Effects of superphosphate and potassium chloride fertilization on alfalfa

A fertilizer application experiment was carried out using a randomized blocks design with 2 factors and 4 levels, applying superphosphate and potassium chloride Under the experimental conditions, the greatest alfalfa fresh forage yield was obtained with the fertilizer application treatment of 600 kg/hm2 superphosphate and 100 kg/hm2 potassium chloride Compared with the control, this treatment increased fresh forage yield by 200%, and the net income increased $988 yuan/hm2 With the different superphosphate application rates, the differences between means of the first and second fresh forage harvest yields, and between the total harvest yields all reached the significance level p005 As the fertilizer rate increased, the yields also increased proportionally With different rates of potassium chloride application, total fresh forage yield differences between applying and not applying the fertilizer were all very significant (p001) With the increase in application rate of potassium chloride, the fresh forage yields increased and then slightly decreased However, total yield differences between application rates of 50 kg/hm2 and 150 kg/hm2 were not significant The optimum rate was 100 kg/hm2 The effects of superphosphate, potassium chloride, and their combinations were more marked in yields of the first harvest than in yields of the second harvest The drop in effect was more evident with potassium chloride and the combination of superphosphate with potassium chloride than with superphosphate Increasing the application rate of potassium chloride was favorable in increasing crude protein content of alfalfa, but protein content did not increase proportionally with increasing potassium chloride Crude protein content was highest at 200 kg/hm2 superphosphate, but at 400 kg/hm2 superphosphate, crude protein content dropped