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Socio-economic aspects and impact of land use change on sediment production dynamics in the northeastern region of India

100%

Sharma U. C. , Sharma V.

Annals of Warsaw University of Life Sciences - SGGW. Land Reclamation

2010

tom 42

nr 1

209-217

The northeastern region of India, with an area of 255 090 km2, is predominantly hilly. Major socio-economic factors affecting sediment production in the region are; shifting cultivation, land tenure system, fast growing population, small land-holdings, deforestation and free range grazing. A multi-disciplinary long- -term study showed that 92.9 to 99.1% of rainwater can be retained in-situ, compared to 66.3% in shifting cultivation. Mean annual soil loss varied from 11.2 to 97.2 t km–2 in new land use systems as against 3621.3 t km–2 in shifting cultivation. The sediment load per litre of runoff from watersheds varied from 1250–20,300 mg suspended sediment, 5.4 to 23.6 mg NO3 – N, 2.3 to 6.5 mg P–PO4, 17.2 to 35.8 mg K2O, 0.4 to 1.8 mg Zn, 0.9 to 2.7 mg Mn, 6.5 to 12.0 mg Mg, 7.1 to 18.4 mg Fe and 4.0 to 7.2 mg SO4. The sediment transport from the catchments showed spatial and temporal variations.

W pracy przedstawiono analizę czynników wpływających na wytwarzanie rumowiska w północno-wschodnim regionie Indii. Do głównych czynników naturalnych można zaliczyć wysokie opady deszczu (średniorocznie 2450 mm) oraz duże nachylenie terenu w zlewniach, dochodzące do 32–53%. Wśród czynników antropogenicznych jako istotne wskazuje się: duży udział gruntów ornych, duże rozdrobnienie i system własności gospodarstw rolnych, postępujące wylesianie oraz swobodny wypas bydła. Stwierdzono, że w wyniku przekształcenia gruntów ornych na inne użytki rolne wzrośnie retencyjność zlewni, a ilości odpływającego rumowiska zmniejszy się o ok. 90%. W tym celu konieczne są działania o charakterze prawnym, planistycznym, z zakresu gospodarki wodnej i zagospodarowania terenu.

Factors driving the shifting of land from rice to aquaculture farming in Bangladesh

100%

Akter S. , Rahman M. S. , Akter S. , Manjira S. , Beg T. H.

Journal of Agribusiness and Rural Development

2023

nr 4[70]

Species diversity and litter dynamics in secondary mixed deciduous forest, Thung Salaeng Lung National Park, Northern, Thailand

84%

Podong C. , Poolsiri R. , Katzensteiner K. , Pengthamkeerati P. , Thongdeenok P.

Folia Forestalia Polonica. Series A . Forestry

2013

tom 55

nr 4

This study present species composition and potential of litter on carbon and nitrogen return in secondary mixed deciduous forest after shifting cultivation. The dominant species of trees were Haldina cordifolia, Albizia odoratissima and Lagerstroemia duperreana. The Important Value Index (IVI) values of trees were 132.91, 17.78 and 14.22, respectively. The pattern for the decomposition coefficients (k) was highest in the wet period (May–September) and lowest in the dry period (October–April). The carbon and nitrogen return patterns increased in the dry period (October– April) and decreased in the wet period (May–September). Carbon and nitrogen loss in the decomposing litter continually decreased during the decomposition process from the initial levels, with a final relatively rapid release in the wet period. Results from this study was understanding of community composition, litterfall production and litter decomposition for understanding potential of secondary mixed deciduous forest for balancing carbon for mitigating greenhouse gas effect in the local area.

Mozliwosci przywrocenia do uzytkowania ugorow i odlogow

67%

Kus J.

Agrochemia

2003

nr 03

4-6

The Effect of Fallow Period Length on the Abundance and Diversity of Usable Plant Assemblages in Shifting Cultivation System (Swidden Agriculture) in Northern Laos

59%

Delang C. O. , Weiyi X. , Brooke B. , Chun K. P.

tom Vol. 64, nr 3

350--356

Shifting cultivation, or swiddening, involves alternating cycles of cropping and fallow periods. Rather than being abandoned, the fallow swidden fields provide a source of important plant products for remote, forest-dwelling human communities. In northern Laos, the traditional length of fallow periods used to range between five and 11 years, depending on the availability of land and quality of the soil. Fallow periods are currently being shortened because of population pressures and government policies. To determine the potential impacts of shorter fallow periods, 128 swidden fallows of various ages (up to 20 years), located at altitudes between 400 and 800 m a.s.l. in northern Laos were sampled for usable plants. The impact of fallow length on plant abundance and species diversity was analysed. The number of usable plant species was found to increase with the fallow age until it was 11–12 years old, and then decline, while the abundance of usable plants increased beyond that period. We conclude that shorter fallows will result in a significantly smaller usable plant abundance and species diversity for the villagers. We propose that 11–12-year-long fallows should be considered in order to fully exploit the greater plant volume of older fallows as well as the compositional shift of species in fallows over time.