• Authors:
    • Chen, C.
    • Yang, M.
    • Zhu, L.
  • Source: Journal of Agricultural Science
  • Volume: 4
  • Issue: 9
  • Year: 2012
  • Summary: Carbon sequestration in cropland soils which could be achieved through improved management practices (IPMs) represents an important opportunity to offset a portion of greenhouse gas emissions. North China is the main wheat and maize production region where many IMPs have been widely used during the last several decades, but the effect size and duration of IMPs on soil organic carbon (SOC) sequestration in wheat-maize double cropping system in this region is scarcely studied. In this study, a meta-analysis was conducted to compare the effect size and duration of four IMPs on SOC sequestration in wheat-maize double cropping system in north China. A total of 29 long-term experiments, consisting of 119 paired treatments were compiled in this analysis. The results indicated that the four IMPs of organic manure application (OM), organic manure combined with chemical fertilizer application (MF), straw return (SR) and reduced or no tillage (RNT) all had significant effects on SOC sequestration in the study area. On average, the IMPs of OM, MF, SR and RNT enhanced SOC density by 260, 328, 278 and 134 kg ha -1 yr -1, respectively. The effect duration of OM, MF, SR and RNT on SOC sequestration were about 48, 26, 22 and 18 years, respectively. Accumulation enhancements of SOC for OM, MF, SR and RNT over SOC sequestration period were about 34.7%, 36.1%, 22.0% and 12.7%, respectively. OM and MF could be the appropriate practices on SOC sequestration in wheat-maize double cropping system in the research area.
  • Authors:
    • Daughtry, C. S. T.
    • Vigil, M.
    • Evans, R.
    • Aguilar, J.
  • Source: Agronomy Journal
  • Volume: 104
  • Issue: 2
  • Year: 2012
  • Summary: Crop residue is important for erosion control, soil water storage, filling gaps in various agroecosystem-based modeling, and sink for atmospheric carbon. The use of remote sensing technology provides a fast, objective, and efficient tool for measuring and managing this resource. The challenge is to distinguish the crop residue from the soil and effectively estimate the residue cover across a variety of landscapes. The objective of this study is to assess a select Landsat Thematic Mapper (TM) and hyperspectral-based indices in estimating crop residue cover and amount for both standing and laid flat, and between two winter wheat ( Triticum aestivum L.) harvest managements (i.e., stripper-header and conventional header) and fallow following proso-millet ( Panicum miliaceum L.) plots. The primary plots were located in Colorado with additional plots in eastern Montana, Oregon, and Washington states. Data collected include hyperspectral scans, crop residue amount (by weight) and residue cover (by photo-grid). Mean analyses, correlation tests, and spectral signature comparison show that the relative position of the crop residues affected the values of some remote sensing indices more than harvest management. Geographical location did not seem to influence the results. There was not enough evidence to support the use of these indices to accurately estimate the amount of residue. Hyperspectral data may deliver better estimates, but in its absence, the use of two or more of these datasets might improve the estimation of residue cover. This information will be useful in guiding analysis of remotely sensed data and in planning data acquisition programs for crop residue, which are essentially nonexistent at present.
  • Authors:
    • Mourik, J. M. van
    • Arocena, J. M.
    • Cano, A. F.
  • Source: CANADIAN JOURNAL OF SOIL SCIENCE
  • Volume: 92
  • Issue: 1
  • Year: 2012
  • Summary: Accelerated conversion of degraded landscapes in mining areas to productive ecosystems requires stimulation of soil formation. The evolution in microstructure and changes to chemical properties in metal mine wastes 5 yr after amendments with pig manure, sewage sludge and marble waste is reported. Mine wastes had <1% organic carbon, <0.05% total nitrogen, pH ~2.0, electrical conductivity up to 20 dS m -1 and high concentrations of metals such as 22000 mg zinc kg -1 and 7000 mg lead kg -1. After 5 yr, one time amendment increased total carbon (g kg -1) from 1.4 (control) to 5.6 (marble waste +sewage sludge) to 8.3 (marble waste+pig manure). Soil pH in amended plots was 6.0 compared with 2.8 in controls. Micromorphological characteristics clearly showed that primary and secondary calcite serve as active sorption sites for organic matter. These calcitic zones were areas conducive to root growth. Soil microstructure in amended mine wastes was dominantly granular, resulting from activities of soil organisms such as fungi and enchytraeds. Results suggest organic matter can be effectively enriched in mine waste deposits through simultaneous additions of pig manure, sewage sludge and calcite. Soil amendments promoting formation of granular structure can accelerate establishment of productive landscapes in degraded mine sites.
  • Authors:
    • Stout, J.
    • Xin, Z.
    • Velten, J.
    • Xu, W.
    • Chen, J.
  • Source: Journal of Soil and Water Conservation
  • Volume: 67
  • Issue: 5
  • Year: 2012
  • Summary: Drought and high temperature are two major environmental factors that severely limit plant productivity in the United States and worldwide, often causing extensive economic loss to agriculture. As global climate change progresses, agricultural production worldwide faces serious threats from frequent extreme weather conditions. Integrated approaches that improve the efficiency of agricultural water use and development of plant varieties that can alleviate the negative impacts of environmental stresses to maintain yield stability are essential to sustain and increase agriculture production. Maize (Zea mays L.) is a major crop in the United States and worldwide. Its production and yield stability are greatly affected by drought and high temperature stresses. Improving drought and heat tolerance in maize has become one of the top priorities for maize breeding programs in both private and public sectors. Identification of maize germplasm with superior drought and/or heat tolerance is essential and prerequisite for such propose. In this report, we evaluated a selection of maize inbred lines for drought and heat stress tolerance under field conditions in 2009 and 2010 and identified several inbred lines that showed high tolerance to drought. Tolerant inbred lines (Tx205, C2A554-4, and B76) were able to maintain relatively high leaf relative water content when subjected to drought stress, while sensitive lines (B73 and C273A) showed a rapid reduction in leaf relative water content at very early stage of drought.The tolerant lines also showed significantly greater ability to maintain vegetative growth and alleviate damage to reproductive tissues under drought conditions compared to the sensitive lines. Maize inbred lines and hybrids were also evaluated, for tolerance to high temperature under well-watered conditions through field observations following the occurrence of major heat events. Maize inbred lines of distinct heat tolerance phenotype were identified. Furthermore, genetic and phenotypic analysis showed that maize hybrids made from inbred lines with superior heat tolerance inherited an enhanced tolerance to elevated temperatures.The tolerant germplasm accessions, like those identified in this study, are essential materials for breeding drought- and/or heat-tolerant maize hybrids. Study for the potential use of such materials to produce maize hybrids that are able to alleviate the negative impacts of drought and heat stress on the growth and development of maize plants is underway.
  • Authors:
    • Borselli, L.
    • Ferrari, G.
    • Billi, P.
    • Ciampalini, R.
    • Follain, S.
  • Source: Agriculture Ecosystems & Enviroment
  • Volume: 146
  • Issue: 1
  • Year: 2012
  • Summary: The aim of the research presented here was to analyse soil erosion in response to changes in agricultural and soil conservation practices throughout history. The Aksum area (Tigray, northern Ethiopia) presents favourable conditions for the development of a long-term approach for assessing soil conservation techniques that have been applied for centuries (i.e., since the Aksumite kingdom, 400 BC to 800 AD). These techniques have been maintained until the present day, and parts of the terraced systems of the area are still in use. During the 1970s, social and political events led to a remarkable change in land use patterns, and large arable areas were converted into grazing land, resulting in a significant increase in soil loss. The rates of soil erosion were evaluated based on analyses of the deep scratches (plough marks) left on stones in the soil by the maresha, the ard plough pulled by oxen used in agricultural practices of the area, and the patinas, varnishes and weathering rinds exposed by soil loss after the abandonment of the fields. The study results show average rates of soil erosion of 2.8 t ha -1 y -1 and 65.8 t ha -1 y -1 for the soil conservation conditions under traditional agriculture (long-term observations) and accelerated erosion after abandonment (short-term observations), respectively. A comparison using recently calibrated erosion evaluation techniques conducted to support the field measurements revealed a close correlation between the calculated and recorded data.
  • Authors:
    • Nariya, J. N.
    • Khanpara, M. D.
    • Butani, A. M.
    • Kapadiya, H. J.
  • Source: Journal of Cotton Research and Development
  • Volume: 26
  • Issue: 1
  • Year: 2012
  • Summary: FLD's with participation of farmers' in production technology was conducted in seven districts of Saurashtra. Thirty four, 50 and 50 farmers were selected for FLD's during 2005-2006, 2006-2007 and 2007-2008, respectively. Varietal, fertilizer, irrigation and inter cropping components were conducted in FLD's. Results indicated that 8.83 per cent average seed cotton yield was increased over improved varieties. In fertilizer components, there was no effect of DAP on seed cotton yield, however without DAP clearly showed the average saving of Rs. 1743/ha. The reduction of 3.98 per cent seed cotton yield was recorded in alternate furrow irrigation, but the cost of cultivation of Rs. 3370/ha was decreased as compared to local practices. In inter cropping practices, 10.13 per cent seed cotton yield was increased over local practices. Overall results clearly indicated that an additional net return of Rs. 5130, 3831, 1002 and 859 was recorded in improved varities, intercropping, irrigation and fertilizer components, respectively. Looking to the over all of three years average results with four improved production technologies of FLD's, recorded a increase of 4.6 per cent in seed cotton yield, reduced by 3.12 per cent in cost of cultivation and increased net return of 9.95 per cent with a net profit of 3371 Rs/ha during three years of cropping season.
  • Authors:
    • Rajput, T. B. S.
    • Sarangi, A.
    • Singh, M.
    • Abedinpour, M.
    • Pathak, H.
    • Ahmad, T.
  • Source: Agricultural Water Management
  • Volume: 110
  • Year: 2012
  • Summary: Crop growth simulation models of varying complexity have been developed for predicting the effects of soil, water and nutrients on grain and biomass yields and water productivity of different crops. These models are calibrated and validated for a given region using the data generated from field experiments. In this study, a water-driven crop model AquaCrop, developed by FAO was calibrated and validated for maize crop under varying irrigation and nitrogen regimes. The experiment was conducted at the research farm of the Water Technology Centre, IARI, New Delhi during kharif 2009 and 2010. Calibration was done using the data of 2009 and validation with the data of 2010. Irrigation applications comprised rainfed, i.e. no irrigation (W 1) irrigation at 50% of field capacity (FC) (W 2) at 75% FC (W 3) and full irrigation (W 4). Nitrogen application levels were no nitrogen (N 1), 75 kg ha -1 (N 2) and 150 kg ha -1 (N 3). Model efficiency ( E), coefficient of determination ( R2), Root Mean Square error (RMSE) and Mean Absolute Error (MAE) were used to test the model performance. The model was calibrated for simulating maize grain and biomass yield for all treatment levels with the prediction error statistics 0.95
  • Authors:
    • Maibody, S. A. M. M.
    • Arzani, A.
    • Golabadi, M.
  • Source: Cereal Research Communications
  • Volume: 40
  • Issue: 2
  • Year: 2012
  • Summary: Grain protein content (GPC) in durum wheat is a crucial determinant of pasta quality and as such is an important economic factor. This study was carried out to determine the microsatellite markers (SSRs) as associated with GPC in durum wheat grown under normal and moisture stress conditions. F 3 and F 4 population derived from 151 F 2 individuals developed from a cross between Oste-Gata (drought tolerant) and Massara-1 (drought susceptible) genotypes, were used. The population was evaluated under four environmental conditions (two irrigation regimes in two growing seasons). The results of single marker regression analysis (SMA) revealed that 2, 4 and 10 markers to be associated with GPC, test weight (TW) and 1000 grain weight (TGW), respectively. These markers explained between 4.4 and 21.8% of the phenotypic variation in either environmental condition. The most significant marker observed for GPC was located on 5B chromosome near Xgwm408 under normal conditions and the other marker was observed on 1A, explaining about 15% of phenotypic variance. However, it was not recognized any marker related to GPC under drought stress conditions. Xgwm408 marker was coincident with the markers identified for TW, TGW and components of grain yield under drought stress conditions. In spite of 5B, the other chromosomes such as 2B and 3B were related to quantitative traits like TW and TGW. Composite interval mapping (CIM) identified 4 and 5 putative minor and major QTL for TW and TGW, respectively. Two QTL near Xbarc101 and Xbarc124 markers on 3B and 2B chromosome, explained up to 45.2 and 6% of phenotypic variations of TGW and TW, respectively.
  • Authors:
    • Kutu, F. R.
  • Source: African Journal of Agricultural Research
  • Volume: 7
  • Issue: 26
  • Year: 2012
  • Summary: Conservation agriculture experiment was conducted under irrigated and dryland conditions during 2007/2008-summer cropping season to determine a suitable soil-crop management practice for increase maize yield. The study consisted of tillage practices (conventional, minimum and zero), cropping systems (sole and intercrop plots) and fertilizer regimes (unfertilized control, low, adjusted low and optimum) as treatments. Minimum and zero tillage practices constituted the conservation agriculture tillage practices while supplementation of low fertilizer rate with seed inoculation using growth enhancing microbial inoculant constituted the adjusted low fertilizer rate. Fertilizer application gave a significant (P
  • Authors:
    • Thomashow, L. S.
    • Parejko, J. A.
    • Mavrodi, D. V.
    • Mavrodi, O. V.
    • Weller, D. M.
  • Source: Applied and Environmental Microbiology
  • Volume: 78
  • Issue: 9
  • Year: 2012
  • Summary: This work determined the impact of irrigation on the seasonal dynamics of populations of Pseudomonas spp. producing the antibiotics phenazine-1-carboxylic acid (Phz +) and 2,4-diacetylphloroglucinol (Phl +) in the rhizosphere of wheat grown in the low-precipitation zone (150 to 300 mm annually) of the Columbia Plateau of the Inland Pacific Northwest. Population sizes and plant colonization frequencies of Phz + and Phl +Pseudomonas spp. were determined in winter and spring wheat collected during the growing seasons from 2008 to 2009 from selected commercial dryland and irrigated fields in central Washington State. Only Phz + bacteria were detected on dryland winter wheat, with populations ranging from 4.8 to 6.3 log CFU g -1 of root and rhizosphere colonization frequencies of 67 to 100%. The ranges of population densities of Phl + and Phz +Pseudomonas spp. recovered from wheat grown under irrigation were similar, but 58 to 100% of root systems were colonized by Phl + bacteria whereas only 8 to 50% of plants harbored Phz + bacteria. In addition, Phz +Pseudomonas spp. were abundant in the rhizosphere of native plant species growing in nonirrigated areas adjacent to the sampled dryland wheat fields. This is the first report that documents the impact of irrigation on indigenous populations of two closely related groups of antibiotic-producing pseudomonads that coinhabit the rhizosphere of an economically important cereal crop. These results demonstrate how crop management practices can influence indigenous populations of antibiotic-producing pseudomonads with the capacity to suppress soilborne diseases of wheat.