Issue 5 2020
Mouthwateringly-good news for pomegranate production
Open a pomegranate and what do you see? As a consumer, your mouth will water with the prospect of the refreshing and distinctive fruit’s flavor. As a farmer, especially in the part of China where farmers cannot grow enough of the fruit to meet demand, your eyes will also be looking for fruit size and color but will want to see how the arils measure up for sugar and acid contents and vitamin C content. Thanks to some recent research, there is a strategy in production that will keep pomegranate consumers and producers happy.

Finding the right fertilizer treatment

In the Heyin region of Henan province, China, where pomegranate production is popular, the merits of fertilizer use are well-known. Farmers have a habit of adding their choice of NPK fertilizer and perhaps some manure. However, yields – and profits – vary. The top 3% of growers harvest 45 ton/ha while over half harvest less than 22.5 ton/ha.

No surprise then, that many local producers of these delicious fruits were delighted – and curious – about the prospect of pomegranate fertilizer nutrition research.
Test and formulate for optimum nutrition

The collaborative team from a regional university and an academy set about comparing the results from different fertilizer strategies: usual farmers’ fertilizer practice (FFP); soil test and fertilizer formulation (STFF) and STFF plus Polysulphate.

And the results? The latter two treatments had the best results. It was the treatment with Polysulphate that lifted yield significantly, by up to 80%, especially amongst the younger trees. You can browse the full report to understand all the findings. But it’s the prolonged supply from Polysulphate of key plant nutrients, S, K, Mg and Ca that seems to make the difference.
Effect of Polysulphate application on appearance of soft-seed pomegranate fruit harvested from 15-year-old tree. Photo by W. Gaige.
Boosting yield and quality of pomegranate with Polysulphate

Compared with farmers’ fertilizer practice, using soil testing and formula fertilizers with Polysulphate significantly increased fruit yield for pomegranate trees of all ages. The yield increase is less significant as tree age increases, 82.4% (10 years), 55.2% (15 years) and 30.5% (20 years).

Polysulphate also significantly increased fruit weight and fruit size. In addition, Polysulphate improved the quality of the fruits by significantly increasing sugar content, sugar-acid ratio and vitamin C content, while decreasing acidity of the fruits.
Effects of fertilizer treatment on fruit yield as a function of tree age in soft-seed pomegranate experiment in Heyin, Henan Province, China. Different letters indicate significant differences (P < 0.05) within each tree age.
Not just more yield but more margin

It’s not just quantity that matters to farmers. So it’s also important to mention here that the research revealed more than just an increase in productivity, there was an increase in profit margin too.

Compared with farmers’ fertilizer practice, using soil testing and formula fertilizers with Polysulphate for pomegranate trees increased farmers’ net income by 148%, 84% and 48% for 10, 15, and 20 year old trees respectively.

No wonder progressive Chinese pomegranate farmers are welcoming this clear guidance to optimizing their production, especially of the newer soft-seed pomegranates, introduced from Tunisia over 20 years ago, that are increasingly popular with consumers.

The welcome sight of even more pomegranates – fresh, juice-packed and delicious – for sale in the markets and shops of Heyin and beyond is now all the more likely.
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Mined in the UK, ICL is the first – and only - producer in the world to mine polyhalite, marketed as Polysulphate