ARCHIVE: Fertiliser Manual (RB209)

Hops

(See pages 157-158 for pre-planting fertiliser recommendations.)

Fertiliser is not required in the establishment year provided appropriate pre-planting fertilisers have been applied.

Established Hops (second and subsequent years after establishment) – Nitrogen

 

kg/ha

Deep silty soils

180

Clay soils

200

Other mineral soils

220

The recommended rates are for maximum yield situations and should be applied annually. Nitrogen can reduce the alpha-acid content of hop cones, though it may produce more alpha-acid per hectare because the crop yield is greater. Where progressive Verticillium wilt is present, high nitrogen rates will make hops more susceptible to this disease so reduce the recommended amount to 125–165 kg N/ha where there is a risk of wilt.

Nitrogen should be split into two or three applications, the first dressing being given in late March or April, the second during May and the third in late June or early July. There is some evidence that late hop varieties especially, respond to a three timing split, with the last application no later than early July. The total rate should be adjusted according to variety, irrigation and soil type.

Where trickle irrigation is used there is benefit in using fertigation to apply nutrients.

Where large and frequent applications of organic manures have been used in previous years, reduce the nitrogen recommendation by 70 kg N/ha. FYM is best applied in the early summer to help minimise aggravating the effect of any wilt present, with alleyways treated in alternate years. Where organic manures have been applied in the previous 12 months the nitrogen rate should be reduced according to the information in Section 2.

Where soil nitrogen residues are potentially large (e.g. where organic manures have been used regularly) the use of soil analysis for SMN can be useful. See pages 95-96 for further details and Appendix 2 for sampling guidelines.

Established hops – phosphate, potash and magnesium

 

P, K or Mg Index

 

0

1

2

3

4

 5 & over

P mg/l (Olsen's)

0-9

10-15

16-25

26-45

46-70

>71

K mg/l

0-60

61-120

121-240

241-400

401-600

>601

Mg mg/l

0-25

26-50

51-100

101-175

176-250

>250

 

kg/ha

Phosphate (P2O5)

250

200

150

100

50

0

Potash (K2O)

425

350

275

200

100

0

Magnesium (MgO)

150

100

50

0

0

0

Hops require the maintenance of large soil nutrient reserves, P Index 4, K Index 3 and Mg Index 2. Potash is important and care must be taken to ensure that the recommended rates are applied annually.
Phosphate fertilisers should contain a large proportion of water-soluble phosphate.

To avoid induced magnesium deficiency, the soil K: Mg ratio (based on soil mg/litre K and Mg) should be no greater than 3:1.

Farmyard manure

Farmyard manure has been traditionally used on hops. As well as supplying nutrients it helps to improve the structure of cultivated soils. Now that few soils growing hops are cultivated there is less need for regular applications of bulky organic manures. Farmyard manure is recommended where the soil continues to be cultivated and where land is being prepared for planting.

Extreme caution should be exercised in the use of farmyard manure or slurry where Verticillium wilt is known or suspected to be present. Heavy applications of manure, in addition to supplying excess nitrogen, can reduce the soil temperature during the critical spring period. Low soil temperatures in the spring are known to make hops more susceptible to the disease.

Don’t forget to deduct nutrients applied as organic manures see (Section 2)

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