Production of dallisgrass in response to NPK fertilizer in southwest China and its implications for cultivation

Dallisgrass (Paspalum dilatatum Poir.), a warm-season forage, is a perennial grass with high nutritional value, good palatability and high-stress resistance in subtropical regions worldwide. However, very limited information is available on the cultivation of dallisgrass, especially in southwest China. Soils in different areas with pasture cultivation histories were collected and mixed evenly as substrate soil. Pot experiments after fertilization with nitrogen (N), phosphorus (P) and potassium (K) are used to analyze the dallisgrass growth characteristics, dry matter biomass (DM), photosynthetic characteristics, nutrient accumulation, agronomic efficiency (AE), partial factor productivity (PFP) and recovery efficiency (RE). A three-factor (N, P, K) and five-level (N: 0, 48.66, 120, 191.34 and 240 kg/ha; P: 0, 68.93, 170, 271.07 and 340 kg/ha; K: 0, 30.41, 75, 119.59 and 150 kg/ha) quadratic regression orthogonal rotation combination design was used with three experimental plots per management strategy for multiple comparisons within each harvest. Compared with no fertilization, the optimal treatment (OPT, N 48.66 kg/ha, P 68.93 kg/ha, K 119.59 kg/ha) increased yield by 46.3%, but the effect of NPK alone was not significant. This is because OPT improves the morphology and photosynthetic characteristics of dallisgrass, cause the dry matter during the growth period is significantly (p < .05) increased, and the average nutrient use efficiency (7.45%) under the OPT management measures was much higher than the under N, P and K fertilization alone (approximately 2.61 times). More meaningfully, we found that the demand for P and K fertilizer in dallisgrass in a typical subtropical mountainous region of China is higher than that for N. Overall, these findings have important implications for the cultivation of dallisgrass.