Specializing in quality soil improvements for better yields, water soakage, drainage & minimises soil erosion & loss of nutrient

Inkerman Lime & Gypsum

 Spreading your dollar further to drive your productivity foward

The Queensland Government has placed a further burden on Growers adjacent to the Great Barrier Reef Marine Park with State Government Legislation concerning the Great Barrier Reef Eco System. It is now mandatory to soil test prior to any crop being planted in the Lower Burdekin, Ingham, Mackay and Whitsunday regions.  This is aimed at recording major and some minor nutrient levels already in the soil and record keeping of total nutrient applied as per the current REEFSMART programme for interpreting and recommending a fertiliser application programme for a specific crop.

With the current increase in Sugar prices and the prospect that it will remain at least at these current levels over the next few years, it is imperative that growers now look to the health of their soils. This is to both minimise any undue erosion and run off that may find its way to the ocean, increase the water and nutrient holding capacity of their soils and thus be able to produce higher yielding crops resulting in the generation of additional revenue from individual fields.


One such way is to strategically apply Soil Amendments that will enable plants to make better use of applied agricultural fertilisers.


What Soil Amendments do I need?


This depends on several factors, all revolving around the pH of the soil and whether it is a clay, clay loam, silty loam, sand or has an imbalance of certain characteristics such as excess (leading to toxic levels) - Sodium (Na), Chloride (Cl), minor trace elements or heavy metals.


The way to check soil pH is by Soil Testing or using a portable pH meter.  Major and secondary nutrients are most available at a pH of 6.5 to 7.0. Therefore, fertiliser dollars are not wasted when the soil is in this pH range.  pH levels can be corrected by using Calcium Limestone (Calcium Carbonate) to raise the pH (the Carbonate is the part of the molecule that has acid neutralizing capabilities) and Gypsum (Calcium Sulphate) to lower the pH in soil.

Dolomite Lime also contains Magnesium, a minor nutrient that is also important for crop growth, therefore the application of Dolomite provides both Calcium and Magnesium (Mg).

Another local source of Limestone available is Earth Lime + Silica (Calcium Limestone with Silicon (Si).


Calcium Limestone, Earth Lime containing Silicate and Gypsum provide Calcium which is necessary in maintaining a desirable soil structure. Gypsum also provides Sulphur which is also an essential element in plant growth.  Moisture and air movement through the soil is essential for plant growth - Calcium keeps the soil mellow and crumbly, encouraging plants to root deeper and grow faster.


From past trials in many crops (including sugarcane and a variety of horticultural crops) it has been proved that the correct regulation of Silicon assists nullify the deleterious effects of salinity and heavy metals.

The application of Calcium Silicate (earth lime + silicon) in sugarcane reduced the uptake and translocation of Sodium (Na), but increased Potassium (K) concentrations in roots and shoots. Chlorophyll contents and photosynthetic rate were also significantly improved by added silicate.  Cane yield and yield attributes such as cane height, internode length, and number of tillers per plant was significantly higher along with juice characteristics such as Brix (% soluble solids in juice), Pol (% sucrose in juice), commercial cane sugar (CCS) and sugar recovery were significantly improved.  Other trials demonstrated that a more vigorous root system developed with the addition of silicon in numerous crop types as well as adding to the plants natural immune system in controlling certain fungal and insect related diseases.


With the addition of the various soil amendments the soil becomes more open; it readily absorbs rainfall thereby cutting down run-off and erosion. This also helps eliminate wet spots that otherwise would remain after the rest of the ground becomes dry. The combination of near neutral pH and an open, well-aerated soil provides the best environment for microorganisms that decompose organic matter, convert fertilizers to usable nutrients, and fix nitrogen from the air to the soil.  In Sodic soils (very high pH readings of 8 and 9+ also associated with high levels of Sodium and Chlorine) the applied Gypsum may be used up as the calcium replaces the sodium held on the clay-binding sites. The sodium can then be leached from the soil as sodium sulphate and soil structure is improved by providing openings in the soil to allow water, air, root and nutrient movement. The calcium in gypsum also works as a controller of the balance of especially the micro nutrients like iron, zinc, manganese and copper in plants, while heavy metal toxicity is regulated.  If all the calcium is used up in displacing Sodium (Na) this can lead to a Calcium deficiency and using a mixture of Gypsum and Lime gives an adequate supply of Calcium for optimum plant growth.


Soil Testing 


A soil test (sample) is only as good as the sampling process and quality of information forwarded to the Laboratory with the sample.  A number of important steps should be followed when soil sampling a block of land.




?Determinethe area that is to be sampled.


?Ensurethat the area being sampled does not exceed 10 - 20 hectares and that it is 

     relatively uniform.


?Takenotice ifa block consists of more than one distinct soil type – if it does,   

     sample them separately.


?Avoidareas that differ in crop growth or where large amounts of mill mud or other

     amendments have been dumped (sample such areas separately if necessary).


?Infield sampling is best done with an auger (either a turning auger or a soil tube).


?Limit to a minimum of at least 10 or 12 ‘augerings’ of soil should be collected from

     the area to a depth of about 20 cm using a zig-zag or grid pattern



?Thebasic principle is that more ‘augerings’ are better than fewer.


?Organise allthe ‘augerings’ to be collected in a good-quality plastic bag or a clean 

     plastic bucket to form a single composite sample.



?Proper care should be taken not to use a bucket with a galvanised handle as this

     source of zinc could contaminate the soil sample.


?Repeated mixing of all ‘augerings’ of composite samples is essential to ensure a

     uniform sample.


?Only dispatch a sub sample if the complete sample is greater than 1kg (500 g – 1

     kg is sufficient for dispatch to the laboratory).


?Forward this sample to a reputable laboratory for analysis.


?It is advantageous to supply as many details as possible on a label and on the

     sample bag to ensure that the sample can be easily identified, and that

     meaningful interpretation of the results is possible.


?The compilation of all information is important in that soil assays conducted by the 

     laboratory correspond to those calibrated for the specific crop production required.




Inkerman lime & gypsum acknowledges that some technical information

                                    contained in this document has been sourced from publications available
                                    from several worldwide media sources.



What application rates should be used?


Generally speaking (this will be confirmed from soil test), apply 2.3 – 4.6t Limestone per ha for upward pH correction.  This recommendation will be dependent on type of limestone or gypsum available and the severity of the pH level of the soil. Soils with a pH level of 5.9 or lower are considered critical and should be treated to increase the pH level to 6.0 or higher.  Maintenance applications should consist of applying Limestone annually or with each full crop cycle.  Similarly gypsum may be used at corresponding rates to lower pH reading or as advised from soil test.  Gypsum and Limestone may be applied to the soil at any time; however the preferred time of application is several weeks prior to planting.


Many growers are opting for a maintenance 50/50 blend applied at 4t per ha to optimise the $ returns and having more friable and productive soils.


Speak to us regarding your anticipated requirements – We have an Agronomist on hand, access to Soil Testing facilities and undertake to visit your farm this season whenever possible or as required.




Kosobryukhov, A1, Shabnova, N1, Kreslavsky, V1 and Matichenkov, V1

1Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino,

Moscow region, Russia 142290


Email: kosobr@rambler.ru


Salt toxicity is a worldwide agricultural problem. Numerous studies have

demonstrated the benefits of silicon (Si) for higher plants, particularly for gramineous

plants. The work presented here studied physiological responses of salt-stressed

wheat plants (Triticum aestivum L.) in the presence and the absence of Si in soil

under controlled conditions.


The treatments in the experiment were: control, 0.5 g Si and 1 g amorphous Si per kg soil with NaCl in irrigation water. The growth parameters, photosynthesis, respiration and chlorophyll fluorescence were determined. Growing of plants under salt stress led to a decrease in photosynthetic rate. The addition of Si to the soil resulted in an increased rate of photosynthesis from 158 to 520%, depending on salt concentration in the soil. Chlorophyll fluorescence and analysis of model parameters of photosynthesis indicated that Si enhanced photochemical efficiency. Leaf and stem dry matter was depressed under salt stress; however, this negative effect was decreased by the addition of Si.


Hence, Si is beneficial in improving the photosynthesis and growth of wheat plants under high soil salinity. Several hypotheses of the active Si impact on salt stress in plants were suggested:     

(i) improved photosynthetic activity,

(ii) increased antioxidant enzyme activity,

(iii) increased concentration of soluble substances in the xylem, which resulted in reduced sodium adsorption by plants.





Botta, A1, Sierras, N1, Marin, C1, Carrion, M1 and Pinol, R1

1R&D Department, Plant Physiology Division, Bioiberica, SA Pol Ind.

Mas Puigvert. Ctra. N-II, Km 680.6, 08389 Palafolls, Barcelona, Spain


Email: abotta@bioiberica.com


Powdery mildew type fungi are among the most persistent and common diseases

limiting production of a wide range of crops worldwide. In addition to direct damage

caused by the pathogen, fungal disease also weakens the plant’s resistance to any

biotic or abiotic stress factor. With this in mind, the R&D Department of Bioiberica,

SA, focused on plant stress management to develop a new foliar spray product

containing amino acids plus soluble active silicon (Si).


This approach combines the well-known beneficial properties of both components: the biostimulant effect of amino acids, which helps plants to rapidly overcome physiological stress, and the effect of Si on the plant’s resistance to fungal infections. Two modes of action have been reported to elucidate the Si effect: a structural reinforcement function due to its deposition underneath the plant cell wall and, more recently, the role of soluble Si as an inducer of plant defense responses.


Regardless of these mechanisms acting in an independent or complementary way, alternative plant disease protection treatments have recently aroused more interest due to limitations on the use of pesticides and environmental concerns. This study sums up the results of several new product trials in different plant-pathogen systems.


Findings confirm a synergic effect of amino acids plus Si on a reduction in the incidence and severity of powdery mildew in different plant species of agricultural interest, such as fruit trees and horticultural crops. The use of this new double-action product permits a reduction in the number of fungicide applications while improving health and yield parameters in sustainable crop management.


Keywords: silicon, biostimulant, stress, powdery mildew






Bernal, J1 

1Carrera 57 #14-44, Phone (1)4177903, Bogota, Colombia, South America


Email: bernaleusse@hotmail.com


Magnesium silicate is a natural product found in Colombia, South America, and is

being used extensively as a soil conditioner and source of soluble Mg and Si for

different crops. Magnesium silicate contains 31% MgO and 32% SiO2.


Applied at low rates of 100 to 300 kg/ha to acid or basic soils, it increases yields of different crops such as sugarcane and rice by between 5 and 20%. It can be applied as dust or pellets, alone or mixed with other conditioners or fertilizers.


Several trials have been conducted in the rice and sugarcane growing zones of the

country. A summary of some results obtained in Cauca valley with sugarcane are

reported in the present paper. Rice trials were also conducted in the eastern planes,

Magdalena valley and the Atlantic coast, the three main rice producing areas of the

country. Determinations basically included cane and sugar production for sugarcane,

and yield of grain (green paddy) for rice.


Results obtained indicate a positive response in yield and other parameters

determined with the application of increasing rates of Mg silicate to agricultural soils

of Colombia, mainly those with low pH and high soluble Al and Fe and a high P-fixing

capacity. Yield of sugarcane increased by 17.37 tons/ha (14.63%) and sugar production increased by 20.5% in relation to the control with an application of 200

kg/ha of Mg silicate.


Rice production increased between 21 and 33% with rates of application ranging between 100 and 200 kg/ha, in relation to the control treatment.



The effect of various calcium amendments applied to sugarcane trash

A.W. Wood1, 4, B.L. Schroeder2, 4 and R.L. Aitken3, 4

1. CSR Technical Field Department, PMB 4, Ingham, Qld.
Bureau of Sugar Experiment Stations, Private Bag 4, Bundaberg DC, Qld.
Bureau of Sugar Experiment Stations, Clarence River, NSW.
CRC for Sustainable Sugar Production, James Cook University, Qld.


Calcium amendments such as lime and gypsum are commonly used to ameliorate soil acidity and sodicity. The effect of these and other amendments on the decomposition of trash (sugarcane crop residues after harvest) was investigated on a range of sugar industry soils. Data from glasshouse pot experiments conducted on five different soil types indicated that certain amendments applied to the surface of sugarcane trash had a significant effect on trash decomposition. Relative to unamended trash, the application of mill mud (a by-product from the sugar milling process) most successfully enhanced the rate of trash decomposition. Of the other amendments considered, significant differences in trash decomposition were also obtained when lime (pure CaCO3 at 3 tonnes ha-1), a combination of lime and gypsum (1.5 and 2.0 tonnes ha-1), potassium hydroxide (1.7 tonnes ha-1) and urea (160 kg ha-1) were applied to the surface of the sugarcane trash. Soil and amendment type had a significant interactive effect on soil pH.

Key words

Sugarcane, trash decomposition, calcium amendments, soil amelioration.



Green cane harvesting and the retention of unburnt crop residues as a surface trash blanket has been widely adopted in the Australian Sugar Industry. The advantages of retaining sugarcane crop residues as a trash blanket have been well documented (Wood, 1991) and the benefits arising from the cycling of nutrients from green cane trash blanketing are currently being investigated (Mitchell and Larsen, 2000). However, little is known about the effects of applying calcium-containing amendments to sugarcane trash on soil properties. A series of glasshouse experiments were initiated to investigate the effects of a range of possible amendments on trash decomposition on different sugarcane soils. The results may have important applications particularly in situations where trash is slow to break down or where trash retention has been implicated in the increased acidification of surface soil horizons.



Three glasshouse experiments were conducted to investigate the effects of a range of possible amendments on the decomposition of trash on different sugarcane soils. In the first experiment, which was a pilot investigation, two acidic topsoils (a Hydrosol and Kurosol) were used. Soil (50mm deep), either unamended or amended with lime, was placed in trays and wet to field capacity. A 50mm thick blanket of cane trash was added to each tray. Lime was applied at rates of 0, 3 and 6 t ha-1 to the surface of the trash or incorporated into the soil prior to spreading the trash. Field moisture capacity was maintained by evenly spraying water onto the surface of the trash in each tray to predetermined masses. Trays were destructively sampled after four and seven months. The undecomposed trash, the 0-10mm soil/decomposed trash layer and the 10-50mm soil layer were separately sampled.The extent of decomposition of the trash was evaluated by measuring the dry mass of remaining trash.

Subsequent to this pilot investigation, two randomised pot trials with two replicates were established, one at the Department of Natural Resources (DNR) glasshouse at Indooroopilly (10-30oC) and the other at CSR Macknade Mill at Ingham in a warmer environment (15->40oC). The Indooroopilly trial consisted of 5 different topsoils: a Hydrosol (Coolum), a Kurosol (Yandina), a Humic Podosol (Nambour), a Dermosol (Ingham) and a Vertosol (Ayr). The Macknade trial included a Rudosol (river levee soil) and a Tenosol (flood plain alluvial soil) from the Herbert sugarcane area as well as the Kurosol and Dermosol soils used in the Indooroopilly experiment for cross referencing purposes.

In both trials, soil (80mm deep) was placed in square containers and partitioned into different depth intervals (0-10, 10-20, 20-50 and 50-88mm below the soil surface) using plastic coarse meshed grids. With the exception of the treatments without trash, effectively 40t ha-1 of air-dried trash was applied to the soil surface in each container. Various amendments were then spread on the surface of the trash (Table 1). The pots were regularly watered twice weekly at average rates of 300ml and 500ml at Indooroopilly and Macknade respectively. The pots were destructively sampled after 7 months.



Table 1. List of amendments included in the Indooroopilly and Macknade pot trials.



Amendment and equivalent rate


Calcium carbonate (3.0t ha-1)
Calcium sulphate (4.10t ha-1)
Calcium hydroxide (2.22 t ha-1)
Calcium carbonate (1.5t ha-1) + calcium sulphate (2.05t ha-1)
Mill mud* (30t dry mud ha-1)
Potassium hydroxide (1.68t ha-1)
Magnesium oxide (1.2t ha-1)
Urea (160 kg N ha-1)
Calcium carbonate (3.0t ha-1), No trash
No amendment, Trash only (40 t ha-1)


(* Mill mud is a by-product from sugar mills containing lime, organic matter and a range of nutrients)


Results and discussion

In the first experiment, the sampling after 4 months indicated that lime had a significant effect on trash decomposition, but the extent of decomposition was dependent on the method of lime application and the soil type. Spreading lime on the surface of the trash layer enhanced decomposition. However, the sampling after 7 months showed that the differences in residual trash had markedly narrowed for both soils and no significant differences existed between treatments. This effect was similar for both soils (data not shown here).

As expected, incorporating lime into the soil in this first experiment increased soil pH in both the 0-10mm and 10-50mm layers. Spreading lime onto the trash layer also resulted in marked increases in soil pH values in the surface soil (0-10mm), but although there was evidence of small pH increases after seven months in the 10-50 mm soil layer (from the application of lime onto the surface of the trash), these differences were not significant. However, the substantially lower exchangeable Al values associated with the 10-50mm soil layer at four and seven months (Figure 1) was evidence that some amelioration had occurred due to the application of lime to the surface of the trash. Based on this preliminary data, it would appear that the interaction between lime application and trash may have important implications for the amelioration of sub-surface soil acidity in minimum tillage systems.

The application of certain amendments had a significant effect on trash decomposition as reflected in the amount of residual trash (%) relative to unamended trash in both replicated pot trials. The data from the Indooroopilly experiment is shown as Figure 2. However the extent of decomposition depended on both soil type and amendment applied. Filter mud most successfully improved trash decomposition on all soils. Although the application of calcium carbonate (lime), potassium hydroxide, and a combination of lime and calcium sulphate (gypsum) all appeared to enhance decomposition, they were more effective on some soils than others. Whereas urea increased trash decomposition on the acid soils, it was ineffectual on the high pH Vertosol (data not shown). Variable results were obtained with the application of gypsum, magnesium oxide and calcium hydroxide.




Figure 1. Extractable Al values of the 10-50mm soil depth as influenced by lime application and time.





Figure 2. Residual trash (relative to unamended trash) associated with the application of various amendments seven months after application (average for all soils). LSD (p=0.05) = 6.6%.

Soil type, treatment and depth below the trash layer had a significant interactive effect on soil pH in the Indooroopilly experiment (Figure 3). To illustrate this effect, selected treatments only are presented - control (no trash, no amendment), trash (no amendment), surface applied lime (no trash), lime on trash, and mill mud on trash. As expected, the surface applied lime increased soil pH across the five soil types. This was most pronounced in the surface layers and generally declined with depth. The presence of a trash blanket (in the absence of any amendments) had variable effects on soil pH. While surface applied trash appeared to increase the pH of the Kurosol (Soil 1) and the Humic Podosol (Soil 3), it had little or no effect on soil pH in the Hydrosol (Soil 1) and the

Dermosol (Soil 5), possibly due to their higher buffering capacity. In contrast the presence of trash   resulted in a decrease in soil pH in the Vertosol (Soil 4). The addition of lime to the surface of the trash layer also resulted in variable effects. In soils 1, 3 and 5, the effect on soil pH was either similar or less than that of surface applied lime (no trash). However, in the case of the Kurosol, lime application to the trash blanket resulted in higher pH values in the sub-surface layers than when lime was applied in the absence of trash. This has important implications for certain acid soils where amelioration of sub-surface layers can be enhanced by this interaction of lime and trash, possibly due to more soluble organo-calcium complexes.

Mill mud application to the surface of the trash layer resulted in some amelioration of the subsurface layers. Although the effect was not as pronounced as that with lime, the trends noted encourage further investigation, particularly in view of the enhanced decomposition rates reported earlier.







Figure 3. The interactive effect of soil type, treatment and depth on soil pH. LSD (p=0.01) = 0.46.



Calcium amendments such as lime and mill mud have potential in accelerating the decomposition of sugarcane trash and in ameliorating sub-surface soil acidity in minimum tillage systems. The enhanced decomposition is probably due to increased microbial activity or under increased pH conditions. This could have important implications for the sugar industry given the problems encountered with green cane trash blanketing in cool, wet areas and the widespread degradation of soil fertility due to accelerated soil acidification with sugarcane monoculture.



The authors thank the Sugar Research and Development Corporation and the CRC for Sustainable Sugar Production for support and Lee Aitken for his contribution to the experimental work.




1. Mitchell, R.D.J. and Larsen, P.J. 2000. Proceedings of the Australian Society of Sugarcane Technologists, 22, 212-216.

2. Wood, A.W. 1991. Soil & Tillage Res. 20, 69-85.