Soil and nutrients for hazels

By Sjef Lamers of Sustainable Nutrition
B. For. Sc., Dip. H.L.S. Dordrecht, MNZSSS

HGA newsletter, February 2009


There are 16 essential nutrients required for plant growth: carbon (C), hydrogen (H), oxygen (O), nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), iron (Fe), manganese (Mn), zinc (Zn), copper (Cu), boron (B), molybdenum (Mo), and chlorine (Cl). Of these 16 nutrients most are derived from the soil except carbon, hydrogen and oxygen.

Nature has provided the soil with a form of nutrient storage (a nutrient cupboard): very small clay and organic particles called colloids. These colloids have electrical charges: they are positively or negatively charged. The amount of these colloids in a soil determines the total amount of charges in a soil. Nutrients are electrically charged ions in the soil. A positively charged ion (called cations e.g. potassium or calcium) will attach itself to a negatively charged colloid. A soil with a small amount of negatively charged colloids will have a very limited capacity to store elements like potassium and calcium. A soil with a high amount of negatively charged colloids is able to store a large amount of cations. The amount of fertilizer to use depends on the storage capacity of the soil. There is no general fertilizer application which will be valid for all soils. Every property will require its own fertilizer program.

Important aspects to monitor in the soil are:

  • pH and Buffer pH: soil acidity determines the growth and health of roots
  • organic matter: plays an important role in soil structure, water and nutrient holding capacity, reservoir of organic nitrogen and other nutrients
  • the major elements phosphorus, sulfur, calcium, magnesium, potassium
  • the trace (or micro) elements boron, zinc, copper, manganese, aluminium and iron.

Soil analysis takes the guesswork out of making fertiliser recommendations and leads to more efficient nutrient management.

Nutrient content and pH vary with soil depth. We suggest to take soil samples from the main soil horizons. Sub soil samples tend to be taken while investigating the suitability of land for hazelnut growing. The analyses results of the sub soil will give information about any chemical imbalances.

Soil analyses of New Zealand top soils (0­150 mm depth) frequently indicate low levels of potassium, boron, magnesium, zinc, relatively low pH levels and high aluminium levels.

Soil pH

Excessive soil acidity can reduce growth and yield of hazelnut trees. A large amount of New Zealand soils are naturally acidic with a pH generally in the range of 5 to 6. Soil pH can decline over time due to the acidifying effects of rain, plant growth, fertilization (nitrogen and phosphate fertilizers). Lime (or dolomite if magnesium is required) can be used to improve the pH of the topsoil. Some laboratories conduct a buffer pH or lime requirement test. This test determines how much lime should be applied to adjust the pH to a target level.


Young hazels require potassium (K) for shoot and root growth. Mature hazels have a need for potassium for nut production. Soils with a low K level or a high Mg level require extra potassium. The amounts of available potassium, magnesium and calcium in the soil are interrelated; an excess of any one of them can cause deficiencies of the others.


Phosphorus (P) deficiency has not been a problem in general in hazelnuts despite the low content of P in some soils. Several factors contribute to this: hazelnuts have a good ability to extract P from the soil, P is mobile in the hazel and crop removal of P is relatively small. Generally P fertilisation is not necessary, but if soil analyses indicate very low P levels you may consider a P application before planting. If the pH is very low or very high then the phosphate fertiliser should be applied close to the plant rather than broad spread. Lock up of phosphate can occur within 48 hours in these soils.

Nutrient functions

The functions different nutrients perform in the hazel are:

  • phosphorus: root growth and flowering
  • sulfur: quality aspects like aromatic properties
  • calcium: soil structure, cell division
  • magnesium: chlorophyll
  • potassium: root, shoot and nut growth
  • boron: bud development and nut quality
  • zinc: leaf size, height growth
  • copper: enzyme systems; please monitor build-up in the soil from fungicide sprays
  • aluminium: toxic element for roots, interferes with phosphorus and magnesium uptake, antagonistic to calcium
  • manganese: chlorophyll, flowering.

Sustainable Nutrition gives independent advice on soil and plant nutrition. We endeavour to help hazelnut growers to achieve optimal production of hazelnuts.

Sustainable Nutrition: PO Box 54, Wakefield 7052.

Healthy Hazelnut Oil

HGA newsletter, autumn 2004


Hazelnuts have found their way into more non-traditional foods due to the recognition of its nutritional and nutraceutical properties. Among nut species, hazelnuts play a major role in human nutrition and health because of its special composition of fatty acids ( mainly oleic acid), fat soluble bioactives ( tocopherols and phytosterols), vitamins (vitamin E), minerals, amino acids, antioxidant phenolics and dietary fibre. Hazelnuts provide an excellent source of energy (631 kCal/100g) due to its high oil content (~61%). Besides nutritional value, the presence of taste-active components together with aroma-active components can improve the taste and flavour of hazelnut-based products.

The presence of palmitoleic acid allows hazelnut oil to be absorbed quickly into the skin as well as acting as a solar UV filter, thus making it an excellent carrier oil and ingredient in skin preparations.

Elevated serum cholesterol level is a well-known risk factor for coronary heart disease and is a leading cause of mortality in many countries around the world. Monounsaturated fatty acids which are in large quantities in hazelnut oil, are known to decrease the low-density lipoprotein cholesterol levels and decrease the risk of heart disease. Research has demonstrated that hazelnut supplementation (40g) in the diet results in total cholesterol, low-density lipoprotein cholesterol, very low-density lipoprotein cholesterol, triacylglycerol Apo B and homosistein reduction of up to 5.3, 2.6, 22.4, 5.3, 0.3, 10.4, and 7.8% respectively. Furthermore, hazelnuts in the diet increases high-density lipoprotein cholesterol and Apo A by 13.9 and 0.3% respectively.

F.Shahidi, Dept. of Biochemistry, Memorial Univ. of Newfoundland, and C. Alasalvar, Dept. of Biological Sciences, Univ. of Lincoln, Brayford Pool, United Kingdom.

Local Research – Hazelnut Oil Composition and Comparisons

The quality of cold pressed hazelnut oil extracted from a mixture of Merville de Bollwiller, Ennis, and Butler hazelnuts grown at ‘The Nutt Ranch’ in Marlborough, was determined by measuring lipid classes, and fatty acids. The oil was tested at Hort. Research in Auckland during September of 2004. The reasons for having our oil tested were:

  • To be able to give more accurate information about our own products to our customers.
  • To make a comparison of the fresh hazelnut oil from our orchard, grown and pressed in Marlborough, with hazelnut oil from other parts of the world.
  • To compare the fatty acids that make up hazelnut oil with virgin olive oil.

The total lipid content, by weight, of the hazelnuts being tested was 48.3%. This is slightly lower than the actual figure due to some oil loss within the extraction equipment. Seven fatty acids were identified by chromatography, among which oleic acid contributed 77.839% to the total, followed by linoleic, palmitic, and stearic acids. Unsaturated fatty acids accounted for 93.183% of the total fatty acids present. Saturated fatty acids made up only 6.817% of the total fatty acids and were composed of palmitic acid and stearic acid.

Fatty AcidClassHazelnut oil sample tested
(oil %)
Comparison with virgin olive oil
(oil %)
International norm for hazelnut oil
(oil %)
16:0 (palmitic acid)Saturated4.614%10.930%4-9
16:1 (palmitoleic acid)Unsaturated0.143%1.158%Max 0.3
18:0 (stearic acid)Saturated2.203%1.981%1-4
18:1 (oleic acid) (=Omega-9)Unsaturated77.839%72.294%70-85
18:2 (linoleic acid (=Omega-6)Unsaturated14.925%9.211%7-25
18:3 (linolenic acid) (=Omega-3)Unsaturated0.143%0.793%Max 0.6
20:1 (gadoleic acid)Unsaturated0.133%0.313%Max 0.3


We were extremely pleased with the results of our data as it shows good consistency with fatty acid measurements internationally. All of the different fatty acids were well within the international norms. The data gained, as well as the investigation of the makeup of our oil will help us in answering questions about the fatty acid content of our oil by interested customers in a more informed way. We found it very interesting that hazelnut oil compares extremely well with Olive oil, the best part, of course, being able to ingest the oil in the form of fresh hazelnuts or as cold pressed oil. We were amazed at the amount of research being done on Omega-3 fatty acid, Omega-6 fatty acid, and Omega-9 fatty acid internationally. The uses that our body makes of each of these are pretty incredible and it is notable that we can only get Omega-3 and Omega-6 within our diet. Our body is able to manufacture a limited amount of Omega-9 but most of what we need must still come from within our diet.

And finally, aside from the fact that hazelnut oil has super health giving properties, it also has a terrific aroma and taste. It is an excellent replacement for butter on potatoes and vegetables and is perfect for use in baking where an oil is called for.

DW & BL Null, Nutt Ranch Products, Marlborough, New Zealand

Bev Taylor & Gordon Mounsey


HGA newsletter, Autumn 2004

In this issue we are visiting the orchard and business of Bev Taylor and Gordon Mounsey on the outskirts of Christchurch.

We bought our 11 ½ acres in 1990 and planted shelter trees. Over the next 5-6 years we planted the hazelnuts; Whiteheart with Alexandra and Merville de Bollwiller as their pollinators. We lost very few and the trees grew.

When they started producing nuts we found there was a shortage of processing units. We joined Ted Kempe, Bob and Grace Laing and Roger Rose in forming “Associated Nut Harvesters”, using Ted’s equipment at Amberley. This worked quite well for 3-4 years. We then disbanded this company. Ted continued north of Christchurch and we developed “Divine Taste of Canterbury”. Divine Taste has a small nutcracker that we use when we have groups on site. Most of the cracking is done by the Hazelnut Company Ltd. As I have found it a labour intensive activity.

Marketing is very select and Niche oriented. In the past we have targeted the supermarkets and to do this you need bar codes and good labelling. We maintain these markets but have not recently expanded in the supermarkets. A distributor may be necessary if we are to do so.

More rewarding financially is the value added products we do. The most popular is Dukkah followed by caramelized hazelnuts. I have worked with a chocolatier and two chefs – Phillipe Meyer (from Celia Hay Cooking School) and Mhairi Maxwell. We have experimented with a range of products. Now I supply gift boxes and boutique shops. I make up the products in packaging and price to suit.

After fourteen years we are in profit from our hazelnuts. Divine Taste has people on site by invitation and we have a selection of Canterbury products which they can buy ex. Kernelz walnuts, NZ kelp and Canterbury olive oils. Hazelnuts have introduced us to a wide variety of people from chefs and journalists as well as growers and nurserymen. We have found this rewarding and interesting.

Using a lawn sweeper for pre-harvest cleaning

Written by Mike Davenport. Originally published in the HGA newsletter November 2020.

Last season, Mike and Kathy Davenport purchased a John Deere tow-behind lawn sweeper, to conquer the mountain of clippings that spring and autumn grass growth causes. Mike realised that the basic principle lends itself to a wider range of orchard management, particularly pre-harvest preparation and perhaps even harvest itself. Mike has kindly agreed to share his experiences.

Continue reading Using a lawn sweeper for pre-harvest cleaning

Managing the orchard floor for optimal soil health

Summary of a presentation given by Charles Merfield, Biological Husbandry Unit (BHU), Lincoln University as part of the winter 2019 AGM/field day weekend

Originally published in the HGA newsletter, August 2019

Merf delivered a fascinating presentation on the key aspects of a healthy soil and how common orchard management practices can destroy soil health.


Merf’s key point was that it’s possible to achieve a healthy orchard and clear floor for harvesting while also maintaining biodiversity in the orchard floor, rather than using herbicides that kill soil microorganisms.

Continue reading Managing the orchard floor for optimal soil health

Basic moisture monitoring after harvest

You can determine how much moisture your hazelnuts have lost by regularly measuring their weight. You need accurate digital scales. This method won’t tell you the absolute moisture level, just whether they are stabilised.

Weigh the sample when nuts are first harvested. Re-weigh regularly until the weight is the same for 3 measurements.

% moisture = (wet weight – dry weight)x 100
dry weight