Issues such as the nutritional needs of citrus trees, the sampling and interpretation of soil, leaf and water samples, the fertilisation of bearing and non-bearing trees, and symptoms of nutrient deficiency are all tackled in a new manual that was released earlier this year in support of South Africa's export driven citrus industry.
The 141-page “Handbook for Fertilisation of Citrus in South Africa" was compiled by Dr Pieter Raath of Citrus Research International (CRI) and the Department of Horticultural Science at Stellenbosch University, in collaboration with members of the Citrus Fertilisation Working Group.
Over the course of the year, Dr Raath and colleagues also introduced key concepts in the handbook to the citrus industry through a series of two-day workshops in Addo (Eastern Cape), Simondium (Western Cape), Hoedspruit (Limpopo) and Groblersdal (Mpumalanga).
The book's publication was funded with support from the Department of Science and Innovation.
“The goal with this handbook is to empower both citrus growers and advisors to obtain a thorough understanding of the theoretical and practical elements that need to be considered for optimal citrus nutrition management," says Dr Raath.
“Being able to deliver the highest quality fruit to highly demanding global markets starts with perfecting the basics of optimal production practices, and that is where nutrition takes centre stage," says CRI chief executive officer Dr Vaughan Hattingh.
Citrus Research International is a research and technical services organisation based in South Africa that focusses primarily on citrus.
Dr Hattingh congratulated the team behind the handbook: “It was a daunting challenge to distil the multitude of recommendations into a handbook, but Dr Raath and his team of contributors have excelled in their task. This handbook represents an invaluable tool in enabling the Southern African Citrus Industry to continue producing the best quality fruit for global markets, and is a must for all horticultural advisers and citrus producers."
The book, presently only available in hardcover, will be available soon in electronic format. It includes up to date, authoritative and practical citrus nutrition guidelines towards a rigorous citrus fertilisation programme that optimises financial returns, sustains yields and maintains soil and water quality. It is a follow-up on Hannes Coetzee's “Fertilisation Guidelines", as published in the “CRI Production Guidelines" of 2007.
“Our new 'Handbook' updates the invaluable guidelines set out in the original 'Fertilisation Guidelines' and combines age-old scientific principles with new practical implementations to reflect the dynamic nature of the South African Citrus Industry," says Dr Raath.
About the need for producers to focus on matters related to fertilisation, Dr Raath says: “Fruit tree nutrition rightfully enjoys much attention in modern citrus production systems. The purpose of fertilisation is to ensure that all mineral nutrients are available to a tree in sufficient quantities to achieve a specific production target. Citrus growers and their technical advisors, therefore, have to ensure balanced nutrition for each specific soil-tree-climate situation."
He says in practice this requires a knowledge of several variables such as soil, climate, fertilisers, tree physiology and fruit quality goals. “Information regarding all these is required to properly compile a fertilisation programme, and to implement it on orchard level."
He thanked the members of the Working Group, among which count soil scientists and citriculturists, for their help in compiling the handbook.
“The result was that scientific principles, which have been established over many years, as well as practical experience, could be uniquely combined to provide the South African Citrus Industry with a fresh, up-to-date and complete guide to successful citrus tree nutrition."
Author: Engela Duvenage