Effect of anhydrous magnesium sulphate fertilizer and cutting frequency on yield and chemical composition of Panicum maximum

Abstract

Effect of anhydrous magnesium sulphate fertilizer on Panicum maximum yield and chemical composition of the resultant herbage harvested at 3, 4 and 5 weeks of age was investigated. The treatments were labeled T1 to T6. T1 was fertilized and harvested at 3 weeks cutting interval, T2 was fertilized and harvested at 4 weeks cutting interval, T3 was fertilized and harvested at 5 weeks cutting interval, T4 was not fertilized but harvested at 3 weeks cutting interval, T5 was not fertilized but
harvested at 4 weeks cutting interval and T6 was not fertilized but harvested at 5 weeks cutting interval. The results showed significant differences (P<0.05) in dry matter yield between treated and untreated
grass and the intervals of cuttings. Although, there was no significant difference (P>0.05) between the treated and the untreated grass at the same cutting interval, there was a marginal increase with the
treated showing superiority in all the cases. Also observed was increase in yield as the cutting interval increased in both cases of treated and untreated grass. It was also found that there was no interaction between fertilizer application and cutting frequency. The crude protein contents of both the treated and untreated grass at different cutting intervals was significantly (P<0.05) different. At the equivalent cutting intervals between the treated and the untreated grass, the crude protein contents, though, not significantly (P>0.05) different was consistently higher than that of the untreated. It was also found that the crude protein content of the grass declined as the plant aged. The NDF contents were higher in the untreated grass than the treated grass. The magnesium fractions of the treated grass at the cutting intervals were significantly (P<0.05) different while those of the untreated grass at all the cutting intervals were similar (P>0.05). The herbage magnesium content between the treated and the untreated
at the same cutting intervals were different as the magnesium contents in treated grass were consistently higher than the untreated at the same cutting intervals. In the treated grass, the magnesium contents of the herbage grass did not show a definite pattern as the cutting interval
increased but did decrease in the untreated grass as the grass matured. The calcium contents of treated and untreated grass at different cutting intervals were similar (P>0.05) in T1 and T3 but different
(P<0.05) in T2. The herbage calcium content seemed not to be influenced by magnesium fertilizer application. Also age at cutting seemed not to show effect on the herbage calcium content in both
cases of treated and untreated grass. The potassium content of both the treated and untreated grass was similar (P>0.05). In both the treated and the untreated grass, the potassium contents of the grass
decreased with age.