Legumes intercropped with spring barley contribute to increased biomass production and carry-over effects

Abstract

Intercropping systems that include legumes can provide symbiotically fixed nitrogen (N) and potentially increase yield through improved resource use efficiency. The aims of the present study were: (a) to evaluate the effects of different legumes (species and varieties) and barley on grain yield, dry matter production and N uptake of the intercrop treatments compared with the associated cereal sole crop; (b) to assess the effects on the yields of the next grain crop and (c) to determine the accumulation of N in shoots of the crops in a low-input rotation. An experiment was established near Edinburgh, UK, consisting of 12 hydrologically isolated plots. Treatments were a spring barley (Hordeum vulgare cvar Westminster) sole crop and intercrops of barley/white clover (Trifolium repens cvar Alice) and barley/pea (Pisum sativum cvar Zero4 or cvar Nitouche) in 2006. All the plots were sown with spring oats (Avena sativa cvar Firth) in 2007 and perennial ryegrass in 2008. No fertilizers, herbicides or pesticides were used at any stage of the experiment. Above-ground biomass (barley, clover, pea, oat and ryegrass) and grain yields (barley, pea and oat) were measured at key stages during the growing seasons of 2006, 2007 and 2008; land equivalent ratio (LER) was measured only in 2006. At harvest, the total above-ground biomass of barley intercropped with clover (4·56 t biomass/ha) and barley intercropped with pea cvar Zero4 (4·49 t biomass/ha) were significantly different from the barley sole crop (3·05 t biomass/ha; P < 0·05). The grain yield of the barley (2006) intercropped with clover (3·36 t grain/ha) was significantly greater than that in the other treatments (P < 0·01). The accumulation of N in barley was low in 2006, but significantly higher (P < 0·05) in the oat grown the following year on the same plots. The present study demonstrates for the first time that intercrops can affect the grain yield and N uptake of the following crop (spring oats) in a rotation. Differences were also linked to the contrasting legume species and cultivars present in the previous year's intercrop. Legume choice is essential to optimize the plant productivity in intercropping designs. Cultivars chosen for intercropping purposes must take into account the effects upon the growth of the partner crop/s as well as to the following crop, including environmental factors.

Nitrous oxide and methane emissions from a vetch cropping season are changed by long-term tillage practices in a Mediterranean agroecosystem

“…Thus, Liu et al (2006) reported that NT can reduce CH 4 uptake compared to that of CT, whereas Jacinthe et al (2014) showed that the maintenance and duration of NT increased CH 4 oxidation. On the other hand, legume-cereal rotations are promoted as sustainable cropping systems, both in conservation and conventional agriculture, because the legume crop provides an additional N supply for the cereal decreasing the requirements for application of N fertilizers (Pappa et al 2012). Jensen et al (2012) found that N 2 O fluxes from legumes were not significantly different to background emissions and were also lower than comparable N-fertilized crops and pastures.…”

Nitrogen leaching and residual effect of barley/field bean intercropping

“…Additional advantages of cereal/legume intercropping include (i) more efficient exploitation of the N resource, due to the complementarity of biological N 2 fixation and soil mineral N use by companion plants; (ii) reduction in leaching N losses; and (iii) a positive residual effect on the next crop (Hauggaard-Nielsen et al 2003, Szumigalski and van Acker 2006, Pappa et al 2012.…”

“…Since the choice of cultivar is a key factor influencing interspecific competition and the amount of N available to the system (Ross et al 2004, Pappa et al 2012, the combination of four barley (two 2-row and two 6-row) and two field bean cultivars was compared.…”

Evaluation of vegetable–faba bean (Vicia faba L.) intercropping under Latvian agro‐ecological conditions

“…In order to shed some light on the mutual interaction of intercropped species, and on the advantages of intercropping, the influence of this management practice on the yield and economic returns has been recently evaluated . These studies have allowed to stress intercrop systems on their capacity to improve the efficiency of irrigation and solar radiation, while enhancing pollination, grain yield, and total protein content …”