Quantifying potassium requirement and removal across crop species

Authors: CARCIOCHI, WALTER - University Of Nebraska; Heuschele, Deborah - Jo; DOBERMANN, ACHIM - International Fertilizer Association, France; MENZA, NICOLAS CAFARO - University Of Nebraska; DONOUGH, CHRISTOPHER - University Of Nebraska; FARRASATI, RANA - University Of Nebraska; LIM, YA - University Of Nebraska; OBERTHUR, THOMAS - African Plant Nutrition Institute; SANDANA, PATRICIO - Austral University Of Chile; SHEHU, BELLO - Bayero University

Submitted to: Field Crops Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/18/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary: High-yielding crops have large potassium (K) requirements. A better understanding of reasons for K uptake and net removal from the soil is key for sustainable K management in agricultural systems around the globe. A large data set of four major crops and 10 minor crops was collected from published papers in addition to private and public databases from around the world that focused on K levels in soil and plants. All crops required excess K to reach high yields. The ability to use K from the soil effectively was significantly different among crops. Cereals had a greater K use efficiency and less K removal from the soil compared to soybean. More K was removed from the soil when yield was high and straw/ stubble was removed. To maintain sufficient K levels within soils, crop choice and straw removal need to be considered for K management along with crop yield potential.

Technical Abstract: CONTEXT: High-yielding crops have large potassium (K) requirements. Understanding drivers of K internal efficiency (KIE), uptake requirement, and net removal, as well as their variation within and among crop species, is essential for sustainable K management in agricultural systems. OBJECTIVES: To determine KIE, K uptake requirement, and K removal for major staple crops and different yield targets and assess the underlying drivers of variation. METHODS: We compiled a large database to determine KIE, K requirement, and K removal in maize, wheat, rice, and soybean for various target yields and yield potentials. A second database was compiled with another ten crop species. We assessed variation in KIE, as influenced by K harvest index (KHI) and K concentration in harvestable yield (KCY), and K removal for typical dry matter yields of each crop species. RESULTS: Requirement of K increased with yield, with an average 2-fold higher KIE (40 versus 23 kg yield kg-1 K) and 4-fold smaller K removal (4.2 versus 18 kg K Mg-1) in cereals than soybean. Variation in KIE within crops was related to KHI in maize and wheat and KCY in soybean. Large differences in KIE were observed among crops, with highest KIE in cassava and sugarcane (87 kg yield kg-1 K), intermediate in cereals, potatoes, and alfalfa (41-58 kg yield kg-1 K), and lowest in banana and protein- and oil-rich crops (10-30 kg yield kg-1 K). The K removal was larger with higher yield, KHI, and straw removal. CONCLUSIONS: The K uptake requirement increases with increasing crop yields, with KIE decreasing as yield approaches yield potential. In turn, KIE varies widely across crop species due to differences in KCY and KHI. Besides yield level, crop choice and straw removal need to be considered for K management. SIGNIFICANCE: This study provides a basis for quantification of K uptake requirement and removal across crop species and yield levels, offering critical input to inform K management in agroecosystems.