facilitation and complementarity [6,8]. Furthermore, intercropping systems combining legumes and cereals are widely acknowledged as highly efficient cropping systems with the potential to optimize the utilization of resources, particularly nitrogen and water [10,11]. Moreover, these systems have demonstrated increased resilience to abiotic stressors, such as drought, and offer effective strategies for weed, pest, and disease management without relying on herbicides [12][13][14].…”

The simultaneous assessment of nitrogen and water use efficiency by intercropped pea and barley under contrasted pedoclimatic conditions

“…Much research has been dedicated to enhancing NUE and WUE, however, these factors have typically been assessed separately at different levels of N-fertilization doses (Sinclair et al 2012;Bouras et al 2023). Nevertheless, the interaction between WUE and NUE has rarely been studied in the literature.…”

“…Bouras et al 2023). Simultaneously, assessing N and water use efficiencies under rainfed conditions in semiarid regions is considered a challenge due to various factors, including irregular rainfall distribution throughout the growing cycle, temperature fluctuations, the choice of intercropped species, interrelations between the two, and especially, competition between crops and weeds (Quemada et al, 2016; Zhang et al, 2022).…”

Drought Impact on the Morpho-Physiological Parameters of Perennial Rhizomatous Grasses in the Mediterranean Environment

“…Morpho-physiological traits play essential roles in growth and development of the plants. However, under limiting water conditions, some species can develop different morpho-physiological adaptation strategies, which give them increased tolerance to drought stress [24][25][26]. Thus, the identification of such drought-response traits in nonfood biomass crops candidates is crucial.…”