Abstract. We examined the use of soil quality (SQ) assessment to predict soil productivity and stability as a component of site potential for rangelands. Two minimum sets of data were compared for the SQ assessment within an area of relatively uniform climate. Data set 1 consisted of total soil N, topsoil depth, effective profile depth (EPD), and grade of structure, thus incorporating only soil chemical and physical properties. Data set 2 included exchangeable soil potassium, EPD, soil water retention capacity at wilting point, a soil slake test, and a nutrient cycling index. The interrelationships between soil properties and plant growth characteristics (i.e. total and herbage yield) were investigated and interpreted by statistical analysis and expert knowledge. By performing multiple regressions for each data set against the plant growth characteristics, we identified the contribution of each data set variable to the variability in plant characteristics and, thus, the predictive potential of each variable and data set. Within data set 1, EPD was important and in data set 2 the nutrient cycling index, which is a landscape function index derived from soil surface attributes, played the most important role in predicting potential. Principal component analysis was used to provide weighting factors for each indicator. We then transformed and combined observed indicator values for each data set using weighting factors and scoring functions into an additive soil quality index (SQI) varying in value from 0 to 1. The SQIs, with values greater than 0.8, provide optimum conditions for high yield. 相似文献
Abstract. In general, agricultural management has focused on differences between fields or on the gross differences within them. Recent developments in agricultural technology, yield mapping, Global Positioning Systems and variable rate applications, have made it possible to consider managing the considerable variation in soil and other properties within fields. This system is known as precision agriculture. More precise management of fields depends on a better understanding of the factors that affect crop input decisions. This paper examines the spatial variation in crop yield, soil nutrient status and soil pH within two agricultural fields using geostatistics. The observed properties vary considerably within each field. The relation between yield and the measured soil properties appears to be weak in general. However, the range of spatial correlation for yield, shown by the variogram, is similar to that of the soil chemical properties. In addition the latter changed little over two years. This suggests that information on the scale of variation of soil chemical properties can be derived from yield maps, which can also be used as a guide to a suitable sampling interval for soil properties. 相似文献
A database which holds results of field and laboratory experiments on the impact of subsoil compaction on physical and mechanical soil parameters and on crop yields and environmental impact is being developed within the EU sponsored concerted action (CA) project “Experiences with the impact of subsoil compaction on soil, crop growth and environment and ways to prevent subsoil compaction”. The database accumulates and can provide all available data from the participants of the European Union countries, and is compatible with the European Soil Database and other related databases.
More than 600 sets of data (Excel workbooks) from participants from the European Union, plus Poland, Switzerland and Norway are included in the database. Through a similar EU sponsored CA, Eastern European countries are expected to deliver 260 sets of data thus bringing the total number of Excel workbooks to approximately 860. In total, the database will contain approximately 13,500 data spreadsheets.
The objective of the database is to collect data on subsoil compaction, to store it in a structured format and to make it available for analysis and use. Thereby it will enable elucidation of the impact of subsoil compaction on soil properties, crop yields and environment and evaluate the vulnerability of soils to compaction. 相似文献
Soil modification via biopedturbation by burrow-building seabirds was examined in a Mediterranean, island ecosystem. Physical and chemical soil properties were compared between a colony of Wedge-tailed Shearwaters (Puffinus pacificus) and adjacent heath across a 14-month period. When compared to heath soil, the biopedturbated soil was 28% drier (6.04±5.40 vol%), had increased bulk density (by 29% to 1.30±0.11 g cm−3, 51% porosity), wetting capacity (by 83% to 0.55±0.83 molarity of ethanol droplet), hydraulic conductivity (by 266% to 398.91±252.04 mm h−1), and a greater range in soil surface temperature (31.7±6.2 °C diurnally to 18.3±3.2 °C nocturnally). Soil penetration resistance was reduced by 26% at a depth of 0–100 mm (326.5±122.4 kPa) and by 55% at 500–600 mm (1116.8±465.0 kPa). Colony soil also had increased levels of nitrate (by 470%), phosphorous (118%), ammonium (102%), sulphur (69%), and potassium (34%), decreased levels of iron (by 50%) and organic carbon (61%), was more alkaline, and had a 78% greater conductivity. Shearwaters deposited guano at a rate of 234.4 kg ha−1 yr−1 (dry mass). Chemical analysis of guano equated this to 50.9, 5.7, 5.5, and 3.6 kg ha−1 yr−1 of nitrogen, potassium, sulphur, and phosphorous, respectively. Experimentally constructed burrows demonstrated that digging alone can alter physical and chemical soil factors, but that changes in the nutrient profile of colony soils are predominantly guano-driven. We argue that the physical impact of seabirds on soil should not be overlooked as a soil-forming and ecosystem-shaping factor in island ecosystems, and that biopedturbation can exert major bottom-up influences on insular plant and animal communities. 相似文献