ACCUMULATION OF DRY MATTER AND NUTRIENTS IN TROPICAL AND TEMPERATE MAIZE CULTIVARS INTRODUCED IN BRAZIL

Autor: AILDSON PEREIRA DUARTE, JORGE DE CASTRO KIEHL, MARCOS ANTÔNIO FABIANO DE CAMARGO, PAULO CÉSAR RECO
Jazyk: angličtina
Rok vydání: 2003
Předmět:
Zdroj: Revista Brasileira de Milho e Sorgo, Vol 2, Iss 3, Pp 1-20 (2003)
Druh dokumentu: article
ISSN: 1676-689X
1980-6477
Popis: The objective of this work was to obtain the accumulation curves of dry matter and nutrients of five maize cultivars grown by farmers in the state of São Paulo, Brazil, differing in respect to the origin of the germoplasm and to the maturation date within each group. The distribution of dry matter and nutrients in leaves, stalk and ears was also studied. The experiment was carried out in Palmital County during the cropping year of 2000/01 under no-till system. Three tropical maize cultivars (AG 1051, BR 3123 and BRS 4157) and two temperate cultivars adapted to the Brazilian climate (DKB 212 and P32R21) were selected. To determine the accumulation curves, plants were sampled at 15-day intervals up to the 105th day after emergence, whereas to study the distribution of dry matter and nutrients in the plant, samples were collected at the end of the male silking and at grain physiological maturity, according to each cultivar. Maximum accumulation of dry matter and nutrients was estimated by means of polynomial regression equations. Nutrient content decreased with plant growth after the 30th day from emergence. For all cultivars, nutrient and dry matter accumulation reached maximum values before the grain physiological maturity, except for Fe whose accumulation continued beyond this stage. Most of the nutrients in the plant were accumulated before silking, except P, Fe and Zn. Only 13% of K in the plant was accumulated after silking. The introduced temperate climate cultivars accumulated more Cu in the whole plant cycle and showed higher proportion of N, Ca, Mg, Cu, Fe, Mn and Zn accumulating after silking, expressed as a percentage of the total amount accumulated, in comparison to the tropical cultivars. The late maturing cultivars, AG 1051 and DKB 212, showed the highest values of maximum accumulation of Mg; also, these maximum values occurred at a later period for these cultivars than for the others. The tropical cultivars were better adapted to the local warm condition than the temperate ones, and also showed higher accumulation of dry matter, K, Ca, Mg, B, Mn and Zn. Only a small proportion of Ca in the plant was accumulated in the ears, while N, P, S and Zn were mostly concentrated in this plant organ.
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