61. Cereal-forage rotations effect on biochemical characteristics of topsoil and productivity of the crops in Mediterranean environment.

• Authors:
  • Martiniello, P.
• Source: European Journal of Agronomy
• Volume: 35
• Issue: 4
• Year: 2011
• Summary: Rotations experiment have been investigated from 1991 to 2008 under irrigated and rainfed condition in Mediterranean environment. The crops studied were: annual winter binary mixture (BM), perennial meadow (ME) and durum wheat (W) continuously rotated for 3 years and W rotated on itself for all period of experiment (CW). The forage rotations emphasized on the impact made on biochemical characteristics of topsoil and productivity of the crops. The 3 years continuous wheat rotation over forage crops assess the advantage of forage crops left in the soil on seed yield and on quality of kernel. The continuous wheat rotation (CW) reduced the soil biochemical parameters, seed yield and quality of kernel. The value of organic carbon, C/N and total nitrogen, under rainfed in comparison to the values present in the topsoil at the beginning of experiment were 6.4% and 2.48 higher and 11.2% lower in ME and lower 5.2% in organic carbon and 2.8% total nitrogen and 0.21 higher in C/N in BM. The agronomic advantages allowed by forage rotations expire their effect after 3 years of continuous wheat. Yearly yield W gain under rainfed was 11.3 kg (ha yr) -1 in BM and 62 kg (ha yr) -1 in ME. The qualitative traits of wheat kernel rotated on forage were higher than those of continuous wheat CW. Results of biochemical characteristics obtained at the end of experiment evidenced that W after BM and ME rotations sustained, under irrigated and rainfed condition, the content of organic carbon and total nitrogen and C/N in the topsoil of the cropping system while continuously CW allowed strong impact of the parameter values present at beginning of experiment (organic carbon, total nitrogen and C/N was reduced under rainfed by 23.5%, 18.2 and 0.32 and 30.3%, 15.4% and 1.72 under irrigated, respectively).

62. Parameterizing canopy resistance using mechanistic and semi-empirical estimates of hourly evapotranspiration: critical evaluation for irrigated crops in the Mediterranean.

• Authors:
  • Fahed, S.
  • Rana, G.
  • Katerji, N.
• Source: Hydrological Processes
• Volume: 25
• Issue: 1
• Year: 2011
• Summary: In this paper two models are presented for calculating the hourly evapotranspiration lambda E (W m -2) using the Penman-Monteith equation. These models were tested on four irrigated crops (grass, soya bean, sweet sorghum and vineyard), with heights between 0.1 and 2.2 m at the adult growth stage. In the first model (Katerji N, Perrier A. 1983. Modelisation de l'evapotranspiration reelle ETR d'une parcelle de luzerne: role d'un coefficient cultural. Agronomie 3(6): 513-521, KP model), the canopy resistance rc is parameterized by a semi-empirical approach. In the second model (Todorovic M. 1999. Single-layer evapotranspiration model with variable canopy resistance. Journal of Irrigation and Drainage Engineering-ASCE 125: 235-245, TD model), the resistance rc is parameterized by a mechanistic model. These two approaches are critically analysed with respect to the underlying hypotheses and the limitations of their practical application. In the case of the KP model, the mean slope between measured and calculated values of lambda E was 1.010.6 and the relative correlation coefficients r2 ranged between 0.8 and 0.93. The observed differences in slopes, between 0.96 and 1.07, were not associated with the crop height. This model seemed to be applicable to all the crops examined. In the case of the TD model, the observed slope between measured and calculated values of lambda E for the grass canopy was 0.79. For the other crops, it varied between 1.24 and 1.34. In all the situations examined, the values of r2 ranged between 0.73 and 0.92. The TD model underestimated lambda E in the case of grass and overestimated it in the cases of the other three crops. The under- or overestimation of lambda E in the TD model were due: (i) to some inaccuracies in the theory of this model, (ii) to not taking into account the effect of aerodynamic resistance ra in the canopy resistance modelling. Therefore, the values of rc were under- or overestimated in consequence of mismatching the crop height. The high value of air vapour pressure deficit also contributed to the overestimation of lambda E, mainly for the tallest crop. The results clarify aspects of the scientific controversy in the literature about the mechanistic and semi-empirical approaches for estimating lambda E. From the practical point of view the results also present ways for identifying the most appropriate approach for the experimental situations encountered.

63. Durum wheat salt tolerance in relation to physiological, yield and quality characters.

• Authors:
  • Pompa, M.
  • Giuzio, L.
  • Ficco, D. B. M.
  • Borrelli, G. M.
  • Cattivelli, L.
  • Flagella, Z.
• Source: Cereal Research Communications
• Volume: 39
• Issue: 4
• Year: 2011
• Summary: Durum wheat (Triticum turgidum L. Desf.) is a species well adapted to the Mediterranean environments where salt stress due to seawater intrusion is an increasing problem. The purpose of this study was to deep insight into the relationships among physiological, productive and qualitative aspects under salinity, being these aspects still poorly investigated in durum wheat. In 2004-2005 crop season 10 durum wheat genotypes of different origin and breeding time were grown in a naturally-lit polycarbonate greenhouse under three irrigation water salinity levels (0.9, 6.0 and 12.0 dS m -1). A complete randomized block design with three replications was adopted. The osmotic damage was evaluated by estimating relative water content (RWC), leaf water potential (Phi w) and osmotic potential at full turgor (Phi pi100). The toxic damage to the plants was evaluated by measuring Na + accumulation and Na +/K + ratio in the leaves. Differences in yield performance were evaluated by assessing the main yield components and some qualitative traits, carotenoid pigment and protein content and Sedimentation test in sodium dodecyl sulphate. A significant effect of genotype, salt stress and of their interaction on all the characters was observed. Durum wheat genotypes generally showed a moderate tolerance to salt stress. The genotype performance was dependent on stress level and RWC maintenance. Osmotic adjustment and low sodium accumulation were found to play a key role in salt tolerance. An improvement in the grain quality characters on increasing salinity level, consistently with a yield decrease, was observed.

64. Faba bean productivity in saline-drought conditions.

• Authors:
  • Maalouf, F.
  • Lahmer, F. Z.
  • Mastrorilli, M.
  • Katerji, N.
  • Oweis, T.
• Source: European Journal of Agronomy
• Volume: 35
• Issue: 1
• Year: 2011
• Summary: The response of faba bean ( Vicia faba L., variety ILB1814) was evaluated in a factorial salinity-drought experiment, combining three levels of salinity in the irrigation water (EC 1.0, 2.3 and 3.6 dS/m) and two levels of plant water status during two successive cropping seasons. The two levels of plant water status were obtained by supplying irrigation when the pre-dawn leaf water potential of the control treatments attained values of -0.3 and -0.6 MPa. The experiment was designed to analyse the effects of soil salinity, the effects of drought (detected by the level of the plant water status), and the combined effect of salinity and drought on the plant-water relationships, nitrogen balance and crop productivity (for both grain and straw). Soil salinity levels equal to or higher than 6.5 dS m -1 affected the plants by reducing the grain number but not the straw weight. Drought at flowering, early podding and grain-filling stages reduced both grain and straw yields. Moreover, yield reductions were associated with increasing soil salinity levels, confirming an interaction between the salinity and drought effects on faba bean productivity. Symbiotic nitrogen fixation, as evaluated by the nitrogen balance, was more affected by drought than by salinity, and it may explain the absence of any observed effects of salinity under drought conditions. The comparison of these results with those obtained in similar experiments on wheat and barley revealed that these cereals and faba bean have contrasting behaviours under saline-drought conditions.

65. Long-term effect of tillage, nitrogen fertilization and cover crops on soil organic carbon and total nitrogen content

• Authors:
  • Risaliti, R.
  • Antichi, D.
  • Barberi, P.
  • Sapkota, T. B.
  • Mazzoncini, M.
• Source: Soil & Tillage Research
• Volume: 114
• Issue: 2
• Year: 2011
• Summary: No-tillage, N fertilization and cover crops are known to play an important role in conserving or increasing SOC and STN but the effects of their interactions are less known. In order to evaluate the single and combined effects of these techniques on SOC and STN content under Mediterranean climate, a long term experiment started in 1993 on a loam soil (Typic Xerofluvent) in Central Italy. The experimental variants are: conventional tillage (CT) and no-tillage (NT), four N fertilization rates (N0, N1, N2 and N3) and four soil cover crop (CC) types (C - no cover crop; NL - non-legume CC; LNL - low nitrogen supply legume CC, and HNL - high nitrogen supply legume CC). The nitrogen fertilization rates (N0, N1, N2 and N3) were: 0, 100, 200, 300 kg N ha(-1) for maize (Zea mays, L); 0, 60, 120,180 kg N a(-1) for durum wheat (Triticum durum Desf.); 0, 50, 100, 150 kg N ha(-1) for sunflower (Helianthus annuus L.). From 1993 to 2008, under the NT system the SOC and STN content in the top 30 cm soil depth increased by 0.61 and 0.04 Mg ha(-1) year(-1) respectively. In the same period, the SOC and STN content under the CT system decreased by a rate of 0.06 and 0.04 Mg ha(-1) year(-1) respectively. During the experimental period, N1, N2 and N3 increased the SOC content in the 0-30 cm soil layer at a rate of 0.14, 0.45 and 0.49 Mg ha(-1) year(-1). Only the higher N fertilization levels (N2 and N3) increased STN content, at a rate of 0.03 and 0.05 Mg ha(-1) year(-1). NL, LNL and HNL cover crops increased SOC content by 0.17, 0.41 and 0.43 Mg C ha(-1) year(-1) and -0.01, +0.01 and +0.02 Mg N ha(-1) year(-1). Significant interactions among treatments were evident only in the case of the N fertilization by tillage system interaction on SOC and STN concentration in the 0-10 cm soil depth in 2008. The observed SOC and STN variations were correlated to C returned to the soil as crop residues, aboveground cover crop biomass and weeds (C input). We conclude that, under our Mediterranean climate, it is easier to conserve or increase SOC and STN by adopting NT than CT. To reach this objective, the CT system requires higher N fertilization rates and introduction of highly productive cover crops. (C) 2011 Elsevier B.V. All rights reserved.

66. Can sunflower provide biofuel for inland demand? An integrated assessment of sustainability at regional scale

• Authors:
  • Villani, R.
  • Triana, .
  • Ragaglini, G.
  • Bonari, E.
• Source: Energy
• Volume: 36
• Issue: 4
• Year: 2011
• Summary: Biofuels could reduce reliance on fossil oil, while helping to reduce greenhouse gas emissions and promoting rural development. This study assessed the viability of using local biodiesel production from sunflower in Tuscany (Italy) to meet inland demand for diesel fuel in compliance with the European Directives. A crop growth model, GIS and geostatistics were used to identify suitable areas for biodiesel production, considering potential sunflower yields alongside essential sustainability criteria: energy efficiency and greenhouse gas (GHG) savings throughout the supply chain. Simulation results indicate that biodiesel potential, estimated at 95,000 t/year, corresponds to 104,400 tCO(2) eq/year of GHG saved and to 26,500 TOE/year of fossil energy saved. Two scenarios of biodiesel requirement, derived from EU targets, were evaluated. The results of the evaluation indicated that the 2010 target of replacing 5.75% of transportation diesel fuel can be met, while the 2020 target (reaching a 10% of replacement) cannot be met, since local biodiesel production could replace only 4.78% of diesel fuel requirement. A third scenario considered replacing diesel fuel currently used in the agricultural sector. Results showed that the fuel requirement of this sector cannot be fulfilled since biodiesel could cover only approximately 36% of the expected demand. (C) 2010 Elsevier Ltd. All rights reserved.

67. Prediction of water status by means of an empirical model in orange bearing trees.

• Authors:
  • Germana, C.
  • Intrigliolo, F.
  • Giuffrida, A.
  • Stagno, F.
  • Continella, A.
• Source: Acta Horticulturae
• Issue: 889
• Year: 2011
• Summary: During three consecutive years, in a citrus orchard planted with Tarocco 'Meli' and 'Scire' on sour orange ( C. aurantium L.) were verified the differences of the plant water status and the possibility to build an empirical model to estimate the psi pd utilizing stem water potential (psi md) and vapor pressure deficit (VPD md) measured at midday. The first results showed statistical differences during the irrigation season in the two clones water potential. These difference permitted to separate the data of Tarocco 'Meli' and 'Scire'. As a result, two empirical models were built. The 2nd degree equation (Psi pd=a+b 1Psi md+b 2VPD md) was obtained by considering the Psipd as dependent variable, the Psi md and the VPD md as explanatory variables. ANOVA applied to the multiple regression resulted highly significant with P-value

68. Strategies to decrease water drainage and nitrate emission from soilless cultures of greenhouse tomato.

• Authors:
  • Maggini, R.
  • Carmassi, G.
  • Campiotti, C. A.
  • Pardossi, A.
  • Massa, D.
  • Incrocci, L.
• Source: Agricultural Water Management
• Volume: 97
• Issue: 7
• Year: 2010
• Summary: In the spring-summer season of 2005 and 2006, we explored the influence of three fertigation strategies (A-C) on the water and nitrogen use efficiency of semi-closed rockwool culture of greenhouse tomato conducted using saline water (NaCl concentration of 9.5 mol m -3). The strategies under comparison were the following: (A) crop water uptake was compensated by refilling the mixing tank with nutrient solution at full strength (with the concentrations of macronutrients equal or close to the corresponding mean uptake concentrations as determined in previous studies) and the recirculating nutrient solution was flushed out whenever its electrical conductivity (EC) surpassed 4.5 dS m -1 due to the accumulation of NaCl; (B) the refill nutrient solution had a variable EC in order to maintain a target value of 3.0 dS m -1; due to the progressive accumulation of NaCl, the EC and macronutrient concentrations of the refill nutrient solution tended to decrease with time, thus resulting in a progressive nutrient depletion in the recycling water till N-NO 3- content dropped below 1.0 mol m -3, when the nutrient solution was replaced; (C) likewise Strategy A, but when EC reached 4.5 dS m -1, crop water uptake was compensated with fresh water only in order to reduce N-NO 3- concentration below 1.0 mol m -3 before discharge. In 2005 an open (free-drain) system (Strategy D), where the plants were irrigated with full-strength nutrient solution without drainage water recycling, was also tested in order to verify the possible influence of NaCl accumulation and/or nutrient depletion in the root zone on crop performance. In the semi-closed systems conducted following strategies A, B or C, the nutrient solution was replaced, respectively, 10, 14 and 7 times in 2005, and in 19, 24 and 14 times in 2006, when the cultivation lasted 167 days instead of 84 days in 2005. In both years, there were no important differences in fruit yield and quality among the strategies under investigation. Strategy C produced the best results in terms of water use and drainage, while Strategy B was the most efficient procedure with regard to nitrogen use. In contrast to strategies A and D, the application of strategies B and C minimized nitrogen emissions and also resulted in N-NO 3- concentrations in the effluents that were invariably lower than the limit (approximately 1.42 mol m -3) imposed to the N-NO 3- concentration of wastewater discharged into surface water by the current legislation associated to the implementation of European Nitrate Directive in Italy.

69. Effect of cover crops and mulches on weed control and nitrogen fertilization in tomato ( Lycopersicon esculentum Mill.).

• Authors:
  • Radicetti, E.
  • Mancinelli, R.
  • Campiglia, E.
  • Caporali, F.
• Source: Crop Protection
• Volume: 29
• Issue: 4
• Year: 2010
• Summary: Cover crops and mulches are a suitable choice for sustainable agriculture because they improve weed control and crop performance. The aim of this research was to investigate weed control and nitrogen supply by using different winter cover crop species which were converted into mulches in spring. We carried out a 2-year field experiment where a tomato crop was transplanted into four different types of mulches coming from winter cover crops [(hairy vetch ( Vicia villosa Roth.), subclover ( Trifolium subterraneum L.), oat ( Avena sativa L.), and a mixture of hairy vetch/oat)] and in conventional treatment (tilled soil without mulch). The mixture of hairy vetch/oat cover crop produced the highest aboveground biomass (7.9 t ha -1 of DM), while the hairy vetch accumulated the highest N in the aboveground biomass (258 kg N ha -1). The oat cover crop was the most effective cover crop for suppressing weeds (on average -93% of weed aboveground biomass compared to other cover crops). After mowing the cover crop aboveground biomass was placed in strips as dead mulch into which the tomato was transplanted in paired rows. Weed density and total weed aboveground biomass were assessed at 15 and 30 days after tomato transplanting to evaluate the effect of mulches on weed control. All mulches suppressed weeds in density and aboveground biomass compared to the conventional system (on average -80% and -35%, respectively). The oat was the best mulch for weed control but also had a negative effect on the marketable tomato yield (-15% compared to the conventional treatment). Amaranthus retroflexus L. and Chenopodium album L. were typical weeds associated with the conventional treatment while a more heterogeneous weed composition was found in mulched tomato. Legume mulches, in particular hairy vetch, gave the best marketable tomato yield 28% higher than the conventional system both with and without nitrogen fertilization. This research shows that winter cover crops converted into dead mulch in spring could be used successfully in integrated weed management programs to reduce weed infestation in tomato crops.

70. Durum wheat-faba bean temporary intercropping: effects on nitrogen supply and wheat quality.

• Authors:
  • Guiducci, M.
  • Tosti, G.
• Source: European Journal of Agronomy
• Volume: 33
• Issue: 3
• Year: 2010
• Summary: Intercropping cereals and grain legumes is a common practice because of the advantages in N use, in pest and volunteer plant smothering, but when the grains need to be separated, there are several technical difficulties. These problems may be overcome by adopting a particular form of intercropping (termed "temporary intercropping") where the coexistence of the crops is limited to a portion of their life cycles. In a cereal-legume temporary row-intercropping, the legume component is ploughed into the soil before cereal shooting; thus the legume is used with a mere fertility purpose in order to improve N availability for the cereal component. The presence of such a positive effect, already confirmed in permanent intercropping, needs to be verified in temporary intercropping systems. In an organic farming system, a field experiment was carried out in two consecutive years (2005 and 2006) to evaluate the technical feasibility of a temporary intercropping between three varieties of durum wheat ( Triticum durum Desf.) and faba bean ( Vicia faba L. var. minor Beck.) and to test the effects on interspecific competition for light, N availability, cereal grain yield and quality. The species were temporarily intercropped following an additive design, and there was no fertilisation or crop protection. The N incorporated into the soil by the faba bean biomass was rather stable across years. The competitive effect of the legume reduced the biomass accumulation of the intercropped wheat, but the cereal N status was considerably improved. After the faba bean incorporation into the soil, the marked asymmetry of the temporary intercropped wheat (i.e. large inter-row space coupled with high plant density in the row) affected the radiation balance, nevertheless the yield was positively affected and the wheat grain protein content was increased to an excellent (from 12.0 to 13.9% in 2005) or a good (from 10.2 to 11.5% in 2006) level. Temporary intercropping was shown to be excellent method to improve the quality of organic durum wheat in the Mediterranean environmental conditions.