• Authors:
    • Soffianian, A.
    • Khodakarami, L.
  • Source: Journal of Science and Technology of Agriculture and Natural Resources,Water and Soil Science
  • Volume: 15
  • Issue: 59(B)
  • Year: 2012
  • Summary: Precision farming aims to optimize field-level management by providing information on production rate, crop needs, nutrients, pest/disease control, environmental contamination, timing of field practices, soil organic matter and irrigation. Remote sensing and GIS have made huge impacts on agricultural industry by monitoring and managing agricultural lands. Using vegetation indices have been widely used for quantifying net annual production on different scales. The aim of this study was to find a rapid method with acceptable precision for the identification and classification of agricultural lands under cultivation (wheat and barley, alfalfa and potatoes). We used multi-temporal AWiFS data and applied Boolean logic and unsupervised classification. Results indicated that Boolean logic approach had a higher accuracy and precision in comparison to unsupervised classification, although it is more complicated and time consuming.
  • Authors:
    • Vanham, D.
    • Laghari, A. N.
    • Rauch, W.
  • Source: Hydrology and Earth System Sciences
  • Volume: 16
  • Issue: 4
  • Year: 2012
  • Summary: The Indus basin is one of the regions in the world that is faced with major challenges for its water sector, due to population growth, rapid urbanisation and industrialisation, environmental degradation, unregulated utilization of the resources, inefficient water use and poverty, all aggravated by climate change. The Indus Basin is shared by 4 countries - Pakistan, India, Afghanistan and China. With a current population of 237 million people which is projected to increase to 319 million in 2025 and 383 million in 2050, already today water resources are abstracted almost entirely (more than 95% for irrigation). Climate change will result in increased water availability in the short term. However in the long term water availability will decrease. Some current aspects in the basin need to be re-evaluated. During the past decades water abstractions - and especially groundwater extractions - have augmented continuously to support a rice-wheat system where rice is grown during the kharif (wet, summer) season (as well as sugar cane, cotton, maize and other crops) and wheat during the rabi (dry, winter) season. However, the sustainability of this system in its current form is questionable. Additional water for domestic and industrial purposes is required for the future and should be made available by a reduction in irrigation requirements. This paper gives a comprehensive listing and description of available options for current and future sustainable water resources management (WRM) within the basin. Sustainable WRM practices include both water supply management and water demand management options. Water supply management options include: (1) reservoir management as the basin is characterised by a strong seasonal behaviour in water availability (monsoon and meltwater) and water demands; (2) water quality conservation and investment in wastewater infrastructure; (3) the use of alternative water resources like the recycling of wastewater and desalination; (4) land use planning and soil conservation as well as flood management, with a focus on the reduction of erosion and resulting sedimentation as well as the restoration of ecosystem services like wetlands and natural floodplains. Water demand management options include: (1) the management of conjunctive use of surface and groundwater; as well as (2) the rehabilitation and modernization of existing infrastructure. Other demand management options are: (3) the increase of water productivity for agriculture; (4) crop planning and diversification including the critical assessment of agricultural export, especially (basmati) rice; (5) economic instruments and (6) changing food demand patterns and limiting post-harvest losses.
  • Authors:
    • Payton, P.
    • Young, A. W.
    • Mahan, J. R.
  • Source: Irrigation Science
  • Volume: 30
  • Issue: 2
  • Year: 2012
  • Summary: Water available for agricultural use is declining worldwide as a result of both declining water resources and increasing application costs. Managing crop irrigation under conditions where the water need cannot be fully met represents the future of irrigation in many areas. On the southern high plains of Texas there is interest among producers to reduce the amount of water applied to cotton. In this study, a producer's efforts to reduce water application to a cotton crop were assessed in terms of a comparison between evapotranspiration, rainfall, and irrigation that is widely used in the region. The producer was able to reduce water application to meet intended reductions relative to the evapotranspiration estimates but, depending on the method used for calculating the crop water need, he tended to over water the crop in two out of three intended deficit irrigation regimes. Analysis of continuously monitored canopy temperatures provided verification of over-irrigation. Continuously monitored canopy temperature is proposed as a useful adjunct to evapotranspiration approaches to deficit irrigation management.
  • Authors:
    • Li, C. J.
    • Tian, C. Y.
    • Mai, W. X.
  • Source: Australian Journal of Crop Science
  • Volume: 6
  • Issue: 5
  • Year: 2012
  • Summary: Long-term use of drip irrigation technology may lead to root degradation and affect shoot growth and yield. A field experiment was conducted to investigate above- and belowground growth responses to drip irrigation under mulch film (DI) in comparison to flood irrigation under mulch film (FI) in cotton. The monolith method was used to harvest roots at seven timepoints in the growth periods, and the root length, and shoot and root dry weight were measured. The total root length per plant in the 0-10 cm soil layer was higher under DI, whereas in the 30-60 cm soil layer roots were longer under FI. From 65 to 96 days after sowing (DAS), the rate of increase in root length was lower under DI than FI. Total root length decreased after 125 DAS under DI, and was mainly centered in the 0-40 cm soil layer and at distances of 30-70 cm from drip-lines. The shoot:root ratio at 125 DAS was higher under DI than FI, but at 160 DAS the shoot:root ratio abruptly declined under DI. The decline in root length under DI during advanced growth stages may be attributable to the higher root density in shallow soil layers and the increase in the shoot:root ratio. These results suggest that, it are important to increase yield of cotton plants under DI early development of a deep root system and initial control of shoot growth by regulation of water and fertilizer supply.
  • Authors:
    • Thomashow, L. S.
    • Paulitz, T. C.
    • Kwak, Y. S.
    • Bonsall, R. F.
    • Parejko, J. A.
    • Mavrodi, O. V.
    • Mavrodi, D. V.
    • Weller, D. M.
  • Source: Applied and Environmental Microbiology
  • Volume: 78
  • Issue: 3
  • Year: 2012
  • Summary: Natural antibiotics are thought to function in the defense, fitness, competitiveness, biocontrol activity, communication, and gene regulation of microorganisms. However, the scale and quantitative aspects of antibiotic production in natural settings are poorly understood. We addressed these fundamental questions by assessing the geographic distribution of indigenous phenazine-producing (Phz +) Pseudomonas spp. and the accumulation of the broad-spectrum antibiotic phenazine-1-carboxylic acid (PCA) in the rhizosphere of wheat grown in the low-precipitation zone (
  • Authors:
    • Vadaria, K. N.
    • Nariya, J. N.
    • Solanki, R. M.
    • Modhvadia, J. M.
    • Rathod, A. D.
  • Source: Journal of Cotton Research and Development
  • Volume: 26
  • Issue: 1
  • Year: 2012
  • Summary: A field experiment was conducted at Junagadh Agricultural University, Junagadh during kharif 2006-2007 and 2007-2008 to evaluate the effect of different levels of nitrogen, phosphorus and potassium on growth, yield and quality of hybrid Bt cotton. The results indicated that significantly higher seed cotton and stalk yields, growth and yield attributes, quality parameters as well as total uptake of N, P, K were obtained with the application of N @ 240 kg/ha, P 2O 5 @ 50 kg/ha and K 2O @ 120 kg/ha. The seed cotton yield of Bt cotton increased to the tune of 20.51, 6.90 and 13.27 per cent with the application of 240 kg N/ha, 50 kg P 2O 2/ha and 120 kg K 2O/ha, respectively as compared to control.
  • Authors:
    • Allen, B. L.
  • Source: Journal of Soil and Water Conservation
  • Volume: 67
  • Issue: 1
  • Year: 2012
  • Summary: Dryland corn (Zea mays L.) production in the northern Great Plains is limited by risk of crop failure due to drought conditions. Altering the row configuration and seeding rate have reduced the risk of yield loss elsewhere, but those areas typically receive greater precipitation than the annual average 300 to 350 mm (11.8 to 13.8 in) of the northern Great Plains. A study in 2007 and 2008 determined the impact of seeding rate and row configuration on dryland corn yield, yield quality and components, and precipitation use efficiency (PUE). Four sites in northeastern Montana were planted to corn (same variety) at four target rates (25,000, 37,500, 50,000 and 62,500 seeds ha−1 [10,000, 15,000, 20,000, and 25,000 seeds ac−1]) in conventional 0.61 m (24 in) spaced rows or in a skip-row configuration, with every third row skipped. Altering the row configuration had no impact on grain yield, harvest index, or grain PUE, but biomass yield and PUE were 12% and 15% greater for the skip-row configuration, compared to conventionally spaced corn. Interactions between row configuration and seeding rate were not significant (p < 0.05). Compared to row configuration, seeding rate had a greater impact on yield and showed an inverse and linear relationship, where biomass, grain yield, harvest index, and PUE for grain and biomass were 19%, 229%, 200%, 222%, and 22% greater for the lowest seeding rate, when compared to the highest. Overall results suggest that for areas with low rainfall, skip-row spacing provides a modest increase in biomass yield and that adjusting seeding rates to 27,000 seeds ha−1 (10,900 seeds ac−1) or lower will likely increase dryland corn biomass and especially grain yield, though caution is warranted in extending broadly the results of this limited dataset considering the variable nature of rainfall in semiarid environments.
  • Authors:
    • Calderón, F. J.
    • Vigil, M. F.
    • Nielsen, D. C.
    • Benjamin, J. G.
    • Poss, D. J.
  • Source: Field Crops Research
  • Volume: 125
  • Year: 2012
  • Summary: Grasspea (GP) (Lathyrus sativus) is a drought-tolerant legume that can be grown for forage and grain. It has potential value to be used as a nitrogen-fixing crop in dryland rotations with non-legume grain crops. However, the agronomy of GP for the Central Great Plains region have not been investigated. The objective of this research was to compare the grain and biomass yield, as well as N accumulation of GP relative to field pea (FP) in two planting configurations. We carried out a 3-year field experiment to compare dryland GP with Admiral yellow field pea (Pisum sativum) in two configurations: (1) a wide row spacing with lower population (WL) with 76-cm rows with 75 kg seeds planted per ha, and (2) a narrower row spacing with a higher population (NH) with 19-cm rows with 136 kg seeds planted per ha. We measured the biomass, grain yield. N content, and soil water use. Our results show that the NH treatment out-yielded the WL treatment in both pea species. The GP had higher yield then FP on the lowest yielding year, while FP yielded better when overall yields were higher. Biomass production was also higher for the NH configuration, and GP was a higher biomass producer than FP over the 3-year study. The GP had higher N concentration in shoots and seed compared to FP, indicating higher N-fixing capacity. The FP matured faster than GP, and had marginally higher grain water use efficiency than GP. Our results show that GP is a viable alternative legume for the Central Great Plains, with comparable yields in low precipitation years. However, the longer growing season required by GP to mature has water use implications in years with reduced water availability in mid to late summer.
  • Authors:
    • Chen, C. C.
    • Neill, K.
    • Burgess, M.
    • Bekkerman, A.
  • Source: Agronomy Journal
  • Volume: 104
  • Issue: 2
  • Year: 2012
  • Summary: The rotational effects and economic potential of incorporating fall-seeded pea ( Pisum sativum L.) and lentil ( Lens culinaris Medik) into conventional wheat ( Triticum aestivum L.)-based cropping systems in the northern Great Plains are not well understood. Two 2-yr crop rotation experiments were conducted in central Montana to investigate how winter pea hay, lentil green manure, and lentil grain affects subsequent winter wheat yield and protein content, as well as the economic returns of the systems under no-till conditions. In Exp. 1, a winter pea hay-winter wheat (WP-WW) rotation was compared to fallow-winter wheat (FW-WW) and spring wheat-winter wheat (SW-WW) rotations. In Exp. 2, a winter lentil for green manure-winter wheat [WL(m)-WW] rotation was compared to a winter lentil grain-winter wheat [WL(g)-WW] rotation. Four different rates of N were applied to the winter and spring wheat. Winter wheat yield in the WP-WW rotation was 2193 kg ha -1, which was equivalent to the yield in the FW-WW rotation (2136 kg ha -1), and much greater than the SW-WW rotation (1155 kg ha -1). Averaged over all N rates, the WP-WW, FW-WW, and SW-WW systems had $196, $116, and $41 ha -1 net return, respectively. In Exp. 2, the WL(m)-WW rotation produced greater grain yield and protein content at lower N input levels, indicating a greater N benefit. Nevertheless, the WL(g)-WW system generated $213 ha -1 net profit while the WL(m)-WW system produced $92 ha -1. Therefore, the winter pea cover crop, used for livestock feed, improves the system profitability.
  • Authors:
    • Hansen, N. C.
    • Allen, B. L.
    • Baumhardt, R. L.
    • Lyon, D. J.
  • Source: Field Crops Research
  • Volume: 132
  • Year: 2012
  • Summary: The Great Plains region of the United States is an area of widespread dryland crop production, with wheat being the dominant crop. Precipitation in the region ranges from 300 to 500 mm annually, with the majority of precipitation falling during hot summer months. The prevailing cropping system is a two-year rotation of wheat and summer fallow. The adoption of no-till practices has resulted in greater precipitation storage and use efficiency, which has led to greater cropping intensity, higher productivity, more diverse crop rotations, and improvements in soil properties. In Colorado, for example, a no-till rotation of winter wheat-maize-fallow increased total annualized grain yield by 75% compared to winter wheat-summer fallow. Soil erosion was reduced to just 25% of that from a conventional tillage wheat-summer fallow system. The primary challenge with reducing fallow frequency is the increase in yield variability and risk of crop failure. Improved approaches for choosing crop or fallow are being developed based on soil water content and forecasted weather. Development of alternative crops, crop rotations, and integrated livestock systems that are sustainable from both economic and ecological perspectives is an on-going effort. Other research is addressing adaptation of cropping practices to climate change and the potential for dryland biomass crop production for the developing biofuel industry.