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New Science

January 2023

How understanding soil chemistry can lead to better phosphate fertilizer practice: a 68 year journey (so far). Plant Soil 476: 117-131.

Barrow, N.J. 2022.

Summary by Dobermann, A.

This paper is one of those rare gems that provide you with decades of scientific knowledge distilled into a very readable and inspiring format. Jim Barrow started doing research at the interface between soil chemistry and plant nutrition in 1954 when, as a new graduate, he was employed by CSIRO in Australia. Here he summarizes what he has learned about phosphorus (P), and why some of our views on it are outdated. He addresses two main questions: (1) Why do farmers reapply phosphate? The short answer is that phosphate effectiveness decreases with time and it is therefore necessary; (2) Why does P effectiveness decrease with time? The major reason for the decline in effectiveness with time is penetration of phosphate ions by diffusion into the reacting soil surfaces, which changes their properties. Readers will also learn a lot about terminology and methodology used in studying the fate of P in soils and how the process of knowledge generation took place over decades, leading to more comprehensive hypotheses and models.

This work has implications for some of the most widely held theories in soil science. These theories are largely based on the notion that soil phosphate exists in discrete compounds with iron, aluminium and calcium. The work summarised here indicates, however, that such compounds do not exist under most common soil conditions. Barrow suggests that long-term fertilized soils no longer lock up or fix applied P. It is then only necessary to feed the plants, not the soil, i.e. annual doses (if they are needed at all) should be much smaller. Failure to appreciate this is the cause of P losses from farmland and consequent pollution of water bodies. He also suggests that for long-term fertilized soils, current soil tests do not give information on two important characteristics: the decrease in P buffering and the slowing of the penetration. This paper provides much food for critical and innovative thinking. Enjoy it.

December 2022

Micronutrient deficiencies among preschool-aged children and women of reproductive age worldwide: a pooled analysis of individual-level data from population-representative surveys.

September 2022

The Consortium for Precision Crop Nutrition (CPCN) has launched a new Crop Nutrient Data web portal, developed and hosted by Agmatix.

June 2022

High probability of yield gain through conservation agriculture in dry regions for major staple crops.

Plowman's folly.

April 2022

Soil organic nitrogen: an overlooked but potentially significant contribution to crop nutrition.

The direct assimilation of inorganic and organic forms of nitrogen by higher plants.

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