Abstract:

To investigate the effects of different nitrogen and phosphorus fertilization on the agronomic traits and quality of silage corn in Yuyang District, this experiment used ‘Dajingjiu 23’ silage corn as the research subject and adopted a split-plot design. Nitrogen fertilizer was applied at four levels: 90, 180, 270 and 360 kg/hm²; phosphorus fertilizer was applied at two levels: 90 and 180 kg/hm²; a blank control (CK) without nitrogen or phosphorus fertilizer was also set up as a reference; the effects of nitrogen and phosphorus fertilization on the agronomic traits, yield and quality of silage corn during various growth stages were investigated. The results showed that under low phosphorus treatment (P 90 kg/hm²), the yield-increasing effect of nitrogen fertilizer was more significant; N270P90 treatment performed best during the jointing stage, with N360P90 plants showing a prominent height advantage after tasseling; excessive phosphorus (P 180 kg/hm²) inhibited stem thickening (P<0.05). The fresh grass yield and dry hay yield were the highest under N360P90 treatment, increasing by 37.8% and 39.4%, respectively, compared to CK; nitrogen fertilizer played a crucial role in the accumulation of fresh and dry matter; N270P90 and N360P90 treatments had the highest crude protein content (P<0.05), increasing by 7.52% and 7.49%, respectively, compared to CK; N180P90 treatment had the lowest NDF and ADF content, at 44.31% and 23.37%, respectively, significantly improving feed quality. The comprehensive analysis showed that N360P90 was the optimal combination of nitrogen and phosphorus.

Key words: nitrogen and phosphorus combined application, silage corn, agronomic traits, yield quality, correlation analysis