Can maize cultivars with low mineral nutrient concentrations in the grains help to reduce the need for fertilizers in third world countries?

Abstract

An earlier study revealed considerable genotypic variation in grain N, P and K concentrations (GNC, GPC and GKC, respectively) in tropical maize. The expression of varietal differences in GNC, GPC and GKC, however, may depend on environmental conditions such as the N status of the soil. Two tropical maize hybrids (Suwan 2301 and CP 1) with comparable yielding capacity, but contrasting GNCs, GPCs and GKCs, were therefore grown at four levels of N in a field experiment at Farm Suwan (Thailand, latitude 14.5°N). Suwan 2301 exhibited a higher GNC than did CP 1 at all rates of N, but large differences in GPC and GKC were found only at high N fertilization. This was obviously due to individual grain yield responses of the cultivars to increasing rates of N fertilizer, demonstrating that grain nutrient concentrations are, at least in part, functions of the amount of grain carbohydrates which dilute a genetically and environmentally fixed amount of grain P and K. As compared to Suwan 2301, CP 1 accumulated less N, P and K in the grains at almost all levels of N fertilization, confirming our hypothesis that the cultivation of maize genotypes with low grain mineral nutrient concentrations may help third-world cash-crop farmers to reduce the need for scarce and costly mineral fertilizers. This finding has to be verified at reduced availability of soil -P, -K, and water.

Nitrogen fertilizer rate increases plant uptake and soil availability of essential nutrients in continuous maize production in Kenya and Zimbabwe

“…The application of N increased P uptake, with the exception of a few hybrids in Embu. Feil et al ( 1992 ) and Holou et al ( 2011 ) also found that N fertilizer applications increased P uptake consistently in continuous maize cropping systems. The application of N fertilizer has been found to increase root branching, particularly closer to the surface where P levels are highest (Postma et al 2014 ).…”

“…Therefore, it is important to look at the status of multiple nutrients at once. Globally, studies have looked at the impact of N fertilizer on the uptake of non-N nutrients such as phosphorus (P), potassium (K), and sulfur (S) (Feil et al 1992 ; Holou et al 2011 ; Ciampitti et al 2013 ) and micronutrients (Ciampitti and Vyn 2013 ), but no such studies exist in SSA. These global studies have primarily focused on higher N fertilizer rates than what is typically applied in SSA, limiting the direct applicability of their findings to smallholder farmers in SSA.…”

Effect of Nitrogen Fertilization on Grain Yield and Accumulation of Nitrogen, Phosphorus and Potassium in the Grains of Tropical Maize*

“…This could change if (i) more Nresponsive genotypes are cultivated or (ii) the soil becomes deficient in P and K. Some experiments conducted at Farm Suwan revealed individual grain yield responses of indigenous cultivars to N fertilization (THIRAPORN et al 1987, FEIL et al 1991. Cultivar by N fertilization interactions in grain yield were paralleled by cultivar by N fertilization interactions in G P C and G K C (FEIL et al 1991 b). This indicates that a more efficient conversion of high N rates into grain yield would decrease the G P C and GKC.…”

Índices De Eficiência De Variedades Locais E Melhoradas De Milho Ao Fósforo

“…Concentrações e conteúdos de P nos grãos de milho de germoplasma tropical semelhantes foram verificados por FEIL et al (1992), em cujo trabalho havia elevado teor de P disponível no solo e o nível de adubação nitrogenada foi o mesmo empregado neste ensaio. No estudo de FEIL et al (1992), os sabugos também apresentaram o menor conteúdo de P e, pela literatura, tem-se que a remobilização a partir deles, bem como a do colmo e palha da espiga, precede à das folhas (GORSLINE, 1965;CLARK, 1975).…”