Spatial Variability of Soil Properties and Rice Yield Along Two Catenas in Southeast China

Rüth, B.; Lennartz, Bernd

doi:10.1016/s1002-0160(08)60032-6

Cited by 54 publications

(29 citation statements)

References 22 publications

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“…CEC was not found to be correlated (P≥0.31) to EI (Fig. 2d), in contrast to other studies (Ruth and Lennartz 2008;Yanai et al 2000Yanai et al , 2001. However, the high fertility of the soils and the tradition of consistently applying FYM to the fields may eliminate or reduce the importance of CEC effects.…”

Section: Environmental Variation and Soil Fertilitycontrasting

confidence: 56%

Recovery of nitrogen fertilizer by traditional and improved rice cultivars in the Bhutan Highlands

2010

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The recovery of soil derived nitrogen (N DFS ) and fertilizer N (N DFF ) was investigated in highland rice (Oryza sativa L.) fields in Bhutan, characterized by high inputs of farmyard manure (FYM). The effect of 60 kg N ha −1 (60 N) applied in two splits to a traditional and an improved cultivar, popular among the farmers, was investigated using the 15 N isotope dilution technique. No differences were found between cultivars with respect to the uptake of N DFS and N DFF , but the improved cultivar yielded 27% more (P≤0.05) grain compared with the traditional cultivar. This was largely due to its greater harvest index (HI). The mean percentage recovery of fertilizer N (REN) applied at 45 days after transplanting (DAT) was 34% compared to 22% at 7 DAT, resulting in 56% greater uptake of N DFF at 45 DAT. The overall REN for both the improved and the traditional cultivars were 25.7% and 30% respectively, with no difference between cultivars, but REN decreased with increasing FYM inputs. Fertilizer N recommendations that allow for previous FYM inputs combined with applications timed to coincide with maximum crop demand (45 DAT), and the use of improved cultivars, could enhance N fertilizer recoveries (REN) and increase rice yields in the Bhutan Highlands.

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Section: Environmental Variation and Soil Fertilitycontrasting

confidence: 56%

Recovery of nitrogen fertilizer by traditional and improved rice cultivars in the Bhutan Highlands

2010

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“…Bulk density, organic matter content and porosity constituted the soil properties with moderate spatial dependency with nugget/sill range of 45.46% to 64.50%. The moderately spatially dependent properties may be controlled by intrinsic variation of the soil such as texture and extrinsic factors such as land use activities (Cambardella et al, 1994;Ruth & Lennartz, 2008;Wu et al, 2010;Liu et al, 2013). MacCarthy et al (2013) also ascribed the low spatial dependency of topsoils to land use and management practices.…”

Section: Spatial Analysis Of Soil Propertiesmentioning

confidence: 99%

Spatial Variability Modeling of Soil Erodibility Index in Relation to Some Soil Properties at Field Scale

Gyamfi¹,

Ndambuki²,

Salim³

2016

ENRR

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Soil erosion is a major land degradation issue affecting various facets of human lives. To curtail soil erosion occurrence requires understanding of soil properties and how they influence soil erosion. To this end, the soil erodibility index which gives an indication of the susceptibility of soils to erosion was examined. In particular, we aimed to determine soil erodibility index at field scale and establish relationships that exist between selected soil properties and soil erodibility index. It was hypothesized that for soil erodibility index to vary spatially, then the existing soil properties should have varying spatial structure. Hundred disturbed and 100 undisturbed soil samples were collected from a 7.3 ha gridded area. The samples were analyzed for particle size distribution, bulk density, particle density, organic matter content and porosity. All soil analyses were conducted following standard procedures. Data were analyzed statistically and geostatistically on the basis of semivariograms. Sandy clay loam was the dominant soil texture in the studied field. Results indicate significant negative relationship between sand content, bulk density, particle density and organic matter with soil erodibility index. Silt correlated significantly with a positive relation with soil erodibility. Estimated erodibility for the sampled field ranged from 0.019 t.ha.hr/ha.MJ.mm to 0.055 t.ha.hr/ha.MJ.mm. The order of dominance of erodibility ranges were 0.038-0.042 t.ha.hr/ha.MJ.mm > 0. 036-0.08 t.ha.hr/ha.MJ.mm > 0.032-0.036 t.ha.hr/ha.MJ.mm > 0.019-0.032 t.ha.hr/ha.MJ.mm > 0.042-0.055 t.ha.hr/ha.MJ.mm . Regression analysis revealed silt to be the most significant variable that influences soil erodibility. The best regression of soil properties on soil erodibility index gave an R 2 of 0.90. A comparison of the regression equation with other studies indicated good performance of the equation developed.

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“…The county-based database usually requires relatively less soil data. However, when the DNDC model is used for a region with high heterogeneity in soil properties, the method produces higher uncertainty due to limited spatially differentiated soil information (Pathak et al, 2005;Cai et al, 2003;Li et al, 2004;Rüth et al, 2008). The study carried out for the Taihu Lake region has provided a chance to test the uncertainty as there is detailed soil information available for the region.…”

Section: Comparison Of Ch 4 Emissions Modeled With Polygon-and Countymentioning

confidence: 99%

Quantifying methane emissions from rice fields in the Taihu Lake region, China by coupling a detailed soil database with biogeochemical model

Zhang

Shi

et al. 2009

Biogeosciences

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Abstract. As China has approximately 22% of the world's rice paddies, the regional quantification of CH 4 emissions from these paddies is important in determining their contribution to the global greenhouse gas effect. This paper reports the use of a biogeochemical model (DeNitrification and DeComposition or DNDC) for quantifying CH 4 emissions from rice fields in the Taihu Lake region of China. For this application, the DNDC model was linked to a 1:50 000 soil database derived from 1107 paddy soil profiles compiled during the Second National Soil Survey of China in the 1980s-1990s. The simulated results showed that the 2.3 Mha of paddy rice fields in the Taihu Lake region emitted the equivalent of 5.7 Tg C from 1982-2000, with the average CH 4 flux ranging from 114 to 138 kg C ha −1 y −1 . As for soil subgroups, the highest emission rate (660 kg C ha −1 y −1 ) was linked to gleyed paddy soils accounting for about 4.4% of the total area of paddy soils. The lowest emission rate (91 kg C ha −1 y −1 ) was associated with degleyed paddy soils accounting for about 18% of the total area of paddy soils. The most common soil in the area was hydromorphic paddy soils, which accounted for about 53% of the total area of paddy soils with a CH 4 flux of 106 kg C ha −1 y −1 . On a regional basis, the annual averaged CH 4 flux in the Taihu Lake plain soil region and alluvial plain soil region were higher than that in the low mountainous and hilly soil region and the polder soil region. The model simulation was conducted with two databases using polygons or counties as Correspondence to: D. Yu (dshyu@issas.ac.cn) the basic units. The county-based database contained soil information coarser than the polygon system built based on the 1:50 000 soil database. The modeled results with the two databases found similar spatial patterns of CH 4 emissions in the Taihu Lake region. However, discrepancies exist between the results from the two methods. The total CH 4 emissions generated from the polygon-based database is 2.6 times the minimum CH 4 emissions generated from the county-based database, and is 0.98 times the maximum CH 4 emissions generated from the county-based database. The average value of the relative deviation ranged from −20% to 98% for most counties, which indicates that a more precise soil database is necessary to better simulate CH 4 emissions from rice fields in the Taihu Lake region using the DNDC model.

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Spatial Variability of Soil Properties and Rice Yield Along Two Catenas in Southeast China

Cited by 54 publications

References 22 publications

Recovery of nitrogen fertilizer by traditional and improved rice cultivars in the Bhutan Highlands

Recovery of nitrogen fertilizer by traditional and improved rice cultivars in the Bhutan Highlands

Spatial Variability Modeling of Soil Erodibility Index in Relation to Some Soil Properties at Field Scale

Quantifying methane emissions from rice fields in the Taihu Lake region, China by coupling a detailed soil database with biogeochemical model

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