Reference Values of Grain Nutrient Content and Removal for Corn

Abstract

Unchanged reference values of grain nutrient contents for corn have been used for over 20 years, despite yield increases, the development of new hybrids, and modifications to cropping systems, especially the establishment of in-season second crops and the wide adoption of no-tillage. This study measured macro-and micronutrient contents in corn grains from different regions, in the first (summer) and second (fall) crop, to update the reference values of estimated nutrient removal. A secondary objective was to determine whether there were correlations between grain nutrient contents and grain yields and densities. In this study, 175 corn grain samples of experiments on cultivar evaluation and 22 samples from soil management trials from five states (SP, PR, MG, MT, and MS) were used. Grain nutrient contents were ranked as follows: N > K > P > Mg > S (g kg-1) and Ca > Zn > Fe > Mn > B > Cu (mg kg-1). Content values for half of the nutrients analyzed were negatively correlated with yield and/or seed weight, whereas grain density was not correlated with nutrient contents. For the first crop of corn, the N, S, and Cu contents clearly decreased with increases in grain yield and seed weight, indicating a lower nutrient removal at higher yields. The great variability of results among environments makes it difficult to differentiate between the first and second crop of corn. The reference values currently in use overestimate the removal of N, P, K, Ca, Mg, S, and Zn grain contents, but underestimate Cu and B in corn. The results of this study can be used to update the reference values of nutrient contents of corn grains to better estimate nutrient removal from the soil.

Nitrogen fertilization in off-season corn crop in different Brazilian Cerrado environments

“…A 63% fertilizer efficiency was assumed, in order to calculate the N proportion usable by the corn crop (Dobermann, 2005). The removal of N was determined considering the average rate of 13.1 kg Mg -1 exported in the harvested grains of the off-season corn crop (Duarte et al, 2019) and the correspondent yield achieved in each condition. These yields were also used to estimate the amount of N extracted by corn, considering the average rate of 21.7 kg Mg -1 reported for off-season crops (Simão et al, 2017).…”

“…For a mean rate of 13.5 kg Mg -1 N exported in corn grains (Silva et al, 2018;Duarte et al, 2019), 81 kg ha -1 N would be needed to replenish the amount removed during the harvest of 6 Mg ha -1 , a yield frequently achieved in the off-season (Conab, 2019). However, the effectiveness of corn in recovering N from fertilizers is not high and varies significantly, with a mean value of 63% under experimental conditions (Dobermann, 2005).…”

The Science of 4R Nutrient Stewardship for Phosphorus Management across Latitudes

“…‡ Removal coefficients assumed to be 5.5 and 2.3 kg P t −1 for soybean (Pauletti, 1998) and maize (Duarte et al, 2019), respectively.…”

Exchangeable potassium reserve in a Brazilian savanna Oxisol after nine years under different cotton production systems

“…The accumulated export of K in each production system was determined by multiplying crop yields by the mean removal rates, equivalent to 17, 20, and 3.7 kg of K 2 O per ton of seed cotton, soybean, and maize grains, respectively (Borin et al, 2019;Duarte et al, 2019;Embrapa, 2013). From exported quantities, partial balances of K (Resende et al, 2019) were estimated, as well as the exported/applied ratios of the K fertilizer used in the period.…”