Productive curves of a natural pasture in mediterranean environment as a function of fertilization [Basilicata]
1992
Falco, E. de | Basso, F. (Universita della Basilicata, Potenza (Italy)) | Carone, F. | Postiglione, L. (Naples Univ., Portici (Italy). Dipartimento Scienze Agronomiche e Genetica Vegetale)
The influence of mineral fertilization on growth dynamics and seasonal yield of a degrade natural pasture was investigated in a five-year (1984-88) study. The research was carried out in a hilly area (550 m asl) of Basilicata (Stigliano-MT), characterized by a sub-arid climate and a loam-clay soil, sub-alkaline pH, N = 0.1%, 12 ppm of P2O5 and 550 ppm of exchangeable K2O. Five experimental plots according to Corrall and Fenlon (1978) were set up, with fertilizer treatments: D1 = 40 kg ha-1 of N per year; D2 = 100 kg ha-1 of P2O5 (given every other year); D3 = 100 kg ha-1 of K2O (given every other year); D4 = unfertilized control; D5 = 40 kg ha-1 of N per year and 100 kg ha-1 of P2O5 every other year. On a different sets of plots with the same treatments, weekly cuts in succession were performed, from vegetative regrowth to flowering. The research period was characterized by dry weather: 640 mm in 1983-84; 410 mm in 1985-86; 353 mm in 1986-87 and 205 mm up to June 1988. Minimum temperatures registered were -2 degree C (1984-1985-1988), -4 degree C (1986), -5 degree C (1987) while maximum temperatures had values between 41 degree C (1987) and 37 degree C (1986). Environmental factors proved more important than fertilization for herbage growth: maximum intensity was recorded between the second decade of April and the first of May in all five years, with a maximum of 60 kg ha-1 per day in the first year. The effects of fertilization were of little entity, but a favourable influence was shown by the use of NP and in a few cases with P or N. Such results were also confirmed by the study of biomass accumulation that was maximum at flowering (5.9 t ha-1 d.m. in 1984 in N treatment). As regards days of utilization, the five-year trend was closely correlated to soil water availability and temperature. The use of NP gave the highest number of days in which herbage was available (84 d. in 1985)
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