• Authors:
    • Booker, J.
    • Lascano, R.
    • Acosta-Martinez, V.
    • Calderon, F.
    • Zobeck, T.
    • Upchurch, D.
  • Source: Biology and Fertility of Soils
  • Volume: 47
  • Issue: 6
  • Year: 2011
  • Summary: In dryland agriculture in semiarid regions, crop establishment is not always possible because precipitation may not be sufficient. Modification of soil properties can improve the soil quality and functioning including soil water capture and storage capacity for crop production in dryland conditions. ARS scientists established a study near Lubbock, Texas in 2003 to compare the soil properties under different dryland cropping systems and tillage management. After only 3 years, this study detected increases in soil microbial community size and enzyme activities important for nutrient cycling under rotations with a winter cover crop such as cotton-rye-sorghum and haygrazer-rye compared to continuous cotton or sorghum-cotton at 0-10 cm soil depth. After 5 years, higher soil total C was found under Hay-Rye compared to the other systems. In addition, microbial properties were already impacted in all alternative systems (haygrazer-rye, cotton-rye-sorghum and cotton-sorghum) studied compared to continuous cotton. Several microbial properties indicative of increased soil water availability were also higher under the alternative rotations to continuous cotton. However, continuation of this study is vitally important for the long-term evaluation and confirmation of these trends, and their implications in water management, soil quality and crop productivity in dryland.
  • Authors:
    • Chamberlain, J. F.
    • Miller, S. A.
    • Frederick, J. R.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 141
  • Issue: 3-4
  • Year: 2011
  • Summary: Use of a simulation model to predict long-term yield, greenhouse gas (GHG) emissions, and water quality impacts can be valuable for assessing land use conversion to bioenergy crops. The objective of this study is to assess the usability of DAYCENT for measuring environmental impacts due to land conversions from cotton and CRP lands (as unmanaged grasses) to switchgrass in the Southern U.S. We use published yield data to calibrate the crop growth parameters and test the calibrated model on independent data sets. We then apply the model to predict other relevant C and N parameters. In the case of cotton, the model simulates long-term mean cotton lint yield within 25% of observed yields across the South and within 4% of yields in the case study area of Darlington County, SC. DAYCENT also matches observed mature switchgrass yields within 25% of the mean in the range of expected fertilization rates across the region and within 6% in the case study area. Long-term simulations predict a decrease in GHG emissions (1.0-3.8 MtCO 2-e/ha-yr) and a reduction of nitrate runoff (up to 95%) for conversions from cotton to switchgrass at N application rates of 0-135 kgN/ha. Conversely, conversion from unmanaged grasses to switchgrass resulted in annual increases of net GHG emissions (0.2-1.4 MtCO 2-e/ha-yr) for switchgrass at no and low (45 kgN/ha) fertilization rates. Sequestration occurs due to increased soil organic C when higher levels of N are applied. At all levels of fertilization, a reduction of nitrate (50-70%) occurs when converting from unmanaged, unharvested grasses. The amount of nitrate leaching is only slightly sensitive to the fertilization rate applied to the perennial switchgrass. DAYCENT sufficiently models the "carbon debt" from land use conversion from CRP grasslands to managed switchgrass and highlights the importance of fertilization rate. Both C and N parameter results fall within published observed ranges. Thus, the long-term (10-15-year) accuracy of the model for both cotton and switchgrass offers promise as a tool for analyzing land use conversions in terms of N-managed yields and subsequent environmental impacts and benefits.
  • Authors:
    • Poswal, R. S.
    • Yadav, A.
    • Gupta, R. K.
    • Gill, S. C.
    • Chhokar, R. S.
    • Kumar, V.
    • Sharma, R. K.
    • Kumar, A.
    • Mehta, A.
    • Kleemann, S. G. L.
    • Cummins, J. A.
    • Coventry, D. R.
  • Source: Field Crops Research
  • Volume: 123
  • Issue: 3
  • Year: 2011
  • Summary: This article reports on field experiments with 4 different rotations that are commonly used throughout Haryana in NW India (rice-wheat, cotton-wheat, pearl millet-wheat, cluster bean-wheat), where we assess wheat yield and chapatti quality measures with different crop establishment methods and input of micronutrients. In a series of experiments conducted on farmers' fields in 2007-2008 and 2008-2009 winter seasons, the addition of micronutrients and sulphur to wheat crops was used alongside the use of a common farmer practice, the use of farmyard manure (FM) and best practice inputs of N-fertilizer (150 kg N ha -1), P-fertilizer (26 kg P ha -1) and K-fertilizer (33 kg K ha -1). The application of FM with the recommended NPK treatment produced 9-13% more grain yield in the rice-wheat rotation when compared with the recommended NPK only treatment. Given that the farm sites used here had low levels of soil P, this may suggest that the recommended rate of 26 kg P ha -1 for the rice-wheat rotation is too low. The addition of FM did not improve any grain quality outcomes at any of the sites. There were no yield responses with S application with any of the rotations but the S input resulted in more wheat protein from all sites (average 8%). The addition of S also gave similar increases in grain hardness and the chapatti score. The inclusion of micronutrients (boron, copper, iron, zinc and manganese) with the recommended NPK treatment did not increase the grain yield at any of the sites when compared with the recommended NPK treatment, and sometimes, but not consistently, gave small responses with protein, grain hardness and chapatti score. In concurrent experiments wheat growth and chapatti quality were compared in zero till and conventionally sown systems, and with and without S fertilizer amendment. Here too there were no grain yield responses to S, and the protein, grain hardness and chapatti score were increased with S addition. Grain yields with zero till and conventional wheat were similar in the rice-wheat system and zero till sowing resulted in small increases in yield at all of the non-rice sites. The grain from the zero till treatments had higher protein (1-3%), grain hardness (3-10%) and chapatti score from all 4 rotations. Zero till has substantial adoption in the rice-wheat districts of Haryana but little farmer awareness and adoption in the areas where the other rotations are used. The data given here show that with zero tillage and an integrated practice of nutrient management farmers in Haryana can maintain grain yields of wheat whilst improving quality outcomes.
  • Authors:
    • Bustamante, M. M. da C.
    • Cruvinel, E. B. F.
    • Kozovits, A. R.
    • Zepp, R. G.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 144
  • Issue: 1
  • Year: 2011
  • Summary: In the last 40 years, a large area of savanna vegetation in Central Brazil (Cerrado) has been converted to agriculture, with intensive use of fertilizers, irrigation and management practices. Currently, the Cerrado is the main region for beef and grain production in Brazil. However, the consequences of these agricultural practices on NO, N 2O and CO 2 emissions from soil to atmosphere are still poorly investigated. The objectives of this study were to quantify soil emissions of NO-N, N 2O-N and CO 2-C in different no-till cultivation systems in comparison with native savanna vegetation. The agricultural areas included: (a) the maize and Brachiaria ruzizienses intercropping system followed by irrigated bean in rotation; (b) soybean followed by natural fallow; and (c) cotton planting over B. ruzizienses straw. The study was performed from August 2003 to October 2005 and fluxes were measured before and after planting, after fertilizations, during the growing season, before and after harvesting. NO-N fluxes in the soybean field were similar to those measured in the native vegetation. In the cornfield, higher NO-N fluxes were measured before planting than after planting and pulses were observed after broadcast fertilizations. During Brachiaria cultivation NO-N fluxes were lower than in native vegetation. In the irrigated area (bean cultivation), NO-N fluxes were also significantly higher after broadcast fertilizations. Most of the soil N 2O-N fluxes measured under cultivated and native vegetation were very low (<0.6 ng N 2O-N cm -2 h -1) except during bean cultivation when N 2O-N fluxes increased after the first and second broadcast fertilization with irrigation and during nodule senescence in the soybean field. Soil respiration values from the soybean field were similar to those in native vegetation. The CO 2-C fluxes during cultivation of maize and irrigated bean were twice as high as in the native vegetation. During bean cultivation with irrigation, an increase in CO 2-C fluxes was observed after broadcast fertilization followed by a decrease after the harvest. Significantly lower soil C stocks (0-30 cm depth) were determined under no-tillage agricultural systems in comparison with the stocks under savanna vegetation. Fertilizer-induced emission factors of N oxides calculated from the data were lower than those indicated by the IPCC as default.
  • Authors:
    • Gürsoy, S. L.
    • Sessiz, A.
    • Kiliç, H.
    • Bayram, N.
  • Source: Archives of Agronomy and Soil Science
  • Volume: 57
  • Issue: 4
  • Year: 2011
  • Summary: Soil properties are very important for plant growth and soil conservation. Although soil properties can be influenced by agricultural production systems, this influence has seldom been studied in the semi-arid South East Anatolia region of Turkey. Thus, a three-year experiment was carried out to evaluate the effect of tillage and residue management systems in wheat ( Triticum durum L.) agriculture following cotton ( Gossypium hirsutum L.) on soil properties. A strip plot design with three replications was used, in which two residue management treatments were collecting cotton stalk (SA) and chopping cotton stalk (SB), and six tillage treatments were conventional tillage-I (CT-I), conventional tillage-II (CT-II), vertical tillage (VT), reduced tillage-I (RT-I), reduced tillage-II (RT-II), no-till ridge planting (RP). While there was no difference at 10-20 and 20-30 cm, the penetration resistance was the lowest for CT-I (1.62 MPa) at 0-10 cm. Although tillage treatments had no significant effect on the soil bulk density at 0-10 and 20-30 cm, the lowest bulk density were obtained in RT-II (1.19 g cm -3) at 10-20 cm. Tillage and residue management treatments did not influence the soil organic matter content and pH.
  • 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:
    • Evett, S. R.
    • O'Shaughnessy, S. A.
    • Colaizzi, P. D.
    • Howell, T. A.
  • Source: Agricultural Water Management
  • Volume: 98
  • Issue: 10
  • Year: 2011
  • Summary: The use of digital infrared thermography and thermometry to investigate early crop water stress offers a producer improved management tools to avoid yield declines or to deal with variability in crop water status. This study used canopy temperature data to investigate whether an empirical crop water stress index could be used to monitor spatial and temporal crop water stress. Different irrigation treatment amounts (100%, 67%, 33%, and 0% of full replenishment of soil water to field capacity to a depth of 1.5 m) were applied by a center pivot system to soybean ( Glycine max L.) in 2004 and 2005, and to cotton ( Gossypium hirsutum L.) in 2007 and 2008. Canopy temperature data from infrared thermography were used to benchmark the relationship between an empirical crop water stress index (CWSI e) and leaf water potential (Psi L) across a block of eight treatment plots (of two replications). There was a significant negative linear correlation between midday Psi L measurements and the CWSI e after soil water differences due to irrigation treatments were well established and during the absence of heavy rainfall. Average seasonal CWSI e values calculated for each plot from temperature measurements made by infrared thermometer thermocouples mounted on a center pivot lateral were inversely related to crop water use with r2 values >0.89 and 0.55 for soybean and cotton, respectively. There was also a significant inverse relationship between the CWSI e and soybean yields in 2004 ( r2=0.88) and 2005 ( r2=0.83), and cotton in 2007 ( r2=0.78). The correlations were not significant in 2008 for cotton. Contour plots of the CWSI e may be used as maps to indicate the spatial variability of within-field crop water stress. These maps may be useful for irrigation scheduling or identifying areas within a field where water stress may impact crop water use and yield.
  • 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.
  • Authors:
    • Nalley, L. L.
    • Popp, M.
  • Source: Journal of Agricultural and Applied Economics
  • Volume: 43
  • Issue: 3
  • Year: 2011
  • Summary: Arkansas cropping pattern changes at the county level were estimated under various scenarios involving a likely decline in water availability, the development of a biomass market for renewable energy production, and the potential of a widely used carbon offset market. These scenarios are analyzed separately and jointly to determine which of the three scenarios is expected to have the largest impact on net (emissions - sequestration) greenhouse gas (GHG) emissions, renewable fuels feedstock supply, and producer net returns. Land use choices included conventional crops of rice, cotton, soybean, corn, grain sorghum, pasture, and hay. Specialty crops of loblolly pine and switchgrass were modeled for their respective potential to sequester carbon and provide feedstock for renewable fuels. GHG emissions were measured across an array of production methods for each crop. Soil and lumber carbon sequestration was based on yield, soil texture, and tillage. Using the concept of additionality in which net GHG emissions reductions compared with a baseline level were rewarded at a carbon price of $15 per ton along with $40 per dry ton of switchgrass, baled at field side, revealed that irrigation restrictions had the largest negative impact on producer net returns while also lowering net GHG emissions. Introducing the higher carbon price led to minor positive income ramifications and greatly reduced net GHG emissions. Biomass production returns were higher than the returns from the carbon offset market, however, at the cost of greater net GHG emissions. The combination of all factors led to a significant increase in switchgrass and pine production. In this scenario, approximately 16% of the total income losses with lower nonirrigated yields were offset with returns from biomass and carbon markets. Lowest statewide net GHG emissions were achieved given least irrigation fuel use and a greater than 15% increase in carbon sequestration with pine and switchgrass.
  • Authors:
    • Vashist, K. K.
    • Mahey, R. K.
    • Barkodia, R.
    • Mahal, S. S.
    • Sidhu, A. S.
  • Source: Journal of Cotton Research and Development
  • Volume: 25
  • Issue: 1
  • Year: 2011
  • Summary: A field experiment was conducted at Punjab Agricultural University, Ludhiana during kharif, 2004. The treatments comprised of four irrigation schedules (Irrigation application at 75, 95, 115 and 135 mm of cumulative pan evaporation) and four dates of irrigation termination (10, 20, 30 September and 10, October). The treatments were replicated four times in randomized block design. Ginning outturn was not affected due to schedule of irrigation upto the last irrigation. Highest oil content (19.34%) was observed under 135 mm CPE, which was significantly higher than 75 and 95 mm CPE but was at par with 115 mm CPE. None of the quality characters were significantly influenced by different irrigation schedules as well as date of termination of last irrigation. Maximum seed cotton yield was recorded at 95 mm (16.23 q/ha) followed by 75 mm (16.22 q/ha) CPE and these two irrigation regimes being at par with one another and they were significantly superior to 115 mm (13.98 q/ha) and 135 mm (12.66 q/ha) CPE. Termination of last irrigation on October, 10 produced highest seed cotton yield (15.64 q/ha) as compared to termination on September, 10 and 20 but at par with September, 30.