Prescribed fire was used in two semiarid grasslands to reduce shrub cover, promote grass production, and reduce erosional loss that represents a potential non–point-source of sediment to degrade water quality. This study measured transported soil sediment, dynamics in soil surface microtopography, cover of the woody shrub, grass, and bare ground cover classes, and soil fertility measured by nit...

For 5 yr we monitored the fertility of a volcanic-ash derived Inceptisol at a site in the humid tropics of Costa Rica. After forest felling and burning, we established four treatments in a randomized block design with six blocks: a sequence of monocultures (two crops of maize [Zea mays] followed by cassava [Manihot esculenta], then the tree species Cordia alliodora), successional vegetation, a ...

Leaf lifespan varies widely among plant species, from a few weeks to >40 years. This variation is associated with differences in plant form and function, and the distribution of species along resource gradients. Longer leaf lifespans increase the residence time of nutrients and are one mechanism by which plants conserve nutrients; consequently, leaf lifespan should increase within species with ...

Removing carbon dioxide (CO2) from the atmosphere and storing the carbon (C) in resistant soil organic matter (SOM) is a global priority to restore soil fertility and help mitigate climate change. Although it is widely assumed that retaining rather than removing or burning crop residues will increase SOM levels, many studies have failed to demonstrate this. We hypothesised that the microbial na...

Soil fertility is one of many factors which influence farmers’ choices regarding agricultural production, fertilisation and soil and water conservation. Before we can study the effects however, we need to measure soil fertility. We use the QUEFTS model (QUantitative Evaluation of the Fertility of Tropical Soils Janssen et al., 1990), which predicts crop yields from chemical soil characteristics...

a field study was undertaken with four farming systems (fs) such as; grasses and fodders, agro-forestry, agriculture (new farming systems) and shifting cultivation (old practice), to investigate the effect of land use on the soil properties, erosion and crop productivity on a loamy acidic alfisol. besides crops, the livestock were also kept and their dropping were incorporated in the respective...

amounts involved are much smaller. The amount of boron in the 7-ton potato crop (if determined) would have been about 0.2 pound. In the case of boron (and to a lesser degree the other micronutrients) if the soil contains excessive amounts, toxic quantities are absorbed by plants and growth is restricted. The need for a reasonable balance in amounts of available nutrients in the soil has been po...

If all resources are harnessed, and adequate measures taken to minimize soil degradation, sufficient food to feed the population in 2020 can be produced, and probably sufficient for a few billion more. These were the key conclusions from a Discussion Meeting held at the Royal Society in London in December 1996. The meeting entitled ‘Land resources: on the edge of the Malthusian precipice?’ atte...