• Authors:
    • You, L. Z.
    • Zhao, J. S.
    • Ringler, C.
    • Yang, Y. C. E.
    • Cai, X. M.
  • Source: Agricultural Water Management
  • Volume: 98
  • Issue: 8
  • Year: 2011
  • Summary: Agricultural water productivity (WP) has been recognized as an important indicator of agricultural water management. This study assesses the WP for irrigated (WPI) and rainfed (WPR) crops in the Yellow River Basin (YRB) in China. WPI and WPR are calculated for major crops (corn, wheat, rice, and soybean) using experimental, statistical and empirically estimated data. The spatial variability of WPI and WRR is analyzed with regard to water and energy factors. Results show that although irrigated corn and soybean yields are significantly higher than rainfed yields in different regions of the YRB, WPI is slightly lower than WPR for these two crops. This can be explained by the seasonal coincidence of precipitation and solar energy patterns in the YRB. However, as expected, irrigation stabilizes crop production per unit of water consumption over space. WPI and WPR vary spatially from upstream to downstream in the YRB as a result of varying climate and water supply conditions. The water factor has stronger effects on both crop yield and WP than the energy factor in the upper and middle basin, whereas energy matters more in the lower basin. Moreover, WP in terms of crop yield is compared to that in terms of agricultural GDP and the results are not consistent. This paper contributes to the WP studies by a basin context, a comparison between WPI and WPR, a comparison of WP in terms of crop yield and economic value, and insights on the water and energy factors on WP. Moreover, policy implications based on the WP analysis are provided.
  • Authors:
    • Negrisoli, E.
    • Crusciol, C. A. C.
    • Castro, G. S. A.
    • Perim, L.
  • Source: Planta Daninha
  • Volume: 29
  • Year: 2011
  • Summary: Tillage and other agricultural production systems can contribute to weed suppression. Thus, the objective of this study was to evaluate weed control using different grain production systems. The treatments were: I. "Harvest-fallow" System-soybean/fallow/corn/fallow/rice/fallow/soybean; II. "Harvest-green manure" System-soybean/millet/maize/pigeon pea/rice/Crotalaria/soybean; III. "Harvest-out of season" System-soy/white oats/corn/dry bean/rice/castor oil/soybean; and IV "Harvest-fodder" System-brachiaria + soy/corn + brachiaria/brachiaria + rice/soybeans. A weed survey was carried out in November 2009, after three growing seasons. A 0.3 x 0.3 m frame was randomly launched four times within each plot. The plants were identified, and the total number of weeds, dry weight, and control percentage of the species were determined according to the production system. The phytosociological analysis of the weed community was also conducted. The systems Harvest-green manure; Harvest-out of season and Harvest-fodder presented a good weed control when compared to the Harvest-fallow system. Therefore, the presence of some type of soil cover is important to maintain favorable soil characteristics and good weed control.
  • Authors:
    • Huang, G. B.
    • Yang, C. H.
    • Chai, Q.
  • Source: ACTA AGRONOMICA SINICA
  • Volume: 37
  • Issue: 9
  • Year: 2011
  • Summary: In oasis irrigation region of northwestern China, the decreasing of multiple cropping areas may lead to significant reduction of land and light use efficiencies due to serious water shortage. Therefore, water-saving irrigation is a priority in the research on theory and technology for intercropping system. Alternate irrigation is a technique to save water and enhance water use efficiency (WUE) simultaneously in common cropping systems. However, its effect is not clear on intercropping system. In 2006-2008 cropping years, we carried out a field experiment in oasis region of Hexi Corridor, Gansu province, China under wheat/maize intercropping to disclose the effects of alternate irrigation on crop yields, water consumption, and WUE. The results showed that, compared to sole cropping treatments, there was a significant increase of land equivalent ratio (LER) in the alternately irrigated wheat/maize intercropping treatment with the LER values ranging from 1.22 to 1.52 under different irrigation levels of the intercropping treatments. However, the difference of LERs between conventionally irrigated and alternately irrigated intercropping systems was not significant at the same irrigation quota. Compared to the conventionally irrigated intercropping treatment, there was no significant change of wheat yield in the alternately irrigated intercropping treatment, but significant increase by 11.4-36.4% in maize yield. Therefore, the total yield of wheat and maize in the alternately irrigated intercropping treatment was increased by 12.9 averagely. The water consumption in the alternately irrigated intercropping treatment had no significant increase compared to that of the conventionally irrigated intercropping treatment, with 1.2-19.4% higher than the weighted average of monoculture of both crops. The WUE of alternately irrigated intercropping treatment was 0.9-22.5% higher than that of the conventionally irrigated intercropping treatment, and 12.0-71.4% and 10.6-37.8% higher than that of wheat and maize monoculture, respectively. These results suggest that alternate irrigation is feasible in intercropping systems in arid oasis regions with the purpose of saving water and increasing WUE.
  • Authors:
    • Huang, P.
    • Chen, G. P.
    • Yu, A. Z.
    • Chai, Q.
  • Source: Chinese Journal of Eco-Agriculture
  • Volume: 19
  • Issue: 6
  • Year: 2011
  • Summary: Several studies have shown that compared to sole cropping, well managed intercropping improves agricultural resources utilization efficiency, include radiation, nutrient, water and land. However, high productivity of traditional intercropping system has mainly depended on high input of agricultural resources. With severe water shortages in recent years (especially in mainland China), intercropping system of farming has continuously declined. The scientific challenge therefore is the determination of water consumption characteristics and systematic development of high-efficiency water-saving theories and technologies of intercropping system. In this study, a field experiment (comprising of wheat or maize sole cropping and wheat-maize intercropping systems under three different irrigation schemes) was conducted in 2008 in the Hexi Corridor oasis region. The study investigated soil evaporation characteristics and associated driving factors under the different cropping systems and treatments with the aim of laying the scientific basis for developing optimized irrigation techniques. The study showed that evapotranspiration ( ET) under wheat-maize intercropping was 41.44%-47.15% higher than the average ET under wheat and maize sole cropping systems. Total soil evaporation ( E) of intercropping system was significantly higher than that of sole cropping systems. However, daily E of intercropping system was significantly lower than that of maize sole cropping system. Also compared with sole cropping system of maize, wheat-maize intercropping system enhanced E/ET ratio. With increasing irrigation, total water consumption increased significantly under intercropping. However, the difference in water consumption between two adjacent irrigation treatments under sole cropping systems of wheat and maize was insignificant. The difference in E of sole cropping maize and intercropping wheat-maize was insignificant for different irrigation schemes. It then implied that high water consumption of intercropping system was mainly driven by high transpiration. Average daily E was positively correlated with water content in the 0-30 cm soil profile, temperature in the 0-25 cm soil profiles and average leaf area index of the crops. High E was driven by high water content in the 0-30 cm soil profile and temperature in the 0-25 cm soil profile of maize sole cropping system. On the average, wheat-maize intercropping not only reduced water consumption but also increased water and land use efficiency compared to sole cropping. This cut down wasteful crop transpiration, which was an effective means of water-saving irrigation.
  • Authors:
    • Giuffre, L.
    • Giardina, E. B.
    • Ciarlo, E. A.
    • Garcia Torres, T. P.
  • Source: REVISTA FACULTAD DE AGRONOMÍA Universidad de Buenos Aires
  • Volume: 31
  • Issue: 1/2
  • Year: 2011
  • Summary: The dynamics of nutrient availability and other soil properties can be strongly altered by agricultural practices like intercropping. A test was made on an agricultural soil with the following treatments: (i) sole cropped soybean, (II) sole cropped maize and (III) intercropped corn-soybean in a 1:2 ratio. Surface soil samplings were made in two moments: the first one (F1) was made with corn at V5 and soybean just emerged; the second one (F2) with corn crop at R1 and soybean crop at V7-R1, both at two distances of the furrows: 5 and 19 cm. Oxidizable C contents were always maximum at the treatments including corn cropping. At both dates, extractable P was maximum at sole corn and minimum at sole soybean crop, which can be attributed to a strong uptake by the leguminous plant. In the first measurement date, at 5 cm of the corresponding furrow, nitrate availability was significantly greater at the soybean treatments with respect to treatments including corn, whereas in the second date, nitrate availability was minimum at sole soybean, which seems to be due to differences in crops development. Finally, the practice of intercropping, within the frame of this test, did not prove to be a viable alternative to limit the existence of high nitrate levels.
  • Authors:
    • Liscano,J. F.
    • Boquet, D. J.
    • Breitenbeck, G. A.
    • Mascagni, H. J.,Jr.
    • Clawson, E. L.
    • McCarter, K. S.
  • Source: Journal of Plant Nutrition
  • Volume: 34
  • Issue: 6
  • Year: 2011
  • Summary: Soil nitrogen (N)-supplying capacity bioassays could present alternatives to traditional soil tests. Objectives were to identify winter crops and associated characteristics with bioassay potential. Saint Joseph and Bossier City, LA experiments used randomized complete block designs with factorial N fertilizer and winter crop treatment arrangements. Nitrogen rates were applied to corn (Zea mays L.) in 2004. Unfertilized winter wheat (Triticum aestivum L.), cereal rye (Secale cereale L.), native winter vegetation, and weed-free winter fallow treatments followed corn. At Saint Joseph, cotton (Gossypium hirsutum L.) followed winter crop treatments. Greater corn N rate consistently increased winter crop biomass and N accumulation, suggesting potential as bioassays, and increased Saint Joseph seedcotton yield. Winter crop-seedcotton yield N-response relationships were non-significant by familywise error rate criteria. However, some winter crop characteristics, such as rye N accumulation, for which a relationship to seedcotton yield closely approached significance, may merit further research as soil N-supplying capacity bioassays.
  • Authors:
    • Paustian, K.
    • Ogle, S.
    • Lee, J.
    • De Gryze, S.
    • Six, J.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 144
  • Issue: 1
  • Year: 2011
  • Summary: We predicted changes in yields and direct net soil greenhouse gas (GHG) fluxes from converting conventional to alternative management practices across one of the world's most productive agricultural regions, the Central Valley of California, using the DAYCENT model. Alternative practices included conservation tillage, winter cover cropping, manure application, a 25% reduction in N fertilizer input and combinations of these. Alternative practices were evaluated for all unique combinations of crop rotation, climate, and soil types for the period 1997-2006. The crops included were alfalfa, corn, cotton, melon, safflower, sunflower, tomato, and wheat. Our predictions indicate that, adopting alternative management practices would decrease yields up to 5%. Changes in modeled SOC and net soil GHG fluxes corresponded to values reported in the literature. Average potential reductions of net soil GHG fluxes with alternative practices ranged from -0.7 to -3.3 Mg CO(2)-eq ha(-1) yr(-1) in the Sacramento Valley and -0.5 to -2.5 Mg CO(2)-eq ha(-1) yr(-1) for the San Joaquin Valley. While adopting a single alternative practice led to modest net soil GHG flux reductions (on average -1 Mg CO(2)-eq ha(-1) yr(-1)), combining two or more of these practices led to greater decreases in net soil GHG fluxes of up to -3 Mg CO(2)-eq ha(-1) yr(-1). At the regional scale, the combination of winter cover cropping with manure application was particularly efficient in reducing GHG emissions. However, GHG mitigation potentials were mostly non-permanent because 60-80% of the decreases in net soil GHG fluxes were attributed to increases in SOC, except for the reduced fertilizer input practice, where reductions were mainly attributed to decreased N(2)O emissions. In conclusion, there are long-term GHG mitigation potentials within agriculture, but spatial and temporal aggregation will be necessary to reduce uncertainties around GHG emission reductions and the delivery risk of the associated C credits. (C) 2011 Elsevier B.V. All rights reserved.
  • Authors:
    • Barford, C. C.
    • Sacks, W. J.
    • Deryng, D.
    • Ramankutty, N.
  • Source: Global Biogeochemical Cycles
  • Volume: 25
  • Issue: 2
  • Year: 2011
  • Summary: Climate change is expected to significantly impact global food production, and it is important to understand the potential geographic distribution of yield losses and the means to alleviate them. This study presents a new global crop model, PEGASUS 1.0 (Predicting Ecosystem Goods And Services Using Scenarios) that integrates, in addition to climate, the effect of planting dates and cultivar choices, irrigation, and fertilizer application on crop yield for maize, soybean, and spring wheat. PEGASUS combines carbon dynamics for crops with a surface energy and soil water balance model. It also benefits from the recent development of a suite of global data sets and analyses that serve as model inputs or as calibration data. These include data on crop planting and harvesting dates, crop-specific irrigated areas, a global analysis of yield gaps, and harvested area and yield of major crops. Model results for present-day climate and farm management compare reasonably well with global data. Simulated planting and harvesting dates are within the range of crop calendar observations in more than 75% of the total crop-harvested areas. Correlation of simulated and observed crop yields indicates a weighted coefficient of determination, with the weighting based on crop-harvested area, of 0.81 for maize, 0.66 for soybean, and 0.45 for spring wheat. We found that changes in temperature and precipitation as predicted by global climate models for the 2050s lead to a global yield reduction if planting and harvesting dates remain unchanged. However, adapting planting dates and cultivar choices increases yield in temperate regions and avoids 7-18% of global losses.
  • Authors:
    • Tarkalson, D. D.
    • Shapiro, C. A.
    • Hergert, G. W.
    • Ferguson, R. B.
    • Wortmann, C. S.
    • Dobermann, A.
    • Walters, D. T.
  • Source: Agronomy Journal
  • Volume: 103
  • Issue: 1
  • Year: 2011
  • Summary: Nitrogen management recommendations may change as yield levels and efficiency of crop production increase. The mean yield with nutrients applied in 32 irrigated corn ( Zea mays L.) trials conducted across Nebraska from 2002 to 2004 to evaluate crop response to split-applied N was 14.8 Mg ha -1 The mean economically optimal nitrogen rates (EONR) for irrigated corn varied with the fertilizer N/grain price ratio. At a fertilizer N/corn price ratio of 7 the EONR was 171, 122, and 93 kg ha -1, respectively, for cropping systems with corn following corn (CC), soybean [ Glycine max (L.) Merr.] (CS), and drybean ( Phaseolus vulgaris L.) (CD). At this price ratio the present University of Nebraska (UNL) recommendation procedure gave mean N recommendations that were 17.2 and 68.1 kg ha -1 higher than the mean EONR determined in this study for CC and CD, respectively, but essentially equal to mean EONR for CS. The UNL algorithm, adjusted for mean cropping system EONR gave more accurate prediction of site-year EONR than alternative N rate predictions for CC and CD with returns to applied nitrogen (RTN) of -$22 and -$13 ha -1 compared with measured site-year EONR. Prediction of site-year EONR using mean EONR adjusted for soil organic matter was more accurate for CS than other methods with an RTN of -$6 ha -1 compared with measured site-year EONR. Further research is needed to extend the results to: lower yield situations, alternatives to split application of N, and adjustment of EONR to protect against inadequate N in atypical seasons or for environmental protection.
  • Authors:
    • Maldaner, G. L.
    • Spera, S. T.
    • Fontaneli, R. S.
    • dos Santos, H. P.
  • Source: PESQUISA AGROPECUARIA BRASILEIRA
  • Volume: 46
  • Issue: 10
  • Year: 2011
  • Summary: The objective of this work was to assess energy conversion and balance of integrated crop-livestock production systems, under no-tillage. The experiment was carried out from 2001 to 2008. From 2001 to 2002, the following systems were evaluated: 1, wheat/soybean, and black oat pasture+common vetch/corn; 2, wheat/soybean, and black oat pasture+common vetch+ryegrass/corn; 3, wheat/soybean and black oat pasture+common vetch/millet pasture; 4, wheat/soybean and black oat pasture+common vetch+rygrass/millet pasture; 5, wheat/soybean, white oat/soybean, and black oat pasture+common vetch/millet pasture; 6, wheat/soybean, white oat/soybean, and black oat pasture+common vetch+rygrass/millet pasture. From 2003 to 2008, the following systems were evaluated: 1, wheat/soybean, and common vetch/corn; 2, wheat/soybean, and black oat pasture/corn; 3, wheat/soybean, and black oat pasture/soybean; 4, wheat/soybean, and field pea/corn; 5, wheat/soybean, common vetch/soybean, and double purpose triticale/soybean; and 6, wheat/soybean, double purpose white oat/soybean, and double purpose wheat/soybean. Corn showed highest returned energy in comparison to the other grain crops, and to winter and summer annual pastures. Of the winter cover crops and green manure species evaluated, field pea was the most efficient in energy conversion. Systems 1, 2, and 4, from 2003 to 2008, had the most efficient energy balance.