scholarly journals Food vs. Wood: Dynamic Choices for Kenyan Smallholders

2016 ◽  
Vol 5 (1) ◽  
pp. 97 ◽  
Author(s):  
Alexandra Peralta ◽  
Scott M. Swinton

<p>Smallholder farmers in many areas of the semiarid tropics are planting exotic tree species that provide alternative income sources, fuel, and building materials. While providing other benefits, these trees often occupy land that could produce annual food crops. This study uses a polyperiod, linear programming model, to explore the opportunity cost of planting <em>Eucalyptus grandis</em> and <em>Grevillea robusta</em> trees compared to crops in the Nyando watershed of western Kenya. Results of the ten-year period wealth maximization model suggest that a representative farmer’s decisions on farm resource allocation are sensitive to changes in the relative prices of short rotation tree products and annual crops. The model also suggests that there are economic tradeoffs between planting trees and crops, as well as between planting different tree species. Timber production is not likely to replace food crops for two main reasons: (1) the high cost of meeting household subsistence requirements from marketed grains, (2) household cash flow needs met by annual crops. Farmers plant eucalyptus for commercial purposes because they can obtain timber products within four years; however if the prices of these short rotation products go down, farmers will prefer to grow timber from high yield grevillea.</p>

1991 ◽  
Author(s):  
John K. Francis ◽  
Henri A. Liogier
Keyword(s):  

1991 ◽  
Author(s):  
John K. Francis ◽  
Henri A. Liogier
Keyword(s):  

2009 ◽  
Vol 70 (1) ◽  
pp. 27-39 ◽  
Author(s):  
Paweł Zarzyński

Identyfikacja i analiza ilościowa substancji o charakterze fenolowym naturalnie występujących w drewnie wybranych gatunków drzew europejskich i egzotycznych


1993 ◽  
Vol 69 (6) ◽  
pp. 727-729 ◽  
Author(s):  
Horst Weisgerber

Investigations so far on the suitability of poplars for biomass production in short rotation periods in Germany were conducted almost exclusively with clones conceived for conventional cultivation. To introduce improved plant material, a special breeding program was implemented in Hann. Münden. It takes into consideration the most important criteria of suitability for the new form of land utilization. A report is given on findings so far from the realization of this program. Comprehensive basic plant material is available for European, North American and East Asian species from the sections Aigeiros, Leuce and Tacamahaca. Interspecific crossings are being carried out mainly in order to make the best possible use of combination and heterosis effects. A period of at least 20 years is necessary to develop new cultivars with high yield performance and yield stability. First results are presented on hybrids of species which are site-tolerant, resistant and particularly fast-growing at the juvenile phase. Plans to produce multiclonal varieties, each with 5 to 10 suitable clones with the same growing rhythm are in place. Special cultivation recommendations advocate clonal mixtures for each of the most important site units and for different rotation periods of from 2 to 5, 6 to 10 and more than 10 years. Key words: poplar, breeding, biomass, short rotation


2020 ◽  
Vol 48 ◽  
pp. 11-25
Author(s):  
Paloma de las Heras ◽  
Silvia Medina-Villar ◽  
M.Esther Pérez-Corona ◽  
Beatriz R. Vázquez-de-Aldana

2018 ◽  
Vol 24 (1) ◽  
pp. 19
Author(s):  
Sobrizal Sobrizal ◽  
Carkum Carkum ◽  
Wijaya M. Indriatama ◽  
Aryanti Aryanti ◽  
Ita Dwimahyani

<p>In the middle of 1980s, rice self-sufficiency in Indonesia has been achieved, but the growth of rice production slowed down since the 1990s. Narrow genetic variability of released rice varieties contributed largely to the occurrence of leveling of potential rice yield over the past decades. To enlarge the genetic variability, an intersubspecies crossing of Koshihikari (japonica) and IR36 (indica) has been performed. Through this crossing, three high yielding and high yield quality promising lines of KI 37, KI 238, and KI 730 have been obtained. The objective of this study was to evaluate the superiorities of these lines through multi-location yield trials, pests, diseases, and grain qualities examinations. Examination methods used followed the release food crops variety procedure issued by the Indonesian Ministry of Agriculture. The result of examinations showed that the average yield of KI 730 was 7.47 t/ha, it was significantly higher than that of Ciherang (6,73 t/ha). KI 730 has a good grain quality, with translucent milled rice, a high percentage of milled rice (78.0%) and head rice (91.01%). The texture of its cooking rice was soft, sticky, with the amylose content of 20.41%. In addition, pests and diseases resistances of KI 730 were better than those of other lines tested. After evaluation by National Food Crops Release Variety Team, the KI 730 line was released as a national superior variety with the name of Tropiko. Tropiko should become an alternative variety to grow widely in order to increase national rice production and farmers income.</p>


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