Land Distribution and International Agricultural Productivity

The unequal distribution of agricultural land is often cited as a source of inefficiency in agriculture. Previous cross-country studies of agricultural productivity differences, though, have not considered land inequality. This article addresses this issue by using cross-country data on inequality in operational holdings of agricultural land from Deininger and Squire (1998) . In an estimation of an agricultural production function, the Gini coefficient for land holdings is found to have a significant negative relationship with productivity. This is consistent with the existence of heterogeneity in productivity by farm size within countries. A one standard deviation drop in the Gini coefficient implies an increase in productivity of 8.5%. Copyright 2007, Oxford University Press.

Efeito de aditivos biológicos comerciais na silagem de capim-elefante (Pennisetum purpureum Schum) Effect of commercial biological additives on elephantgrass (Pennisetum purpureum Schum.) silage

Avaliaram-se o pH e a composição bromatológica de silagens de capim-elefante var. Napier, sem e com três aditivos biológicos comerciais (B, C e D) em duas concentrações de diluição, a recomendada pelo fabricante (concentração 1) ou com o dobro (concentração 2), feitas em microsilos de PVC. O delineamento experimental foi inteiramente ao acaso, com sete tratamentos e seis repetições por tratamento. Apenas o aditivo B em ambas as concentrações (3,73; 4,07) foi eficiente em reduzir (P<0,05) o pH em relação ao tratamento-controle (5,01). A porcentagem de matéria seca aumentou (P<0,05) com o uso do aditivo B, nas concentrações 1 (29,9) e 2 (31,3), e dos aditivos C e D, na concentração 2 (26,8; 25,7). Quanto à proteína bruta, somente houve diferença (P<0,05) entre o tratamento-controle (6,6) e os dois tratamentos com aditivo B (13,4; 12,09). As frações de fibra em detergente neutro e lignina foram menores (P<0,05) nos tratamentos com aditivo B em relação ao tratamento-controle. A duplicação da dose do aditivo B não aumentou sua eficiência. Nos macro-elementos cálcio e fósforo das silagens, todos os aditivos elevaram a concentração de cálcio e não alteraram a de fósforo. Concluiu-se que o aditivo B, constituído de Lactobacillus plantarum e Pediococcus acidilactici, melhorou tanto a qualidade de fermentação quanto o valor nutritivo da silagem de capim-elefante, e que a duplicação da concentração dos produtos não aumentou (P<0,05) a qualidade das silagens.<br>A completely randomized design with seven treatments and six replicates per treatment was conducted to study the effect of three commercial biological additives (B, C and D), in two concentrations (manufacturer’s recommended dose - concentration 1 or double dose -concentration 2) on pH and chemical composition of elephantgrass (var. Napier) silage. A lower pH (P<0.05) was observed in silage with additive B at concentrations 1 (pH=3.73) and concentration 2 (pH=4.07), when compared to the control treatment (pH=5.01). Silage dry matter (%) increased (P<0.05) with the use of additive B at concentrations 1 and 2 (29.9% and 31.3 %, respectively) and additives C and D at concentration 2 (26.8% and 25.7%, respectively) in comparison to the control treatment (24.0%). Silage with additive B had higher crude protein levels than the control treatment (6.6%) at concentrations 1 (13.4%) and 2 (12.1%). Lignin and neutral detergent fiber levels were lower (P<0.05) for treatments with additive B. The use of doble level of additive B did not increase its efficiency. All additives increased calcium concentration, but not phosphorus concentration. These results indicated that additive B (Lactobacillus plantarum and Pediococcus acidilactici) improved elephantgrass silage fermentation process and its nutritional value. Increasing commercial biological additives above the manufacturer’s recommended level did not improve (P<0.05) silage quality

Monitoring the world's agriculture

To feed the world without further damaging the planet, Jeffrey Sachs and 24 food-system experts call for a global data collection and dissemination network to track the myriad impacts of different farming practices