Effects of fertilization and row spacing on microenvironment within population canopy and dry matter accumulation of waxy maize

Using "Fengnuo 6" waxy maize as material, the influences of different combinations of fertilization amount (600 kg·hm^-2, 750 kg·hm^-2 and 900 kg·hm^-2) and row spacing (50 cm, 60 cm, 70 cm and 80 cm) on population canopy temperature, light intensity, relative humidity, CO₂ concentration, light/temperature distribution, as well as dry matter accumulation, growth rate, water use efficiency and cooking quality of waxy maize were studied in field trials at the same planting density. The results showed that row spacing and fertilization as well as times of the day and period of the filling stage affected waxy maize population canopy microenvironment at filling stage. Average canopy temperature was lowest at row spacing of 70 cm. During the early, middle and late periods of grain filling stage, 70 cm row spacing with 600 kg·hm^-2 fertilization amount presented the maximum values of light intensity of 236.2 μmol·m^-2·s^-1, 275.3 μmol·m^-2·s^-1 and 285.4 μmol·m^-2·s^-1, respectively. The relative canopy humidity were highest during the three periods of grain filling stage at 70 cm row spacing and 900 kg·hm^-2 fertilization amount, which were respectively higher than the minimum values by 41.99%, 33.98% and 36.11%. CO₂ concentration was highest (362.4 mg·m ^-3) at 80 cm row spacing and 600 kg·hm^-2 fertilization amount during the early period. However, during the middle and late periods, CO₂ concentration was highest at 70 cm row spacing and 600 kg·hm^-2 fertilization amount, and respectively was 363.4 mg·m^-3 and 385.7 mg·m^-3. At 70 cm row spacing and 900 kg·hm^-2 fertilization amount, water use efficiency was highest for all the three periods, which was higher by 14.75%, 15.18% and 14.46%, respectively, than the lowest value. The maximum dry matter accumulation and growth rate were highest too, with the values of 5 066.4 kg·hm^-2, 383.2 kg·hm^-22 and 13 213.4 kg·hm ^-2 for dry matter accumulation, and 14.3 kg·hm ^-2·d^-1, 15.3 kg·hm^-2·d^-1 and 19.7 kg·hm^-2·d^-1 for growth rate. The cooking quality of waxy corn (including sensory quality, smell/flavour, color, waxiness, tenderness and thinness/thickness) was also best at 70 cm row spacing and 900 kg·hm ^-2fertilization amount.