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| Registros recuperados: 10 | |
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| Zapata, Hector O.; Maradiaga, David Isaias; Pujula, Aude Liliana; Dicks, Michael R.. |
| This study conducts an investigation on the application of classical unit-root tests using parametric tests (the augmented Dickey-Fuller, 1979 – ADF), and nonparametric tests (Phillips and Perron, 1988—PP) to corn and soybean yields in the Delta states using county-level data from 1961 to 2009. The main concern of the paper is to assess what would be drawn about nonstationarity in crop yields using these tests versus using modified versions of these tests (Ng and Perron, 2001) that are assumed to solve size and power problems associated with the ADF and PP tests. The investigation focuses on methodological aspects of the classical tests, uncovers the nature of filtered yields often needed prior to density estimation, sheds light on the effect of lag... |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Crop yields; Nonstationarity; Unit-roots; Density estimation; Production Economics; Research Methods/ Statistical Methods; Risk and Uncertainty. |
| Ano: 2011 |
URL: http://purl.umn.edu/103871 |
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| Kwesiga, Freddie; Franzel, Steven Charles; Mafongoya, Paramu; Ajayi, Olu Clifford; Phiri, Donald; Katanga, Roza; Kuntashula, Elias; Place, Frank; Chirwa, Teddy. |
| The decline in soil fertility in smallholder systems is a major factor inhibiting equitable development in much of sub-Saharan Africa. Some areas fallow in order to strength soil fertility for later planting, but as populations increase, demand follows. and continuous cropping becomes the norm and there is a reduction in yields. This case study summarizes the development of improved tree fallows by researchers and farmers in eastern Zambia to help solve the problem of poor soil fertility. Many farmers are finding that by using improved fallows, they can substitute relatively small amounts of land and labor for cash, which they would need to buy mineral fertilizer. The study has three phases: the historical background (phase 1); an assessment of problems,... |
| Tipo: Working or Discussion Paper |
Palavras-chave: Zambia; Fallows; Crop yields; Soil fertility; Crop Production/Industries. |
| Ano: 2005 |
URL: http://purl.umn.edu/59247 |
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| Brookes, Graham; Yu, Tun-Hsiang (Edward); Tokgoz, Simla; Elobeid, Amani E.. |
| Biotech crops have now been grown commercially on a substantial global scale since 1996. This paper examines the production effects of the technology and impacts on cereal and oilseed markets through the use of agricultural commodity models. It analyses the impacts on global production, consumption, trade and prices in the soybean, canola and corn sectors. The analysis suggests that world prices of corn, soybeans and canola would probably be, respectively, 5.8%, 9.6% and 3.8% higher, on average, than 2007 baseline levels if this technology was no longer available to farmers. Prices of key derivatives of soybeans (meal and oil) would also be between 5% and 9% higher, with rapeseed meal and oil prices being about 4% higher than baseline levels. World prices... |
| Tipo: Working or Discussion Paper |
Palavras-chave: Biotechnology; Cereals; Crop yields; Oilseeds; Price effects; Productivity.; Crop Production/Industries; Demand and Price Analysis; Productivity Analysis. |
| Ano: 2010 |
URL: http://purl.umn.edu/56984 |
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| Wood, Stanley; You, Liangzhi; Zhang, Xiaobo. |
| From a theoretical perspective crop yields should tend to converge over time and space as: growth in yield potential exhibits diminishing returns; an increasing share of farmers shift to using high yielding varieties (HYVs); barriers to the free flow of knowledge and information are removed; and significant investments continue to be made in supporting institutions whose mandates include facilitating and accelerating the cross-border flow of improved agricultural technologies. Using a new, sub-national crop yield database for Latin America and the Caribbean (LAC) we examine whether convergence is indeed occurring, and discover it is not. On the contrary, there is evidence of divergence. We test three hypotheses that might help account for this finding:... |
| Tipo: Working or Discussion Paper |
Palavras-chave: Crop yields; Maize; Rice; Soybeans; Latin America; Caribbean; South America; Crop Production/Industries. |
| Ano: 2004 |
URL: http://purl.umn.edu/60322 |
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| Joshi, P.K.; Birthal, Pratap Singh; Minot, Nicholas. |
| This study examines the sources of crop income growth in Indian agriculture over the 1980s and 1990s. Using a method developed by Minot (2003), the analysis decomposes crop income growth into the contribution of yield increases, area expansion, price increases, and diversification from low-value crops to higher-value crops. The results confirm that at the national level, technology (higher yield) was the main source of crop income growth during 1980s, while rising prices and diversification emerged as the dominant sources of growth in agriculture during 1990s. Diversification towards higher-value crops such as fruits and vegetables accounted for about 27% of crop income growth in the 1980s and 31% in the 1990s. However, these national averages hide... |
| Tipo: Working or Discussion Paper |
Palavras-chave: Crops; Income growth; Agriculture; Grain production; Agricultural research; Research and development; High value commodities; Crop yields; Prices; High-value crops; Decomposition; Crop Production/Industries. |
| Ano: 2006 |
URL: http://purl.umn.edu/58572 |
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| Registros recuperados: 10 | |
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