Determining soil hydraulic properties using infiltrometer techniques: An assessment of temporal variability in a long-term experiment under minimum-and no-tillage soil management

Conservation agriculture is increasingly accepted by farmers, but the modeling studies on agro-environmental processes that characterize these agricultural systems require accurate information on the temporal variability of the soil's main physical and hydraulic properties. Therefore, specific investigations carried out in long-term experiments can increase our knowledge on the pros and cons of different measurement techniques. In this work, the simplified falling head (SFH) technique and the Beerkan Estimation of Soil Transfer (BEST) procedure were applied to investigate the temporal variability of some main soil physical and hydraulic properties, including bulk density (BD), field saturated hydraulic conductivity (Kfs), macroporosity (Pmac), air capacity (AC), plant available water capacity (PAWC), and relative field capacity (RFC). For this purpose, a long-term experiment was selected, and the experimental information obtained was used to verify the long-term impact (fifteen years) determined by two alternative forms of soil management, minimum tillage (MT) and no tillage (NT), for the cultivation of durum wheat. The main results of the comparison between MT and NT showed: (i) A comparable temporal variability in Kfs values when SFH was considered, given that in 75% of considered cases, the same result (i.e., significant or not significant) was obtained; (ii) a comparable temporal variability in Kfs values under MT (but not under NT) when both SFH and BEST were used, as a result of a possible Kfs, SFH overestimation under NT; (iii) differences in Kfs estimations by a factor of 6 or 7 (Kfs, SFH > Kfs, BEST) when comparable soil conditions (moisture and soil density) were considered; (iv) a comparable temporal variability when other soil indicators (BD, Pmac, AC, PAWC, and RFC) were simultaneously considered. After about fifteen years of field experiments characterized by continuous soil management and conducted with the methodological rigor typical of experimental farms, the SFH-and BEST-derived experimental information showed a substantial equivalence between MT and NT for the fine-textured soil investigated

How spatial and temporal variability can effect fertilization trial results

The objectives of this paper were to study the influence of nitrogen fertilization on crop production using a linear mixed effects model with a first order continuous autoregressive correlation structure. On a 2-ha field, the most relevant soil properties were determined. Four fertilizer treatments were applied in a completely randomised block design with four replications (blocks) and repeated crop measurements were made in three crop seasons. The most relevant sources of variation in wheat production might not be ascribed to management of soil fertilization but to soil intrinsic variation and between-season variability. More advanced methods of statistical analysis need to be used to separate the residual error from error sources

Alternative fertilisation for processing tomato in Southern Italy.

Two field trials were carried out in Foggia (Southern Italy) in 2002 and in 2003 on a silty-clay soil for evaluating the effect of three organic fertilisers on yield and quality of tomato for processing. The treatments were: 1) organic biological fertiliser (ORG), 2) experimental compost composed of olive residues, sludge and straw (COMP), 3) organic fertiliser mixed with ammonium nitrate (1:1) (MIX), and 4) traditional chemical fertiliser (ammonium nitrate, MIN). All were applied on a 100 kg N ha-1 basis. At harvest, total and marketable fresh and dried yield were measured as well as shoot biomass. N content in the soil and in the shoot tissues was assessed in order to evaluate the N mineral deficit and to calculate N use efficiency (NUE). Meanwhile in the first year no differences were observed among fertiliser treatments, in the second year the ORG fertiliser yielded more than MIX and MIN treatments. The COMP fertiliser showed an intermediate behaviour. No effect due to the fertilisers was observed on fruit quality. The N deficit was positive for the MIX treatment in both years, while in the second year ORG and COMP fertilisers showed negative values and greater N uptake. Higher values of NUE were observed for the MIX treatment in both years

Epidemiological data on burn injuries in Angola: a retrospective study of 7230 patients.

This study describes the work carried out at the Burn Unit of the Neves Bendinha Hospital, Luanda, Angola, during the 3-year period July 1991 to June 1994. During this period we admitted 2569 burned patients to our burn unit and 4661 were treated on an outpatient basis. The data From the patients were analysed to indicate the distribution according to age, sex TBSA, cause of the lesion and mortality. Our study gives some epidemiological data on burns in an undeveloped country undergoing a war out lining the specific problems compared to the reality in civilized countries

Fertilizzanti azotati altenativi su pomodoro da industria

Le tecniche di fertilizzazione organica (compost da più matrici o concime biologico) appaiono promettenti in quanto non riducono o possono aumentare le rese quanti- qualitative, oltre a esplilcare favorevoli effetti sulle caratteristische del suol