• Authors:
    • Grace, P. R.
    • Ogle, S.
    • Paustian, K.
    • Antle, J.
    • Basso, B.
    • Aggarwal, P. K.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 146
  • Issue: 1
  • Year: 2012
  • Summary: Soil organic carbon sequestration rates over 20 years based on the Intergovernmental Panel for Climate Change (IPCC) methodology were combined with local economic data to determine the potential for soil C sequestration in wheat-based production systems on the Indo-Gangetic Plain (IGP). The C sequestration potential of rice-wheat systems of India on conversion to no-tillage is estimated to be 44.1 Mt C over 20 years. Implementing no-tillage practices in maize-wheat and cotton-wheat production systems would yield an additional 6.6 Mt C. This offset is equivalent to 9.6% of India's annual greenhouse gas emissions (519 Mt C) from all sectors (excluding land use change and forestry), or less than one percent per annum. The economic analysis was summarized as carbon supply curves expressing the total additional C accumulated over 20 year for a price per tonne of carbon sequestered ranging from zero to USD 200. At a carbon price of USD 25 Mg C -1, 3 Mt C (7% of the soil C sequestration potential) could be sequestered over 20 years through the implementation of no-till cropping practices in rice-wheat systems of the Indian States of the IGP, increasing to 7.3 Mt C (17% of the soil C sequestration potential) at USD 50 Mg C -1. Maximum levels of sequestration could be attained with carbon prices approaching USD 200 Mg C -1 for the States of Bihar and Punjab. At this carbon price, a total of 34.7 Mt C (79% of the estimated C sequestration potential) could be sequestered over 20 years across the rice-wheat region of India, with Uttar Pradesh contributing 13.9 Mt C.
  • Authors:
    • Gruber, S.
    • Pekrun, C.
    • Möhring, J.
    • Claupein, W.
  • Source: Soil & Tillage Research
  • Volume: 121
  • Year: 2012
  • Summary: The study provides information to more reliably estimate the value of conservation tillage in a temperate climate. Tillage effects on yield and weeds were evaluated in field experiments at two sites in SW Germany between 1999 and 2010. Tillage varied at site Ihinger Hof from mouldboard plough (P), chisel plough (CP), rototiller (RTT), varying P and CP (VAR), to no tillage (NT), partially combined with stubble tillage (S). Tillage at site Meiereihof was S/P, S/CP, and NT. Crop rotations included winter wheat (WW, Triticum aestivum), triticale (TR, Triticosecale), oat (OA, Avena sativa), silage maize (SM, Zea mays) and oilseed rape (OSR, Brassica napus) at Ihinger Hof, and winter wheat, spring barley (SB, Hordeum vulgare), silage maize, sugar beets (SBE. Beta vulgaris) and faba bean (FB, Vicia faba) at Meiereihof. At Ihinger Hof, tillage had an effect on yield (P > F = 0.0049), but no effects were found on crop emergence and crop density. Tillage effects on yield were consistent across crops though differences between crops appeared to exist. The yield of S/P, the standard tillage, was 8.5 (WW), 7.7 (TR), 4.7 (OA), 18.3 (SM) and 4.1 (OSR) t DM ha(-1) at Ihinger Hof, with yield under NT always significantly lower than S/P by 7.3% on average for all crops. At Meiereihof, yields ranged from 7.2 to 8.0 (WW), 3.3 to 4.2 (SB), 19.8 to 21.5 (SM) and 3.1 to 3.2 (FB) t DM ha(-1), and 61.3 to 67.6 FM ha(-1) for SBE. Yield was reduced by 4.5% from S/P to S/CP (P > F = 0.0516), and by about 10% from S/P to NT (P > F = 0.0009). Weed density ranged between 0.5 and 44 plants m(-2) at Ihinger Hof and was higher in treatments without stubble tillage and under non-inversion tillage, though significance differed for the different classes of weeds. NT led to weed infestation about 2-20 times higher than S/P. The interaction crop x treatment indicated that factors other than tillage influenced weed infestation. It is unlikely that weed infestation and reduced yield will be problems in temperate climates if soil disturbance through tillage is reduced. Non-inversion tillage can easily replace inversion tillage, and stubble tillage can be added to primary tillage if needed to reduce weeds. Since no specific tillage method was unequivocally superior to another one, any method well suited to specific regional and farm conditions can be adopted successfully.
  • Authors:
    • Avares Filho, J. T.
    • Feltran, C. T. M.
    • Oliveira, J. F. de
    • Almeida, E. de
  • Source: Revista Brasileira de Ciência do Solo
  • Volume: 36
  • Issue: 1
  • Year: 2012
  • Summary: Soil penetration resistance is an important property that affects root growth and elongation and water movement in the soil. Since no-till systems tend to increase organic matter in the soil, the purpose of this study was to evaluate the efficiency with which soil penetration resistance is estimated using a proposed model based on moisture content, density and organic matter content in an Oxisol containing 665, 221 and 114 g kg -1 of clay, silt and sand respectively under annual no-till cropping, located in Londrina, Parana State, Brazil. Penetration resistance was evaluated at random locations continually from May 2008 to February 2011, using an impact penetrometer to obtain a total of 960 replications. For the measurements, soil was sampled at depths of 0 to 20 cm to determine gravimetric moisture (G), bulk density (D) and organic matter content (M). The penetration resistance curve (PR) was adjusted using two non-linear models (PR= a D b G c and PR′= a D b G c M d), where a, b, c and d are coefficients of the adjusted model. It was found that the model that included M was the most efficient for estimating PR, explaining 91% of PR variability, compared to 82% of the other model.
  • Authors:
    • Barbera, V.
    • Poma, I.
    • Gristina, L.
    • Novara, A.
    • Egli, M.
  • Source: Land Degradation & Development
  • Volume: 23
  • Issue: 1
  • Year: 2012
  • Summary: A calcareous and clayey xeric Chromic Haploxerept of a long-term experimental site in Sicily (Italy) was sampled (0-15 cm depth) under different land use management and cropping systems (CSs) to study their effect on soil aggregate stability and organic carbon (SOC). The experimental site had three tillage managements (no till [NT], dual-layer [DL] and conventional tillage [CT]) and two CSs (durum wheat monocropping [W] and durum wheat/faba bean rotation [WB]). The annually sequestered SOC with W was 2.75-times higher than with WB. SOC concentrations were also higher. Both NT and CT management systems were the most effective in SOC sequestration whereas with DL system no C was sequestered. The differences in SOC concentrations between NT and CT were surprisingly small. Cumulative C input of all cropping and tillage systems and the annually sequestered SOC indicated that a steady state occurred at a sequestration rate of 7.4 Mg C ha -1 y -1. Independent of the CSs, most of the SOC was stored in the silt and clay fraction. This fraction had a high N content which is typical for organic matter interacting with minerals. Macroaggregates (>250 m) and large microaggregates (75-250 m) were influenced by the treatments whereas the finest fractions were not. DL reduced the SOC in macroaggregates while NT and CT gave rise to higher SOC contents. In Mediterranean areas with Vertisols, agricultural strategies aimed at increasing the SOC contents should probably consider enhancing the proportion of coarser soil fractions so that, in the short-term, organic C can be accumulated.
  • Authors:
    • Oztekin, M. E.
  • Source: Journal of Food, Agriculture and Environment
  • Volume: 10
  • Issue: 2 part 3
  • Year: 2012
  • Summary: Land use is an important global issue in terms of preserving the soils, agricultural crop production and farmers' economy as well as the other usage purposes. There are many useful approaches and tools for efficient determination of the land use types. In this study, distribution of different field crops and citrus orchards were monitored and determined for land use types (LUTs) using the low cost ASTER satellite images and GIS in Akarsu Irrigation District of Lower Seyhan Plain (9495 ha) in southern Turkey. Prior to parceling in the field, study area maps of 1:5000 scale were digitized by using ArcGIS software. The enhanced satellite images were overlaid onto the digitized parcel map for ground observations. The images were printed and checked for all crops of the fields. Commonly grown different field crops and orchards were mapped during the field work. A database for this research was established after an intensive field work. The crop types and their coordinates were determined and recorded during the field works. Five LUTs were identified in the study area, and corn and citrus were the most planted LUTs. Furthermore, suitability of soil series for LUTs was investigated; Canakci and Mursel soil series in the study area were found to be highly suitable for all LUTs. It was concluded that cost effective ASTER images could be potentially used for the determination of different crops and orchards which have different reflection values. However, the images must be obtained during the appropriate time period.
  • Authors:
    • Misra, R. K.
    • Padhi, J.
    • Payero, J. O.
  • Source: Field Crops Research
  • Volume: 126
  • Year: 2012
  • Summary: Plant growth and soil water deficit can vary spatially and temporally in crop fields due to variation in soil properties and/or irrigation and crop management factors. We conducted field experiments with cotton (Gossypium hirsutum L.) over two seasons during 2007-2009 to test if infrared thermography can distinguish systematic variation in deficit irrigation applied to various parts of the field over time. Soil water content was measured with a neutron probe and thermal images of crop plants were taken with a thermal infrared camera. Leaf water potential and stomatal conductance were also measured on selected occasions. All measurements were made at fixed locations within three replicate plots of an irrigation experiment consisting of four soil-water deficit treatments. Canopy temperature related as well with soil water within the root zone of cotton as the stomatal conductance index derived from canopy temperature, but it neglected the effect of local and seasonal variation in environmental conditions. Similarities in the pattern of spatial variation in canopy temperature and soil water over the experimental field indicates that thermography can be used with stomatal conductance index to assess soil water deficit in cotton fields for scheduling of irrigation and to apply water in areas within the field where it is most needed to reduce water deficit stress to the crop. Further confidence with application of infrared thermography can be gained by testing our measurement approach and analysis with irrigation scheduling of other crops. (C) 2011 Elsevier B.V. All rights reserved.
  • Authors:
    • Conesa, M. R.
    • Domingo, R.
    • Perez-Pastor, A.
    • Pagan, E.
    • Caro, M.
  • Source: Agricultural Water Management
  • Volume: 111
  • Year: 2012
  • Summary: A two year experiment on Fortune mandarin trees (Clementina * mandarina Dancy ( Citrus clementina Hort. Ex. Tanaka * Citrus reticulata Blanco)) grafted onto Cleopatra mandarin ( Citrus reshni Hort. ex. Tanaka) rootstock was carried out with the aim of studying the suitability of midday stem water potential (psi stem) and trunk diameter reference baselines for irrigation scheduling. Plants were drip-irrigated with saline water during the second year (EC 25°C ~ 4 dS m -1). Measurements of psi stem, trunk daily growth rate (TGR) and maximum daily trunk shrinkage (MDS) were related with meteorological variables. Among them, MDS presented the best behavior. The mean temperature during the period 10.00-15.00 h solar time ( Tmd) was the environmental variable that best correlated with MDS, although there were no differences with other T-related variables (daily mean and daily maximum values). MDS data from stage III did not correlate with meteorological variables and fit-linear regressions became better with data from stages I and II (March-October), this being the period which covers 80% of total crop water requirements. Despite the different conditions that the trees were submitted to during the experimental period, i.e. irrigation water with different salinity and crop load, inter-annual differences were not observed in the reference baselines obtained.
  • Authors:
    • Espadaler, X.
    • Ribes, J.
    • Ribes, E.
    • Piñol, J.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 158
  • Year: 2012
  • Summary: The Heteroptera assemblage of a citrus grove and how it was affected by ant-exclusion was examined during transformation from conventional to organic agriculture. The results showed that the Heteroptera assemblage changed dramatically over the eight years of the study: at first, it mainly consisted of herbivorous lygaeids and predatory anthocorids but became dominated by predatory mirids in 2008-2009. The predator/herbivore ratio increased steadily over the eight years of the study. Ants can form mutualistic relationships with heteropteran pests. However, exclusion of ants from canopies did not affect the Heteroptera assemblage at the beginning of the study, but had a profound effect later on. In particular, ant-exclusion increased the abundance of most predatory Heteroptera, except for the myrmecomorphic mirid Pilophorus perplexus, which was approximately five times more abundant in control than in ant-excluded trees; the analyses showed that the only mimicked ant species was Lasius grandis.
  • Authors:
    • Amanullah, M. M.
    • Rajendran, K.
    • Vaiyapuri, K.
  • Source: Madras Agricultural Journal
  • Volume: 99
  • Issue: 1/3
  • Year: 2012
  • Summary: Field experiments were conducted during winter 2006-07 and 2007-08 at Tamil Nadu Agricultural University, Coimbatore to find out the effect of drip irrigation on the productivity and water use efficiency in Bt-cotton ( Gossypium hirsutum L.). The experiments were laid out in a randomized block design replicated four times. The treatments consisted of drip irrigation at 0.40, 0.60, 0.80 and 1.0 ET c (Crop evapotranspiration) compared with farmers' method (flood irrigation method). The results revealed that application of water to Bt-cotton through drip resulted in better growth, higher seed cotton yield and better quality of lint than the surface method. The yield advantage due to different irrigation schedules through drip based on ETc was 26.2 and 12.8% over surface method during 2006-07 and 2007-08, respectively. Among the irrigation through drip, irrigation at 0.80 ET c recorded better growth and gave higher seed cotton yield than irrigation at 0.60 ET c. The water use efficiency with drip irrigated Bt-cotton was 44.4% higher than the flood method of irrigation.
  • Authors:
    • Fuller, M. P.
    • Al-swedi, F.
    • Al-Issawi, M.
    • Rihan, H. Z.
  • Source: Scientia Horticulturae
  • Volume: 141
  • Year: 2012
  • Summary: The effects of using PPM (plant preservative mixture) (Apollo Scientific Limited, UK) on the growth of cauliflower microshoots were determined. A negative correlation was found between the concentration of PPM in the liquid medium and the number of microshoots developed: the greater the concentration, the lower microshoot number. The stage of the culture process most suitable for the introduction of PPM was also investigated. While the use of PPM with blending medium (S23: 4.4 g L-1 MS + 30 g L-1 sucrose) did not control the later contamination in the culture medium, the use of 0.5 mL L-1 of PPM with culture medium (S23 supplemented with 2 mg L-1 (9.29 mu M) of kinetin + 1 mg L-1 (4.9 mu M) of IBA (indole butyric acid)) was found to be effective in controlling contamination and keeping the growth capacity of microshoots. Cauliflower microshoots were encapsulated in sodium alginate as artificial seeds. Artificial seeds conversion rate and viability assessed as fresh weights of plantlets produced were evaluated in different culture substrates (compost, perlite, sand and vermiculite). The effects of PPM concentrations used with S23 irrigation solutions were also evaluated. This study showed the effectiveness of using PPM in controlling the contamination and the necessity for determination the correct concentration and the correct stage for the use of this material in order to obtain optimum results. (C) 2012 Elsevier B.V. All rights reserved.