Contribution of interspecific interactions and phosphorus application to sustainable and productive intercropping systems

Rational soil/rhizosphere-plant phosphorus (P) management strategies in intercropping systems are poorly understood. Three years of field experiments with different rates of P fertilizer (0, 40 and 80 kg ha−1) as main effects and maize (Zea mays L.) intercropping with oilseed rape (Brassica napus L.), turnip (Brassica campestris L.), faba bean (Vicia faba L.), chickpea (Cicer arietinum L.) and soybean (Glycine max L.) with the respective monocultures as subplot effects were carried out to study the influence of fertilizer P application on productivity, shoot P content, apparent recovery of fertilizer P and soil Olsen-P in intercrops and monocultures. Average total grain yields and shoot P contents of maize/turnip, maize/faba bean, maize/chickpea and maize/soybean intercropping increased by 30.7%, 24.8%, 24.4%, and 25.3% and by 44.6%, 30.7%, 39.1%, and 28.6%, respectively, compared with the weighted means of the corresponding monocultures, and were highest at 40 kg P ha−1. Moreover, the average apparent recovery of fertilizer P of the intercropping systems increased from 6.1% to 30.6% at 40 kg P ha−1 and from 4.8% to 14.5% at 80 kg P ha−1 compared with overall monoculture systems on average over three years. The results indicate that intercropping and a rational P application rate (e.g. 40 kg P ha−1) maintained maximum total grain production and shoot P content, P balance of inputs/outputs and soil Olsen-P at an appropriate level (21.3 mg kg−1), and maximum apparent recovery of fertilizer P (30.6%) through exploitation of the biological potential for efficient acquisition of P and other resources by interspecific interactions toward a sustainable and productive agricultural system.