Effects of Basic Fertilizer Treatments and Nitrogen Topdressing at Joint-ing Stage on Starch RVA Characteristics of Waxy Maize

Abstract

Proper fertilizer managements can improve the starch pasting properties of waxy maize (Zea mays L. Ceratina Kulesh). To understand the starch Rapid Visco Analyzer (RVA) characteristics of waxy maize, we used Suyunuo 4 in a field experiment with different treatments of basic and topdressing fertilizers, especially the N fertilizer. The split design was employed with main plot of 4 basic fertilizer treatments (N 75 kg ha-1, N 75 kg ha-1 + K2O 70 kg ha-1, N 75 kg ha-1 + P2O5 65 kg ha-1, and N 75 kg ha-1 + P2O5 65 kg ha-1 + K2O 70 kg ha-1) and split plot of 3 N topdressing treatments (N 0, 150, and 300 kg ha-1). The peak vis-cosity (PV), trough viscosity (TV), final viscosity (FV), breakdown (BD), and setback (SB) varied in different fertilizer treatments except peak time (PT) and pasting temperature (PTP). Compared with the treatment of only N applied in basic fertilizer, adding P or (and) K fertilizers decreased the PV and BD, but increased TV, FV, and SB. With larger amount of N topdressing at jointing stage, PV, TV, and FV increased gradually, SB rose first and fell later. BD showed no significant differences in treatments of top-dressing N 150 and 300 kg ha-1. Among the RVA characteristics, PV was positively correlated with TV, FV, and BD (r = 0.80, 0.87, and 0.75, respectively, P0.01), while PTP negatively correlated with PV, TV, and FV (r = -0.65, -0.62, and -0.60, respec-tively, P0.05). The RVA characteristics of waxy maize starch were improved to be the better when the top dressing was N 300 kg ha-1 at jointing stage on the basis of N 75 kg ha-1 or N 75 kg ha-1 + P2O5 65 kg ha-1 as the basic fertilizer, and the top dressing was N 150 kg ha-1 at jointing stage on the basis of N 75 kg ha-1 + P2O5 65 kg ha-1 + K2O 70 kg ha-1 as the basic fertilizer.