Growth, yield components and micronutrient nutrition of field-grown maize (Zea mays L.) as affected by nitrogen fertilization and plant density
Growth and yield components in field-grown maize (Zea mays L.) were enhanced by nitrogen fertilization ranging from 50 to 200 kg N ha−1. Ear diameter, kernel depth, grain: stover ratio, number of ears plant−1, plant height and dry matter production increased as N fertilization rate was increased up to 100 or 150 kg N ha−1. Tasselling in maize was hastened by N fertilization. Increasing plant density from 25000 to 75000 plants ha−1 increased plant height, dry matter production and delayed tasseling but reduced ear diameter, kernel depth, grain: stover ratio and number of ears plant−1. Increased N supply and plant density had no influence on the concentrations of Mn, Zn, Cu, and Fe in ear leaf; except that Mn concentration increased as N fertilization rate was increased up to 150 kg N ha−1. Nitrogen × plant density interactions on the concentrations of the micronutrients in maize ear leaf were not significant.
Effect of nitrogen and potassium fertilization on micronutrient content in grain maize (Zea mays L.)
MAŇASEK JOSEF, LOSAK TOMAS, PROKES KAREL, HLUSEK JAROSLAV, VITĚZOVA MONIKA, SKARPA PETR, FILIPCIK RADEK: Eff ect of nitrogen and potassium fertilization on micronutrient content in grain maize (Zea mays L.). Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, 2013, LXI, No. 1, pp. 123–128 A two-year small-plot fi eld experiment with the grain maize hybrid KWS 2376 was conducted on heavy soil with a low supply of available nutrients incl. potassium (K) at Otrokovice, Czech Republic, during 2010–2011. The experiment included 4 treatments: unfertilized control; nitrogen (N) fertilisation with urea (120 kg N/ha) alone or combined with two forms of K fertiliser (potassium chloride (KCl) or potassium sulphate (K2SO4); 125 kg K2O/ha). Biomass samples for determination of Zn, Mn, Cu and Fe were taken as the whole aboveground biomass in the DC 32 (fi rst node stage), the ear-leaf in the DC 61 (fl owering stage) and grain during the harvest. Between the two years the content of micronutrients in the individual treatments varied irregularly. In DC 32 and DC 61 the order of the content of micronutrients was as follows: Fe > Mn > Zn > Cu. The Fe content was signifi cantly the highest in the unfertilised control and the Mn content a er the application of N + K2SO4 in both samplings. In the grain the order was as follows: Zn > Fe > Mn > Cu (mg/kg DM): at the following contents: Zn: 19.20–23.19; Fe: 15.12–19.87; Mn: 0.85–3.60; Cu: 0.19– 1.34. We can recommend fertilisation of maize with urea and with both potassium mineral fertilisers without any negative eff ects on the content of the micronutrients in the maize biomass. zinc, manganese, copper, iron, leaf, plant Maize (Zea mays L.) is a crop of worldwide importance whose grain is used primarily in the food and feed industries or as silage for feeding animals or as a substrate for biogas stations. The current situation in the Czech Republic is that maize is grown for grain and silage on about 98,000 and 192,000 ha, respectively, of the country’s total arable land of about 3.2 million ha (Losak et al., 2010). However the maize acreage is continuing to increase. Cultivation of high yielding quality crops including corn is dependent on adequate and balanced nutrient fertilization (Sahrawat et al., 2008; Prokes, 2008). In this respect nitrogen is of crucial importance (Berenguer et al., 2009; Gallais et al., 2008) particularly in raising yields and fodder production. Indeed under conditions in the Czech Republic, nitrogen is o en the only nutrient which is supplied as a fertiliser, crops in many cases being dependent on the natural fertility of the soil as a source of other macronutrients – P, K, Ca, Mg, S (Losak et al., 2006, 2011). In terms of micronutrient supply, maize is usually fertilised with zinc (Potarzycki and Grzebisz, 2009; Hossain et al., 2008; Fecenko and Ložek, 1996), the other micronutrients considered here (Mn, Cu, Fe) not normally being supplied. The importance the micronutrients in plant nutrition should not be underestimated. As pointed out by Marschner (1995), even though micronutrients are present in the plant in only minute concentrations, plant and crop growth is crucially dependent on an adequate supply of all essential elements regardless of the amounts in which they are required. Interactions 124 Josef Maňasek, Tomas Losak, Karel Prokes, Jaroslav Hlusek, Monika Vitězova, Petr Skarpa, Radek Filipcik between macroand micronutrients (ions) may result in their increased (synergism) or reduced (antagonism) uptake by the plant and in this way they may have a fundamental eff ect on the entire metabolism of the plant. The aim of the work reported here, a two-year fi eld small-plot experiments with grain maize, was to assess the impact of nitrogen and potassium on the content of four micronutrients (Zn, Mn, Cu, Fe) in maize biomass at the DC 32 (1st node), DC 61 (fl owering stages) and in the grain at harvest. MATERIALS AND METHODS Two-year fi eld small-plot experiments with grain maize were established in 2010 and 2011 in co-operation with the fi rm KWS OSIVA on heavy cambisol at the site Otrokovice near Zlin (SouthEast Moravia, Czech Republic, 49°11’23.046”N, 17°32’39.020”E, 200 m above sea level). This is a sugar beet production area, with typical spells of drought during the growing season. The average annual temperature is 8.9 oC and average annual precipitation 619 mm. For the experiment we intentionally selected a plot with a low supply of available nutrients in the soil according to Mehlich III (Tab. I). In both years the grain maize hybrid KWS 2376 (FAO 340) was used a er conventional pesticide treatments. The seed rate was 78,400 seeds/ha and sowing was carried out on 27 April 2010 and 9 April 2011 using a Kverneland Accord Optima pneumatic precision seed drill. The experimental plots (randomised complete block Latin square design) were laid out within the normal fi eld area. Each plot measured 6 m x 30 m (8 rows at 0.75 m spacing). Urea (46% N), muriate of potash (KCl; 60% K2O) and potassium sulphate (K2SO4; 50% K2O, 18% S) were applied manually prior to sowing and harrowed into the soil to avoid N (ammonia) losses via volatilisation (Tab. II). Each treatment included 4 replicates. In both years weed control was carried out by conventional chemical methods. The entire aboveground biomass in DC 32 (fi rst node stage), and ear-leaf in DC 61 (fl owering stage) and grain during the harvest was taken as biomass sample for the determination of Zn, Mn, Cu and Fe. During manual harvest (7 November 2010 and 17 October 2011) at the DC 89 stage (dry straw, yellow leaves), 15 cobs from each plot were taken for sampling following yield measurements. The soil was extracted using the Mehlich III method (CH3COOH, NH4NO3, NH4F, HNO3 and EDTA). The content of available phosphorus (P) in the extract was determined colorimetrically and the content of available potassium (K), magnesium (Mg) and calcium (Ca) by atomic absorption spectrometry (AAS). The ion-selective electrode (ISE) method was used to determine the pH value a er extraction in 0.01 M CaCl2. Plant and grain samples were dried at 60 oC to a constant weight. A er wet oxidation (HNO3+H2O2) of the samples in a standard laboratory microwave, micronutrient chemical analyses were carried out using atomic absorption spectrometry (AAS). The data were statistically analysed by means of variance analysis (ANOVA) using the statistical programme Statistica. Scheff e’s test (P < 0.05) was used to determine statistically signifi cant diff erences between the factors within methods of subsequent tests. RESULTS AND DISCUSSION The four micronutrients in this study Zn, Mn, Cu and Fe, function in numerous ways in plant metabolism with roles that are now reasonably well established and have been reported in detail in the texts of Marschner (1995), Bergmann (1992), Mengel and Kirkby (2001) and the review paper of Kirkby and Romheld (2004). All four of these micronutrients activate particular enzyme systems and are closely involved in various plant physiological processes. A lack of availability of this micro nutrient is particularly evident on high pH, calcareous, clay soils, low in organic matter (Mengel and Kirkby, 2001). I: Plant-available nutrient content and soil reaction (Mehlich III) of the cambisol at the study site
The question of grain content and forage quality in maize: comparisons between isogenic fertile and sterile plants
SUMMARY Results are presented from four experiments in which comparisons were made between isogenic sterile and fertile plants of maize to study the effects of grain content on yield and quality of shoot dry matter. In two experiments comparisons were made over a range of densities, extending from 5 to 25 plants/m2 in 1972 and 5 to 20 plants/m2 in 1973. The other two experiments, grown in 1974 at a density of 10 plants/m2, were sampled 30, 60 and 90 days after flowering. In 1972 and 1973 yield of shoot dry material was about 10% higher in fertile plants at the lowest density, 5 plants/m2, but grain formation had a negligible effect at higher densities. In 1974, at 10 plants/m2, the yield advantage for fertile plants was 6–7%. These results are in line with other European data, but show a much smaller effect of grain formation on shoot dry matter yield than is normally recorded in USA trials. The discrepancies probably reflect differences in environmental conditions. Absence of grain had little effect on contents of nitrogen, ash and in vitro digestible dry matter, and increased content of pepsin soluble material and hot water soluble carbohydrates. Percentage content of dry matter in the shoot was higher in fertile plants in 1973, and during the later stages of crop development in 1974. The results suggest that the importance attached to high grain content as an essential requirement for yield and quality in forage maize is exaggerated, and that the restriction of maize breeding and testing programmes to assessments of grain production, in the belief that the best grain varieties will also be best for forage, can no longer be justified in northern European countries.