It is good to do trials on your own property to find out how things work. It is best to leave test strips on the paddocks, including a nil strip to see what would have happened if you hadn’t done something. It is important to keep good records and markers in the field to be able to keep track of a treatment in one season and over subsequent years. Current yield monitors are providing grain growers with a good tool to quantify differences.
Monitoring – “you can’t manage what you don’t measure” – Monitoring of soil and plants is important to be able to see improvements when changing management, and to allow early detection of required management. It is important to monitor different paddocks and use these records to try to quantify different solutions to a problem. Monitoring is a great learning tool, especially when comparing a similar crop across different paddocks or on a given paddock over seasons. Keeping good records facilitates discussion with other landholders and advisors. For example, a Soil Health Card with recording instructions was developed by a Landcare group in the Northern Rivers region of NSW (NR 2006).
A home-made penetrometer (see tools) is the great tool to monitor progress in and between paddocks as an improving soil biology alleviates soil compaction, making soils more aerated and easier to penetrate by roots.
Pulling plants out of the soil is a test to help assess microbial activity. Naked roots usually mean a dense soil with little microbial activity. A thick soil layer stuck to roots (i.e. the rhizosphere) with prolific branching of the roots is an indication of a well aerated soil with active soil biology. Plants will have more solid stems, especially perennials like lucerne. Keep records of weeds as indicators of movements in soil mineral availabilities.
Smell the soils and discover the sweet smell of a healthy soil. Lab soil tests are the classic tool to get some chemistry numbers on what’s in the soil. However, it is important to also assess the biological availability of essential elements and their balance, as provided by special labs. Deficiencies are relative, as productivity can be adversely affected by excess. Soil minerals can work together or be antagonistic to each other. An excess of one will create a deficiency of another.
Tools – Descriptions of home-made equipment are given with the Soil Health Card (NR 2006). A wire quadrat is used for soil cover estimates or weed/plant population densities, a penetrometer (from fence wire) to monitor hardness of soil, and an infiltrometer tube to measure rate of water infiltration.
Plant sap will reflect improvement in mineral availability and sugar content, and can be monitored in the field with a refractometer giving a brix reading, which needs to be above a crop-specific minimum to keep insects and diseases away (Anderson 2000). Increasing fussiness of the measurement line indicates increased presence of minerals (e.g. Calcium).
A pH-meter can provide you with information as to whether plant sap is at the healthy neutral level, meaning the soil is in balance energetically. In Biological Agriculture a pH-meter should also be used to make sure any herbicides are applied with a pH as low as 4, and with fulvic acid as additive, to greatly increase effectiveness.