Cropped land

Until recently, the NRA has not participated during the approval process in assessing the potential environmental impact of pesticides. However, the NRA does supply monitoring data to MAFF and HSE for pesticide reviews. These occur once a pesticide has been approved for use for a certain length of time, or when further information is needed on an approved pesticide. In supplying these data, the NRA comments on any areas of concern. This contributed to the 1993 ban on the use of atrazine and simazine on non-cropped land. In January 1995 the NRA s National Centre for Toxic and Persistent Substances (TAPS) was made advisor to the DoF, on the potential impact on the aquatic environment of... 

Between 1935 and 1960 outputs per man-hour of labor increased about 4.5 times, and crop production per hectare of crop-land almost doubled. Inputs of labor were decreased by 50 percent, inputs of land remained relatively stable, but inputs of non-real-estate capital inputs were nearly tripled. Among these capital inputs, those of seed, feed, and livestock purchased increased by about four times, and those of mechanical power and machinery by more than 2.5 times. 

About 1.5 billion hectares of crop land are planted for annual crops and permanent crops. About one third of the arable and permenant crop-land is located in the United States, India, and China. Out of 1.5 billion hectares, 263 million hectares arc irrigated. Irrigated lands in China and India account for the largest share—about 110 million hectares. 

In this chapter we are focusing on two different plants which appear to express allelopathy in quite different fashions. The first, Parthenium hysterophorus Linn, is recognized in many parts of theworld as causing serious agricultural problems due principally to its invasion of crop lands and the subsequent lowering of crop yields (1). Although this plant is native to the North and Central Americas, it has now been spread to many other... 

Quimby, PC., King, L. R. and Grey, W.E. (2002). Biological control as a means of enhancing the sustainability of crop/land management systems , Agricultural Ecosystem and Environment, 88, 147-152. 

The model was forced with agricultural application data of the insecticide DDT compiled by Semeena and Lammel (2003). Statistical data of DDT consumption reported by member of the UN states to Food and Agriculture Organisation (FAO) were combined with other published data (details in Semeena and Lammel (2003)). The emission inventory assumed 100 % of p,p -DDT. After scaling the DDT consumption with crop land distribution, the data were extrapolated to the model grid. The result was a data set with spatially and temporally varying applications (accumulated application and temporal evolution shown in Figure 3.1). No seasonal or diurnal variation of the applications is considered. 

The main objective of this project was to study some of the ecological processes that occur during secondary succession in warm and humid tropics. This process is triggered after a perturbation in the tropical rain forest or the abandonment of crop land. ... 

Fig. 12 Concentrations of atrazine and diazinon in streams draining row-crop land and urban-use land in the Lake Erie Basin seasonal and spatial trends. From [89]...

While the forest was a supply of timber for homes, fuel, and often times, food, they were also sometimes regarded as a barrier. The labor to cut and burn the forest, to eke out crop land and impediments to vehicular travel, were not regarded as a benefit. Thus, for years the migrants cut and burned their way until they crossed the Appalachians and began the process again at the Rockies after having crossed the Great Plains. 

Rather than strictly segregating forests and crop land, agroforestry practices strive to combine the two elements on the same area. Constituting a mixture of annual and perennial plants, many forms of agroforestry can be considered functional mimics of natural ecosystems. 

Uses herbicide, cotton, citrus, non crop lands... 

Uses herbicide, growth regulator, non crop lands, pastures, maize,... 

Uses herbicide, sugar cane, non crop lands, lakes, ponds, ditches... 

Control of a wide range of annual and perennial broadleaved weeds in fruits, orchards, vineyards, citrus, non-crop land... 

Chemical weed control technology has progressed greatly during the past 30 years. The discovery of new classes of highly selective, effective, safe and relatively inexpensive herbicides helped revolutionize modern weed control. In the United States herbicides are used on more than 80 million hectares of crop and noncrop lands for control of numerous species of weeds, and more than 50% of the total crop land was treated with herbicides in 1988. Chemical names and structures for most of the herbicides discussed in this paper are given in Table 1. Most weeds are... 

Further support of rapid recovery of hydrological functions in secondary forest comes from the Zona Bragantina, east of Belem. Here, Holscher et al. (1997) used a Bowen ratio approach to measure evapotranspiration in a 2.5-3.5-year-old secondary forest on abandoned crop land, and found an average daily rate (3 9 mm d ) very close to that of mature forests receiving similar amounts of radiation. During the dry season, this secondary forest was absorbing water from below 3 m depth, and therefore had recovered a portion of its deep soil water uptake capacity. 

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