The influence of lime application on the chemical and physical characteristics of acidic grassland soils with impeded drainage

Abstract

Soil acidity and poor nutrient use efficiency are major limiting factors as regards output potential on heavy soils, soils which are dominated by high proportions of clay and organic matter, with impeded drainage, high buffering capacity and located in high rainfall areas. Lime is applied in order to counteract these limiting factors and in turn improve agricultural output and productivity. The current study investigates the effects of two commonly used lime products at three comparable treatment rates, ground lime (7.5, 5 and 2.5 tonne/ha) and granulated lime (7.5, 2.5 and 1.5 tonne/ha), applied across three distinct sites. The ability of each lime product and treatment rate to counteract soil acidity, increase nutrient availability and influence soil physical structure was assessed over time. On average across sites, 1 tonne/ha of each lime product increased soil pH by 0.15 and 0.21 pH units between ground and granulated lime, respectively. Site 3 experienced the greatest increase change in soil pH in comparison to the other two sites, largely due to lower clay content and cation exchange capacity. Granulated lime was 5.7 times more expensive than ground lime in its ability to reduce soil acidity. The high treatment rate showed the greatest reduction in soil acidity, aluminium and iron concentration as a mean across all sites. Morgan's soil test phosphorus concentration increased across all sites, with treatment rates having no effect on the rate of increase. There was evidence of reduced soil compaction and lime application showed no negative implication on soil physical structure.

The response of finely textured and organic soils to lime and phosphorus application: Results from an incubation experiment

“…The application of lime increases soil pH, thus indicating a reduction in acidity and an increase in base saturation (Goulding, 2016). The application of lime in an on‐farm plot experiment assessing these particular soils showed a variation in their ability to increase soil pH and soil P availability (Corbett et al, 2021). In the current study, there was a reduction in soil pH on both mineral and organic soil textural classes that received no lime application.…”

“…A soil's chemical environment is largely dictated by soil pH, this has a major influence on plant nutrient availability (McKenzie et al, 2004). Previous work carried out in a plot trial on these particular soils showed that liming had a significant impact on reducing soils the concentration of metallic cations, particularly iron and aluminium, and also increased the availability of soil test P (Corbett et al, 2021).…”

The influence of phosphorus application and varying soil pH on soil and herbage properties across a range of grassland soils with impeded drainage

“…Site 1 experienced a much lower change in STP in comparison to sites 2 and 3, this was largely attributed to soil composition and initial STP levels. This was clearly evident in the previous study where there were differences in initial soil Al and Fe concentration, and also differences in the change in soil test P across sites despite similar treatment rates (Corbett et al ., 2021). Site 1 had a significantly lower initial STP concentration, therefore more P was required to experience an equivalent change in STP in comparison to sites 2 and 3.…”

“…In the previous liming study carried out on these particular sites (between 2015 and 2018), similar trends were observed across individual sites with site 1 experiencing a significantly smaller change in STP. It was also noted that site 1 experienced a significantly lower reduction in soil test aluminium concentration (Corbett et al ., 2021). Aluminium has previously shown to significantly reduce P availability due to its high P fixation capacity (Daly et al ., 2015).…”

“…This highlights the increased potential of soils less confounded by high Al and Fe and clay content to increase mineralization of dissolved P into plant available forms. It can also be noted that the level of increased P availability was linked directly to liming rate in the current study and also the original liming study carried out at these sites (Corbett et al ., 2021). The use of the Mehlich soil test in the original liming study allowed a better understanding of P dynamics and soil elements dictating P availability.…”