EFFECTS OF THE COUPLING OF WATER AND NITROGEN ON THE YIELD AND QUALITY OF KING GRASS (PONNISETUM PURPUREUM SCHUMACHER X P. GLAUCUM (LINNAEUS) R. BROWN)

Using the method of pot culture, the effect of different water and nitrogen conditions on the growth of King grass [Ponnisetum purpureum Schumacher x P. Glaucum (Linnaeus) R. Brown] and its physiological response mechanisms were examined. The results showed that under the soil moisture conditions designated as W1 (35%-45%), W2 (55%-65%) and W3 (75%-85%), the application rate of nitrogen corresponded to maximum yields of 271.78, 355.05 and 329.06 kg hm(-2), and protein contents of 361.54, 505.44 and 647.88 kg hm(-2). With the increase of water stress, the proline content of King grass increased, while the CAT enzyme significantly decreased, and the CAT enzyme increased significantly with the nitrogen content under the same moisture condition. Soil moisture conditions had a greater effect on the yield and quality of King grass than the application rate of nitrogen, but there was a synergistic effect between them. Therefore, if water and nitrogen are properly matched, higher yield and quality can be obtained. The best conditions for water and nitrogen were found to be a soil moisture content of 75%-85% of field capacity and an application rate of 329.06 kg hm(-2) for nitrogen.