To clarify the regulatory effects of a polyaspartic acid (PASP) combined with chitosan (CTS) on soil moisture content, tobacco plant and root growth and development, and tobacco leaf quality in the arid tobacco area of Bijie, field experiments were conducted using Yunyan 87. Different concentrations of PASP and CTS (CK: same amount of water; T1: 3.0 kg/ha PASP+0.3 kg/ha CTS; T2: 3.0 kg/ha PASP+0.6 kg/ha CTS; T3: 6.0 kg/ha PASP+0.3 kg/ha CTS; T4: 6.0 kg/ha PASP+0.6 kg/ha CTS) were applied. Soil and root indexes, growth and development parameters and quality indexes of flue-cured tobacco leaves were measured at different growth stages. The results showed that compared with other treatments, T3 treatment significantly increased soil moisture content. At the rosette stage, the moisture content of the shallow soil layer increased by 15.01% and that of deep soil layer increased by 10.16% compared with CK. T4 treatment significantly increased the number of lateral roots and adventitious roots, as well as root volume and root activity, by 34.07%, 29.12%, 25.70% and 29.56% respectively compared with the CK. The combined application of PASP and CTS significantly promoted growth, development, and dry matter accumulation of flue-cured tobacco, with higher concentrations leading to more obvious effects. Compared with CK, the leaf area and stem circumference of T4 treatment increased by 18.3% and 12.3% respectively, and the dry matter accumulation increased by 26.04%. The chemical composition, sensory and appearance quality of tobacco leaves were improved to varying degrees. The improvement effect of T2 treatment was the most significant, with increases of 10.36%, 7.76% and 7.30% respectively, compared with the CK. The quality evaluation of tobacco leaves was 7.57% higher than that of CK. The combined application of PASP and CTS can effectively increase the soil moisture content, promote the root development of flue-cured tobacco, and improve leaf quality. The optimal treatment (3.0 kg/ha PASP+0.6 kg/ha CTS) alleviated the decline in yield and quality of flue-cured tobacco caused by drought in Bijie.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |