• Authors:
    • Tivet, F.
    • Khamxaykhay, C.
    • Rattanatray, B.
    • Jullien, F.
    • Quoc, H. T.
    • Lestrelin, G.
  • Source: Renewable Agriculture and Food Systems
  • Volume: 27
  • Issue: 1
  • Year: 2012
  • Summary: Over the past half-century, major efforts have been made worldwide to develop sustainable alternatives to agricultural tillage. In line with these efforts, two main research development initiatives have supported the experimentation and dissemination of conservation agriculture (CA) in Laos. Here we present the results of a 4-year monitoring and evaluation study conducted in 21 villages targeted for dissemination. In a context of rapid transition to intensive commercial agriculture in Laos, CA has become an important constituent of agricultural landscapes. However, there are significant variations in adoption rates across the study region. Statistical and qualitative evidence suggests that experimentation and adoption are not contingent upon farm-level variables such as capital, labor, age and education. While access to land helps shape local decision-making, the land tenure threshold under which farmers are not willing to experiment with alternative cropping systems is relatively low and highly variable in both space and time. Rather, experience and awareness of land degradation, production costs, social cohesion and leadership appear to be key factors in explaining most variations in local adoption rates. These results indicate that the practice of CA is not necessarily incompatible with smallholder farming. However, while complex crop associations and rotations are necessary for integrated weed control and reduced chemical use, their diffusion would require a broader transformation of the agricultural industry and the current market demand.
  • 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:
    • Teixeira Junior, T.
    • Colombo, G. A.
    • Afferri, F. S.
    • Cancellier, L. L.
    • Pires, L. P. M.
    • Peluzio, J. M.
    • Ribeiro, G. R. dos S.
  • Source: Ciência Rural
  • Volume: 42
  • Issue: 3
  • Year: 2012
  • Summary: In order to evaluate the genetic divergence among soybean cultivars, an assay was carried out at Formoso do Araguaia, TO, Brazil, in off-season of 2007, in irrigated lowland conditions. The experimental design were randomized blocks with 12 treatments and three replications. Genetic divergence was evaluated by multivariate procedures: Mahalanobis distance, Tocher clustering method's and nearest neighbor method. It was observed the formation of two distinct groups by the dendrogram of genetic dissimilarity, which were identical to those groups formed by Tocher's method. The Tocher optimization method and the nearest neighbor agreed among themselves. The traits number of days to maturity, plant height and weight of 100 seed were the ones that most contributed for genetic dissimilarity. The presence of genetic variability allowed the identification of dissimilar cultivars with high average for the evaluated traits. The hybridations 'DOKO' * 'CONQUEST' and 'DOKO' * 'FT-2000' are promising to obtain segregating populations with high variability.
  • Authors:
    • Cornet, D.
    • Gaiser,T.
    • Srivastava, A. K.
    • Ewert, F.
  • Source: Field Crops Research
  • Volume: 131
  • Year: 2012
  • Summary: Soil fertility restoration and crop performance in many developing countries with low input agriculture strongly relies on fallow duration and management. More precise information about the availability of fallow land may provide a way to improve the simulation of yarn (Dioscorea spp.) yields at the regional scale which has hardly been considered in prevailing approaches to model regional crop production. The probable reason behind this is scarce availability of data on fallow duration and variation across the farms in a region. Therefore, this study attempts to estimate effective fallow availability for yam production at the regional scale and to simulate the effect of fallow on regional yam yield. Yam growth and yield were simulated with the EPIC model which was incorporated into a Spatial Decision Support System (SDSS) covering a typical catchment with variable land use intensity within the sub-humid savannah zone of West Africa. Yarn-fallow rotations were simulated within 1120 quasi-homogenous spatial units (LUSAC = Land Use-Soil Association-Climate units) and aggregated to the 121 sub-basins and ten districts within the catchment under three different scenarios of fallow availability: (Si) Total savannah area was available as fallow land, (S2) 50% of the bush savannah was available as fallow land and (S3) 25% of the bush savannah was available as fallow land. The aggregation procedure adopted in this study was based on changes in the frequency of fallow-cropland classes within the sub-basins to render the SDSS sensitive to changes in fallow availability. Comparison of the average simulated tuber yield with the observed mean yield over the entire catchment showed that the simulations slightly overestimated the yields by 0.4% for scenario S1, whereas, underestimated by 14.2% and 36.8% in scenario S2 and S3 respectively. When compared with the effective fallow availability to maize, it was concluded that, (1) due to farmers preferences to plant yam mainly on virgin savanna land and as the first crop in the rotation after fallow, the effectively available fallow area for yam is higher than for maize and (2) the applied approach is suitable to derive effective fallow availability for yarn production at the district scale. (C) 2012 Elsevier B.V. All rights reserved.
  • Authors:
    • MacCarthy, D. S.
    • Fosu-Mensah, B. Y.
    • Vlek, P. L. G.
    • Safo, E. Y.
  • Source: Nutrient Cycling in Agroecosystems
  • Volume: 94
  • Issue: 2-3
  • Year: 2012
  • Summary: Under low input subsistence farming systems, increased pressure on land use and decreased fallow periods have led to a decline in soil productivity. The soils in sub-humid region of Ghana are generally poor and require mineral fertilizer to increase crop productivity. This paper presents the use of Agricultural Production Systems sIMulator (APSIM) to simulate the long term influence of nitrogen (N) and phosphorus (P) on maize (Zea mays L.) yield in Sub-humid Ghana. The APSIM model was evaluated at two sites in Ejura, on a rainfed experiment carried out on maize in 2008 major and minor seasons, under various nitrogen and phosphorus rates. The model was able to reproduce the response of maize to water, N and P, and hence simulated maize grain yields with a coefficient of correlation (R-2) of 0.90 and 0.88 for Obatanpa and Dorke cultivars, respectively. A 21-year long term simulation, with different rates of N and P mineral fertilizer application, revealed that moderate application of N (60 kg N ha(-1)) and 30 kg P ha(-1) improves both the long term average and the minimum yearly guaranteed yield. Variability in grain yield increased with increasing application of N fertilizer in both seasons. Treatments with P fertilizer application shows a similar trend for the major season and reverse trend for the minor season, thereby suggesting an interactive effect with rainfall amounts and distribution. Application of 30 kg P ha(-1) significantly increased the response to N. The response to mineral fertilizer (N and P) applications varied between seasons, suggesting the need to have a range of fertilizer recommendations to be applied based on seasonal weather forecast.
  • Authors:
    • Wilson, B.
    • Ghosh, S.
    • Mandal, B.
    • Senapati, N.
    • Ghoshal, S.
  • Source: Agriculture Ecosystems and Environment
  • Volume: 156
  • Year: 2012
  • Summary: Soil organic carbon is considered to be of central importance in maintaining soil quality. We assessed the effects of a range of commonly applied organic and inorganic amendments on soil quality in a rice-wheat cropping system in the Indo-Gangetic plains of eastern India and evaluated the carbon sequestration potential of such management approaches using a 25 year old long-term fertility experiment. Results showed that there were significant increases in soil nutrient availability with the application of farm yard manure (FYM @ 7.5 t ha -1), paddy straw (PS @ 10 t ha -1) and green manure (GM @ 8 t ha -1) along with inorganic fertilizer. Both microbial biomass C and mineralizable C increased following the addition of the organic inputs. Continuous cultivation, without application of organic inputs, significantly depleted total C content (by 39-43%) compared with treatments involving the addition of organic amendments. A significant increase in the non-labile C fraction resulted from both organic and inorganic amendments, but only 26, 18 and 6% of the C applied through FYM, PS and GM, respectively was sequestered in soils. A significant increase in yield of kharif rice was observed as a result of the addition of these organic amendments.
  • Authors:
    • Roy-Macauley, H.
    • Jalloh, A.
    • Sereme, P.
  • Source: Agriculture Ecosystems and Environment
  • Volume: 157
  • Year: 2012
  • Summary: The West and Central Africa (WCA) sub region covers a total area of over 11.5 million km 2 with a population of over 318 million. Most of the rural population in WCA are poor and food insecure and about 70% of the people in the region depends on agriculture, which accounts for over 35% of Gross Domestic Product (GDP) and over 40% of its export. The agroecological zones of WCA are closely related to the agro climatic zones of the region with rainfall decreasing from the southern coast in the forest region to the sub humid and semi arid Sahelian region in the north. The major agroecosystems of WCA include the semi arid, sub humid, humid forest, and swamp. Growing populations, inappropriate agricultural practices and changing climate in the region are influencing the composition and ability of agroecosystems in providing much needed ecosystem services. Coordinating efforts to tackle these challenges and leverage opportunities for sustainable agricultural production while ensuring conservation of the diverse ecosystems in the region is therefore a major preoccupation of the West and Central African Council for Agricultural Research and Development (CORAF/WECARD).
  • Authors:
    • Patnaik, U. S.
    • Dass, A.
    • Sudhishri, S.
    • Lenka, N. K.
  • Source: Agriculture Ecosystems and Environment
  • Volume: 158
  • Year: 2012
  • Summary: Contour hedgerows and grass filter strips are important towards enhancing and sustaining productivity of sloping agricultural lands in medium to high rainfall regions. However, impact of such measures on erosion control, soil carbon sequestration and agronomic productivity have not been widely assessed for the small land holders in eastern India. Therefore, an on-farm study was conducted between 2001 and 2006 to evaluate the impact of the techniques on soil organic carbon (SOC) concentration and pool; losses of water, soil and nutrients; soil moisture storage and agronomic yield on arable lands of 2-5% slope. The study was taken in 5.95 ha area with six treatments and nine replications. Treatments consisted of two hedgerow species ( Gliricidia sepium and Indigofera teysmanni) and a control, with or without grass filter strip (GFS) of a local species ( Saccharum spp.). Using finger millet ( Eleusine coracana) as the test crop, the hedgerow species were planted at 0.5 m * 0.5 m spacing in staggered double rows and the GFS in a single row at 0.3 m spacing. In general, Gliricidia + GFS was most conservation effective followed by Indigofera + GFS. It reduced runoff by 33% (10.7% runoff compared to 16.1% in control), soil loss by 35% (6.3 Mg ha -1 compared to 9.71 Mg ha -1 in control), and SOC loss through runoff by 50 kg ha -1 yr -1. In addition, it resulted SOC build up at 0.352-1.354 Mg ha -1 yr -1 at three graded distance from hedgerows, out of which 0.352 Mg ha -1 yr -1 was sequestered due to soil reclamation and about 1.0 Mg ha -1 yr -1 was retained due to barrier effect. With higher soil moisture storage by 28-37 mm and 22-43 mm at 12 and 17 days of dry spell, respectively, the grain yield of finger millet increased by 49% from 952 kg ha -1 in control to 1413 kg ha -1 in Gliricidia + GFS treatment. Addition of GFS significantly reduced the losses of water runoff, soil and nutrients in all the treatments, and increased SOC stock by 0.38-1.0 Mg ha -1 in the 0.6 m soil profile. The GFS also improved soil moisture storage by 9-12 mm and 6-15 mm at 12 and 17 days of dry spell, respectively. As compared to the pre-treated initial, the SOC stock decreased by 60-112 kg ha -1 yr -1 in the control indicating on-going erosion process in unprotected lands. The study showed the C sink potential of erosion control measures in the sloping agricultural lands of eastern India.
  • Authors:
    • Dass, A.
    • Sudhishri, S.
    • Choudhury, P. R.
    • Lenka, N. K.
    • Patnaik, U. S.
  • Source: Agriculture Ecosystems and Environment
  • Volume: 150
  • Year: 2012
  • Summary: Sloping hills ravaged by shifting cultivation often causes soil erosion problems in the downstream cultivated lands. This study was carried out in the highland zone of Eastern India to evaluate selected horti-silvi-pastoral systems in terms of soil carbon build up, soil aggregation and soil moisture retention in a degraded sloping land. The experiment was taken up during 2000-2006 in a degraded hillock of about 4.0 ha area with eight treatments involving two fruit species (cashew and guava), two grass species ( Stylosanthes hamata and natural grass) and two in situ (trench or no-trench) moisture conservation measures. Hedge rows of Indigofera teysmanni (silviculture component) were used uniformly for all the treatments. Trenches of 0.45 m * 0.45 m * 1.0 m dimension at 0.5 m u/s side of fruit plants conserved 2.18 g 100 g -1 higher soil moisture on an average in the 0-30 cm layer. The effect of fruit tree component was visible during 6th year of study in terms of soil organic carbon (SOC) only. In 6 years, the average increase in SOC and water stable aggregates in the 0-30 cm profile was 89% and 46% under rehabilitation treatments. The SOC stock at the end of 6 years was 34-40 Mg ha -1 in the 0-30 cm profile under treatments as compared to 21 Mg ha -1 under control. The SOC build up rate increased linearly with time and the average rates were 4.5, 3.5 and 0.64 Mg ha -1 yr -1 for Stylosanthes and natural grass based treatments and control, respectively. In all the systems, macroaggregates (>250 m) were higher in proportion and contained higher organic carbon. Guava+Stylosanthes+Trench system proved better in terms of soil carbon build up, soil aggregation and soil moisture retention.
  • Authors:
    • Birkmose, T. S.
    • Hansen, M. N.
    • Nyord, T.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 160
  • Year: 2012
  • Summary: To provide better advice to farmers and authorities on the most efficient way to reduce ammonia volatilisation from slurry applied to fields with standing crops, various treatments and injection methods were tested in field trials. In six separate experiments conducted at Research Centre Foulum, Denmark from 2007 to 2009, pig slurry was applied to winter wheat ( Triticum aestivum L.) to determine how anaerobically digestion, solid-liquid separation of slurry and different soil injection techniques influence crop yield and ammonia emissions (NH 3). The NH 3 emission was measured by either a wind-tunnel method or by a micro-meteorological mass balance method. Both injection and solid-liquid separation were found to reduce NH 3 emission. The emission from the separated slurry did not include the emission from the solid fraction. Most effective injection techniques were found to be a winged tine or a combination of discs and a tine, which reduced NH 3 emission from approximately 20% (surface band spreading) to approximately 5% of applied Total Ammoniacal Nitrogen (TAN). The NH 3 emission from surface-applied anaerobically digested slurry was found to be almost twice that from surface-applied untreated slurry. Injection did not affect yields significantly compared with surface application in any of the experiments, but did result in a significantly increased protein content in grains compared to band application, which increased the nitrogen utilisation of slurry nitrogen. Of the techniques tested, soil injection and solid-liquid separation reduced NH 3 emissions most effectively.