Soil Profile

The potential fl)r extending the production of winter oilseed crops into the drier region of the cereal belt of eastern Australia was examined by comparing canola, Indian mustard and Linola in field experiments in the contrasting environments of Junee and Condobolin, NSW. Junee is in the region where canola production is concentrated, and Condodolin is in the drier part of the cereal belt currently considered marginal for canola. Different rates of nitrogen (N) fertilizer were applied in all experiments, and there were two times of sowing at Condobolin. Wheat was grown for comparison in all experiments. Crop performance was evaluated over two seasons by measuring dry-matter production, grain yield, water-use efficiency, and seed oil and protein contents. Maximum grain yields of all crops at Junee were higher than at Condobolin, and yield responses to N fertilizer in both environments were greater in the wetter 1992 season than in the drier 1991 season. Canola and wheat showed the largest yield responses to N fertilizer, but Linola generally had the lowest yield responses because of poor seedling emergence at high N rates, intolerance of drought during grain filling (1991) and lodging (1992). Based on the overall growth and grain yield responses to N fertilizer, and on N (protein) removal in grain, it is suggested that about 25% more N be applied to canola than to wheat, that Indian mustard receive about the same N fertilizer rate as wheat, and that Linola requires about 20% less N than wheat. Sowing late at Condobolin, when there was below-average rainfall during grain filling (1991) reduced the yield of canola and Linola, but not Indian mustard. There was no yield penalty for sowing the crops late in 1992 when conditions were favourable during grain filling. Grain harvest indices based either on dry matter or the biosynthetic cost of seed production were higher tk)r wheat and canola than for Indian mustard and Linola, and were largely unaffected by the N treatments. A potential transpiration efficiency value of 12.5 kg seed ha i mm ~ was derived for the oilseeds based on the biosynthetic costs of seed production. Oil concentrations were reduced by dry conditions during seed filling, by late sowing and by N fertilizer. Oil concentrations were higher at Junee than Condobolin, due mainly to differences in ambient temperature as there was a 2.7% decrease in oil concentration tor each I°C rise in mean temperature during seed filling. Oilseed meal and wheal grain protein levels were more responsive to N fertilizer when conditions were dry during grain filling. Protein levels in oilseed meals were higher but wheat grain protein was lower when conditions were favourable during grain filling. The study indicated that there arc prospects for extending the production of canola and Indian mustard into drier regions of the cereal belt because, when sown early, they • Corresponding author. have similar water-use efficiencies to wheat based on the biosynthetic costs of grain production. While the yield of Indian mustard is limited by a low harvest index, its yield stability under dry post-anthesis conditions indicates greater potential than current canola cultivars for more marginal areas. Linola showed the least potential as an oilseed for the drier parts of the cereal belt because of shallow rooting and susceptibility to drought.

Senegal river water has positive alkalinity (0.55 meq l À 1 ) and positive calcite-residual alkalinity (0.30 meq l À 1 ). Without leaching, this water presents a possible alkalinization and sodication hazard for the soil. The effect of flooding on soil solution chemistry in an irrigated nondrained vertisol under rice was monitored during 3 years in northern Senegal. During flooding, soil solution redox potential dropped to about À 0.15 V, and alkalinity increased to 15 meq l À 1 . Mg content increased as well, from about 1 to 5 meq l À 1 , whereas Cl and SO 4 contents decreased to very low levels at the end of the growing season (0.05 meq l À 1 ). After the fallow, nonflooded period between two crop cycles, the soil solution composition returned to its initial neutral sulfate and chloride composition. The observed cycle in soil solution chemistry could not be explained by water and solute transfer because infiltration rates were very low, due to air entrapment in the soil profile. Geochemical control by calcite and gypsum was excluded during irrigation. Mössbauer spectroscopy showed that iron oxides were both well-and poorly crystallized goethite. Goethite dissolution was assessed by pH -Eh stability diagrams.

The persistence, mobility and degradation of tebuconazole were assessed under field conditions in a sandy clay loam soil amended with spent mushroom substrate (SMS) at two rates. The aim was to evaluate the environmental impact of the simultaneous application of SMS and fungicide in a vineyard soil. SMS is the pasteurized and composted organic material remaining after a crop of mushroom is produced. SMS is generated in increasing amounts in La Rioja region (Spain), and could be used as soil amendment in vineyard soils, where fungicides are also applied in large amounts. The study was carried out in 18 experimental plots (6 treatments and 3 replicates per treatment) over one year. Laboratory experiments were also conducted to verify the changes over time in the adsorption of fungicide by soils and in soil dehydrogenase activity caused by the fungicide and/or SMS. Tebuconazole dissipation followed biphasic kinetics with a rapid dissipation phase, followed by a slow dissipation phase. ...

In soil magnetometry, two types of measurements are usually performed. The first type is measurements performed on the soil surface, frequently using an MS2D sensor. The second type includes measurements of magnetic susceptibility carried out in the soil profile, usually to a depth of about 30 cm. Up to now, such measurement results were analyzed separately. However, it is possible and advantageous to integrate these two types of measurements. The goal of the study was to integrate measurements of magnetic susceptibility performed on the soil surface and in the soil profile. More specifically, the goal was to obtain 3-dimensional spatial distributions of magnetic susceptibility of the topsoil horizon. Results show that it is possible to effectively integrate measurements of magnetic susceptibility per-formed on the soil surface and in the soil profile. Moreover, the 3-dimensional spatial distribution that is obtained shows the magnetic susceptibility of the top 20 cm of soil, which includes the soil horizons where most of the heavy metals are accumulated. The analysis of such a spatial distribution can be very helpful in delineating areas where the heightened magnetic susceptibility is a result of the influence of anthropogenic pollution from those areas where it results from lithogenic origin. It is possible to investigate where the volumes of soil with heightened magnetic susceptibility are located in the soil profile and in this way investigate which characteristic type of soil profile it is.

Changes to vegetation and soil were assessed in primeval forests of the Eastern Carpathians after a period of 59-68 years. We hypothesized that forest ecosystems were acidified through the long-distance transport of air pollutants. A total of 141 relevés and 20 soil profiles that had been studied in 1938 in spruceand beech-dominated forests along an altitudinal gradient ranging from 1085-1575 m a.s.l. were re-surveyed from 1997 to 2006. Relevés were analyzed using multidimensional statistics and plant community characteristics (Shannon-Wiener's index, equitability, fidelity, Ellenberg indication values -EIV); soil reaction and sorption complex properties were analyzed in soils.