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There is an ever-larger need for designing an integrated weed management (IWM) program largely because of the increase in glyphosate-resistant weeds, not only in the United States but also worldwide. An IWM program involves a combination of various methods (cultural, mechanical, biological, genetic, and chemical) for effective and economical weed control (Swanton and Weise 1991). One of the first steps in designing an IWM program is to identify thecritical period for weed control(CPWC), defined as a period in the crop growth cycle during which weeds must be controlled to prevent crop yield losses (Zimdahl 1988).

Field experiments were conducted in Nebraska with the experimental herbicide KIH-485 on soils with three different levels of organic matter (OM) to ascertain a dose response for weed control and corn tolerance. Dose–response curves based on the log-logistic model were used to determine the effective dose that provides 90% weed control (ED90 values) for three grasses (green foxtail, field sandbur, large crabgrass) and two broadleaf weeds (velvetleaf, tall waterhemp). The ED90 values for green foxtail control were 143, 165, and 202 g ai/ha for soils with 1, 2, and 3% OM, respectively at 28 d after treatment (DAT). The highest dose of 371 g ai/ha was needed for field sandbur control at 28 DAT, compared with 141 g ai/ha for large crabgrass, 152 g ai/ha for tall waterhemp, and 199 g ai/ha for velvetleaf. There was no significant corn injury observed. Grain yield increased with increasing doses of KIH-485; optimum yield was achieved at about 195 g ai/ha. From the dose–response curves it is clear that the proposed label rate of KIH-485 of 200 to 300 g ai/ha will provide excellent control of most grasses and certain broadleaf weeds in corn for at least the first 4 wk of the growing season on soils up to 3% OM in the state of Nebraska.

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The government of Bangladesh has long been striving to increase food security and to reduce poverty and malnutrition. In this regard, home gardens can play an important role in providing enhanced food supply and increased diversity of food to some extent. Studies on niche/ecosystem based homestead gardening were carried out at Lahirirhat Farming Systems Research and Development site, Rangpur under the On-Farm Research Division of Bangladesh Agricultural Research Institute during 2008-2009, resulting in the development of a year round production model, known as the Rangpur (Syedpur) model, for Tista Meander Floodplain agro-ecological region of Bangladesh. The objective of the study was to utilize the homestead resources in scientific ways for producing fresh vegetables and fruits over space and time and to enhance the nutritional supplies for the family throughout the year. A total of 12 households were selected from landless (no cultivable land), marginal (0.2-0.6 ha) and small (0.61-1.0 ha) farmer groups and seven production niches were intervened for round the year production following the Rangpur model.The niches were open sunny place, roof top, trellis, fence, boundary, marshy land and partially shady place. After the intervention, the highest amount of vegetables was produced by the small farmer groups (511 kg/year) followed by marginal (499 kg/year) and landless (422 kg/year) farmers. The yearly vegetable requirements of farmers were largely met by the homestead garden with a supply between 55 and 79 kg/head/year compared with the bench mark level of 21-30 kg/head/year before the intervention. The highest total income (BDT 5030/year) and net income (BDT 4290/year) were obtained from homestead at small farmers followed by marginal and landless farmers. From this study it is evident that the target farmers were able to fulfill their daily requirement of vegetables in most parts of the year by following the Rangpur model. This suggests an increase in food security and a reduction in malnutrition of farm families in the target households of Rangpur region in Bangladesh. The upscaling of the production model based on niche/ecosystem in different poverty stricken regions of Bangladesh is recommended to achieve food security and malnutrition reduction.

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