Corn and Rice Crop Study Results

2 March 2015

RNS Reach

Sirius Minerals Plc

Corn and Rice Crop Study Results

§ Polyhalite outperformed MOP in corn, improving cob height by 9% and reducing the severity of sheath blight by 71%

§ Polyhalite supports an average 38% increase over MOP in potassium uptake in rice and improves micro-nutrient uptake from 5 to 27%

The Directors of Sirius Minerals Plc (AIM: SXX, OTCQX: SRUXY) ("Sirius" or the "Company") provide an update on the latest results from its ongoing global crop study programme.

This update provides results from the recently completed corn study at the Sichuan Academy of Agricultural Science and the rice study undertaken with Nanjing Institute of Soil Science.

Corn is the largest cereal crop in the world, demanding 7.33 million tonnes of MOP, which is the equivalent to 31.4 million tonnes of polyhalite. Cultivated rice in China represents 18% of the global hectares grown, equating to over 200 million tonnes annually.

In relation to the corn study, MOP was compared to polyhalite as the K source and measured the above ground corn biomass, plant height, cob height and resistance to disease (sheath blight). The study revealed a decrease of 14% of yellow leaves, and an increase of healthy (green) leaves by 8%.

In relation to the rice study, MOP was compared against polyhalite as the K source, but also measured the percentages of individual nutrient uptake for both the macro- and micro-nutrients. Polyhalite supports a 4% yield premium at recommended 90 kg K2O/ha over MOP and increased nutrient uptake of K by 38%. Polyhalite was also shown to improve the micro-nutrient uptake of manganese by 27%.

Chris Fraser, Managing Director and CEO of Sirius, commented:

"Another strong performance from polyhalite on such widespread and important crops is welcome and will continue to aid our discussions with current and future customers."

An agronomy update presentation and webcast has been uploaded to the Company website www.siriusminerals.com.

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About Sirius Minerals Plc

Sirius Minerals is a potash development company with properties in the United Kingdom (North Yorkshire) and the United States (North Dakota). Its primary focus is the development of the York Potash Project which has the world's largest and highest grade deposit of polyhalite, a multi-nutrient form of potash containing potassium, sulphur, magnesium and calcium. Incorporated in 2003, Sirius Minerals' shares are traded on the London Stock Exchange's AIM market. Its shares are also traded in the United States on the OTCQX through a sponsored ADR facility. Further information on the Company can be found at www.siriusminerals.com.