The current study evaluated alternative sources of nutrients to improve the soil fertility status and yield of maize-wheat succession in Southern Brazil. The treatments were: T1: no fertilization; T2: liming with dolomitic marble; T3: alternative liming (AL) with limestone interbedded with shale; T4: AL + 50% P - with Arad natural phosphate (P-ANP) + 50% P – triple superphosphate (P-TSP); T5: AL + 100% P-ANP; T6: AL + 100% P-ANP + 100% K-rich monzogranite; T7: AL + 100% P-ANP + 100% N (50% N from tung pressed cake (N-TPC) + 50% N-urea); T8: AL + 100% P-ANP + 100% K-rich monzogranite + 100% N (50% N-TPC + 50% N-Urea) + 100% S; T9: AL + regional average rate of NPK (5-20-20) formulation. Except for T7 and T8, all treatments received the full recommended rate of N through Urea. Immediate and residual effects were evaluated over 2.5 years (90, 360 and 900 days) on soil fertility and maize - wheat yield. The limestone interbedded with shale released Ca, Mg and corrected soil acidity similarly to dolomitic marble. The fertilization strategies used in T4, T7 and T8 presented the highest cumulative productivities while T3 (U$ = 1223), T9 (U$ = 1174) and T4 (U$ = 1122) resulted in higher profits than the other evaluated fertilization strategies. The limestone interbedded with shale (T3), alone or combined with 50% of P-ANP + 50% of P – TSP (T4) provided the best economical and technical results, highlighting the potential of selected alternative regional sources for soil fertility improvement and plant-nutrients supply.

The aim of the current study was to evaluate the effect of long-term (56 years) liming on changes in soil pH and aluminium (Al) forms in the soil profile compared with an unlimed soil in a sandy moraine loam of a Dystric Glossic Retisol. Long-term liming had a significant influence on soil acidity of the whole profile, causing increased pH values in the following horizons to 120 cm depth: the ploughing horizon (Ahp), where humus accumulates; the eluvial horizon (E), from which clay particles are leached; a horizon having retic properties and predominantly coarser-textured albic material (E/B); and a horizon with retic properties and predominantly finer-textured argic material (B/E). In the solid phase, non-crystalline Al in limed soil decreased in the Ahp horizon; meanwhile a decrease in total organically bound Al (Alp) and organo–Al complexes of low to medium stability was detected in the deeper El and ElBt horizons. High-stability Al complexes with organic matter were the predominant form of Alp in the unlimed and limed whole soil profile. The concentration of total water-soluble Al ranged from 0.61 to 0.80 mg/l in the limed soil profile but 0.62–1.15 mg/l in the unlimed soil. The highest concentration of exchangeable Al was determined in the upper horizons of the unlimed soil profile and the concentration decreased significantly in the same horizons of the limed soil profile. Long-term liming promoted changes in Al compounds throughout the soil profile.

The publicly available Digital Soil Map of Sweden (DSMS) contains topsoil clay content information in a 50 m×50 m grid, and can be used as decision support in precision agriculture. However, it is also common that farmers have undertaken their own soil sampling (one sample per hectare with texture analysed in every third sample). In the present study, such soil samples from 403 farms were used to validate topsoil clay content information derived from 1) DSMS, 2) DSMS locally adapted by residual kriging, 3) DSMS locally adapted by regression kriging and 4) inverse distance weighting interpolation of the soil sample data without using DSMS. The latter has been common practice until now. The best method differed depending on the local accuracy of DSMS, the quality of the soil sampling and the spatial variation structure of the topsoil texture. The ‘Best method’ strategy, which meant to apply all the above methods and choose the one that performed best at each farm, significantly reduced the mean absolute error. We recommend using this strategy to locally adapt regional digital soil maps to derive accurate decision support for use in precision agriculture.

Loch Fleet is an upland loch in SW Scotland, distant from significant local pollution, and unlikely to be affected by changes during the five-year project. The underlying geology is granitic. The 111 ha catchment is 90% moorland, dominated by heather and flying bent; 10% is planted with conifers.

Rainfall is approximately 2200 mm per year, predominantly from W and SW. More than half of rain events are pH>4·7; mean pH is 4·84 (1985). Marine salts are the major solutes. Deposition of acidity is about 0·1 g H+ m−2 per year, about twice that of eastern Scotland; deposition of non-seasalt sulphur is 1·6 g S m−2 per year. Soils are shallow and comprise organic peats, peaty gleys, and peaty rankers; base saturation is 3–19%. Soils (pH 2·5 to 4·6) are most acid in the forested area.

The loch is more acid (×5) than bulk deposition; additional acidity is mobilised from soils by the predominantly (>90%) superficial drainage. Moorland drainage dominates; that from the forest is more acid, but very variable in quantity and composition.

Catchment interventions in 1986 and 1987 are designed to alter the chemistry of drainage waters and the loch, so that the fishery can be restored. In addition to the work reported, extensive soils, sediment and biological investigations are underway.