Early Strawberry Nutrition Guidelines

Strawberries are a high value crop and fruit quality is absolutely paramount as growers know. What happens pre-flowering has a large influence on crop yield and quality so the importance of pre-plant & early crop nutrient management cannot be understated.

Pre-planting – Before planting you need to ensure your soil pH and calcium levels are optimal. Low pH will reduce availability of phosphorous and molybdenum and has potential to cause toxicity issues (eg. aluminium). Ideally aim for a pH (water) of 6.0-6.5 which provides good availability of most nutrients. On heavier poorly structured soils you may want to apply gypsum if not applying lime. Calcium is the most important nutrient for berry quality so you simply cannot skimp in this area otherwise you will pay the price (literally) come harvest time. Lime or gypsum should be applied well before planting (at least 3 months) though the full benefit will likely not be seen for at least 12 months following application.

On lighter soils the application of compost or animal manures can be most advantageous as they provide nutrients as well as organic carbon, that will enhance nutrient and moisture retention during the season. Organic nutrient forms are released more slowly than conventional mineral fertilizers so manures/composts will still need to be supplemented with mineral sources in most situations. Pre-plant rates of 50 kg/ha of each major nutrient (NPK) should be sufficient on most soil types.

Transplanting – This is a critical time and plants often suffer transplant shock during the first week and root uptake of nutrients is usually restricted. This is a good time to foliar feed the bushes to supplement reduced soil nutrient uptake. Complete nutrient sprays such as VLP are ideal in this situation while LIG-POLYPHOS also helps stimulate root development. LIG-KELP contains growth stimulants that also aid recovery from transplant shock.

Early Vegetative Development – This is an important phase where you are preparing the bush for flowering and fruit production. If correct nutrient inputs and balance are not maintained, it is very difficult to rectify once flowering begins. While major nutrients such as nitrogen, phosphorous and potassium are important for vegetative growth (see CR NPKomplete), calcium, magnesium and trace elements are equally important for bush health. New growth requires significant amounts of calcium (for cell walls) and this is one reason why excessive nitrogen causes calcium deficiency in fruit. Calcium is also critical for reproduction/flowering so levels need to be maintained right through the growing season, but it is essential to push hard with calcium pre-flowering to build robust bushes that can maintain good levels of fruit production. Calcium nitrate is a good option and can be used in conjunction with our control release equivalent (see CR CAL-NIT + Boron). Also be mindful of nutrient balance as calcium is immobile in the soil and excessive levels of nitrogen, potassium and magnesium can induce deficiencies.

Trace elements are essential for growth (photosynthesis) and plant health (low levels can reduce disease resistance). Zinc is especially important for early growth & deficient plants will be stunted and weak. LIG-TRACE is a fully chelated foliar trace spray ideally suited for crop establishment. Boron is another critical nutrient for strawberry production due to its role in flowering, calcium uptake and sugar transport. A combination of both soil (Calcium + Boron PLEX) and foliar (LIGNO-BORON) application will provide the best results.

On lighter soil types the addition of humates can aid fertilizer efficiency and stimulate microbial activity in the soil. LIG-HUMATES is extensively used in strawberry production in South East Queensland with excellent results & contains high levels of organic carbon (16%). With regard to nitrogen management, humates slow down nitrate release from urea leading to a better soil nutrient balance, controlled vigour and reduced leaching losses.

Here is some information on the role of essential nutrients in strawberry production.

Autumn Citrus Nutrition

Heading into Autumn, citrus growers are not only trying to size their crop but also ensure Autumn flush leaf health is optimal for carbohydrate production.

Zinc is a critical nutrient for leaf expansion and health of new growth, and regardless of soil type or growing area Autumn zinc sprays should be standard practice amongst citrus growers. Other nutrients of importance for leaf health include manganese, iron and magnesium. Deficiencies of manganese and iron are common on alkaline soils (eg. Sunraysia & SA Riverland) while magnesium deficiency is common on lighter acid soils such as you have in much of Queensland, WA & the MIA. If you have done February leaf analysis then your zinc levels ideally should be above 25 mg/kg and at least 35 mg/kg for manganese. If levels are lower than this then you need to look at your zinc & manganese spray program in spring and either increase rates or look at alternate products. LIG-ZINC + Mn has been used in citrus for more than 20 years in Australia’s most deficient soils with excellent results (see this zinc trial). For young trees a multi-nutrient mix like LIG-TRACE is ideal for improving growth and maintaining tree health.

As far as major nutrients are concerned, autumn is a good time to apply phosphorous, as this not only helps with sizing but the trees will also store some of this P for reproduction and cell division in the spring. Mature citrus trees are fairly efficient at mining P from the soil so levels do not need to be high for adequate supply and generally 30 kg/ha should be sufficient for maintenance requirements. Young trees may require extra due to limited root development and particularly on alkaline soils with high P fixing characteristics. MAP or DAP are good soluble sources of phosphorous as is MKP if you are on low potassium soils. If soil sulphur is low then Single Super is a better option as sulphur is required for utilization of phosphorous.

Usually by this time most or all of the tree’s nitrogen requirements should have been supplied (200-300 kg N/ha for a 50 T/ha crop). On very light soils with high rainfall there may be continued need for nitrogen to maintain general health and vigour, but always apply smaller more frequent doses of nitrogen where practical. Excess nitrogen during autumn can compromise fruit quality through increased split fruit, albedo breakdown, delayed ripening and poor colour. If nitrogen is applied during this period then it is essential that other nutrients including potassium, phosphorous, magnesium, calcium and boron are also maintained at optimal levels to balance nitrogen inputs.

Potassium is a very important nutrient for fruit sizing and ripening. Potassium requirements for bearing trees are similar to nitrogen (200-300 kg K/ha) however soil availability is quite low during Autumn and winter and therefore growers should look at supplementing soil uptake with foliar sprays during sizing. Potassium is mobile in the tree (ie. readily moves from leaves to developing fruit) so foliar sprays are an efficient and effective option for enhancing fruit quality. LIG-K + BORON has been specifically formulated for enhancing fruit size & sugar levels and is a good option for growers looking to improve fruit quality.

The autumn-winter period is also the optimum time to apply phosphonate if you feel phytophthora (eg. root, collar or brown rot) is an issue in your orchard or if you have had a wet spring and summer with soil conditions suitable for disease outbreak. PHOSIC 600 is a cost effective option for treating disease and improving general tree health. Its buffered 7.2 pH also provides superior crop safety when foliar spraying.

 

Foliar sprays

LIG-ZINC + Mn (5+5)LIG-ZINC + Mn (6+2)

LIG-K + BORON

LIG-IRON

LIG-TRACE

PHOSIC 600 (Systemic Fungicide)