Wheat–chickpea intercrops are not well studied, despite the importance of these two species in increasing agricultural profitability and ensuring nutritional and food security. The present study aims to assess the intercropping arable system’s services under contrasting field management and climate conditions. Simultaneously, this assessment focuses on the most agronomic and ecological indices widely used in the literature. Durum wheat (Triticum turgidum durum L.cv. VITRON) and chickpea (Cicer arietinum L.cv. FLIP 90/13 C) were cultivated, both in sole crop and intercrop during the 2018/2019 growing season. A field experiment was carried out under controlled conditions at three contrasting pedoclimatic sites and under three levels of N fertilization. Both grain and N yield of mixture crop were significantly higher (+11%) when chickpea and durum wheat were grown together under either low or moderate N application. Soil N availability as compared to the critical level increased by more than 19% from flowering to harvest stage for intercropped wheat under low N application (N-30 and N-60), while it decreased significantly for intercropped chickpea. In rich N soils and under low rainfall conditions (site 1 and 3), intercropping was generally more advantageous for yield (+14%), N yield (+23%), and land use (103 and 119.5% for grain and N yield, respectively) only with reduced N fertilization as assessed using both land equivalent ratio (LER) and land-use efficiency (LUE). Competition dominance was directly affected by changes in climatic conditions over sites; intercropped wheat was more competitive than their respective chickpea under low rainfall conditions. These findings illustrate the crucial role of competitive index assessment in intercropping to promise a robust method for crop N and yield diagnosis during fertilization decision-making.

No abstract

No abstract

It is well known that multiple interactions can occur between nitrogen and water use, depending on climate, soil and crop characteristics, in crop growth and yield development. However, little is known about the simultaneous change in both water and N use efficiency (WUE and NUE) and their possible interactions in cereal–-legume intercropping systems. In order to advance our knowledge on the N and water facilitation mechanisms involved in the intercropping responses of N and water input co-limitations, we investigated, via four experiment years, the simultaneous optimization of water and N-fertilizer inputs, as well as its possible effects on growth, yield, N acquisition, and the NUE and WUE in intercropped species. The results indicated that intercropping increases the leaf area index by more than +0.14 and +1.03 units when compared to durum wheat and chickpea monoculture systems, respectively. This increase is particularly noticeable under higher rainfalls during the crop period (i.e., as can be seen in the 2022, 2020, and 2019 seasons). Moderate N-application enhanced both the grain yield and protein accumulation in the mixed crops by more than 0.22 t ha−1 and 57 kg ha−1, respectively. Conversely, intercropping significantly decreased the mixed grain yield when compared to durum wheat monocultures. Intercropping advantages in terms of biomass (ranged from 1 to 44%) and N-acquisition (2 to 91%) was confirmed in either low- (2021) or high- (2019 and 2022) rainfall growing periods, but only under low and moderate N-applications. Improving N nutrition under both rainfall and drought growth periods was confirmed only for the mixed crops under all applied N-fertilizer doses. Such improvements in growth, N acquisition, and yield quality were most likely achieved by positive interactions (r2 = 0.73, p ≤ 0.001) between the NUE and WUE for the chickpea–wheat intercropping. Thus, 0.62 kg m−3 of WUE promotes a significant increase of 1 kg kg−1 in NUE by mixing chickpea-durum wheat. Rain-fed chickpea-durum wheat intercropping provides a higher performance in growth and yield quality compared to sole cropping systems; this may occur from the simultaneous optimizations of both water and N fertilizer inputs in low-N soil under semiarid conditions.