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)
Показать больше [+] Меньше [-]