Component crop physiology and water use efficiency in response to intercropping

• Published in: European journal of agronomy 2018-02, Vol.93, p.27-39
• Main Authors: Franco, Jose G., King, Stephen R., Volder, Astrid
• Format: Article
• Language: English
• Subjects: Biodiversity; Crop ecophysiology response; Functional diversity; Intercropping; Sustainable agriculture; Water use efficiency
• ISSN: 1161-0301; 1873-7331
• DOI: 10.1016/j.eja.2017.11.005

•Peanut leaf water potential was lower when intercropped as compared to monoculture.•Watermelon exhibited morphological plasticity in response to competition.•Differences in gas exchange were detected only in one of five species.•Water use efficiency was enhanced in dominant crops but reduced in subordinate crops. Interspecies specific interactions are generally regarded as drivers of plant productivity in multispecies agroecosystems. Complementary use of resource in diverse communities can enhance community productivity through optimal use of plant-available resources and positive interactions such as facilitation can ameliorate high abiotic stress conditions. We studied the effects on physiological response, leaf traits and water use efficiency of a multifunctional species intercropping system consisting of peanut (Arachis hypogaea L.), watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai], okra [Abelmoschus esculentus (L.) Moench], cowpea [Vigna unguiculata (L.) Walp.], and pepper (Capsicum annuum L.) planted alone or in various intercropping combinations in a low fertilizer input system in the peak of summer heat in Texas. Differences in gas exchange measurements were detected only in watermelon in year 2 of the study when okra was the dominant crop. This same year watermelon specific leaf area (SLA) was significantly higher when okra was present in a treatment and particularly in the three and four species combinations, Wpwo and Wpwoc, 27.5 and 31.0m2kg−1, respectively, as compared to watermelon grown in monoculture, strip intercropped with peanut (Spw) and within row intercropped with peanut (Wpw), 20.4, 20.1, and 19.8m2kg−1, respectively. This corresponds with an increase watermelon leaf N concentration and a decrease in leaf C:N ratio in Wpwo and Wpwoc treatments. No differences in d13C composition, a measure of water use efficiency over the leaf lifespan, were detected across cropping system for each species. Water use efficiency based on per plant production (WUEyield) indicated an increase in water use efficiency in dominant crops such as watermelon in 2011 and okra in 2012, but a reduction in WUEyield subordinate crops such as cowpea and pepper both years of the study. Peanut grown in monoculture and strip intercropped with watermelon had significantly lower leaf water potential values in 2012, −2.2 and −2.1MPa, respectively, as compared to intercropping systems increasing in level of integration (Wpw=−1.1,Wpwo=−0.6,Wpwoc=−1.3,Wall=−1.1MPa),