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?

Merredin, WA, 2018

Summary

This trial was established near Merredin on the 4thof May 2018, in order to investigate alternative methods of combating/ “band-aiding”acid soils. There are two issues with the current standard practice ofbroadcasting bulk quantities of limesand. Firstly, lime dumps are hundreds ofkilometres from many parts of the wheatbelt – high transportation costs.Secondly, the limesand used is course and insoluble, meaning it won’t affectthe pH below ~5cm, unless incorporated – increasing financial outlay. Below Idescribe the thought process behind some of the treatments:

Prilled Lime – A micro-fine lime that has beenprilled for handling purposes. In theory the smaller the particle size thegreater the surface area available to ameliorate pH. Benefits include lowertransportation costs and fine lime delivered at depth. The big question is howlong will it take for the prills to disassociate?
Liquid Lime – Same concept as above, however thelime is ground to a much finer particle size and placed at even lower rateswith the Flexi-N. This is logistically more realistic and the lime is insolution – quicker acting.
Low pH results in the lock-up of many nutrientsand increased solubility of Aluminium. Rather than trying to raise the pH torectify this, we have aimed to apply plant available nutrients in the seedfurrow. ClearStart 22KZ is a liquid starter fertiliser which contains 22% Phosphorousin the orthophosphate form, 7.5% Potassium, 1.8% Nitrogen, 1% Zinc, Cobalt andMolybdenum. All of which are plant available. This product is not just asoluble mixture of various fertilisers, its been through a chemical reaction thatresults in forms of phosphorous that are immediately plant available andresistant to becoming locked up. Researchindicates a 3-4x efficiency of Phosphorous when applied in this way.
The addition of 50Kg prilled lime to the aboveaims at ameliorating and band-aiding simultaneously. In this trial, thecombination performed exceptionally well. Anecdotal evidence interstate showsthe same results but the reasoning as to why, is not yet fully understood.
Molybdenum has been shown to help mitigateAluminium toxicity, hence the addition of CoMo as a foliar. (Cobalt/Molybdenum)

In this trial, the control out yielded all treatments. Rep 1displayed the type of response seen in Kukerin, however the remaining two repswhere noisy. The western end of the trial, reps 2&3 were significantlyaffected by kangaroos throughout the season. In addition, high winds from theNorth West in June/July filled furrows and damaged small emerged plants acrossthe North West corner of the trial. The macro & micro nutritional status ofthe soil was extremely poor. Hence, the addition of high pH products in theroot zone may have crucially limited micro-nutrient availability.

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

Treatments 6,8 and 12 were slightly more vigorous throughout the season. There were slight numerical differences in establishment between treatments, however with an LSD of 42 plants/m2 there are no statistically significant differences.

Yield Vs. ROI

In this trial, the control out yielded all other treatments. However, with an LSD of 570 Kg/Ha there are no significant differences. Below rep 1 shows very similar trends to the results in Kukerin. Rep 3 was the lowest yielding repetition due to kangaroo damage and the treatments closer to the fence line end performed worse.

Yield of Each Repetition

Soil Test Results

pH Core Sample Results

Table 1: Core samples were taken before seeding and again in September. The % change has been adjusted to assume 0% change in the untreated.

Grain Quality

Table 2: CBH grain quality results (AVG)

Conclusion

In this trial, we did not achieve what we set out to. This may be a result of a number of factors including Kangaroo damage, wind damage and poor nutritional status. In hindsight, this trials fertiliser program should have aimed at addressing a number of these deficiencies. In particular, Potassium. In addition, the site was very variable with the surrounding crop extremely variable.