Using laboratory analysis to inform adaptive management

Abstract

Soil and plant analysis is a tool of critical importance to the management of soil based production systems. Management by use of visual crop symptoms alone is retrospective, as by the time visual symptoms are present production has already been seriously compromised and biomass yields reduced. The modern soil laboratory is pivotal to informing the soil manager what adaptive practices are needed to address chemical and physical imbalance before they occur. The most reliable analysis is calibrated against crop trials, to the plant variety level, in a particular soil type (Asher et al. 2002). Yet despite the fact that thousands of such field experiments have been conducted, there remain gaps for regions and species, and the information itself is out of reach for many soil managers. Thus, in the absence of correlated field trials soil managers are very often faced with making informed judgments from the laboratory data they have at hand. Soil testing may be used for pre-emptive purposes (pre-plant or benchmark analysis), routine monitoring to identify soil change (particularly fertility decline), monitoring in field trials (usually to help explain results) or for diagnostic purposes (specifically, deficient element analysis). Plant tissue analysis adds a further layer of explanatory data, confirming deficiencies evident in soil analysis. Different test methods and demands on accuracy and precision apply to the different soil and plant testing purposes. A basic laboratory capable of assessing most soil and plant tissue needs can be set up quite cost effectively with only seven key pieces of equipment, plus ancillary equipment (acids, extraction agents, glassware, etc.). Soil and plant tissue analysis is not only relevant to the agricultural production manager, but also for rehabilitation, and in the urban context such as greenhouses and hydroponics. The effective use of laboratory data is the single-most important tool for adapting soil management practices to the production situation.