The research assesses the productivity of mixture of oats (Avena sativa) and wheat (Triticum aestivum), and compares two different approaches used in plant competition studies: replacement (substitutive) designs and additive designs. The experiment was carried out on sandy loam soil at the Experimental Station of Agricultural University of Wrocław (Poland). Oats and wheat were grown for grain as sole crops and in 1 : 1 replacement mixtures at three rates of seeding: 150, 300 and 600 viable seeds m )2 . These designs allowed mixtures seeded at a rate of 300 and 600 seeds m )2 to be analysed according to either a replacement or an additive approach. In 1999, pure stand wheat and oats-wheat mixture yielded significantly more grain than oats grown alone but in 2000 there was no difference in yield. Wheat outcompeted oats in mixture but the relative competitive ability of the two species changed little with increasing seeding density. Relative yield total (RYT) for grain was significantly >1.0 (RYT ¼ 1.07) in 1999 for the lowest seeding density, showing partial complementarity in use of limiting resources by the species in mixture. Based on grain yields, the results obtained from substitutive and additive mixtures were similar with respect to the relative yields and relative competitive ability of the two species concerned.
47The rationale behind intercropping, as a method of sustainable crop production is that the more diverse system represented by two or more crops grown together should better utilize common limiting resources than the species grown separately. The first problem that can be met when planning efficient cereal-legume intercrop is the choice of the appropriate ratio of component species that produces maximum yield of the intercrop. However the highest yielding ratio of species cannot be known beforehand, in many experiments researchers form the intercrop by adding half of the recommended in pure stand seeding density of each of the component species. The design is termed then "proportional replacement series design" or "proportional substitutive design" (Jolliffe 2000) with 50%/50% proportion of the components. In the design, proportion means the percentage of seeding density derived from pure stand and used to form the intercrop. Using the only one ratio of species in the intercrop is usually the result of limitation in size of any intercrop experiment because an additional factor is often used in such research, for instance different rates of fertilizer. Levels of the factor are then multiplied by pure stand and the intercrop treatments enlarging experimental structure. Such an approach is appropriate, but according to Connolly (1986) the most productive ratio of components in the intercrop can be found only experimentally.The second problem in the intercropping practice is the proper choice of total density of plants per unit area for an intercrop, namely the lowest total density of plants that produces maximum yield of the intercrop. Plant density of a most productive intercrop may be higher than that imposed by the rule used in proportional substitutive design because it may be assumed that component species are able to better utilize resources when intercropped then when they are grown alone (Spitters 1983). Even if the issues are being considered prior to sowing, the next difficulty in designing the efficient intercrop results from unpredictable outcome of interactions between component species and between the species and the environment (Fukai and Trenbath 1993 ABSTRACTIn a microplot experiment conducted in 1999 and 2000 on light soil triticale and field beans were grown as sole crops and in the intercrop system. Two pure stand plant densities were established: 200 and 400 plants/m 2 for triticale and 50 and 100 plants/m 2 for field beans. Four possible intercropping combinations were obtained by adding densities of both crops. Triticale was a better competitor than field beans in all intercrops resulting in competitive balance index significantly greater than zero. The number of pods per plant of field beans was significantly reduced in all intercropping combinations compared to the pure stands, however quality of grain of the legume was unaffected by competition. Intercrop comprising 200 plants/m 2 of triticale and 50 plants/m 2 of field beans was most productive in the experiment but addition 50 more pla...
A field experiment of split-plot design was conducted in 1999 and 2000 on light soil to study the effect of different levels of mineral nitrogen fertilization: 0, 25 and 50 kg N/ha on dry ma�er yield, N uptake and N efficiency indices of spring triticale and field beans grown in pure stands and in intercrop. The intercrop was composed using half of the seeding densities from pure stands. Intercropping increased protein content in grain and plant biomass of triticale irrespective of N input. Increasing N rate from 0 to 25 kg/ha increased plant biomass yield of triticale and intercrop. Nitrogen uptake with grain and biomass of intercrop was significantly higher than by sole crops showing partial complementarity in N use by intercropped species despite strong dominance of triticale over field beans. The higher the N fertilizer rate, the lower was the gain from intercropping mainly due to increased suppression of field beans by triticale. Agronomic efficiency was similar for triticale and intercrop but it was significantly smaller for field beans indicating there were other limited resources hampering growth of the legume.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2025 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.