Land use effects on soil hydraulic properties and the contribution of soil organic carbon

Effect of irrigation on soil physical properties on temperate pastoral farms: a regional New Zealand study

“…Results from this study showed at 10-20 cm depth, and averaged over the 0-30 cm depth, that macroporosity was significantly lower under irrigated grazed pasture. A similar trend was observed in the Otago (Houlbrooke and Laurenson 2013) and Canterbury regions (Drewry et al 2021a;Fu et al 2021), showing that soil physical quality is degrading under different land use beyond the commonly measured 0-10 cm depth that is typically used in soil quality monitoring. Compared to a national scale paired site study of carbon (Mudge et al 2021), our paired site regional study was not designed to specifically examine differences from soil order.…”

“…Previous research has shown that irrigated pastoral soils can have greater microporosity compared with non-irrigated areas (da Costa et al 2014). Similarly, Houlbrooke and Laurenson (2013) showed that soil water content at −100 and −1500 kPa matric potentials was higher under irrigated land than dryland for cattle-grazed pasture, while Fu et al (2021) also found higher PWP and SAWC under dryland sheep and beef compared to irrigated dairy paddocks. This effect could be due to several factors, including the in-filling of pores with time from soil compaction (Houlbrooke and Laurenson 2013;Drewry et al 2021a) as indicated from reduced pore and water storage indicators, and wetting and drying cycles (da Costa et al 2014;Pires et al 2017).…”

“…The plot study of Houlbrooke and Laurenson (2013) showed no significant difference when comparing AWC under the same cattle or sheep grazed land use, but for irrigated cattle grazing was significantly lower than both irrigated and dryland sheep-grazed pasture. The regional study of Fu et al (2021) also found dryland sheep and beef to have significantly greater AWC than irrigated dairy at the 7.5-15 cm depth, but when individual depths were averaged over 0-30 cm there was no significant difference. In contrast, in the single paddock land use comparison of Drewry et al (2021a), the AWC response varied between depth increments but was greater at the dairy site for 0-30 cm than at the dryland sheep site.…”

“…It is particularly important to better determine the effects of irrigation on drainage and water storage properties over a soil profile, including both topsoil and subsoil, to understand the potential effect on drainage and nutrient movement. Previous studies under pasture have also either compared dryland with irrigation between different paddocks and farms (Fu et al 2021), which makes it difficult to separate the irrigation effect from other land management practices associated with intensification (Rickard and Cossens 1966;Drewry et al 2021b), or have focused on the single paddock (Drewry et al 2021a) or plot scale (Houlbrooke and Laurenson 2013).…”

Land degradation resistance potential of a dry, semiarid region in relation to soil organic carbon stocks, carbon management index, and soil aggregate stability

“…Soil aggregates influence root penetration, erosion, CO 2 emission, air soil and water movement, biological action, and nutrient retention (Hassan et al, 2021; Pagliai et al, 2004). In general terms, soil structure can also be encouraged by the interaction of aggregate agents, soil management, type of soil, and conservational conditions (Delelegn et al, 2017; Fu et al, 2021). One characteristic of soil that reacts quickly to ecological changes is soil aggregation (Kubar et al, 2018; Ma et al, 2020).…”