19602015
  • Authors:
    • Grant, C.
    • Khakbazan, M.
    • Mohr, R.
  • Source: López-Francos A. (comp.), López-Francos A. (collab.). Economics of drought and drought preparedness in a climate change context. Zaragoza : CIHEAM / FAO / ICARDA / GDAR / CEIGRAM / MARM, 2010 (Options Méditerranéennes : Série A. Séminaires Méditerranéens;
  • Issue: 95
  • Year: 2010
  • Summary: The objective of this paper was to study the impact of drought and adaptation measures on the economics of production for some major crops grown in Western Canada. Crop yields, yield variability, and crop losses were analyzed to quantify drought impacts and statistical models were developed to estimate the relationship between yield and growing season precipitation for wheat, canola, oats, and barley. The linear and quadratic precipitation terms were found to have the correct sign and to be significantly related to yield (p
  • Authors:
    • Towett, B. K.
    • Ogola, J. B. O.
    • Kinyua, M. G.
    • Gottschalk, K.
    • Kimurto, P. K.
  • Source: Agricultural Engineering International: CIGR Journal
  • Volume: 12
  • Issue: 3/4
  • Year: 2010
  • Summary: Carrying out field trial-research in dryland areas is usually expensive and costly for most national breeding programmes; hence development of simple crop simulation models for predicting crop performance in actual semi-arid and arid lands (ASALS) would reduce the number of field evaluation trials. This is especially critical in developing countries like Kenya where dry areas is approximately 83% of total land area and annual rainfall in these area is low, unreliable and highly erratic, causing frequent crop failures, food insecurity and famine. This paper used data generated from the rain shelter by measurement of evapotranspiration together with weather variables in Katumani to predict wheat yields in that site. Maximum yield of the wheat genotype considered for genotype Chozi under ideal conditions was 5 t/ha. Total above-ground biomass was obtained and grain yield was to be predicted by the model. Transpiration was estimated from the relationship between total dry matter production and normalised TE (7.8 Pa). The results presented are based on the assumption that all agronomic conditions were optimal and drought stress was the major limiting factor. Predicted grain yield obtained from the conceptual model compares very well with realised yields from actual field experiments with variances of 14%-43% depending on watering regime. This study showed that it is possible to develop simple conceptual model to predict productivity in wheat in semi-arid areas of Kenya to supplement complicated and more sophisticated models like CERES-maize and ECHAM models earlier used in Kenya. The presence of uncontrolled factors in the simulation not accounted for in the estimation and could have contributed to decrease in observed yield need to be included in the model, hence modulation of the equations by introducing these factors may be necessary to reduce variances; thus need to be quantified. To improve the accuracy of prediction and increase wheat production in these areas measures that conserve water and/or make more water available to the crop such as prevention or minimisation of run-off, and rain water harvesting for supplemental irrigation are necessary.
  • Authors:
    • Kismanyoky, A.
    • Lehoczky, E.
  • Source: Novenytermeles OR ACTA PHYTOPATHOLOGICA ET ENTOMOLOGICA HUNGARICA or Agrokémia és Talajtan ?
  • Volume: 59
  • Issue: Supplement
  • Year: 2010
  • Summary: Soil cultivation (the factor A) and nitrogen fertilization (the factor B) effects on yields of winter wheat and maize and weeds-cover was tested in the long-term experiment conducted on Keszthely Eutric cambisol (Ramann type brown forest soil) in 2005-2008 period. The bi-factorial trial was arranged in split plot design with four replications (basic plots 435 m 2 and 87 m 2, for A and B, respectively). Conventional tillage (ploughing=PL), no-till drill (NT) and disking (D) were the treatment of soil cultivation, while five rates of nitrogen (kg N ha -1: 0; 120; 180; 240; 300) were applied on blanket application of phosphorus and potassium (kg ha -1: 100 P 2O 5+100 K 2O). There was no weed control until our investigation. The weed surveys were made with Balazs-Ujvarosi coenological method. The fewer yields were obtained in the wheat-maize no-tillage system compared to the others. It was proved at high and low level alike (good and unfavourable years). In the average of years the decreasing of yield was 10-15% compared to the traditional cultivation. In survey the weed cover (%) at wheat in springtime it can be said that the weed cover increased parallel with the amount of N fertilizer and above 200 kg/ha N doses declined. The dynamic of relation of weeds v.s. N fertilizer it is similar to the square equation of yield curve. In case of maize there were not significant differences between the N treatments (25-30%) regarding the weed cover. The results draw ones attention to that facts that with the propagation of the reduced soil cultivation systems it is necessary to modify and harmonize the practice of weed control and fertilization.
  • Authors:
    • Lehoczky, É.
    • Kismányoky, A.
  • Source: Agrokémia és Talajtan
  • Volume: 59
  • Issue: 1
  • Year: 2010
  • Summary: A long-term soil tillage experiment was conducted in 2005 to 2008 on a Ramann-type brown forest soil (Eutric Cambisol) in Keszthely, Hungary, with different cultivation methods (no-till, drill, disc tillage, conventional tillage (ploughing)) and five increasing N doses. Treatment A was the cultivation method: conventional tillage (ploughing), no-till, drill, disc tillage; and Treatment B was N fertilizer application: N 0-N 4 (0, 120, 180, 240 and 300 for maize, and 0, 120, 160, 200 and 240 kg/ha per ton for wheat, respectively). Both plots received a blanket application of 100 kg P 2O 5/ha and 100 kg K 2O/ha. With soil cultivation and N fertilization treatments, winter wheat yield varied between 2.5 and 6.0, while maize yield ranged from 6 to 10 t/ha. The influence of the annual circumstances (mostly rainfall) on the yields was measurable and from time to time statistically significant. The different amounts of N fertilizer significantly increased the yields of maize and wheat. The highest increases were found in the case of N 1 and N 2 treatments. The maximum yields of maize and wheat were obtained with the 200-250 kg N/ha doses. On the average of years, the largest weed cover (28%) was recorded in the no-tillage treatment, while the ploughing system was the least weedy (10-15%).
  • Authors:
    • Yang, D. W.
    • Lei, H. M.
  • Source: Global Change Biology
  • Volume: 16
  • Issue: 11
  • Year: 2010
  • Summary: In China, croplands account for a relatively large form of vegetation cover. Quantifying carbon dioxide exchange and understanding the environmental controls on carbon fluxes over croplands are critical in understanding regional carbon budgets and ecosystem behaviors. In this study, the net ecosystem exchange (NEE) at a winter wheat/summer maize rotation cropping site, representative of the main cropping system in the North China Plain, was continuously measured using the eddy covariance technique from 2005 to 2009. In order to interpret the abiotic factors regulating NEE, NEE was partitioned into gross primary production (GPP) and ecosystem respiration (R(eco)). Daytime R(eco) was extrapolated from the relationship between nighttime NEE and soil temperature under high turbulent conditions. GPP was then estimated by subtracting daytime NEE from the daytime estimates of R(eco). Results show that the seasonal patterns of the temperature responses of R(eco) and light-response parameters are closely related to the crop phenology. Daily R(eco) was highly dependent on both daily GPP and air temperature. Interannual variability showed that GPP and R(eco) were mainly controlled by temperature. Water availability also exerted a limit on R(eco). The annual NEE was -585 and -533 g C m-2 for two seasons of 2006-2007 and 2007-2008, respectively, and the wheat field absorbed more carbon than the maize field. Thus, we concluded that this cropland was a strong carbon sink. However, when the grain harvest was taken into account, the wheat field was diminished into a weak carbon sink, whereas the maize field was converted into a weak carbon source. The observations showed that severe drought occurring during winter did not reduce wheat yield (or integrated NEE) when sufficient irrigation was carried out during spring.
  • Authors:
    • Ediriwickrema, J.
    • Shao, Y.
    • Lunetta, R. S.
    • Lyon, J. G.
  • Source: International Journal of Applied Earth Observation and Geoinformation
  • Volume: 12
  • Issue: 2
  • Year: 2010
  • Summary: The Moderate Resolution Imaging Spectrometer (MODIS) Normalized Difference Vegetation Index (NDVI) 16-day composite data product (MOD12Q) was used to develop annual cropland and crop-specific map products (corn, soybeans, and wheat) for the Laurentian Great Lakes Basin (GLB). The crop area distributions and changes in crop rotations were characterized by comparing annual crop map products for 2005, 2006, and 2007. The total acreages for corn and soybeans were relatively balanced for calendar years 2005 (31,462 km(2) and 31,283 km(2), respectively) and 2006 (30,766 km(2) and 30,972 km(2), respectively). Conversely, corn acreage increased approximately 21% from 2006 to 2007, while soybean and wheat acreage decreased approximately 9% and 21%, respectively. Two-year crop rotational change analyses were conducted for the 2005-2006 and 2006-2007 time periods. The large increase in corn acreages for 2007 introduced crop rotation changes across the GLB. Compared to 2005-2006, crop rotation patterns for 2006-2007 resulted in increased corn-corn, soybean-corn, and wheat-corn rotations. The increased corn acreages could have potential negative impacts on nutrient loadings, pesticide exposures, and sediment-mediated habitat degradation. Increased in US corn acreages in 2007 were related to new biofuel mandates, while Canadian increases were attributed to higher world-wide corn prices. Additional study is needed to determine the potential impacts of increases in corn-based ethanol agricultural production on watershed ecosystems and receiving waters. Published by Elsevier B.V.
  • Authors:
    • Di Tizio, A.
    • Campiglia, E.
    • Mancinelli, R.
    • Marinari, S.
  • Source: Applied Soil Ecology Volume 46, Issue 1, September 2010, Pages
  • Volume: 46
  • Issue: 1
  • Year: 2010
  • Summary: Carbon sequestration in soil is an important means for reducing net emissions of CO(2) into the atmosphere. We hypothesized that organic cropping systems (ORG) would reduce soil CO(2) emission and increase C storage compared to conventional cropping systems (CONV). The objectives of this study were to: (i) analyze the ORG and CONV systems in terms of soil CO(2) emission and soil C balance and (ii) establish if the soil in the ORG and CONV systems represents a source or a sink of C. A3-year crop rotation (durum wheat-Triticum durum Desf., tomato - Licopersicum esculentum Mill., and pea - Pisum sativum L) was carried out in both cropping systems, but the crop rotation was implemented with common vetch (Vicia sativa L.) before tomato planting and sorghum (Sorghum bicolor (L) Moench.) before pea sowing and both green manured only in the ORG system. It was found that the soil CO(2) emission rate at peak times (in spring or at the end of summer - beginning of autumn) in the ORG system was higher than the CONV system. The peak of CO(2) was attributed to the fact that at this time the soil temperature and the relative soil water content (RWC) were probably in the optimal range for soil respiration (17.2 degrees C and 36.4% of RWC) and the difference between ORG and CONV was probably due to the green manuring of the cover crops in the ORG system. However, even if the cropping systems had a temporary impact on the rate of soil CO(2) emissions, the soil C output calculated as the average of cumulative CO(2) emission over the 3-year period did not show significant differences between the ORG and CONV systems (8.98 Mg C-CO(2) ha(-1) vs. 8.06 Mg C-CO(2) ha(-1)). On the other hand, the C input in the ORG system was higher than in the CONV (9.46 Mg C ha(-1) vs. 5.57 Mg C ha(-1)) as well as the C input/output ratio (1.10 vs. 0.72). The 3-year average of TOC content and C stock were higher in the ORG than in the CONV system (1.24% vs. 1.10% and 27.4 Mg C ha(-1) vs. 23.9 Mg C ha(-1), respectively). However, the decrease of TOC and C stock over 3 years period suggested that further studies over a longer period are needed to verify if C limitation for soil microbial growth and nitrogen limitation for crop growth in the organic system could hinder soil C accumulation over a longer period. (C) 2010 Elsevier B.V. All rights reserved.
  • Authors:
    • Moscatelli, M. C.
    • Lagomarsino, A.
    • Marinari, S.
    • Di Tizio, A.
    • Campiglia, E.
  • Source: Soil & Tillage Research
  • Volume: 109
  • Issue: 2
  • Year: 2010
  • Summary: The scientific literature regarding the use of C and N mineralization kinetics as a tool to highlight the effects of different cropping systems on soil C and N release is scarce. In this study we aimed to assess the effectiveness of these parameters in evaluating soil C and N potential release in organic (ORG) and conventional (CONV) three-year cropping systems. A long-term field study was established in 2001 at the University of Tuscia experimental farm (Viterbo, Italy) in a randomized block design. The soil is classified as Typic Xerofluvent or Dystric Fluvisol. In the CONV system the Good Agricultural Practice is adopted, whereas the ORG system is managed following the Regulation 2092/91/EEC. Both systems had a three-year crop rotation (pea - Pisum sativum L.; durum wheat - Triticum durum Desf.; tomato - Licopersicum esculentum Mill.). One of the main differences between the two systems is the soil N fertilization program: organic fertilizers (Guano: 6% N, 32% organic carbon and DIX10: 10% N, 42% organic carbon, both produced by Italpollina. Italy) and mineral nitrogen fertilizers (NH(4)NO(3)) were applied to ORG and CONV fields.respectively. Moreover, the rotation in the ORG system included common vetch (Vicia sativa L) and sorghum (Sorghum vulgare L) as green manure crops. Our results supported the hypotheses in that the two systems differed significantly on potentially mineralizable C (C(o)) in 2008 and on potentially mineralizable N (N(o)) as nitrate form (N(0)-NO(3)(-)) in 2006 (318 mu g C-CO(2) g(-1) 28 d(-1) vs. 220 mu g C-CO(2) g(-1) 28 d(-1); 200 mu g N-NO(3)(-) g(-1) vs. 149 mu g N-NO(3)- g(-1) in ORG and CONV, respectively). The reduction of N(o) in soil during the crop rotation period could reflect the N microbial immobilization since a negative correlation between microbial biomass N:total N ratio and No as ammonium form (N(0)-NH(4)(+))(P < 0.001) as well as a positive correlation between N0-NH4+ and C:N ratio of microbial biomass (P < 0.05) were observed. Moreover, a lower potential mineralization rate of N was observed in soil with Guano (25%) than in soil with DIX10 (35%); nevertheless the former fertilizer might cover a longer period of crop N demand as a more gradual release of N0 was observed. In this work we demonstrated that the use of mineralization kinetics parameters can offer a potential to assess the mineralization–immobilization processes in soils under different climatic and management conditions. Moreover, they can be used to evaluate the most suitable N release pattern of organic fertilizers used in various cropping systems.
  • Authors:
    • Vigil, M. F.
    • Benjamin, J. G.
    • Mikha, M. M.
    • Nielson, D. C.
  • Source: Soil Science Society of America journal
  • Volume: 74
  • Issue: 5
  • Year: 2010
  • Summary: The predominant cropping system in the Central Great Plains is conventional tillage (CT) winter wheat ( Triticum aestivum L.)-summer fallow. We investigated the effect of 15 yr of cropping intensities, fallow frequencies, and tillage (CT and no-till [NT]) practices on soil organic C (SOC) sequestration, particulate organic matter (POM), and wet aggregate-size distribution. A crop rotation study was initiated in 1990 at Akron, CO, on a silt loam. In 2005, soil samples were collected from the 0- to 5- and 5- to 15-cm depths in permanent grass, native prairie, and cropping intensities (CI) that included winter wheat, corn ( Zea mays L.), proso millet ( Panicum miliaceum L.), dry pea ( Pisum sativum L.), and summer fallow. The native prairie was sampled to provide a reference point for changes in soil parameters. The most intensive crop rotation significantly increased C sequestration compared with the other CIs where fallow occurred once every 2 or 3 yr. Legume presence in the rotation did not improve SOC sequestration relative to summer fallow. Significant amounts of macroaggregates were associated with grass and intensive cropping compared with the rotations that included fallow. Reduced fallow frequency and continuous cropping significantly increased soil POM near the surface compared with NT wheat-fallow. Macroaggregates exhibited a significant positive relationship with SOC and POM. A significant negative correlation was observed between microaggregates and POM, especially at 0- to 5-cm depth. Overall, a positive effect of continuous cropping and NT was observed on macroaggregate formation and stabilization as well as SOC and POM.
  • Authors:
    • Jauhiainen, L.
    • Peltonen-Sainio, P.
  • Source: Agricultural and Food Science
  • Volume: 19
  • Issue: 4
  • Year: 2010
  • Summary: The balance between applied and harvested nitrogen (yield removed nitrogen, YRN %) is a recognized indicator of the risk of N leaching. In this study we monitored the genetic improvements and environmental variability as well as differences among crop species (spring cereals and rapeseed) in YRN in order to characterize changes that have occurred and environmental constraints associated with reducing N leaching into the environment. MTT long-term multi-location field experiments for spring cereals (Hordeum vulgare L., Avena sativa L. and Triticum aestivum L.), turnip rape (Brassica rapa L.), and oilseed rape (B. napus L.) were conducted in 1988-2008, covering each crop's main production regions. Yield (kg ha(-1)) was recorded and grain/seed nitrogen content (N(grain), g kg(-1)) analyzed. Total yield N (N(yield), kg ha(-1)) was determined and YRN (%) was calculated as a ratio between applied and harvested N. A mixed model was used to separate genetic and environmental effects. Year and location had marked effects on YRN and N(yield). Average early and/or late season precipitation was often most advantageous for N(yield) in cereals, while in dry seasons N uptake is likely restricted and in rainy seasons N leaching is often severe. Elevated temperatures during early and/or late growth phases had more consistent, negative impacts on YRN and/or N(yield) for all crops, except oilseed rape. In addition to substantial variability caused by the environment, it was evident that genetic improvements in YRN have taken place. Hence, YRN can be improved by cultivar selection and through favouring crops with high YRN such as oat in crop rotations.