Estimating maize harvest index and nitrogen concentrations in grain and residue using globally available data

Estimating nutrient concentrations and uptake in rice grain in sub-Saharan Africa using linear mixed-effects regression

“…The GVIF is more appropriate than the VIF if the model includes categorical variables leading to a degree of freedom > 1. As in Ludemann et al (2022) , GVIF< 10 was considered acceptable. The assumptions of normality and homoscedasticity of residuals were assessed with the normal quantile-quantile plots.…”

“…Only grain Fe models did not meet the normal distributions of residuals but no data transformations were done to remedy this since our very large observations (>10 per variable) would nullify any influence of such on the outcomes ( Schmidt and Finan, 2018 ). Interaction effects of explanatory variables were omitted to reduce the probability of introducing false inferences or type 1 errors ( Ludemann et al, 2022 ).…”

“…Nutrient concentration and uptake in crops can vary from individual fields to whole countries and the world ( Ludemann et al, 2022 ). Studies on cereal crops in various regions of the world suggest environmental factors ( Du et al, 2013 , Huang et al, 2016 ) such as climatic conditions ( Dobermann and Fairhurst, 2000 , Shimoyanagi et al, 2021 ), soil fertility level ( Kekulandara et al, 2019 ), nutrient supply ( Dobermann and Fairhurst, 2000 ) and crop management practices ( Dobermann and Fairhurst, 2000 , Tenorio et al, 2019 ) including fertilizer applications ( Haefele et al, 2022 , Ludemann et al, 2022 , Tenorio et al, 2019 ) and crop genotype ( Huang et al, 2016 , Pinson et al, 2015 ) are the most reported factors impacting variations of nutrient concentrations in grain. For the case of SSA, recent results obtained from on-farm surveys observed agroecological zones (AEZ - ( HarvestChoice, 2015 )) and production systems which can be both categorized as environmental factors, as the main factors affecting most variations in the concentration of macronutrients and micronutrients in rice grain ( Johnson et al, 2021 ).…”

“…It was attempted to identify if estimation-based nutrient uptakes have greater relationships with actual nutrient uptakes than average-based uptakes. A modified workflow used by Ludemann et al (2022) was implemented toward our aims in which the hypotheses were elaborated based on key bases allowing us to define which of the above factors are expected to influence nutrient concentrations of rice grain ( Fig. 1 ).…”

Exploring the Potential of Heterosis to Improve Nitrogen Use Efficiency in Popcorn Plants

“…N represents up to 5% of total dry matter [11] and is a constituent of leaf pigments, such as chlorophyll, amino acids, nucleic acids, proteins, and plant hormones [12,13]. The low availability of nitrogen in the soil directly impacts corn yield, with adverse effects on the weight and length of ears [14], 100-grain weight, prolificacy [15,16], as well as plant height [17]. These compromises in the agronomic components of production result from the effects of N limitation on photosynthetic capacity [18].…”