Quantifying stoichiometry of crop N and P acquisition(i.e.removal from farmland)under different agronomic practices is essential for understanding nutrient budgets and optimizing N and P fertilizer application in agro...Quantifying stoichiometry of crop N and P acquisition(i.e.removal from farmland)under different agronomic practices is essential for understanding nutrient budgets and optimizing N and P fertilizer application in agroecosystems.It is not clear how plant N and P uptake and N:P stoichiometry vary between monoculture and intercropping throughout an entire growing season under different N fertilization and mulching practices.Here,we addressed how plant interspecific competition for nutrients have affected the temporal dynamics of crop N and P uptake(and N:P ratios)in five cropping systems(wheat,maize and barley monocultures,and wheat/maize and barley/maize intercropping),under two N levels(0 and 225 kg N ha^(−1))and two maize mulching treatments(with and without).Wheat and barley had greater N and P competitive ability than maize,leading to an increase in N and P uptake of wheat and barley and a decrease in N and P uptake of maize during co-growth stages in intercropping.N:P ratios of three crop species decreased with plant growth.Crop-level N:P ratios were either not affected by intercropping or did not change consistently with N fertilization while film mulching decreased maize N:P ratios.Community-level N:P ratios of the two intercrops were different from those of the corresponding monoculture at maturity.Because(i)the proportion of N and P removal from intercropping differs from monocultures,and(ii)N and P uptake by crops is decoupled under N fertilization and mulching,these findings may have practical implications for the nutrient budget of intercropping systems.展开更多
基金funded by the National Key Research and Development Program of China(2016YFD0300202)the Natural Science Foundation of China(31971450,31500348,31430014)Chinese Universities Scientific Fund(2020TC051)and the European Research Council Synergy grant(ERC-SyG-2013-610028,IMBALANCE-P).
文摘Quantifying stoichiometry of crop N and P acquisition(i.e.removal from farmland)under different agronomic practices is essential for understanding nutrient budgets and optimizing N and P fertilizer application in agroecosystems.It is not clear how plant N and P uptake and N:P stoichiometry vary between monoculture and intercropping throughout an entire growing season under different N fertilization and mulching practices.Here,we addressed how plant interspecific competition for nutrients have affected the temporal dynamics of crop N and P uptake(and N:P ratios)in five cropping systems(wheat,maize and barley monocultures,and wheat/maize and barley/maize intercropping),under two N levels(0 and 225 kg N ha^(−1))and two maize mulching treatments(with and without).Wheat and barley had greater N and P competitive ability than maize,leading to an increase in N and P uptake of wheat and barley and a decrease in N and P uptake of maize during co-growth stages in intercropping.N:P ratios of three crop species decreased with plant growth.Crop-level N:P ratios were either not affected by intercropping or did not change consistently with N fertilization while film mulching decreased maize N:P ratios.Community-level N:P ratios of the two intercrops were different from those of the corresponding monoculture at maturity.Because(i)the proportion of N and P removal from intercropping differs from monocultures,and(ii)N and P uptake by crops is decoupled under N fertilization and mulching,these findings may have practical implications for the nutrient budget of intercropping systems.
