Peanut yield,nutrient uptake and nutrient requirements in different regions of China

Nutrient balance is essential for attaining high yield and improving profits in agricultural farming systems,and crop nutrient uptake ratio and stoichiometry can indicate crop nutrient limitations in the field.We collected a large amount of field data to study the variations in yield,nutrient uptake and nutrient stoichiometry of peanut(Arachis hypogaea L.)in Southeast China(SEC),North-central China(NCC),and Northeast China(NEC),during 1993 to 2018.Peanut pod yield gradually increased from 1993 to 2018,with average yields of 4148,5138,and 4635 kg ha–1 in SEC,NCC,and NEC,respectively.The nitrogen(N)internal efficiency(NIE,yield to N uptake ratio)was similar among the three regions,but phosphorus(P)IE(PIE,yield to P uptake ratio)changed from low to high among regions:NCC<SEC<NEC,while potassium(K)IE(KIE,yield to K uptake ratio)portrayed a different pattern of SEC<NCC<NEC.Based on the nutrient IE,to produce 1 Mg of pod yield,the average N,P,and K requirements of the above-ground parts of peanut were roughly 47.2,5.1,and 25.5 kg in SEC,44.8,5.7,and 20.6 kg in NCC,and 44.6,4.4,and 14.7 kg in NEC,respectively.The N/P ratio changed in the sequence NCC<SEC<NEC,and the N/K ratio was similar in NEC and NCC,but lower in SEC.The N harvest index(HI)and KHI declined with increasing nutrient uptake across all regions under high nutrient uptake.The low PIE and N/P ratios in NCC could be explained by the high P accumulation in stover,and high KIE and N/K ratios in NEC may be attributed to the low soil K supply.The frontier analysis approach provides a practical framework and allows documentation of a decline in nutrient HI as nutrient uptake increases.Lastly,this study reveals the limitation and surplus of nutrients of peanut in different regions of China.