Pikamenetelmät kasvin ravinnetilan kuvaajana

Translated title of the contribution: Quick methods for analyzing plant nutritional status

Tuomas J Mattila, Veera Manka, Jukka Aaro Rajala

Research output: Book/ReportCommissioned report

Abstract

Plant nutrient status can be analyzed with tissue testing. A pooled sample of plants is shipped to a laboratory for analysis and the results describe the average nutrient concentrations in the sampled plant population. This is a standard practice, but it is also costly, time consuming and applies to plant population instead of individual plants. Several quick methods have been developed to monitor plant nutritional status without delay. An additional benefit is that these methods can be applied to individual plants and that since the cost per sample is low, large sample sizes are possible.

This report presents the results from a test of five methods on 24 test fields. The methods were plant chlorophyll analysis (Atleaf +), dissolved solids analysis (refractometer), plant sap pH, false colour photography (Publiclab Infragram) and manganese stress measurement (NN-Easy55). The results were compared to traditional plant analysis on small grains, legumes, rapeseed, potato and onions.

Based on the results, the correlation between quick methods and plant analysis was weak. Plant chlorophyll results did not correlate with nitrogen concentrations. Plant sap pH correlated with cation-anion difference and nitrogen, but there were some plants which were clear outliers. The sugar content of the plant was correlated with nitrogen, but this held only within a certain plant group. Manganese concentrations and Mn-meter readings had no correlation. The Mn-meter measures plant stress, so it could be that the plants differed in their tolerance to low Mn-concentrations.

A major difference between quick methods and plant analysis is their sample size: quick meters measure individual plants and plant analysis is a pooled sample. Therefore the variation between the results could be expected. The reliability of quick methods can be increased by increasing sample size, but this also increases the time cost of applying the methods.

As a conclusion we do not recommend using the quick methods as a replacement for plant analysis. Instead they can be used as a source of complementary information. In order to use quick methods for practical fertilizer planning, the results should be calibrated for plant species and growth stage.
Translated title of the contributionQuick methods for analyzing plant nutritional status
Original languageFinnish
Place of PublicationMikkeli
PublisherRuralia-instituutti
Number of pages23
ISBN (Electronic)978-951-51-3763-0
Publication statusPublished - 2018
MoE publication typeD4 Published development or research report or study

Publication series

NameRaportteja
PublisherHelsingin yliopisto Ruralia-institutti
No.185
ISSN (Electronic)1796-0630

Fields of Science

  • 4111 Agronomy

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