[Contribution of nutrient uptake and utilization on yield advantage in maize and potato intercropping under different...

Intercropping of maize and potato, as an important intercropping planting pattern, has a prominent advantage of resource utilization and yield. However, contribution of nutrient uptake and utilization to crop yield advantage and its response to N application rates remain unclear. Through a 2-year plot experiment, including maize monoculture, potato monoculture and maize intercropping with potato at 4 N-fertilized levels of N₀(0 kg·hm^-2), N₁(125 kg·hm^-2), N₂(250 kg·hm^-2) and N₃(375 kg·hm^-2), nutritional contribution of yield advantage of intercropping was studied. The results showed that weighted average uptake of nitrogen, phosphorus and potassium was gradually increased with N application rate in monocultures, but increase followed by a decrease in intercropping. Compared with monoculture at the same N level, nutrient uptake advantage of intercropping was the highest at N₁, which increased nitrogen, phosphorus and potassium uptake by 14.9%, 38.6% and 27.8%, respectively. However, the nutrient use efficiencies were highest in intercropping at N₀ and N₃ with increment of 3.5%-14.3% for nitrogen, 3.5%-18.5% for phosphorus and 10.6%-31.6% for potassium. Maize and potato intercropping had a significant yield advantage at N₀ and N₁. Yield advantage in intercropping attributed to improvement of nutrient use efficiency at N₀ while to increase of nutrient uptake at N₁. To utilize the yield advantage from nutrient uptake, controlling input of nitrogen fertilizer is necessary in intercropping.