Extending yield/density equations for intercropping

Five experiments agronomically managed differently investigated yield/density relationships in wheat/faba bean (bean) intercrop system. Mostly wheat seed yields (SY) responses were asymptotic to increase in wheat seed rate (wsr). For the wheat sole crop (WSC), SY ranged from 102 g/m2-734 g/m2. Intercropping reduced wheat SY but this did not always depend on wsr. The maximum bean sole crop SY was 392g/m2: bean SY declined as wsr increased. In most cases biomass yield (BY) responses followed similar pattern as the SY. The total intercrops (TI) SY were greater than the sole crops (SC) mostly where wheat intercrop BY were not substantially reduced. Also, mostly the TI accumulated more photosynthetically active radiation (PAR) whilst WSC was better at radiation use efficiency (RUE) as wsr increased. Intercrop performance (IP) were assessed from results and fitted values (FV) after yield/density equations (YDE) were applied (for the SY) using land equivalent ratio (LER), crop performance ratio (CPR) and another index. For the SY, a maximum LER of 2.20, and a maximum CPR of 1.61 were obtained. In two experiments LER > 1.0 but CPR < 1.0 were obtained, indicating that the TI were less efficient than Se. Estimates of IP using FV, did not consistently agreed with estimates of IP using results. In one experiment, sulphur application increased bean but reduced wheat SY. The effects of sulphur on SY were mainly determined by the BY and the PAR. In another experiment, delaying bean sowing reduced bean and increased wheat SY. Effects of different bean sowing dates on SY were determined by variables similar to the effect of sulphur above. Moreover, across the experiments, wsr and intercropping reduced weed biomass substantially, and weeds biomass inclusions had effects on the estimate of RUE. In conclusion, wheat/bean intercrop system is beneficial, and YDE can quantify the intercrop yields well.EThOS - Electronic Theses Online ServiceGBUnited Kingdo