Nitrogen Defeciency in Maize: I. Effects on Crop Growth, Development, Dry Matter Partitioning, and Kernel Set

Abstract

Variations in N availability affect growth and development of maize (Zea mays L.) and may lead to changes in crop physiological conditions at flowering and in kernel set. The objectives of this study were (i) to establish the effect of N availability on crop development, crop radiation interception, radiation use efficiency, and dry matter partitioning; and (ii) to study the relationship between kernel number and crop growth at flowering and between kernel number and crop N accumulation at flowering. Three experiments with a commercial hybrid (DK636) were carried out under field conditions at the INTA Baicarce Experimental Station, Argentina, without water limitations. The treatments consisted of different radiation levels, obtained by shading, combined with different levels of N availability obtained by the addition of N fertilizer or organic matter to inmobilize N. Nitrogen deficiencies delayed both vegetative and reproductive phenological development, slightly reduced leaf emergence rate, and strongly diminished leaf expansion rate and leaf area duration. Nitrogen deficiencies reduced radiation interception as much as radiation use efficiency and their effects on the ear dry matter/total dry matter ratio at harvest were associated with crop growth rate reductions at flowering. Dry matter partitioning to reproductive sinks at flowering and the ear dry matter/total dry matter ratio at harvest were reduced by N shortages. Significant relationships between kernel number and N accumulation rate or crop growth rate at flowering were fitted by linear + plateau functions with thresholds above which kernel number and grain yield did not increase.

Exogenous glycinebetaine and humic acid improve growth, nitrogen status, photosynthesis, and antioxidant defense system and confer tolerance to nitrogen stress in maize seedlings

“…Decreased TDM production due to N shortage in the maize plants was found to be associated with reductions in leaf photosynthetic capacity as earlier observed by Uhart and Andrade (1995) and it was mainly ascribed to a smaller total N content and GB content in the plants (Figures 1 and 2). The ameliorative effects of GB and HA on most plants exposed to various stresses have been widely reported in the literature (Chen & Aviad 1990;Demiral & Turkan 2004;Ashraf & Foolad 2007;Cimrin et al 2010).…”

“…The mesophyllic activity is another cause of limiting maize leaf P n under NS (Cruz et al 2003). Decrease in P n due to N deficiency has been reported to be one of the major causes that limit plant growth and productivity (Uhart & Andrade 1995;Zhao et al 2003Zhao et al , 2005.…”

“…Although C 4 crops such as maize (Zea mays L.) are known for their higher use efficiency of nitrogen (N), CO 2 , and solar radiation than most C 3 crops, N stress (NS) is still one of the major limiting factors for crop yield in arid and semiarid areas of the world (Greenwood 1976;Uhart & Andrade 1995;Pandey et al 2000;Sage & Zhu 2011). Understanding the physio-biochemical mechanisms in maize under NS could be vital for achieving increased crop yield by increasing N use efficiency (Chapin et al 1988;Ding et al 2005).…”

Crescimento e desenvolvimento de milho: acúmulo de massa seca do grão

“…Nas situações em que a capacidade dos grãos em alocar fotoassimilados é o fator limitante, como em plantios mais precoces na Região Sul do Brasil, pode-se aumentar a densidade de plantas, para que haja um aumento na interceptação e conversão da radiação, de modo a promover um equilíbrio na relação fonte/dreno, sem que a taxa e a duração do período de enchimento de grãos sejam substancialmente alteradas (Daynard et al, 1971;Schoper et al, 1982;Magalhães & Jones, 1990a;Stewart et al, 1997). O aumento da densidade de plantas, nesse caso, seria acompanhado por um aumento do número de grãos por unidade de área, e não pelo aumento no número de grãos por planta, que parece ser predeterminado, refletindo o potencial genético da planta (Magalhães & Jones, 1990b;Uhart & Andrade, 1995). Apesar de tolerar altas densidades de plantas, os híbridos modernos são mais sensíveis a condições de estresse em anos com baixa precipitação pluvial, provocando diminuição na capacidade dos drenos em acumular os fotoassimilados disponíveis (Ouattar et al, 1987;Cox, 1996).…”

Effects of Alternate Furrow Irrigation and Nitrogen Application Rates on Yield and Water-and Nitrogen-Use Efficiency of Winter Wheat (Triticum aestivumL.)

“…Uhart and Andrade (1995) indicated that the grain yield of maize was reduced by reduced application of nitrogen. It is important to use an optimum amount of water and nitrogen for best management of crop production in arid and semi-arid regions, because the application of an excess amount of water causes nitrogen leaching (Artiola, 1991).…”