Wheat yield and grain quality as affected by tillage, sowing time and nitrogen fertilization under rainfed Mediterranean conditions

The research was carried out in 9 sites (5 in 1999-00 and 4 in 2000-01) of inner area of Sicily different for soil type, slope, exposure and preceding crop. The following treatments were studied: (i) conventional tillage and sowing at conventional time (CT); (ii) no tillage and sowing at conventional time (NTc); and (iii) no tillage and early sowing (NTe). In 2000-01 the effect of three nitrogen fertilization treatment (single application at planting, P, and split dressing at two different rates, S and S+) were also evaluated. No tillage systems (NTc and NTe) significantly increased grain yield compared to CT treatment; no differences were observed between the two sowing dates. The productive benefits of no tillage were associated with a decrease of grain protein content that was heavier with early sowing. Regarding N fertilization treatments, S compared with P allowed a significant yield increase; no interaction with tillage technique was found. At the lowest fertilizer rates, split fertilization allowed a significant increase of grain protein content only in NTe

Berseem-annual ryegrass intercropping: effect of plant arrangement and seeding ratio on N2 fixation and yield

Various agronomic factors can affect the productivity and the efficiency of legume-grass intercropping systems. This research was carried out in a Mediterranean semi-arid environment (37°30’N; 13°31’E; 178 m a.s.l.) with the aim to study on berseem clover- annual ryegrass mixture (Trifolium alexandrinum L. – Lolium multiflorum Lam subsp. wersterwoldicum) the effects of different plant arrangement (sowing of the two components in alternate rows or in the same row) and seeding ratios (100:0; 75:25; 50:50; 25:75; 0:100) on forage yield, nitrogen content and nitrogen fixation. The experimental design was a split-plot with four replications. The 15N isotope dilution technique was used to estimate nitrogen fixation by berseem clover. All plots were cut four times (first cut 85 DAS; rest period of four weeks). The DM yield of mixtures and pure stand clover were similar; annual ryegrass in pure stand produced the lowest yields. No significant differences for DM yield were observed due to the plant arrangement and seeding ratio in the mixture. Intercropping berseem had always a significant higher percentage of Ndfa than monocropped berseem. The %Ndfa of mixed berseem was not influenced by plant arrangement but gradually decreased when proportion of berseem in the mixture increased

Caratterizzazione della dinamica produttiva di pascoli naturali italiani

This work studies herbage production and its seasonal distribution in indigenous pastures, and analyses the relationship between the environmental factors (soil, clima, vegetation) and the productivity of these resources. The investigations have been carried on during the period 1983-90 by the joint activity of 10 different University Istitutions in 23 different environments distributed along the Italian peninsula and the main islands. For each environment, pasture production has been measured with the Corrall and Fenlon method, analysing the more important vegetational and ecological conditions; altogether the total yearly production and the seasonal pattern of herbage production have been detected on 104 pastures. The total herbage yield is not significantly influenced by the latitudinal gradient, and the overall regional (alps, central Appenine, south Apennine and islands) production is about 2.3 t ha-1 year-1 The wide range (0.5-6.3 t ha-1 year-1) of herbage production, on small or medium scale, seems to be due to evident changeof environmental or management factors. Five types of seasonal distribution of herbage growth are evidenced with multivariate analysis methods, based on the growing season and the amplitude of the growth. With mean temperature above 12°C and total rainfall below 800 mm, herbage distribution shows a standstill during summer period and an evident regrowth in autumn. On the contrary, for the 4 other distribution types, the winter standstill become important, and the types are distinct by summer growth amplitude and by the growing season lenght. With cluster analysis method, for each type of herbage distribution, have been pointed out under-types characterized by interannual herbage production variation. Among the environmental factors, vegetation characheristics, expressed as Pasture Value following Daget and Poissonet seems to be strictly correlated with total production. The comparative poor role played by the soil and climatic factor, may be due to the strong past and present antropic influence, related with management and utilization techniques. Il presente lavoro ha come scopo l'approfondimento delle conoscenze sulla produzione e sulla distribuzione stagionale della crescita dell'erba dei pascoli naturali, nonché l'analisi delle interazioni tra i fattori ambientali, pedo-climatici e vegetazionali, e la risposta produttiva di queste risorse. La ricerca è stata condotta nel periodo 1983-90 da 10 diverse Istituzioni Universitarie, in 23 ambienti differenti, distribuiti lungo tutta la penisola e le isole maggiori. Per ogni ambiente, con il metodo di rilievo di Corrall e Fenlon, è stata saggiata la risposta produttiva di pascoli rappresentativi delle principali situazioni vegetazionali e di giacitura; complessivamente sono state rilevate la produzione totale annua e la curva di produttività media pluriennale di 104 pascoli. Riguardo la produzione annua complessiva si è osservato che essa non presenta variazioni significative lungo il gradiente latitudinale, collocandosi tra le diverse regioni (alpina, centro appenninica, suq, appenninica e insulare) attorno a 2.3 t ha-1 anno-1. La fitomassa raccolta è soggetta invece a variazioni sensibili (0.5-6.3 t ha-1 anno-1) riconducibili a fattori ambientali e gestionali che si esprimono su piccola e media scala. Con metodi di analisi multivariata si sono individuate 5 tipologie distributive della crescita dell'erba, in rapporto alla stagione vegetativa e alle variazioni dell'intensità di crescita nel corso della stagione stessa. Con temperature medie e precipitazioni annue rispettivamente maggiori di 12°C e minori di 800 mm, risulta evidente la stasi vegetativa nel trimestre estivo e la ripresa vegetativa autunnale. Nel caso opposto la stasi è invernale e le 4 tipologie afferenti a questo modello, sono distinguibili dall'entità della crescita nei mesi estivi e dalla durata della stagione vegetativa. Per ogni tipologia produttiva, sono state evidenziate, tramite l'analisi cluster, sotto-tipologie distinte per la variabilità produttiva interannuale. Tra i fattori ambientali, la vegetazione, espressa attraverso l'indice del valore pastorale di Daget e Poissonet, presenta una buona capacità predittiva nei confronti del livello produttivo dei pascoli. Il contributo comparativamente modesto offerto dai fattori pedoclimatici sembra attribuibile alla forte influenza antropica, pregressa e attuale, attraverso le cure colturali e l'utilizzazione

Technical Note: Comparison of Techniques for Evaluating the Relative Preference by Sheep Among Saltbush Clones

This research compared 4 field methods of evaluating the relative preference by sheep of 28 clones of saltbush (Atriplex halimus L.). The methods were as follows. 1) Leaf dots (LD): 8 leaves per shrub were marked on the lower surface with a small dot using a water-resistant, nontoxic ink. 2) Twig marks (TM): 2 current-year twigs per shrub were marked with 3 lines using the same ink approximately in the middle of the basal, median, and apical thirds. 3) Branch length (BL): 2 branches per shrub were marked with ink at the base of the current year's growth. The twigs were measured from the marked point to the top, before and after sheep browsing. 4) Ocular estimation (OE): the percentage of the total number of current-year twigs browsed was visually estimated for each shrub. The percentage of use was calculated by counting the residual dots (LD) or marks (TM) after browsing and by calculating the difference between the 2 measures in the BL method. The trial was conducted in August and repeated in November and in both grazing periods 4 observations were made. Highly significant differences among clones were observed. The different methods generally gave similar results for the ranking of the clones, but each method showed a different discriminatory capacity. On the basis of the F ratio, the OE method seemed more efficient, although results were subjective and mainly dependent on the experience and skill of the observer. Among the methods based on the counting or measurement of markers, the discriminatory capacity decreased from LD to BL and TM, but the opposite order was observed for the ease of setting and counting the markers.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202

Technical Note: Comparison of Techniques for Evaluating the Relative Preference by Sheep Among Saltbush Clones

This research compared 4 field methods of evaluating the relative preference by sheep of 28 clones of saltbush (Atriplex halimus L.). The methods were as follows. 1) Leaf dots (LD): 8 leaves per shrub were marked on the lower surface with a small dot using a water-resistant, nontoxic ink. 2) Twig marks (TM): 2 current-year twigs per shrub were marked with 3 lines using the same ink approximately in the middle of the basal, median, and apical thirds. 3) Branch length (BL): 2 branches per shrub were marked with ink at the base of the current year's growth. The twigs were measured from the marked point to the top, before and after sheep browsing. 4) Ocular estimation (OE): the percentage of the total number of current-year twigs browsed was visually estimated for each shrub. The percentage of use was calculated by counting the residual dots (LD) or marks (TM) after browsing and by calculating the difference between the 2 measures in the BL method. The trial was conducted in August and repeated in November and in both grazing periods 4 observations were made. Highly significant differences among clones were observed. The different methods generally gave similar results for the ranking of the clones, but each method showed a different discriminatory capacity. On the basis of the F ratio, the OE method seemed more efficient, although results were subjective and mainly dependent on the experience and skill of the observer. Among the methods based on the counting or measurement of markers, the discriminatory capacity decreased from LD to BL and TM, but the opposite order was observed for the ease of setting and counting the markers.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202

Productivity of an Atriplex halimus shrubbery and effects of grazing on lambs

The objectives of this study were to 1) evaluate the productivity and forage quality of Atriplex halimus, 2) investigate modifications to shrub structure induced by grazing, and 3) assess live weight changes in lambs grazing on A. halimus with and without a feed supplement (wheat straw &plusmn; barley grain). The results showed that A. halimus had low productivity (approximately 1000 kg DM ha&ndash;1) but high tolerance to grazing by lambs, although minor modifications in plant structure due to grazing were observed. Lambs grazing A. halimus as a sole diet lost weight (about 60 g lamb&minus;1 d&ndash;1; P < 0.01), probably as a consequence of the high salt content of the forage reducing both intake and digestibility. No significant benefits were obtained from the provision of wheat straw as an ad libitum supplement, possibly because the lambs were able to utilize understorey plants having a chemical composition similar to straw. Lambs supplemented with both wheat straw and barley grains (200 g lamb&minus;1 d&ndash;1) had a significantly higher live weight (P < 0.01) than those grazing on A. halimus alone. The results suggest that a diet of A. halimus is not sufficient to maintain lamb live weight, and that supplementation with an energy source is necessary for lambs to gain weight

Nitrogen efficiency component analysis in wheat under rainfed Mediterranean conditions: effects of crop rotation and nitrogen fertilization

The research was carried out in 1999-01 in a typical Sicilian semi-arid area to evaluate the effect of crop rotation and N fertilization on the nitrogen use efficiency (NUE) in wheat. Crop rotation were: wheat-faba bean, wheat-chickpea, wheat-pea and continuous wheat; nitrogen fertilizer rates were: 0, 40, 80 and 120 kg N/ha. A split-plot design with three replications were used. Analysis of nitrogen efficiency components was performed according to the procedure of Higgins and Pan (1993) using grain yield, aboveground plant N, grain N and post-harvest inorganic soil N. Continuous wheat (WW) recorder the lowest grain yields while no differences were found in wheat grown after the three legumes crops (LW); the yield benefits of LW vs WW declines as fertilizer rates increased. The differences in wheat grain yields were due mainly to N supply component at low N fertilization rates and to NUE at high N rates