• Authors:
    • Shevtsov, V.
    • El-Haramein, F.
    • Grando, S.
    • Sariev, B.
    • Abugalieva, A.
  • Source: Russian Agricultural Sciences
  • Volume: 38
  • Issue: 2
  • Year: 2012
  • Summary: A method is given for determining the content of beta-glucan in grain of barley varieties, and polymorphism of the species in this trait, including collection and breeding accessions, is shown. Within the breeding nurseries of Kazakhstan, the beta-glucan content varies from 2.6 to 6.2% in spring and from 2.2 to 5.7% in winter barley grain, increasing under dry-farming conditions. For brewing purposes, accessions with a value of this index lower than 4%, some of which displayed relative stability across reseedings, are singled out. The need for purposeful breeding for the given trait, for which it is necessary to introduce it into the selection scheme, and use of identification methods are substantiated.
  • Authors:
    • Bejiga, G.
    • Khalil, Y.
    • Kumar, S.
    • Haddad, A.
    • Piggin, C.
    • Ahmed, S.
  • Source: Soil & Tillage Research
  • Volume: 121
  • Year: 2012
  • Summary: Conservation agriculture is becoming popular due to its potential for enhanced productivity and cost savings among small scale farmers in developing countries. The International Center for Agricultural Research in Dry Areas is promoting conservation cropping systems that involve cereal-legume rotation in West Asia and North Africa region. Studies were made on the impact of long-term rotation trial on diseases of chickpea and lentil as well as the evaluations of lentil genotypes for their reactions to Fusarium wilt and downy mildew under two tillage practices. In the long-term rotation trials, the two season results showed no significant differences between tillage practices, crops and planting dates and their interactions in affecting mean percent cyst nematode disease. The mean cyst nematode disease incidence ranged from 7.3% on early planted lentil on CT to 14.5% in late planted chickpea on ZT. Tillage practices significantly ( P≤0.05) affected Ascochyta blight incidence but not its severity. The incidence ranged from 4% to 22.5% under early planted chickpea on both tillage practices. Moreover, the mean severity ranged from 3.2 to 5.5 rating in early planted CT and ZT, respectively. The combined analysis showed significant differences ( P≤0.05) among genotypes but not their interactions with tillage for Fusarium wilt and downy mildew reactions. All the genotypes showed less than 10% Fusarium wilt mortality indicating high levels of resistance. The mean downy mildew severity ranged from 1.3 in ILL-7991 to 2.6 rating in ILL6994. This study showed that both soil borne and foliar diseases could be a problem in conservation cropping system and continuous monitoring of diseases is essential to prioritize management practices in relation to conservation agriculture in Mediterranean type environments. Moreover, cool-season legume genotypes with disease resistance and high yield can be developed under conservation agriculture that could also serve traditionally tilled production systems.
  • Authors:
    • Limon, M.
    • Blanco-Moure, N.
    • Lopez, M.
    • Gracia, R.
  • Source: Soil & Tillage Research
  • Volume: 118
  • Year: 2012
  • Summary: Conservation tillage has been encouraged as a management alternative to preserve soil and water resources in semiarid Aragon (NE Spain). In fact, its adoption by farmers, and especially of no tillage (NT) systems, has increased in recent years. However, little information concerning the soils on which these techniques are applied is available for this region. The objective of this study was to assess the potential of NT to increase organic carbon content at the soil surface (0-20 cm) in rainfed Aragon. To this aim, 22 pairs of adjacent farm fields under NT and conventional tillage (CT) were compared in different cereal production areas. The fields were under continuous NT between 5 and 19 years but half were over 10 years. Soil organic carbon (SOC) in NT ranged from 7.06 to 18.53 g kg -1 (0-20 cm depth) and was higher than 12 g kg -1 in nearly 30% of the fields. These contents represented between 8% less (only one case) and 55% more SOC under NT than under CT with an average gain of 20% in favour of NT. The highest SOC contents were found in the NT fields of longer duration (>10 years) and/or managed with practices that enhance the return of more crop biomass to the soil (complete residue return, cropping intensification and manure application). The identification of the current management practices used by farmers has allowed us to know the diversity of the NT-based cropping systems and the reality of the conservation agriculture in our region. Overall, results from this on-farm study indicate that NT can be recommended as a viable alternative to CT to increase organic carbon at the soil surface in cereal production areas of Aragon.
  • Authors:
    • Manukyan, R.
    • Asadi, H.
    • Nazmi, L.
    • Naderi, H.
  • Source: Canadian Journal of Soil Science
  • Volume: 92
  • Issue: 4
  • Year: 2012
  • Summary: In hilly landforms subject to long-term cultivation, erosion has denuded the upper slope positions of topsoil, and accumulated topsoil in the lower slope positions. Slope gradient and position effects aggregation processes, which in turn impact soil productivity. A field experiment was conducted to assess the tillage-induced soil displacement and its effects on the soil properties and barley ( Hordeum vulgare var. Sahand) biomass production for three different landscapes. The study was conducted on a hill slope seeded with barley (1.4-10.1° slope) located in the Mollaahmad watershed of the Ardabil province in northwestern Iran. For this purpose, soil samples were collected from four slope positions in a grassland as well as an agricultural field (dryland). A field experiment was conducted to evaluate the effects of slope gradient and position on barley growth and soil quality. Soil generally had lower organic carbon, available phosphorus, calcium carbonate equivalent, soil water content and mean weight diameter of soil aggregates in the farmland than the grassland, and in the upper slope positions than in the lower slopes. Significantly higher barley growth indices were associated with lower slope positions. Agronomic productivity of the soil was lowest for landscapes with the highest slope gradient. The relationships between tillage erosion and yield components were found to be significant. Spike weight and slope position had the largest contribution for the explanatory capacity of canonical variables (tillage erosion and yield components) estimated when compared with other parameters (slope gradient, dry matter, spike number, grain yield and 1000-grain weight). The findings in this study can be used as a tool to assist farmers, soil and water conservationists, and other policymakers in decision making regarding the use of lands.
  • Authors:
    • Cole, D.
    • Orozco, F.
  • Source: Ecohealth research in practice: innovative applications of an ecosystem approach to health
  • Year: 2012
  • Summary: This chapter describes an agricultural project (Ecosalud II) in Ecuador that aims to tackle the complex drivers of inappropriate use of highly hazardous pesticides, with the long-term goal of greater agroecosystem sustainability, including better human health. The project is similar to Ecosalud I, apart from some modifications, including an expansion of the project to 3 provinces (Carchi, Chimborazo and Tungurahua,). Furthermore, in Ecosalud II, "potato platforms" were used as social spaces that encouraged diverse actors with different knowledge, experience and decision-making power to gather monthly to address issues related to potato farming. The participants included small-scale farmers, leaders of community organizations, technical staff of nongovernmental development organizations (NGOs), staff of various municipal governments, provincial government representatives and provincial university faculty members. Drivers that affected the livelihoods and health of farm families are as follows: cheap and readily available highly hazardous pesticides; farmers' lack of knowledge about handling pesticides and reducing their exposure in the field and at home; poor general awareness of the extent of health impacts among both NGO and government actors; and weak policy responses to promote alternative crop-management technologies and practices that favour the sustainability of agro-ecosystem and farmers' health. These issues are tackled based on knowledge production, capacity building and multi-stakeholder collaboration. Data show that the strategic communication and use of research results with farmers, key government officials, NGOs and other stakeholders was effective in fostering change in potato-production systems in the three provinces targeted by the project and helped make potato production a safer income-generating activity with less damage to farmers' health and their environment.
  • Authors:
    • Thomashow, L.
    • Weller, D.
    • Mavrodi, O.
    • Mavrodi, D.
    • Parejko, J.
  • Source: Microbial Ecology
  • Volume: 64
  • Issue: 1
  • Year: 2012
  • Summary: Certain strains of the rhizosphere bacterium Pseudomonas fluorescens contain the phenazine biosynthesis operon ( phzABCDEFG) and produce redox-active phenazine antibiotics that suppress a wide variety of soilborne plant pathogens. In 2007 and 2008, we isolated 412 phenazine-producing (Phz +) fluorescent Pseudomonas strains from roots of dryland wheat and barley grown in the low-precipitation region (
  • Authors:
    • Kazemayni, S.
    • Sadeghi, H.
  • Source: Iranian Journal of Field Crop Science
  • Volume: 42
  • Issue: 4
  • Year: 2012
  • Summary: A 2-years (2007-2009) field study was carried out at the college of Agriculture, Shiraz University, to evaluate the influence of crop residues management and nitrogen (N) rates on soil quality and barley grain protein under dryland conditions. The experiment was conducted as strip split plot with four replications. Horizontal plots were three crop residues rates (0, 750 and 1500 kg ha -1), vertical plots consisted of two barley cultivars (CVs) (Afzal and Reyhan), and sub-plots were three N rates (0, 40, and 80 kg N ha -1). The Results of ANOVA showed that there were significant differences for year effects and Y * C * N for total N grain and protein percentage. When the crop residues were completely added (100%), N rates should be added according to residues rates. Increasing crop residue level increased soil organic carbon. Crop residue application had no effect on grain protein percentage. There were no significant differences between two cultivars for Crop residue application. High N increased grain protein percentage significantly.
  • Authors:
    • Lartey, R.
    • Jabro, J.
    • Caesar-Tonthat, T.
    • Lenssen, A.
    • Sainju, U.
    • Evans, R.
    • Allen, B.
  • Source: Nutrient Cycling in Agroecosystems
  • Volume: 93
  • Issue: 3
  • Year: 2012
  • Summary: Management practices may influence dryland soil N cycling. We evaluated the effects of tillage, crop rotation, and cultural practice on dryland crop biomass (stems and leaves) N, surface residue N, and soil N fractions at the 0-20 cm depth in a Williams loam from 2004 to 2008 in eastern Montana, USA. Treatments were two tillage practices (no-tillage [NT] and conventional tillage [CT]), two crop rotations (continuous spring wheat [ Triticum aestivum L.] [CW] and spring wheat-barley [ Hordeum vulgaris L.] hay-corn [ Zea mays L.]-pea [ Pisum sativum L.] [W-B-C-P]), and two cultural practices (regular [conventional seed rates and plant spacing, conventional planting date, broadcast N fertilization, and reduced stubble height] and ecological [variable seed rates and plant spacing, delayed planting, banded N fertilization, and increased stubble height]). Nitrogen fractions were soil total N (STN), particulate organic N (PON), microbial biomass N (MBN), potential N mineralization (PNM), NH 4-N, and NO 3-N. Crop biomass N was 30% greater in W-B-C-P than in CW in 2005. Surface residue N was 30-34% greater in NT with the regular and ecological practices than in CT with the regular practice. The STN, PON, and MBN at 10-20 and 0-20 cm were 5-41% greater in NT or CW with the regular practice than in CT or CW with the ecological practice. The PNM at 5-10 cm was 22% greater in the regular than in the ecological practice. The NH 4-N and NO 3-N contents at 10-20 and 0-20 cm were greater in CT with W-B-C-P and the regular practice than with most other treatments in 2007. Surface residue and soil N fractions, except PNM and NO 3-N, declined from autumn 2007 to spring 2008. In 2008, NT with W-B-C-P and the regular practice gained 400 kg N ha -1 compared with a loss of 221 kg N ha -1 to a gain of 219 kg N ha -1 in other treatments. No-tillage with the regular cultural practice increased surface residue and soil N storage but conventional tillage with diversified crop rotation and the regular practice increased soil N availability. Because of continuous N mineralization, surface residue and soil N storage decreased without influencing N availability from autumn to the following spring.
  • Authors:
    • van Ranst, E.
    • Fadlaoui, A.
    • Moussadek, R.
    • Mrabet, R.
  • Source: Field Crops Research
  • Volume: 132
  • Year: 2012
  • Summary: Moroccan agriculture is characterized by the co-existence of both modern and smallholder traditional agriculture. Both types of agriculture are under degradative processes due to mis-use of tillage implements, mis-management of crop residues and inappropriate links between grain and livestock productions. From the research conducted over the last three decades, the vast majority of beneficial tillage effects are transient. Conversely, the harmful effects of conventional tillage (CT) systems are long-lasting, if not permanent. The present paper aims at evaluating major achievements in conservation or no-tillage agriculture (CA or NT) research conducted in dry areas of Morocco and presenting important ways to implement these achievements within the Moroccan rural society. CA has been introduced in response to issues of soil conservation, drought mitigation and soil quality management. NT systems have resulted in reduced soil erosion, greater soil water conservation, improved soil quality and stable and higher crop yields. Changes in crop production practices due to shifting to NT or CA systems and retention of crop residues at or near the surface produced progressive qualitative and quantitative variations in soil organic matter. This can allow agriculture to contribute to country's efforts to reduce and control greenhouse gas emissions. These effects benefited both farmers and society in terms of higher returns and efficiencies. Under NT, benefits from improved agriculture's environmental performance must be added to remunerations of reducing costs of production and improving well-being of farmers. The other strong benefits that CA brings come from the opportunity for early sowing and savings in time, machinery and fuel. Even though, many agronomic, socio-economic and environmental benefits accrue from NT and increasing crop diversity; lack of incentives from the government and social factors encourage the continued use of CT systems. CA systems were sufficiently tested in research stations but found limited adoption in farm communities. The shift in the late nineties to more on-farm research did not result in the envisaged breakthroughs, mainly due to poor research-extension linkages and several social and technical barriers. Consequently, in order to realize durable agricultural growth, there is a huge challenge to out- and up-scale CA in Morocco through linkage of all stakeholders (farmers, developers, researchers, industrials and policy makers). This paper fulfills information gaps and presents a thorough discussion on constraints to CA adoption as well. (C) 2011 Elsevier B.V. All rights reserved.
  • Authors:
    • Caesar, A.
    • Caesar-TonThat, T.
    • Sainju, U. M.
  • Source: Soil and Tillage Research
  • Volume: 118
  • Issue: January
  • Year: 2012
  • Summary: Portable chamber provides simple, rapid, and inexpensive measurement of soil CO2 flux but its effectiveness and precision compared with the static chamber in various soil and management practices is little known. Soil CO2 flux measured by a portable chamber using infrared analyzer was compared with a static chamber using gas chromatograph in various management practices from May to October 2008 in loam soil (Luvisols) in eastern Montana and in sandy loam soil (Kastanozems) in western North Dakota, USA. Management practices include combinations of tillage, cropping sequence, and N fertilization in loam and irrigation, tillage, crop rotation, and N fertilization in sandy loam. It was hypothesized that the portable chamber would measure CO2 flux similar to that measured by the static chamber, regardless of soil types and management practices. In both soils, CO2 flux peaked during the summer following substantial precipitation and/or irrigation (>15 mm), regardless of treatments and measurement methods. The flux varied with measurement dates more in the portable than in the static chamber. In loam, CO2 flux was 14-87% greater in the portable than in the static chamber from July to mid-August but 15-68% greater in the static than in the portable chamber from late August to October in all management practices. In sandy loam, CO2 flux was 10-229% greater in the portable than in the static chamber at all measurement dates in all treatments. Average CO2 flux across treatments and measurement dates was 9% lower in loam but 84% greater in sandy loam in the portable than in the static chamber. The CO2 fluxes in the portable and static chambers were linearly to exponentially related (R-2 = 0.68-0.70, P < 0.01, n = 40-56). Although the trends of CO2 fluxes with treatments and measurement dates were similar in both methods, the flux varied with the methods in various soil types. Measurement of soil CO2 flux by the portable chamber agreed more closely with the static chamber within 0-10 kg C ha(-1) d(-1) in loam soil under dryland than in sandy loam soil under irrigated and non-irrigated cropping systems. Published by Elsevier B.V.