Alternative Liming Methods

Can we achieve a 1st year response from alternative liming methods such as prilled and liquid limes compared to broadcasting of limesand?
Can we “band-aid” soil acidity by providing plant available nutrition and molybdenum?

Kukerin, WA, 2018

Summary

This trial was established near Kukerin on the 25th of April 2018, in order to investigate alternative methods of combating/“band-aiding” acid soils. There are two issues with the current standard practice of broadcasting bulk quantities of limesand. Firstly, lime dumps are hundreds of kilometres from many parts of the wheatbelt – high transportation costs. Secondly, common limesand is course and insoluble, meaning it won’t affect the pH below ~5cm, unless incorporated – increasing financial outlay. Described below, is the thought process behind some treatment decisions:

Prilled Lime – A micro-fine lime that has been prilled for handling purposes. In theory, the smaller the particle size the greater the surface area available to ameliorate pH. Benefits include lower transportation costs and fine lime delivered at depth. The big question is how long will it take for the prills to disassociate?
Liquid Lime – Same concept as above, however, the lime is ground to a much finer particle size and placed at even lower rates with the Flexi-N. This is logistically more realistic and the lime is insolution – quicker acting.
Low pH results in the lock-up of many nutrients. Rather than trying to raise the pH to rectify this, we have aimed to apply plant available nutrients in the seed furrow. ClearSart 22KZ is a starter fertiliser which contains 22% orthophosphate, 7.5% Potassium, 1.8% Nitrogen, Zinc, Cobalt and Molybdenum. All of which are plant available form. This product is not just a soluble mixture of various fertilisers, its been through a chemical reaction that results in forms of phosphorous that are immediately plant available and resistant to becoming locked up. Research indicates a 3-4x efficiency of phosphorous when applied in this way.
The addition of 50Kg prilled lime to the above aims at ameliorating and band-aiding simultaneously. In this trial, the combination performed exceptionally well. Anecdotal evidence interstate shows the same results but the reasoning as to why, is not yet fully understood.
Molybdenum has been shown to help mitigate Aluminium toxicity, hence the addition of CoMo. (Cobalt/Molybdenum)

In this trial, the prilled lime performed poorly with no response. Assessments in September revealed intact prills (See Photos). The liquid lime treatments showed slight improvements in early vigour and yield. Both ClearStart treatments showed significant improvement in early vigour and yield.

Methodology

Treatment List 1

Experimental Design

Site, Crop and Application Details

Assessment Methods

Data Analysis

All data analysis in this report was conducted using Microsoft Excel. Simple means, analysis of variance and the student t-test were used to determine statistical significance using the least significant difference method with a 90% confidence interval.

Results

Vigour Ratings

Establishment

Figure 2: Average of 5 counts per plot. Total of 15 counts per treatment.

The ClearStart treatments were better established and more vigorous. The crop was slightly ahead as can be seen in the photos in the appendix. The first 6 weeks are critical in a plant’s life and with the dry start experienced, we suspect treatments with only Macro Pro suffered due to lack of moisture to solubilise the fertiliser.

Yield Vs. ROI

The prilled lime treatments have adversely affected the yield by 0-200 Kg/Ha. This may be a consequence of excessive elevation of pH around the root/fertiliser zone locking up phosphorous and micronutrients. The liquid limes provided a 100-200 Kg/Ha numerical yield increase with ROI’s not sufficient to justify their use. However, it is possible that significant year 2/3 responses may occur.

A ~300 kg/Ha and ~600 Kg/Ha response is observed with the addition of ClearStart in treatments 11 and 12 respectively.

Grain Quality

Table 1: CBH grain quality results

There are no major grain quality differences to speak of except that the gypsum treatments seem to have reduced protein levels in the grain.

Conclusion

The trial found prilled lime failed to generate a positive result in the 1st year with a reduction in both yield and ROI. However; may prove to have significant benefits in the 2nd or 3rd year.

The liquid lime treatments showed a small improvement in both vigour, yield and ROI.

The addition of ClearStart and prilled lime significantly improved both vigour, yield and ROI.

Note: 24 Kg/Ha Macro Pro was removed from the ClearStart treatments to offset the cost of ClearStart. In 2019 we aim to investigate multiple rates of ClearStart standalone and in combination with compound fertilisers.

Regardless of soil type, acidity and other compounding factors. We believe there is a considerable fit for ClearStart. The first 6 weeks of a crop’s life are critical and we often compromise this period during dry starts. Granular fertiliser has to become 1) solubilised and then 2) go through microbial breakdown to become plant available. Often occurring after yield potential has already been lost.