Monday, April 20, 2009

Vineyard Soil Profiles

Monday 20th April

Well a rainy day today at last, not heavy, but drizzly. It is forecast to pass quite quickly, then we are back into fine, dry conditions again. The drive into the vineyard is looking beautiful in full autumn colour now. As not a lot is happening with the harvest, I thought it would be good to talk a bit about our soils at our vineyard.

It has often been said that the soils and climate of Martinborough are very similar to that of the world’s greatest Pinot Noir vineyards; being the plantings of the Côte d’Or, in Burgundy. While it is true the climate is similar, the soils in most of Martinborough have much more in common with the gravely soils of Bordeaux, than the Côte d’Or.

10 kilometres south of Martinborough, in the Dry River region, it is a different story. Murdoch James Estate’s “Blue Rock” vineyard exhibits characters much closer to Burgundy. While retaining the low rainfall necessary to grow premium grapes, the soils here are quite different to the rest of Martinborough. On close scrutiny, the soil at “Blue Rock” has much more in common with those at Domaine Romanee Conti, Richbourg, and La Tache. They are free draining, limestone-based soils that give an added element of opulent richness and ‘flesh’ to the wines made from grapes grown on them.

For those interested in more detail, at Blue Rock the various blocks have slightly different characteristics. The Blue rock vineyard sits on five river terraces, four of which are elevated. All the elevated ones are predominately north facing. However there are subtle and interesting differences in the soil structure of each block.

1. Lower Flats Block: 1 ha, located on an old riverbed with very shallow loam soils over gravel beds.

2. Nelson Block: Lower First Terrace, 6.6ha - Sloping to the north, with moderate silt loam soils over gravels

3. Pipers Block: Back First Terrace, 2.85ha - Sloping to the northeast with moderate silt loam soils over gravels

3. Jims Block: Second Terrace, 3.07ha - Sloping north with deep silt loam soils over very deep gravels

4. Highfold: Third Terrace, 6.33ha - Sloping direct north contour, with deep silt loam soils with very deep gravels, and a high lime content.

Other observations:
• All soil pits dug on the property show deep silts with high mineral and lime content over varied gravel depths.
• Past profile holes have shown grape vine roots penetrating over 3 meters down.
• At this depth, they are still approximately 5mm thick.
• Machinery use is restricted in winter to avoid soil compaction.
• Summer irrigation is used on the sloping blocks