Effects of Polyaspartic Acid on Growth, Yield and Nutrient Absorption of Flue-cured Tobacco with Reduced Fertilization

To improve the utilization of nutrients and reduce the application of chemical fertilizers in flue-cured tobacco farming, a field experiment was conducted to study the effects of polyaspartic acid on the tobacco growth, yield and mineral elements absorption with ‘Nanjiang No.3’. The results indicated that with 20% reduction of fertilizer application, polyaspartic acid could promote flue-cured tobacco growth and dry matter accumulation, and increase the root system activity, ATPase physiological activity and photosynthetic characteristics. Furthermore, the high-level polyaspartic acid was more conducive to the tobacco final growth than any other levels. Compared with the contrast, the treatment which combined the reduction of fertilizer with the application of polyaspartic acid revealed that the accumulation of N, P and K in tobacco leaves increased by 2.79%-8.66%, 2.3%-9.2% and 1.15%-4.45%, respectively; the siol available N, P and K contents increased by 6.79%-32.29%, 5.71%-21.31% and 1.36%-31.08%, respectively; the output of tobacco leaves varied from -6.28% to 2.46% with no significant difference was found between the two treatments. It was concluded from this study that the addition of polyaspartic acid could increase the flue-cured tobacco absorption of nutrients and reduce the use of chemical fertilizer, and that the application of 5% polyaspartic acid showed the best effect.