The allometric relationships between biomass and nitrogen of vegetative organs affect crop N status in maize at silking stage

MALTESE, N.E.; MADDONNI, G.A.; MELCHIORI, R.J.M.; CIAMPITTI, I.A.; CAVIGLIA, O.P.

FIELD CROPS RESEARCH

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2023

0378-4290

In maize (Zea mays, L.) changes in the partitioning of biomass (W) and nitrogen (N) between organs linked to photosynthetically active tissues, such as leaves (with high N concentration, %N) and organs related to supporting functions, such as stems (with low %N) at silking stage, could modify the diagnosis of crop N status (i.e., N nutrition index, NNI) for fertilizer N recommendations. To test this hypothesis we used a database of maize measurements performed at silking stage of crops cultivated under different N fertilization rates, plant densities, hybrids, and sowing dates, to investigate i) the allometric relationships between %N and W of leaves (%NL and WL) and stems (%NS and WS), ii) changes in N uptake in vegetative organs for crops with low (6700 kg ha-1) crop W and contrasting NNIs, iii) the responses of crop W at silking stage to N fertilization relative to responses of WL, WS, %NL and %NS, and iv) the inclusion of the %NL/%NS ratio in a predictive model of relative grain yield based on crop NNI at silking. Variations of WS (from 2143 to 10067 kg ha-1) were greater than those of WL (from 1010 to 4107 kg ha-1), whereas the values of WL/WS ratio (for low W crops) and leaf/stem ratio for N uptake (for both high and low W crops) were lower for NNI>1.1 than for NNI