Data/hora: 23/09/2024 19:00:13

Biblioteca(s): 	Embrapa Caprinos e Ovinos.	
Data corrente: 	30/01/2018	
Data da última atualização: 	30/01/2018	
Autoria: 	MCINTOSH, P. D.; ALLEN, R. B.; PATTERSON, R. G.	
Título: 	Temporal changes of vegetation and soil carbon, nitrogen and pH on seasonally dry high country, South Island, New Zealand.	
Ano de publicação: 	1994	
Fonte/Imprenta: 	The Rangeland Journal, v. 16, n. 1, p. 3-15, 1994.	
Idioma: 	Inglês	
Conteúdo: 	Abstract: Vegetation cover, and the values of organic C, N and pH in topsoils at 38 sites sampled on a high country farm in 1978 and 1979, before any topdressing or oversowing had been begun, were compared to values at the same sites in 1992, after soils had been progressively fertilised with a total of 1100 kg per ha of 28 percent S-superphosphate and oversown with legumes. In 1992 the cover of native species and the area of bare ground had declined relative to cover in 1978-79, whereas cover introduced pasture species tolerant of grazing had increased. Organic C in topsoils rose from a mean value of 3.3 percent in 1978-79 to 5.5 percent in 1992. There was insignificant change of total N values. The pH of topsoils (0-7.5 cm) declined at 36 out of the 38 sites. The average pH decline was 0.41 units, and the largest pH decline was 0.7 pH units. Results from an additional 7 sites outside the main survey area suggest that the pH decline occurs on upper midslopes and near-ridge sites rather than on lower midslopes and toeslopes. If topdressing and the associated pH decline continue, then by the year 2005, pH will be close to 5.0 in topsoils, and lime will be needed to maintain legume-based pasture production on the affected soils. Approximately 1 tonne of lime per ha every 4 years is estimated to be required to offset the pH decline. On present returns from livestock and wool, liming would be uneconomic.	
Palavras-Chave: 	Feed legumes.	
Thesaurus Nal: 	Botanical composition; New Zealand; Rangelands; Soil fertility.	
Categoria do assunto: 	P Recursos Naturais, Ciências Ambientais e da Terra	
Registro original: 	Embrapa Caprinos e Ovinos (CNPC)	
Exemplares: 	CNPC - (36242-1) - ADD - AP - PP -  -  -  - DIS