Differential accumulation of nutrients by five cultivars of corn (Zea mays L.): II - micro nutrients accumulation

Abstract

The objective of the present work was to examine the differences in growth, yield, accumulation and transport of nutrients between the cultivars Agroceres 256, Agroceres 504, Centralmex, H-7974 and Piranão. The experiment was carried out in the municipality of Piracicaba, State of São Paulo, Brazil. The soil type was a sandy oxisol of medium fertility, except for K which was low. The experimental set-up was a randon block design with four replications. Common cultivation practices were followed, and the fertilizer used consisted of 83 g of a formula: 30-120-70, per meter lenght at planting, and 33 g of the formula: 50-0-45 per meter lenght as dressing 22 days after germination. The plant population density was 50,000 per hectare. Plants were collected for analysis at 20 days after germination, and there after at intervals of 20 days up to 120 days. The plants were divided into "stems + leaves", tassels, and ears for chemical analysis of Cu, Fe, Mn and Zn. Conclusions: Accumulation of nutrients - Differences in the accumulation of micronutrients appeared before the period of rapid growth (20 days) although afterwards no differences were detectable. - The maximum level of nutrients are attained in the following period (in days): Cu (101 -104); Fe (106-120); Mn (82-94); Zn (87-108). - The maximum quantities taken-up (in mg/plant) are: Cu (2.06-3.49); Fe (26.66- -36.29); Mn (9.92-14.39); Zn (5.88-6.69). Transport of nutrients - The transport of nutrients into the ears of the different cultivars are (per ha harvested): Cu (26-35 g); Fe (200-220 g); Mn (90-140 g); Zn (160-250 g).