• Authors:
    • Kabir, M. J.
    • Islam, M. M.
  • Source: Bangladesh Journal of Agricultural Research
  • Volume: 37
  • Issue: 1
  • Year: 2012
  • Summary: The study area was Shanuhar village of Babugonj Upazila of Barisal district, which was selected purposively based on agronomic suitability of growing Rabi crops. Necessary data were collected through focus group discussion (FGD) with 30 farmers including small, medium, and large farm households, school teachers, village leaders all the remaining by using pre design check list and structure schedule during May 2007 considering Rabi season of 2006-2007. Usually, farmers of the village could not sow their crops within the optimum time. They transplanted Aman rice in late due to inundation of land and planting of Rabi crops in late because of land unsuitability and long duration of T. Aman rice. Boro rice was adopted about 75% of the cropped area in Rabi season and but yield was low because of inadequate irrigation facilities. In contrast wheat needs comparatively less irrigation than Boro rice. Moreover, mungbean, mustard, lentil and grass pea produce reasonability good yield in rainfed condition. About 20-25% land become suitable for seeding wheat by first week of December after harvesting NfV T. Aman which indicated good prospect of growing wheat in the study village. Wheat is a more profitable Rabi crop than other crops like grass pea, mustard, lentil. Farmers earned the highest per hectare gross return (Tk.98646) and gross margin (Tk.22870) from the Wheat - Aus rice - T. Aman rice pattern whereas Boro rice - Fallow - T. Aman pattern produced the lowest gross return (Tk.65918) and gross margin (Tk.10134). Higher benefit was achieved from the pattern Wheat - Aus rice - T. Aman rice because of less production cost and high price of wheat grain, though three cereals crops could exhaust soil nutrient so that Mungbean-Aus rice - T. Aman pattern may be alternate option to sustain soil health as well as productivity of the selected area.
  • Authors:
    • Oweis, T.
    • Karrou, M.
  • Source: Agricultural Water Management
  • Volume: 107
  • Year: 2012
  • Summary: Selecting appropriate crops and applying deficit irrigation can help increase water productivity in water-limited regions such as the Mediterranean. The objective of this study was to develop water production functions of major cereal and legume crops under the same environmental and management conditions. Bread and durum wheat, faba bean, chickpea, and lentil were grown under full supplemental irrigation (FSI), two deficit irrigations levels of 2/3 of FSI (2/3SI) and 1/3 of FSI (1/3SI), and under rainfed conditions (no irrigation). In average, the actual evapotranspirations (ETs) under FSI were 549, 552, 365, 451 and 297 mm, for bread wheat, durum wheat, faba bean, chickpea and lentil, respectively. For the same crops, they were 463, 458, 330, 393 and 277 mm for the treatment 2/3SI and 357, 351, 265, 318 and 244 mm for the treatment 1/3SI, respectively. In the case of the rainfed treatment, ETs for the mentioned crops were 250, 251, 227, 237 and 215 mm, respectively. The experiment was conducted at the ICARDA experimental station at Tel Hadya, near Aleppo, Syria, over three growing seasons from 2007 to 2010. Results showed that, in general, the treatment with 1/3 of FSI gave the highest rate of increase in grain yield and water productivity. The mean grain yield from rainfed, 1/3SI, 2/3SI, and FSI were 1.36, 3.82, 5.18, and 5.70 t/ha for bread wheat; 1.24, 3.80, 5.10, and 5.75 t/ha for durum wheat; 1.57, 2.35, 2.86, and 3.54 t/ha for faba bean, 1.36, 2.63, 3.36, and 3.74 t/ha for chickpea, and 0.64, 1.16, 1.42, and 1.58 t/ha for lentil respectively. Grain yield reductions due to the application of 2/3SI were around 10, 5, 15.6, and 10.2% of FSI on average for wheat, chickpea, faba bean, and lentils, respectively. Deficit irrigation at 2/3SI increased water productivity compared to rainfed treatments, by 200, 223, 126, 148 and 190% for bread wheat, durum wheat, faba bean, chickpea, and lentils, respectively. However, differences in total water productivity of crops grown under full irrigation compared to deficit irrigation were not significant. Irrigation water productivity ranged from 25 kg ha -1 mm -1 in wheat with 1/3SI to 10 kg ha -1 mm -1 for legumes under the FSI treatment. Unlike legumes, maximizing wheat grain yield caused a decline in water productivity.
  • Authors:
    • Van Remortel, R.
    • Smith, E.
    • Mehaffey, M.
  • Source: Ecological Applications
  • Volume: 22
  • Issue: 1
  • Year: 2012
  • Summary: Meeting future biofuel targets set by the 2007 Energy Independence and Security Act (EISA) will require a substantial increase in production of corn. The Midwest, which has the highest overall crop production capacity, is likely to bear the brunt of the biofuel-driven changes. In this paper, we set forth a method for developing a possible future landscape and evaluate changes in practices and production between base year (BY) 2001 and biofuel target (BT) 2020. In our BT 2020 Midwest landscape, a total of 25 million acres (1 acre = 0.40 ha) of farmland was converted from rotational cropping to continuous corn. Several states across the Midwest had watersheds where continuous corn planting increased by more than 50%. The output from the Center for Agriculture and Rural Development (CARD) econometric model predicted that corn grain production would double. In our study we were able to get within 2% of this expected corn production. The greatest increases in corn production were in the Corn Belt as a result of conversion to continuous corn planting. In addition to changes to cropping practices as a result of biofuel initiatives we also found that urban growth would result in a loss of over 7 million acres of productive farmland by 2020. We demonstrate a method which successfully combines economic model output with gridded land cover data to create a spatially explicit detailed classification of the landscape across the Midwest. Understanding where changes are likely to take place on the landscape will enable the evaluation of trade-offs between economic benefits and ecosystem services allowing proactive conservation and sustainable production for human well-being into the future.
  • Authors:
    • Horwath, W. R.
    • Wroble, J. F.
    • Munk, D. S.
    • Wallender, W. W.
    • Singh, P. N.
    • Mitchell, J. P.
    • Hogan, P.
    • Roy, R.
    • Hanson, B. R.
  • Source: California Agriculture
  • Volume: 66
  • Issue: 2
  • Year: 2012
  • Summary: Reducing tillage and maintaining crop residues on the soil surface could improve the water use efficiency of California crop production. In two field studies comparing no-tillage with standard tillage operations (following wheat silage harvest and before corn seeding), we estimated that 0.89 and 0.97 inches more water was retained in the no-tillage soil than in the tilled soil. In three field studies on residue coverage, we recorded that about 0.56, 0.58 and 0.42 inches more water was retained in residue-covered soil than in bare soil following 6 to 7 days of overhead sprinkler irrigation. Assuming a seasonal crop evapotranspiration demand of 30 inches, coupling no-tillage with practices preserving high residues could reduce summer soil evaporative losses by about 4 inches (13%). However, practical factors, including the need for different equipment and management approaches, will need to be considered before adopting these practices.
  • Authors:
    • Rodrigues, J. G. L.
    • Fernandes, D. M.
    • Bicudo, S. J.
    • Nascimento, F. M.
    • Fernandes, J. C.
    • Furtado, M. B.
  • Source: Científica (Jaboticabal)
  • Volume: 40
  • Issue: 1
  • Year: 2012
  • Summary: The objective of this research work was to evaluate the effects of doses and time of application of N on the C/N ratio of the straw cover and on the growth and productivity of maize plants growing in a no tillage system. The experiment was carried out at the Experimental Farm of the College of Agriculture of the Sao Paulo State University (UNESP) on its campus of Botucatu, state of Sao Paulo, Brazil. The treatments were distributed in the field according to a randomized complete block design in a split plot arrangement. The treatments consisted of four doses of N (0, 20, 40, and 60 kg ha -1) applied to oat crop and N doses (60, 80, 100, and 120 kg ha -1) sidedressed to corn. The development and productivity of the maize crop in a no-tillage system were found to be dependent of the C/N ratio and the straw cover. The response of the maize plants to the early application of N is dependent on doses and time of application.
  • Authors:
    • Mkwinda, S.
    • Aune,J. B.
    • Ngwira, A. R.
  • Source: Field Crops Research
  • Volume: 132
  • Year: 2012
  • Summary: Low crop yields due to continuous monocropping and deteriorating soil health in smallholder farmers' fields of sub-Saharan Africa have led to a quest for sustainable production practices with greater resource use efficiency. The aim of the study was to elucidate the short term effects of conservation agriculture (CA) systems on soil quality, crop productivity and profitability. In Balaka market and Ntonda sections of Manjawira Extension Planning Area (EPA), in Ntcheu district, central Malawi, we compared continuous monocropped maize (Zea mays) under conventional tillage practice (CP) with different CA systems in continuous monocropped maize (CAM) and intercropping with pigeonpea (Cajanus cajan) (CAMP), Mucuna pruriens (CAMM), and Lablab purpureus (L) (Sweet) (CAML). The study was conducted from 2008 to 2011 in 72 plots in 24 farmers' fields. In Balaka market section CA plots with maize + legumes produced up to 4.3 Mg ha(-1) of vegetative biomass against 3.5 Mg ha for maize alone in CP. In Ntonda section CA plots with maize + legumes produced up to 4.6 Mg ha(-1) of vegetative biomass against 2.4 Mg ha(-1) for maize alone in CP. In both sections, during the entire study period. CA did not have a negative effect on crop yields. During the drier seasons of 2009110 and 2010/11, CA had a positive effect on maize grain yield at both sites (average yield of 4.4 and 3.3 Mg ha(-1) in CA and CP respectively). However, associating maize with legumes reduced maize yields compared to CAM particularly in drier years of 2009-10 and 2010-11. Farmers spent at most 47 days ha(-1) producing maize under CA systems compared to 65 days ha(-1) spent under conventional tillage practices. However, total variable costs were higher in CA systems compared to conventional practice (at most US$416 versus US$344 ha(-1)). CAMP resulted in more than double gross margin compared to CPM (US$705 versus uS$344 hat). Infiltration estimated as time to pond was highest in CA maize legume intercrops (8.1 s) than CP (6.8 s). Although it was not feasible to directly estimate effects on water balances of these farmer-managed experiments, it can be assumed that the yield differences between CA and CP could be attributed to tillage and crop residue cover since other farm operations were generally the same. Intercropping maize and pigeonpea under CA presents a win-win scenario due to crop yield improvement and attractive economic returns provided future prices of maize and pigeonpea grain remain favourable. (C) 2011 Elsevier B.V. All rights reserved.
  • Authors:
    • De Neve, S.
    • Sleutel, S.
    • Ngwira, A.
  • Source: Nutrient Cycling in Agroecosystems
  • Volume: 92
  • Issue: 3
  • Year: 2012
  • Summary: Conservation agriculture (CA) characterised by minimal soil disturbance, permanent soil surface cover by dead or living plants and crop rotations is one way of achieving higher soil organic carbon (C) in agricultural fields. Sandy loam and loamy soil samples from zero tillage (ZT) and conventional tillage (CT) plots were taken from farmers' fields during the dry season in August 2006. Soil organic carbon (SOC) and soil organic nitrogen (SON), microbial biomass carbon (MB-C) and microbial biomass nitrogen (MB-N), C mineralization and SOC distribution in particle size fractions in 0-20 cm layer were evaluated. Forty eight farmers' fields were randomly sampled at four different locations in Central and Northern Malawi, representing ZT plots maintained for a different number of years, and ten fields under CT with similar soil type and crop grown were selected. SOC and SON in ZT fields were 44 and 41 % (4 years ZT) and 75 and 77 % (5 years ZT) higher, respectively, than CT plots. MB-C and MB-N in ZT fields were 16 and 44 % (4 years ZT) and 20 and 38 % (5 years ZT) higher, respectively, than CT plots. However, MB-C and MB-N in ZT fields were 27 and 25 % (2 years ZT) and 17 and 9 % (3 years ZT) lower than in CT plots. The proportion of the total organic C as microbial biomass C was relatively higher under CT than ZT treatments. The higher SOC and MB-C content in the ZT fields resulted in 10, 62, 57 % higher C mineralization rate in ZT plots of 3, 4 and 5 years of loamy sand soils and 35 % higher C mineralization rate in ZT plot of 2 years than CT of sandy loam soils in undisturbed soils in the laboratory. Simulating plough from the undisturbed soils that were used for C mineralization experiment resulted in linear curves indicating that all organic C was already depleted during the first incubation period. The relative distribution of soil organic matter (SOM) in silt and clay size fractions was strongly correlated (r = 0.907 and P a parts per thousand currency sign 0.01) with silt percentages. Easily degradable carbon pool (C-A,C-f) was correlated (r = 0.867 and P a parts per thousand currency sign 0.05) with organic carbon in sand size fraction. In developing viable conservation agriculture practices to optimize SOC content and long-term sustainability of maize production systems, priority should be given to the maintenance of C inputs, crop rotations and associations and also to reduced soil disturbance by tillage.
  • Authors:
    • Larsen, S. E.
    • Kristensen, K.
    • Elsgard, L.
    • Blicher-Mathiesen, G.
    • Schäfer, C. -M
    • Hoffmann, C. C.
    • Petersen, S. O.
    • Torp, S. B.
    • Greve, M. H.
  • Source: Biogeosciences
  • Volume: 9
  • Issue: 1
  • Year: 2012
  • Summary: The use of organic soils by agriculture involves drainage and tillage, and the resulting increase in C and N turnover can significantly affect their greenhouse gas balance. This study estimated annual fluxes of CH4 and N2O, and ecosystem respiration (R-eco), from eight organic soils managed by agriculture. The sites were located in three regions representing different landscape types and climatic conditions, and three land use categories were covered (arable crops, AR, grass in rotation, RG, and permanent grass, PG). The normal management at each site was followed, except that no N inputs occurred during the monitoring period from August 2008 to October 2009. The stratified sampling strategy further included six sampling points in three blocks at each site. Environmental variables (precipitation, PAR, air and soil temperature, soil moisture, groundwater level) were monitored continuously and during sampling campaigns, where also groundwater samples were taken for analysis. Gaseous fluxes were monitored on a three-weekly basis, giving 51, 49 and 38 field campaigns for land use categories AR, PG and RG, respectively. Climatic conditions in each region during monitoring were representative as compared to 20-yr averages. Peat layers were shallow, typically 0.5 to 1 m, and with a pH of 4 to 5. At six sites annual emissions of N2O were in the range 3 to 24 kg N2O-N ha(-1), but at two arable sites (spring barley, potato) net emissions of 38 and 61 kg N2O-N ha(-1) were recorded. The two high-emitting sites were characterized by fluctuating groundwater, low soil pH and elevated groundwater SO42- concentrations. Annual fluxes of CH4 were generally small, as expected, ranging from 2 to 4 kg CH4 ha(-1). However, two permanent grasslands had tussocks of Juncus effusus L. (soft rush) in sampling points that were consistent sources of CH4 throughout the year. Emission factors for organic soils in rotation and with permanent grass, respectively, were estimated to be 0.011 and 0.47 gm(-2) for CH4, and 2.5 and 0.5 gm(-2) for N2O. This first documentation of CH4 and N2O emissions from managed organic soils in Denmark confirms the levels and wide ranges of emissions previously reported for the Nordic countries. However, the stratified experimental design also identified links between gaseous emissions and site-specific conditions with respect to soil, groundwater and vegetation which point to areas of future research that may account for part of the variability and hence lead to improved emission factors or models.
  • Authors:
    • Plieninger, T.
  • Source: Applied Geography
  • Volume: 32
  • Issue: 2
  • Year: 2012
  • Summary: This study explores the potential of historical maps to detect, measure and monitor changes of trees outside forests. The main goal is to assess local-level changes of scattered trees and orchards and their land-use determinants in two areas in Southern Germany between 1901/1905 and 2009. Firstly, overall landscape changes are recorded. Secondly, the spatial-temporal trajectories of scattered trees and their land-use determinants are identified. Thirdly, changes in quantity and fragmentation patterns of traditional orchards are analyzed in their relationship to overall land-cover change. The results confirm major losses in scattered trees, mainly due to urbanization, agricultural intensification, and land abandonment. They further reveal that, while orchards have persisted in total area, they have undergone critical changes toward a simplified landscape structure and loss of the traditional land-use mosaic, which is a characterizing feature of high nature value landscapes. Multi-temporal assessment showed that most trends have been continuous and did not change directions over time, but rather accelerated during periods of rapid change (most dramatically in the 1950-1990 period). The case of orchards and scattered trees illustrates a major problem of cultural landscapes in Europe: Semi-natural landscape features of high nature value are threatened by both intensification and abandonment of land uses. This makes their conservation a potentially costly enterprise, as both opportunity costs for lost alternative land uses and for conservation management costs arise. (C) 2011 Elsevier Ltd. All rights reserved.
  • Authors:
    • Shah, S. C.
    • Chen, Z. S.
    • Adhikari, K. R.
    • Ghimire, R.
    • Dahal, K. R.
  • Source: Paddy and Water Environment
  • Volume: 10
  • Issue: 2
  • Year: 2012
  • Summary: Despite being a major domain of global food supply, rice-wheat cropping system is questioned for its contribution to carbon flux. Enhancing the organic carbon pool in this system is therefore necessary to reduce environmental degradation and maintain agricultural productivity. A field experiment (November 2002-March 2006) evaluated the effects of soil management practices such as tillage, crop residue, and timing of nitrogen (N) application on soil organic carbon (SOC) sequestration in the lowland of Chitwan Valley of Nepal. Rice ( Oryza sativa L.) and wheat ( Triticum aestivum L.) were grown in rotation adding 12 Mg ha -1 y -1 of field-dried residue. Mung-bean ( Vigna radiata L.) was grown as a cover crop between the wheat and the rice. Timing of N application based on leaf color chart method was compared with recommended method of N application. At the end of the experiment SOC sequestration was quantified for five depths within 50 cm of soil profile. The difference in SOC sequestration between methods of N application was not apparent. However, soils sequestered significantly higher amount of SOC in the whole profile (0-50 cm soil depth) with more pronounced effect seen at 0-15 cm soil depth under no-tillage as compared with the SOC under conventional tillage. Crop residues added to no-tillage soils outperformed other treatment interactions. It is concluded that a rice-wheat system would serve as a greater sink of organic carbon with residue application under no-tillage system than with or without residue application when compared to the conventional tillage system in this condition.