• Authors:
    • Dawson, J. C.
    • Murphy, K. M.
    • Huggins, D. R.
    • Jones, S. S.
  • Source: Organic Agriculture
  • Volume: 1
  • Issue: 2
  • Year: 2011
  • Summary: There is growing interest in breeding crop cultivars specifically for organic agriculture, based on recognized differences in environmental conditions and management in organic systems compared to conventional systems, and especially due to environmental heterogeneity among and within individual organic systems. There is a need to develop effective strategies for improving crop performance in organic systems through plant breeding. This study evaluated 12 diverse winter wheat breeding lines chosen from conventional and organic breeding nurseries, six historic varieties, and an experimental perennial wheat population under organic management in the Inland Pacific Northwest region of the USA. A randomized complete block design with three replications in two locations over 2 years was used. Based on an analysis of variance, significant genetic differences and crossover interactions across years were found for grain yield, grain percent nitrogen, grain total nitrogen, and aboveground biomass. There were no main effects of locations or location-by-genotype effects for these traits. Based on comparisons among these breeding lines, it appears that there is a possibility of selecting for performance across a limited ecological zone as top-yielding lines were the same in both locations. However, individual entries may have variable performance across years within a single location so selection for stability of performance over years is also necessary. Using an analysis of direct measures of grain yield and grain %N in each location-year combination and overall, we identified breeding lines with relatively high yield, acceptable grain protein, and stable performance over all four location-year combinations. The use of indirect measures or index selection to simultaneously select for grain yield and protein did not appear to be more effective than direct selection based on yield and grain %N measured under organic management.
  • Authors:
    • Fourie, J.
    • Joubert, M.
    • Freitag, K.
  • Source: SA Fruit Journal
  • Volume: 10
  • Issue: 1
  • Year: 2011
  • Summary: Five soil management practices applied in a micro-sprinkler irrigated 'Pink Lady' (Cripps Pink/M7) orchard established on a loam soil near Grabouw were evaluated from October 2003 to March 2010. Dry matter production by the cover crops at the end of September was higher under integrated soil management (IP) than under organic soil management (Organic) during 2004, 2007 and 2008, with the same trend being observed during 2005, 2006, and 2009. Cover crops in the IP and Organic treatments suppressed the winter growing weeds significantly over all seasons compared to treatments in which no cover crop was sown and weeds were slashed during the growing season of the trees (Weeds (IP) and Weeds (Organic) treatments). Except for September 2004, a similar result was achieved where a full surface straw mulch was packed out annually during October, followed by hand weeding during the growing season of the trees (Straw Mulch (Organic) treatment). Summer growing weeds were controlled effectively by the Cover Crop (IP) and Straw Mulch (Organic) treatments. Weeds (IP) and Weeds (Organic) caused broad leaf weeds to disappear and perennial grasses to dominate the weed spectrum. Although not as drastic, a similar trend developed in the Cover Crop (Organic) treatment. In contrast, annual weed species became dominant where Cover Crop (IP) was applied. All soil cultivation practices caused changes in the weed spectrum, with species dominance shifting with time. This aspect of weed control should be studied more extensively in future.
  • Authors:
    • Garland, G. M.
    • Suddick, E.
    • Burger, M.
    • Horwath, W. R.
    • Six, J.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 144
  • Issue: 1
  • Year: 2011
  • Summary: Knowing underlying practices for current greenhouse gas (GHG) emissions is a necessary precursor for developing best management practices aimed at reducing N2O emissions. The effect of no-till management on nitrous oxide (N2O), a potent greenhouse gas, remains largely unclear, especially in perennial agroecosystems. The objective of this study was to compare direct N2O emissions associated with management events in a cover-cropped Mediterranean vineyard under conventional tillage (CT) versus no-till (NT) practices. This study took place in a wine grape vineyard over one full growing season, with a focus on the seven to ten days following vineyard floor management and precipitation events. Cumulative N2O emissions in the NT system were greater under both the vine and the tractor row compared to CT, with 0.15 ± 0.026 kg N2O–N ha−1 growing season−1 emitted from the CT vine compared to 0.22 ± 0.032 kg N2O–N ha−1 growing season−1 emitted from the NT vine and 0.13 ± 0.048 kg N2O–N ha−1growing season−1 emitted from the CT row compared to 0.19 ± 0.019 kg N2O–N ha−1 growing season−1 from the NT row. Yet these variations were not significant, indicating no differences in seasonal N2O emissions following conversion from CT to NT compared to long-term CT management. Individual management events such as fertilization and cover cropping, however, had a major impact on seasonal emissions, indicating that management events play a critical role in N2O emission patterns.
  • Authors:
    • Hammond, R.
  • Source: IOBC/WPRS Bulletin
  • Volume: 64
  • Year: 2011
  • Summary: Slugs are often problems in field crops grown using conservation tillage practices in the eastern United States, as well as certain locations in the Midwest and the southern USA, as well as in Canada. Although most concern has been on corn and soybean, reports of problems from dry beans, cotton, oil-seed rape, sunflowers, winter wheat, and fall planted alfalfa are often received. Although most problems are in fields located in the original forested areas of eastern and southern USA, reports are also being received from the Great Plains' grass lands of slug issues in irrigated no-till fields. Overall, slug problems have increased in geographical area as growers in the USA and Canada have adopted conservation tillage practices. As in other areas of the world, determining new methods of slug control is of utmost importance in order to allow growers to continue using conservation tillage practices. In areas that are new to slugs, a primary concern is educating growers on IPM approaches to slug management.
  • Authors:
    • Backiyavathy, M. R.
  • Source: Advances in Plant Sciences
  • Volume: 24
  • Issue: 1
  • Year: 2011
  • Summary: A field experiment was conducted to evaluate the effect of different organic manures and its sources at different levels (FYM - 20, 25 & 30 t ha -1, vermicompost - 2.5, 5.0 & 7.5 t ha -1, poultry manure - 2.5, 5.0 & 7.5 t ha -1 and pig manure - 2.5, 5.0 & 7.5 t ha -1) on yield and quality of fodder in perennial fodder crops. The field experiment was conducted at New Area Farm, Department of Forage Crops, TNAU, Coimbatore. The experiment was laid out in randomized block design replicated twice with 14 treatments. Perennial fodder crops viz., cumbu napier hybrid grass CO 3, guinea grass CO 2, sorghum COFS 29, lucerne CO 1 and hedge lucerne were studied under this investigation. The results revealed that the organic manure treatments were compared with recommended dose of inorganic fertilizers with respect to each fodder crop. Among different organics, application of FYM @ 30 t ha -1 registered the maximum green fodder, dry fodder and crude protein yields in all perennial fodders. However the maximum green, dry fodder and crude protein yields were recorded in RDF treatment over the rest of the other treatments.
  • Authors:
    • Avci, M.
  • Source: Agronomy for Sustainable Development
  • Volume: 31
  • Issue: 2
  • Year: 2011
  • Summary: Central Anatolian soils have high risk of erosion, degradation and intensive cultivation. Consequently, they are in danger of exhausting their agricultural use unless conservation agricultural practices are adopted. Conservation agriculture is a key tool in sustainable production systems throughout the world and is developed around soil management technology that minimizes soil disturbance, maximizes the soil cover and promotes crop diversity to offer benefits to farmers and to the environment. It has been particularly effective at sustaining crop production in semi-arid rain-fed regions such as the Central Anatolian soils, where potential evaporation exceeds precipitation during most months of the year, dry farming is extensively practiced, water and wind erosion is common, and proper application of water- and soil-conserving tillage technology is critical. The area under plow expanded its limits as the number of tractors in agriculture dramatically increased in the 1960s. This is the starting point for inappropriate use of the agricultural land. The conservation agricultural technologies, therefore, are of utmost importance for the region. Common farmers' practices of a fallow-wheat system in the central plateau of Turkey are incompatible with the conservation agriculture concept. The objective of this review is to re-evaluate the performances of the partial and full conservation tillage practices previously tried in the region. This review reached the following conclusions: (1) agreeing with the conservation principles, fall tillage as a primary operation in the fallow phase was found to be useless compared with leaving the land without tillage; (2) therefore, much research has focused on spring tillage as a primary operation and employed conventional, semi-conservative and conservative methods. Results showed that the conventional system, in addition to being ecologically unfriendly, is unprofitable as compared with other conservation practices regarding the updated cost analysis; (3) similarly, tillage depth in primary spring tillage was determined to be shallower than the depths currently practiced by farmers, in agreement with the conservation principles; (4) fallow tillage operations in summer to create dust mulch for eliminating soil moisture loss did not increase the crop yields and soil moisture as compared with chemical fallow; (5) no-till fallow was similar to the conventional clean fallow system in terms of moisture and yield levels. However, no-tillage resulted in 50% reduction in the cost of tillage besides its ecologically-friendly effects; (6) the existing dryland agricultural systems in the plateau should be transformed into or changed toward sustainable systems, although further research is required on residue and stubble management, and integrated weed control methods to drill the soil with high amounts of residue on the field.
  • Authors:
    • Basch, G.
    • Freixial, R.
    • Carvalho, M. de
    • Barros, J. C.
  • Source: Revista de Ciências Agrárias
  • Volume: 34
  • Issue: 1
  • Year: 2011
  • Summary: The study was carried out over 2 years (2007/2008 and 2008/2009) on a private farm in the Alentejo region (Evora), in the South of Portugal where rainfed wheat is sown after the beginning of the autumn rainfall season. The wheat crop was established using no-till which permits the post-emergence application of herbicides at an early weed development stage. To control J. bufonius and different broad-leaved weeds, a mixture of two herbicides was used when the weeds were at the 3-4 pair of leaves development stage. The herbicides applied were mesosulfuron-methyl+iodosulfuron-methyl-sodium+mefenpyr-diethyl (H1) and clortoluron (H2) at two different doses. Best J. bufonius control was achieved with the higher dose of the herbicide H2 and the highest broad-leaved weeds control was obtained when the higher dose of the herbicide H1 was applied. Although no significant differences in grain yield were observed between the different herbicide treatments, there was a tendency for higher grain yields with an increase of control efficacy of Juncus bufonius L.
  • Authors:
    • Bene, C. di
    • Tavarini, S.
    • Mazzoncini, M.
    • Angelini, L. G.
  • Source: European Journal of Agronomy
  • Volume: 35
  • Issue: 3
  • Year: 2011
  • Summary: The introduction of perennials in the Mediterranean crop rotations can have a positive effect on soil organic matter (SOM) concentration, thus improving the long-term sustainability of cropping systems, affected by the progressive degradation in soil fertility. Ramie [ Boehmeria nivea (L.) Gaud.], a perennial herbaceous species used for its high quality bast fibre, has recently received renewed attention for production in Europe due to the increasing natural fibre demand globally. Little attention has been focused on the ramie cultivation management and on its effect on soil chemical characteristics. A long-term field experiment was carried out in Pisa (Central Italy, 43 degrees 40′N; 10 degrees 19′E) since 1996, with the aim to assess the long-term environmental sustainability of ramie in terms of productivity, nutrient balance, soil fertility and SOM pool. The fertiliser management of ramie consisted of 150-100-100 kg N-P-K ha -1 in the establishment year and 150-65-165 kg N-P-K ha -1 year -1 from the second year onwards. Plant nutrient uptake was analysed to optimise the crop mineral nutrition and to evaluate the nutrient balance and the efficiency of fertiliser management. The SOM dynamic was evaluated using the actual investigated data and Henin-Dupuis's equation in order to estimate the organic requirements for SOM equilibrium. Over the 13-year cultivation period, a mean value of 14 Mg ha -1 year -1 of total above-ground dry biomass was obtained. In the 0-30 cm soil depth, SOM, total nitrogen (N), available phosphorus (P), exchangeable potassium (K) and pH varied significantly throughout the cultivation period. SOM increased significantly, from 13.4 g kg -1 to 25.3 g kg -1. A significant correlation between the measured SOM and the cumulative organic matter (OM) inputs ( r2=0.908; P=0.012) was found. The average annual N and P balances were positive (equal to 14 kg ha -1 and 38 kg ha -1, respectively), while the K balance was negative (-57 kg ha -1). The results show that ramie crop has a positive effect on SOM pool, thus representing an interesting sustainable fibre crop for the Mediterranean area.
  • Authors:
    • Rypowski, K.
    • Cortes, M.
    • Osorio, A.
    • Burgos, M.
  • Source: Acta Horticulturae
  • Issue: 889
  • Year: 2011
  • Summary: Six tests were done to evaluate the application of irrigation rates in Limari River Valley (3036′ South Latitude 7112′ West Longitude and 218 m of altitude) in avocado and mandarin tree orchards during two agricultural seasons. Assessments were made in volumes of water applied, discharge of the drippers and irrigation frequency used. Also, the water stored in the soil profile was monitored by moisture direct sampling with drill, performed deeply and transversely to the drip lines and plantation rows. In the cases studied it was possible to appreciate a wide variety of situations regarding water stored in the profile. In the vast majority of cases, excess water conditions were found, both in the root zone and below it. In very few cases, the moisture in the root zone of trees reached levels close to permanent wilting percentage (PWP). This would reflect poor efficiency in the implementation and management of irrigation water through drip irrigation, regardless of the uniformity coefficient (UC) of drippers. This situation becomes much more problematic in those soils which present high percentages of clay; creating low aeration conditions for root development. It is also possible to observe an important deviation from moisture profiles to the lower or steeper sectors of the plantation system; generating drier soil or less humid conditions in higher zones, with a big impact on root development. When calculating the relation between the water stored in the root zone versus the total water available in the profile, results between 44 and 73% were obtained, values that reflect inefficient irrigation conditions. These results were corroborated by the high variation coefficients (VC) in the moisture content in the profile, with values higher than 19.00% and with maximum value equal to 43.64% VC.
  • Authors:
    • Hachum, A. Y.
    • Farahani, H. J.
    • Oweis, T. Y.
  • Source: Agricultural Water Management
  • Volume: 98
  • Issue: 8
  • Year: 2011
  • Summary: Cotton ( Gossypium hirsutum L.) is the most important industrial and summer cash crop in Syria and many other countries in the arid areas but there are concerns about future production levels, given the high water requirements and the decline in water availability. Most farmers in Syria aim to maximize yield per unit of land regardless of the quantity of water applied. Water losses can be reduced and water productivity (yield per unit of water consumed) improved by applying deficit irrigation, but this requires a better understanding of crop response to various levels of water stress. This paper presents results from a 3-year study (2004-2006) conducted in northern Syria to quantify cotton yield response to different levels of water and fertilizer. The experiment included four irrigation levels and three levels of nitrogen (N) fertilizer under drip irrigation. The overall mean cotton (lint plus seed, or lintseed) yield was 2502 kg ha -1, ranging from 1520 kg ha -1 under 40% irrigation to 3460 kg ha -1 under 100% irrigation. Mean water productivity (WP ET) was 0.36 kg lintseed per m 3 of crop actual evapotranspiration (ET c), ranging from 0.32 kg m -3 under 40% irrigation to 0.39 kg m -3 under the 100% treatment. Results suggest that deficit irrigation does not improve biological water productivity of drip-irrigated cotton. Water and fertilizer levels (especially the former) have significant effects on yield, crop growth and WP ET. Water, but not N level, has a highly significant effect on crop ET c. The study provides production functions relating cotton yield to ET c as well as soil water content at planting. These functions are useful for irrigation optimization and for forecasting the impact of water rationing and drought on regional water budgets and agricultural economies. The WP ET values obtained in this study compare well with those reported from the southwestern USA, Argentina and other developed cotton producing regions. Most importantly, these WP ET values are double the current values in Syria, suggesting that improved irrigation water and system management can improve WP ET, and thus enhance conservation and sustainability in this water-scarce region.