• Authors:
    • Akmal, M.
    • Hassan, M. F.
    • Habib, G.
    • Ghufranullah
    • Ahmad, S.
  • Source: Pakistan Journal of Botany
  • Volume: 43
  • Issue: 2
  • Year: 2011
  • Summary: The experiment was conducted to compare Pigeon pea (PP) and Sesbania gentia (SG) legumes as catch crop in a permanent cereal based (Wheat-maize) rotation. The residual effect of legumes with or without added fertilizer (N) was studies on subsequent maize crop grown as fodder. The study aimed to evaluate catch crop response as manure or fodder on the following maize. The results showed that SG was higher in crude protein (p
  • Authors:
    • Holm, F. A.
    • Johnson, E. N.
    • Blackshaw, R. E.
    • O'Donovan, J. T.
    • Harker, K. N.
    • Clayton, G. W.
  • Source: Weed Science
  • Volume: 59
  • Issue: 3
  • Year: 2011
  • Summary: Growing crops that exhibit a high level of competition with weeds increases opportunities to practice integrated weed management and reduce herbicide inputs. The recent development and market dominance of hybrid canola cultivars provides an opportunity to reassess the relative competitive ability of canola cultivars with small-grain cereals. Direct-seeded (no-till) experiments were conducted at five western Canada locations from 2006 to 2008 to compare the competitive ability of canola cultivars vs. small-grain cereals. The relative competitive ability of the species and cultivars was determined by assessing monocot and dicot weed biomass at different times throughout the growing season as well as oat (simulated weed) seed production. Under most conditions, but especially under warm and relatively dry environments, barley cultivars had the greatest relative competitive ability. Rye and triticale were also highly competitive species under most environmental conditions. Canada Prairie Spring Red wheat and Canada Western Red Spring wheat cultivars usually were the least competitive cereal crops, but there were exceptions in some environments. Canola hybrids were more competitive than open-pollinated canola cultivars. More importantly, under cool, low growing degree day conditions, canola hybrids were as competitive as barley, especially with dicot weeds. Under most conditions, hybrid canola growers on the Canadian Prairies are well advised to avoid the additional selection pressure inherent with a second in-crop herbicide application. Combining competitive cultivars of any species with optimal agronomic practices that facilitate crop health will enhance cropping system sustainability and allow growers to extend the life of their valuable herbicide tools.
  • Authors:
    • Farajzadeh, N.
    • Yarnia, M.
    • Tabrizi, E. F. M.
    • Ahmadzadeh, V.
  • Source: Annals of Biological Research
  • Volume: 2
  • Issue: 5
  • Year: 2011
  • Summary: Potato tuber products that has an important role in feeding the world with annual production of 31 million tons of food products is important and different types of soil and climatic conditions is growing culture. Potato after wheat, rice and corn for the fourth position and the number of producing countries is in the second after the corn. A factorial experiment based on randomized complete block design with three replications was conducted during growing season of 2009 at Islamic Azad University, Tabriz branch, Agricultural Research Station. Treatments including: irrigation of 70 (control), 110, 150 mm evaporation from basin class A and different varieties of potato, including (Agria, Satyna, Savalan, Kaizr and Markis) respectively. The results showed that water stress decreased yield and lowest yield was in cultivar Markis with 150 mm of irrigation water evaporation basin level and most resistant cultivars in the rate of tuber production with 10.68 numbers has been obtained Satyna. Equivalent of 96.12 percent increase than sensitive cultivars. Therefore aim of this study reaction of different cultivars of potato on different traits.
  • Authors:
    • Liu, S. H.
    • Liu, S. P.
    • Hu, W.
    • Wan, S. Q.
    • Kang, Y. H.
    • Wang, R. S.
  • Source: Agricultural Water Management
  • Volume: 100
  • Issue: 1
  • Year: 2011
  • Summary: A 3-year experiment was conducted in an extremely dry and saline wasteland to investigate the effects of the drip irrigation on salt distributions and the growth of cotton under different irrigation regimes in Xinjiang, Northwest China. The experiment included five treatments in which the soil matric potential (SMP) at 20 cm depth was controlled at -5, -10, -15, -20, and -25 kPa after cotton was established. The results indicated that a favorable low salinity zone existed in the root zone throughout the growing season when the SMP threshold was controlled below -25 kPa. When the SMP value decreased, the electrical conductivity of the saturation paste extract (EC e) in the root zone after the growing season decreased as well. After the 3-year experiment, the seed-cotton yield had reached 84% of the average yield level for non-saline soil in the study region and the emergence rate was 78.1% when the SMP target value was controlled below -5 kPa. The average pH of the soil decreased slightly after 3 years of cultivation. The highest irrigation water use efficiency (IWUE) values were recorded when the SMP was around -20 kPa. After years of reclamation and utilization, the saline soil gradually changed to a moderately saline soil. The SMP of -5 kPa at a depth of 20 cm immediately under a drip emitter can be used as an indicator for cotton drip irrigation scheduling in saline areas in Xinjiang, Northwest China.
  • Authors:
    • McClymont, L.
    • McAllister, A.
    • O'Connell, M. G.
    • Whitfield, D. M.
    • Abuzar, M.
    • Sheffield, K.
  • Source: Acta Horticulturae
  • Issue: 922
  • Year: 2011
  • Summary: The METRIC algorithm (Allen et al., 2007) was applied to a Landsat 5 image to assess the range of vegetation cover (measured as Normalised Difference Vegetation Index; NDVI), and rates of evapotranspiration (ET), of major horticultural crops grown in the Sunraysia Irrigation Region of SE Australia. The image represented the period of maximum foliage cover of horticultural crops grown in the Region. The range in mid-season NDVI of almond, grape and citrus crops almost matched the whole-of-season range reported for broad-acre irrigated annual crops grown in Idaho, USA. Alfalfa reference ET (ETr) constituted the upper limit to ET rate seen in Sunraysia crops. The range of ET and NDVI observations in this study therefore complied with limits on ET and NDVI seen in irrigated crops in Idaho, USA. ET-NDVI relationships seen in USA crops appear to provide a useful reference framework for well-watered irrigated crops in cases where ETr is the upper limit on ET. ET rates in Sunraysia crops were strongly related to NDVI. The dependence of ET rates on NDVI, combined with the large range in NDVI, meant that irrigation water requirement varied widely within and between crop types in the Sunraysia region: results support the use of NDVI measures to account for site-specific differences in crop water requirement attributable to vegetation cover. Findings suggest that satellite-based METRIC methods of ET estimation may be used to formulate region- and crop-specific estimates of the crop coefficients (Kcb, Ke, and Kc) required for optimal irrigation water management of horticultural crops.
  • Authors:
    • Williams, J. D.
    • Long, D. S.
  • Source: Crop Management
  • Issue: March
  • Year: 2011
  • Summary: In the intermediate annual precipitation zone (14 to 18 inches) of northeastern Oregon, there is interest in increasing the intensity of cropping with spring crops. Mechanical tillage remains popular for seedbed preparation and weed control, but contributes to environmental problems and high labor and fuel cost. No-tillage (NT) crop production can reduce on site and off site problems and has lower labor and fuel costs, but soil-borne disease and weed control problems can limit yields. We compared crop yields, production costs, and economic returns of an intensive, four-year crop production rotation under two management systems: (i) minimum tillage (MT) with cultivation by chiseling, sweeping, and rod weeding; and (ii) NT with chemical weed control. The rotation was fallow-winter wheat-dry spring pea-winter wheat in which a spring broadleaf crop is included to aid in the control of winter annual weeds and reduce host pathogen levels of soil-borne cereal diseases. Four year averages of wheat yields in the NT treatment were equal to or greater than those in the MT treatment whereas dry green pea production was roughly equal in each treatment. Crop productivity differed significantly in each phase of the rotation in descending order from winter wheat following fallow [4,578 lb/acre (76 bu/acre)], winter wheat following dry spring pea [3,548 lb/acre (59 bu/acre)], to dry spring pea (1,505 lb/acre). Partial budget analysis shows that NT is substantially less costly than MT in terms of labor and fuel, potentially making NT economically viable for intensive cropping systems in the intermediate precipitation dryland region of northeastern Oregon.
  • Authors:
    • Nagih, A.
    • Lemalade, J. L.
    • Alfandari, L.
    • Plateau, G.
  • Source: Annals of Operations Research
  • Volume: 190
  • Issue: 1
  • Year: 2011
  • Summary: We propose a Mixed-Integer Linear Programming model for a class of multi-period crop rotation optimization problems with demand constraints and incompatibility constraints between cultivation and fallow state on a land plot. This model is applied to a case study on Madagascan farms in the scope of a sustainable development campain against deforestation, where the objective is to better control agricultural space while covering seasonal needs of farmer. We propose an efficient upper bound computation and study the variation of the minimum number of plots and total space needed in function of the unitary surface area of a plot. Numerical results associated with the Madagascan case are reported.
  • Authors:
    • Risede, J.-M.
    • Foster, J.
    • Rhodes, R.
    • Berry, S. D.
    • van Antwerpen, R.
  • Source: International Journal of Pest Management
  • Volume: 57
  • Issue: 4
  • Year: 2011
  • Summary: Plant-parasitic nematodes cause significant yield losses to sugarcane crops in South Africa. The currently available chemicals for nematode control are both expensive and potentially detrimental to the environment. Various alternative crops have been reported to reduce the numbers of plant-parasitic nematodes. Mindful of this, we evaluated 27 cover crops in pot trials to assess their host status to important plant-parasitic nematodes of sugarcane. All of the crops tested in pots hosted significantly lower numbers of Pratylenchus than did sugarcane. Crops such as cowpeas, tomato and grazing vetch were good hosts for Meloidogyne and would not be good choices as part of a sugarcane rotation system in heavily-infested soils. Conversely, crops such as oats, wheat, forage peanuts and marigolds reduced numbers of Meloidogyne. Velvet beans increased the abundance of Helicotylenchus, a beneficial nematode genus. A field trial was also conducted to study the effect of different cover cropping sequences. Our results show that changes in nematode communities occurred within three months of growing these crops and often remained low for the duration (the remaining 15 months) of the crops' growth. Nematodes such as Pratylenchus and Tylenchorhynchus were significantly lowered and remained so for the duration of the trial.
  • Authors:
    • Helgason, B. L.
    • Walley, F. L.
    • Germida, J. J.
  • Source: Applied Soil Ecology
  • Volume: 46
  • Issue: 3
  • Year: 2010
  • Summary: Aggregation is important for soil functioning, providing physical protection of organic matter and microbial inhabitants. Tillage disrupts aggregates, increases wind and water erosion of soils and exposes formerly protected organic matter to decomposition and losses. Microbial biomass and community dynamics in dry-sieved aggregate-size classes from long-term no-till (NT) and conventionally tilled (CT) soils were examined using phospholipid fatty acid analysis (PLFA). Bacterial, fungal, and total biomass were up to 32% greater in NT compared to CT aggregates. Aggregate size also affected microbial biomass, which was highest in the 1-2 mm size class. Arbuscular mycorrhizal fungi (AMF) were particularly affected by tillage disturbance with increases of 40-60% among aggregate-size classes in NT vs. CT, but glomalin related soil protein concentration was not different between tillage treatments or among aggregate-size classes. Bacterial stress biomarkers were higher in CT than NT aggregates but were not significantly correlated with total C, total N or C:N ratio, indicating that the physiological status of bacteria within aggregates was not simply governed by the quantity of available resources. Ordination analysis of PLFA profiles demonstrated a shift in microbial community structure between NT and CT aggregates, correlated with AMF abundance in NT aggregates and increased bacterial stress biomarkers in CT aggregates. Our results demonstrated greater microbial biomass and altered microbial community structure in NT vs. CT aggregates. This work demonstrates that tillage management influences microbial community structure within aggregates and may provide a potential explanation for differences in process rates observed in NT vs. CT soils. Further research into the processes that govern community structure in aggregates from NT and tilled soils is needed to better understand how the interaction of microorganisms with their physical environment affects nutrient turnover and availability.
  • Authors:
    • Kukal, S. S.
    • Christen, E. W.
    • Hira, G. S.
    • Balwinder-Singh
    • Sudhir-Yadav
    • Sharma, R. K.
    • Humphreys, E.
  • Source: Advances in Agronomy
  • Volume: 109
  • Year: 2010
  • Summary: Increasing the productivity of the rice-wheat (RW) system in north-west India is critical for the food security of India. However, yields are stagnating or declining, and the rate of groundwater use is not sustainable. Many improved technologies are under development for RW systems, with multiple objectives including increased production, improved soil fertility, greater input use efficiency, reduced environmental pollution, and higher profitability for farmers. There are large reductions in irrigation amount with many of these technologies compared with conventional practice, such as laser land leveling, alternate wetting and drying (AWD) water management in rice, delayed rice transplanting, shorter duration rice varieties, zero till wheat, raised beds, and replacing rice with other crops. However, the nature of the irrigation water savings has seldom been determined. It is often likely to be due to reduced deep drainage, with little effect on evapotranspiration (ET). Reducing deep drainage has major benefits, including reduced energy consumption to pump groundwater, nutrient loss by leaching, and groundwater pollution. The impacts of alternative technologies on deep drainage (and thus on irrigation water savings) vary greatly depending on site conditions, especially soil permeability, depth to the watertable, and water management. More than 90% of the major RW areas in north-west India are irrigated using groundwater. Here, reducing deep drainage will not "save water" nor reduce the rate of decline of the watertable. In these regions, it is critical that technologies that decrease ET and increase the amount of crop produced per amount of water lost as ET (i.e., crop water productivity, WP ET) are implemented. The best technologies for achieving this are delaying rice transplanting and short duration rice varieties. The potential for replacing rice with other crops with lower ET is less clear.