Nitrogen fertiliser recommendations

Kale. As this crop (like maize) is not normally sown until late April or May, there is usually a good opportunity to apply slurry from the wirrter accumulatioa There should be no need for any phosphate and potash fertihser following a slurry application, although extra nitrogen will normally be necessary. This fertiliser recommendation also applies to forage maize. 

Nitrogen-fixing Rhizobia on the roots provide the crop with nitrogen. Fertiliser N or FYM has no benefit and can delay or suppress nodulation. For a soil with an index of 2, the fertiliser recommendations for fresh peas wonld be 85 kg/ha of PjOj and 40-90 kg/ha of K O and for vining peas would be 40/ha of P Oj and 20-40 kg/ha of Kp. 

The latest date recommended for the application of nitrogen fertiliser is mid-August. In most seasons further applications are unnecessaiy since warm soils and autumn rainfall frequently result in nitrogen being mineralised from the... 

Table 20.4 Fertiliser nitrogen timing recommendations for grazing swards and for swards cut for silage...

The new Defra nitrogen recommendations continue to use Soil Nitrogen Supply (SNS) as their basis but the system has been fully revised with clearer definitions of soil type and revised index tables. Defra defines SNS as the amount of nitrogen (kg N/ha) in the soil (apart from that applied for the crop in manufactured fertilisers and manures) that is available for uptake by the crop throughout its entire life, taking accoimt of nitrogen losses . It is calculated using the equation ... 

A well-drained soil with a pH of over 6 is essential and the crop is best sown after cereals or fallow. A rotation of one year in five or six is recommended to reduce the risk of infection from Sclerotinia sclerotiomm. Fertilisers used are 25-50 kg/ha of nitrogen, and 40-60 kg/ha of phosphate and potash which should be applied to the seedbed as a compound. Too much nitrogen can cause lodging, can favom disease development, delay matmity and lower seed oil content. Sunflowers are sensitive to boron deficiency. 

Total plant nutrients required are summarised in Table 18.4. Less ititrogen is required if kale follows grass. Fertiliser is usually applied during final seedbed preparations. The nitrogen application can be split and partly top dressed when the young plants have up to five leaves. A pH of 6-6.5 is recommended. 

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