Manuscrito
Short term sustainability of pasture restoration improvement methods for degraded permanent pastures
Autor
Descalzi, Constanza A
López-Campbell, Ignacio Fernando
Kemp, Peter D
Ordoñez-Vásquez, Iván
Dorner, J
Institución
Resumen
Low sustainability and short persistence of renovated pastures are main issues for pastoral
6 production systems. Pasture establishment and production were evaluated following
7 different pasture improvement methods. On a naturalised degraded pasture (control,
8 NFNP), Valdivia, Chile, treatments of fertilised naturalised pasture (FNP), cultivated
9 pasture (Lolium perenne [Lp]) and Trifolium repens [Tr]), direct-drilled pasture (Lp and Tr)
10 and diverse direct-drilled pasture (Lp, Bromus valdivianus [Bv], Holcus lanatus [Hl],
11 Dactylis glomerata [Dg] and Tr) were established in autumn, 2013, and evaluated within a
12 completely randomized block design until autumn, 2014. The trial was grazed by sheep.
13 Soil fertility levels, seedling establishment and development, pasture growth, herbage mass
14 and botanical composition were analysed using ANOVA, LSD and Canonical Variate
15 Analysis. As a result of liming and fertiliser application soil aluminium saturation was low,
16 Olsen-P medium and exchangeable potassium high. At 110 days after sowing, Lp had
17 greater tillering than other grass species (P≤0.001; number of tillers/plant (mean±sem;
18 n=3): Lp 38.8± 1.1a, Bv 18.4± 3.0b, Dg 10.0± 1.6c, Hl 19.4± 1.2b) and its development
19 and production at plant level was similar in all sowing methods. The total leaf area of the
20 sown species was similar for all sowing methods and the improved pastures had a greater
21 maximum pasture growth rate than NFNP (P≤0.05; kg DM/ha per day (mean±sem; n=3):
22 FNP: 104±8.8a, CP: 89±9.7a, DP: 89±12.2a, DDP: 68±6.7b, NFNP: 39±3.1c) but differed
23 in their growth distribution across seasons. The accumulated herbage mass for the year was
24 similar for all improved pasture treatments (P≤0.001; kg DM/ha (mean±sem; n=3): FNP:
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8089±512.5a, CP: 7499±618.1a, DP: 7302±663.8a, DDP: 25 6729±498.5a, NFNP:
26 4069±234.3b). In conclusion, direct-drilling and pasture cultivation appeared to give a good
27 pasture establishment. At the seedling stage, Lp was faster growing than neighbouring
28 species. Increasing species diversity diminished the seasonality of pasture growth. All
29 pasture improvement methods gave a higher total yield than the degraded pasture, but the
30 FNP required no soil disturbance or risk of poor establishment. Also they stimulate the
31 spontaneous colonisation and growth of fast growing species improving agronomical and
32 ecological pasture features.
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34 Additional keywords: Pasture renovation, tillage, direct-drilling, pasture condition,
35 diversity, CSR pasture model 43