Academic literature on the topic 'Fallowing'

Shifting cultivation is considered to be a key cause of deforestation in the tropics as agriculturalists transform the rain forest into cropland and later allow for its regeneration through fallowing. Forest fallows strongly influence the ecological and economic potential of shifting cultivation, yet, secondary forest management among shifting cultivators remains poorly understood. This study focuses on secondary forest management among peasant households in a land-abundant ejido, near the Calakmul Biosphere Reserve of Mexico. Data were gathered through in-depth household interviews and field visits with 44 households, accounting for more than 450 fields. Striking differences were found in fallowing practices in Nuevo Becal. The holding of secondary forest is related to access to male labour, wealth in land-assets, household age, and the holding of pasture. Fallow length at the plot level is associated with household age, land holding size and the manner in which land is acquired. Fallow periods tend to be longer for cycles begun from primary forest and appear to have become longer over time. This study demonstrates the importance of the microdynamics that influence differential land use decisions among households under apparently similar environmental and macroeconomic conditions.

Thesis (MScFor)--Stellenbosch University, 2001.<br>ENGLISH ABSTRACT: Agroforestry researchers in Eastern Zambia have identified improved fallows as an intervention for soil fertility problems faced by small-scale farmers. In both on-station and on-farm research experiments which have been conducted since 1989, results have shown that improved fallows can mitigate soil degradation and eventually improve land productivity. Both researchers and extensionists have since embarked on disseminating these fallows to the farming community. Researchers were initially entirely dependent on the conventional agricultural extension services to disseminate the technology to the farmers but the process was slow and so was the uptake for the technology by farmers. As researchers were anxious to see that farmers took up improved fallows in a fastest possible way, they opted to use alternative dissemination pathways such as farmer trainers and local leaders. The purpose of this study was to investigate the three dissemination pathways and determine their effectiveness as regards improved fallows. This study assumed that farmers were not taking up improved fallows because they lacked knowledge of it, and also that the lack of knowledge was exacerbated by the ineffective pathway used to reach the farmers. The study was conducted in Chadiza, Chipata and Katete districts of Eastern Zambia. Data were collected using questionnaires in 28 villages across the three districts. Included in the sample were 296 small-scale farmers for whom this technology is intended. Additionally, 51 farmer trainers, 15 local leaders and 14 agricultural extension officers were interviewed as disseminators of this technology. Farmers were randomly sampled; local leaders were systematically sampled while a total enumeration was done for farmer trainers and agricultural extension officers present at the time of the interviews. This study found that 92% of the farmers were aware of the technology, with 68% having only known about it between 1998 and early 2000. This was the period when farmer trainers were already working. Farmer trainers were source of initial information to 41% of the farmers and yet they only started working recently. Although 92% of the farmers had heard about improved fallows, only 33% had ever planted some. Ten percent cf the entire population of farmers could be said to have adopted improved fallows because they have planted more than one fallow. Lack of knowledge is therefore not the only reason that farmers were not taking up improved fallows. Farmer trainers were found to currently be a more effective dissemination pathway as they were able to reach more farmers even in areas where agricultural extension officers had not been before. Local leaders have not been involved with disseminating improved fallows. Agricultural extension officers were hampered by lack of resources but were still trying to assist farmers with resource assistance from external institutions such as NGOs. The findings point to a need for participatory extension approaches as well as participatory monitoring and evaluation systems.<br>AFRIKAANSE OPSOMMING: Agrobosbou-navorsers in Oos-Zambië het braaklandbewerking geïdentifiseer as ingryping in grondvrugbaarheidsprobleme wat ondervind word deur boere wat op klein skaal boer. Die resultaat van eksperimente wat gedoen is as deel van beide proefplaas- en plaasnavorsing sedert 1989 het daarop gewys dat die bewerking van braaklande die agteruitgang van grond kan temper en geleidelik die produktiwiteit daarvan kan verhoog. Navorsers sowel as voorligtingsbeamptes het sedertdien onderneem om braaklandbewerking aan die boeregemeenskap bekend te stel. Navorsers was aanvanklik ten volle afhanklik van die konvensionele landbou-voorligtingsdienste om die verspreiding van tegnologiese kennis onder boere te hanteer. Hierdie verspreidingsproses was egter stadig en die boere het ook te lank geneem om die tegnologie in werking te stel. Aangesien dit vir die navorsers belangrik was dat boere braaklandbewerking so spoedig moontlik begin. het hulle daarop besluit om alternatiewe metodes van kennisverspreiding te gebruik. Hierdie alternatiewe metodes het behels dat inligting versprei is deur opleidingsbeamptes onder boere sowel as deur plaaslike leiers. Die doel van hierdie studie was om die drie kanale wat gebruik is om inligting te versprei, te ondersoek en die effektiwiteit daarvan vas te stel. Hierdie studie het voorveronderstel dat boere nie braaklandbewerking gebruik nie omdat hulle nie oor die nodige kennis beskik het nie, en dat die gebrek aan die nodige kennis veroorsaak en vererger is deur die oneffektiewe kanale wat gebruik is om die inligting onder boere te versprei. Die studie is uitgevoer in die distrikte Chadiza, Chipata en Katete van Oos-Zambië. Data is ingesamel deur die gebruik van vraelyste in 28 dorpe dwarsdeur die drie distrikte. Dié steekproef sluit 296 boere in wat op klein skaal boer en op wie dié tegnologie gemik was. Onderhoude is gevoer met 'n aantal addisionele persone, as verspreiders van tegnologiese kennis, bestaande uit Slopleidingsbeamptes onder boere, 15 tradisionele plaaslike leiers, en 14 landbou-voorligtingsbeamptes. Boere is lukraak getrek vir die steekproef Plaaslike leiers is sistematies getrek, terwyl die totale aantal opleidingsbeamptes en landbou-voorligtingsbeamptes wat teenwoordig was ten tye van die onderhoude, as proefpersone gebruik is. Daar is bevind dat 92% van die boere bewus was van dié tegnologie, waarvan 68% eers tussen 1998 en vroeg 2000 daarvan gehoor het. Dit was die periode waarin opleidingsbeamptes alreeds onder die boere werksaam was. Opleidingsbeamptes was vir 41% van die boere die bron van die oorspronklike inligting, en tog het hulle onlangs eers onder die boere begin werk. Alhoewel 92% van die boere al van die bewerking van braaklande gehoor het, het slegs 33% al ooit braaklande aangelê. Daar kan gesê word dat tien persent van die totale boerebevolking braaklandbewerking prakties toegepas het omdat hulle meer as een bewerkte braakland aangelê het. Die gebrek aan kennis is daarom nie die enigste rede vir boere se traagheid om die praktyk van braaklandbewerking te aanvaar nie. Opleidingsbeamptes blyk tans die mees effektiewe verspreiders van inligting onder boere te wees aangesien hulle daartoe in staat was om meer boere te bereik, selfs in gebiede waar landbou-voorligtingsbeamptes nog nooit voorheen was nie. Plaaslike leiers was nie betrokke by die verspreiding van braaklandbewerking me. Landbou voorligtingsbeamptes is gekniehalter deur'n gebrek aan hulpbronne, maar het steeds probeer om boere by te staan met behulp van bystand wat verleen is deur eksterne instellings soos Nie-Regeringsorganisasies (NRO's). Dié bevindinge dui op 'n behoefte aan voorligtingsbenaderings sowel as monitering- en evalueringstelsels wat deelnamegeoriënteer is.

碩士<br>國立中興大學<br>環境工程學系所<br>95<br>Abstract Eddy Covariance (EC) system was recommended a fine instrument to measure flux of greenhouse gases and turbulence heat flux.And this study is to measure and analysis to surface fluxes over rice paddies during flooded and fallowing seasons(2006/4-2006/5、2006/9-2006/10、2006/12、2007/1) in Wu-Feng Agricultural Research Institute, Taichung, Taiwan (24°01´ N ,120°41´ E).The soil during flooded seasons is coverd by water and the soil during fallowing seasons is not. It is found the value of latent heat fluxes are between 0 and 120 Wm-2, and the value of sensible heat fluxes are between -10 and 70 Wm-2 during flooded seasons.The energy balance ratio is 0.88 during flooded seasons daytime(7:00 am~5:00 pm). The value of latent heat fluxes are between 0 and 120 Wm-2, and the value of sensible heat fluxes are between -10 and 100 Wm-2 during fallowing seasons.The energy balance ratio is 0.7during fallowing seasons daytime(7:00 am~5:00 pm) The mean value of albedo during the fallowing seasons daytime period was 0.127 and the mean value of Bowen Ratio during the fallowing seasons daytime period was 0.82. The mean value of aerodynamic resistance(ra) during the daytime period was 50 sm-1,and canopy resistance(rc) was 406 s m-1. The aerodynamic resistance are always higher than canopy resistance.