New Zealand Journal of Agricultural Research abstracts
Effect of phosphorus, potassium and lime application on pasture in
acid soil in Yunnan Province, China
Zhao Junquan1,3
D. L. Michalk4
Wen Yifei2,3
D. R. Kemp2
Du Guozhen1
Helen Nicol2
1Lanzhou University
Gansu 730000, PR China
2Charles Sturt University/University of Sydney
Rural Management
Orange, NSW 2800
Australia
3Yunnan Agriculture University
Yunnan, 650201
PR China
4NSW Department of Primary Industries
Orange Agricultural Institute
Orange, NSW
Australia
Abstract Inadequate provision of winter
and early spring
forage is a major problem for ruminant production in Yunnan Province,
China. Temperate legumes (e.g., white clover) combined with perennial
grasses (e.g., perennial ryegrass, cocksfoot) have the potential to
fill this feed gap for livestock production when high fertiliser inputs
are maintained. In commercial practice, however, these legume/grass
pastures perform poorly and lack persistence due to poor fertiliser
management. This paper describes a low-input fertiliser strategy
developed to maintain productive pastures on moderately acid (pH = 5.3)
Hapludult (red earth) soils in Malong County, Yunnan. Since initial
soil tests showed major deficiencies of phosphorus (P) (<6 mg kg–1
Bray P) and potassium (K) (16 mg kg–1), a three-replicate
experiment was done that included four rates of fused calcium magnesium
phosphate (CaMgP) fertiliser (0, 500, 1000 and 1500 kg ha–1 yr–1),
four rates of potassium sulphate (K2SO4)
fertiliser (0, 100, 200 and 300 kg ha–1 yr–1)
and four rates of quick (or burnt) lime (0, 500, 1000 and 1500 kg ha–1
yr–1) to define a low-input P, K and Ca strategy for
white clover/cocksfoot/perennial ryegrass pasture. Our results
indicated that the lowest P rate (117 kg P ha–1 3 yr–1)
when combined with adequate K (123 kg K ha–1 3 yr–1)
and Ca (1.3 t Ca ha–1 3 yr–1) inputs produced 86%
of the white clover production and 96% of the cocksfoot production
measured at the highest P rate. Potassium had no effect on pasture
production when applied without P, but had a significant effect on the
yield of white clover when combined with P fertiliser. Lime application
had no effect on either pasture production or the levels of available
soil P and K, but it did raise soil pH to above 6.5. Potassium
deficiency was more serious for white clover than for the grasses, and
an annual application of c. 50 kg K ha–1 was needed to
retain white clover as a stable pasture component on these soils. We
conclude from our results that it is technically feasible to make
introduced temperate pastures on acid soils in Malong County productive
through an annual application of a modest fertiliser rate comprising
500 kg ha–1 of fused CaMgP and 100 kg ha–1 of
sulphate of potassium to overcome nutrient deficiencies. Due to the
complexity of acid soil problems, we recommend a three-step process for
successful pasture management: (1) undertake soil tests to identify the
specific soil properties and nutrient deficiencies that are likely to
limit pasture productivity; (2) choose pasture combinations that
correctly match pasture species with existing soil constraints; and (3)
tailor fertiliser strategies to specifically meet the nutrient
requirements of the chosen pasture combination. Using this approach we
recommend that low inputs of P and K be applied annually and that
perennial ryegrass be deleted from the temperate pasture species
combination recommended for moderately acid soils in Malong County.
Keywords acid soil; phosphorus fertiliser;
potassium
fertiliser; pasture yield; Yunnan Province
A07035; Online publication date 2 November 2007; Received 16 May
2007; accepted 20 September 2007
New Zealand Journal of Agricultural Research, 2007, Vol. 50:
523–535
0028–8233/07/5004–0523 © The Royal Society of New Zealand 2007
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