‘Parna’ the clayey loess of southeastern Australia, is assumed to have been transported by wind as fine sand- and silt-sized pellets, but little direct evidence of such pellets has been shown. The micromorphological and granulometric properties of several soils derived from parna have been investigated. In upper (younger) subsoils derived from parna, prolate fine sand-sized pellets are identifiable and have a distinctive mosaic-speckled b-fabric. However, in lower subsoils derived from older parna deposits, abundant illuviation features and a lack of identifiable pellets suggest that weathering and various pedologic processes have destroyed them.

Liming and trash blanket are commonly used for remediating soil acidity and managing trash residues. This study has shown that liming improves soil microbial growth, but trash blanket placement increases labile carbon and nitrogen availability in a sugarcane soil of subtropical Australia.

Extensive areas with low clay soils will be converted to agriculture to meet global food demand, and K is prone to leaching in these soils. We compared a conventional K fertilizer with a fertilizer coated with humic substances, and showed that the protected fertilizer, although not avoiding K leaching, is an adequate fertilizer in low clay soils with very low K content.

Global demand for rooibos tea is increasing whereas yields are decreasing in the primary production area of Clanwilliam, South Africa. The aim of this study was to investigate soil quality and plant properties in cultivated rooibos plantations of various ages (1–60 years) and adjacent, wild rooibos stands in pristine fynbos. Long-term rooibos production resulted in declines in soil organic matter, basic cations and accumulation of phosphorus which correlated with rooibos yield declines and suppressed mycorrhizal colonization.

Soil salinity decreases plant water uptake and crop yields in arid and semiarid regions. We develop an approach to estimate soil salinity after irrigation or precipitation events. Knowledge the influence of soil salinity on the plant water uptake will become useful in designing of irrigation scheme and field management to achieve more crops.

Few studies considered the effect of soil pH on nitrification at the microsite scale which is associated with mineralization. The aim of the research was to investigate how increasing pH affected mineralization and then nitrification in the subtropical acid forest soil. Results suggested that pH-induced increase in N mineralization provided more microsites surrounded with NH₄⁺ substrate and favorable pH for the development of ammonia-oxidizing bacteria populations and their nitrifying activity. A good understanding the synergistic effects of soil pH and mineralization on nitrification will improve our knowledge about the effects of land management practices on the subtropical acid forest soils and underlying mechanisms.

Soil organic C (SOC) retention is affected by texture, but it is not known how this relation is affected by altitude. Sampling coarse- and fine-textured soils at two altitudes, we found that texture affected SOC only at lower altitudes (1,060 m). SOC retention at >1,200 m is thus marked by weaker interaction with soil minerals, and probably less stable.

The use of DMPP significantly reduced N₂O emission from soil, but NBPT did not in a rain-fed cropping system. A two-year field experiment failed to demonstrate positive crop yield response by using either DMPP or NBPT. Unless financial incentives for environmental benefits are provided, the lack of additional agronomic benefit and their additional cost will preclude the use of N inhibitors.

Tropical forests are among the most threatened and important biomes for exchanging large quantities of carbon and nutrients every year through decomposition of leaf and root litters. In tropics, secondary forests have become dominant landscape to provide many ecosystem services including the potential to function as sinks for atmospheric carbon. Therefore, these secondary forests have strong potential to provide similar ecosystem services to that of natural forest within 2 decades by managing their litter carbon and nitrogen fluxes.

Soil carbon stock is about four times more than in vegetation and about three times more than in the atmosphere, yet remains understudied upon land use change. This paper quantified soil organic carbon in a grassed catchment before and eight years after commercial afforestation, indicating that Pinus elliottii, Eucalyptus nitens decreased, and Pinus patula slightly increased soil organic carbon. This provides a valuable southern hemisphere reference for global carbon calculations and highlights the impact of land use change.