Winter wheat shoot and root phenotypic plasticity under fertilized and nutrient-deficient field conditions

While it is widely recognized that nitrogen (N), phosphorus (P), and potassium (K) addition, and liming are crucial for high agricultural yields and soil fertility, field studies examining shoot-root responses to nutrient deficiencies remain limited. Understanding crop adaptation strategies to nutrient-poor soils is crucial for optimizing low-input agriculture. In this study, we investigated the shoot and root responses of winter wheat cultivated in two growing periods (2019/20 and 2020/21) at the long-term fertilizer experiment in Dikopshof, Germany, under no fertilization, or specific omission of N, P, K, and liming with two fully fertilized treatments (NPKCa without and with farmyard manure). We analyzed crop phenology, leaf area index (LAI), plant height, shoot biomass, grain and straw yield, root biomass, root length, root length density (RLD), root-to-shoot ratio (R/S), specific leaf area (SLA), specific root length (SRL) and root length per shoot biomass. Our results showed that the fully fertilized treatment with manure consistently had the highest values for shoot traits, root length, and root biomass in both growing periods. The unfertilized and N omission treatments led to a decrease in shoot biomass, LAI, plant height, yield, root length, and root biomass while leading to an increase in SRL, R/S, and root length per shoot biomass. The omission of P, K, and liming reduced the straw yield. Our findings highlight the complex interactions between nutrient deficiencies, shoot and root performance, and environmental factors, emphasizing the need for further research on cultivar differences and higher temporal resolution sampling to enhance crop productivity and nutrient management strategies. • Winter wheat shoot and root traits were evaluated under various nutrient deficiencies in a long-term fertilizer experiment over two growing periods. • Full fertilization with manure resulted in the highest grain yield, shoot and root biomass, root length, and SLA. • N deficiency and no fertilization reduced the grain and straw yield, shoot, and root biomass/length. • Shoot and root trait responses to P and K deficiencies and the omission of liming varied across sampling dates, showing inconsistent patterns that preclude generalization. • Root biomass showed positive correlations with LAI, shoot biomass, and total root length.