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, per cent N) and organs related to supporting functions, such as stems (with low per cent 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 per cent N and W of leaves (per cent NL and WL) and stems (per cent NS and WS), ii) changes in N uptake in vegetative organs for crops with low (<6700 kg ha− 1) and high (>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, per cent NL and per cent NS, and iv) the inclusion of the per cent NL/ per centNS ratio in a predictive model of relative grain yield based on crop NNI at silking. Variations of WS (from 2143 to 10,067 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 minor to 0.9, reflecting the key role of stems as N storage organs when N is non-limiting. Changes in WS largely modulate the response of crop W to N fertilization, while changes in per cent NL largely modulated the response of crop per cent N to N fertilization for high W crops. Optimal crop N status (i.e., NNI=~1) was attained with a greater per cent NLper cent NS ratio for high (2.0) than for low (1.2) W crops, suggesting that this allometric ratio should be taken into account at this crop growth stage, particularly for low crop W. Accordingly, the prediction of relative grain yield based on NNI at silking was improved by the inclusion of per cent NL/ per cent NS. Therefore, our results are useful to better understand the response of maize crop W, grain yield, and crop per cent N (for leaves and stems) to late N fertilization, adding valuable insights to improve current NNI-based N diagnostic tools.
Maltese, N.; Maddonni, G. A.; Melchiori, R. J. M.; Ciampitti, I. A. & Caviglia, O. P. (2023).The allometric relationships between biomass and nitrogen of vegetative organs affect crop N status in maize at silking stage.Field Crops Research,294,art.108861
10.1016/j.fcr.2023.108861
Maltese, Nicolás Elías, Maddonni, Gustavo Angel, Melchiori, Ricardo José Miguel, Ciampitti, Ignacio Antonio, Caviglia, Octavio Pedro.2023. "The allometric relationships between biomass and nitrogen of vegetative organs affect crop N status in maize at silking stage".Field Crops Research 294:art.108861.
Recuperado de http://ri.agro.uba.ar/greenstone3/library/collection/arti/document/2023maltese