A general model of crop yield response to herbicide application is proposed. The model includes three components: the effect of herbicide dosage on weed density, the effect of surviving weed density on crop yield and the effect of herbicide directly on the crop. The model is used to estimate the response of wheat yield to application of diclofop-methyl to control ryegrass .(Lolium rigidum) in A...

than 90% were interested in using farm management decision support software (Frasier et al., 1997). The GPFARM is an ARS decision support system for strategic (longsame survey also showed that 57% of 219 producer term) planning. This study evaluated its performance for comparing alternative dryland no-till cropping systems and established limits of respondents were interested in a farm manageme...

A wheat growth model that includes the direct responses of canopy photosynthesis and transpiration to elevated CO, and the response of crop growth to water stress has been developed and tested. Sensitivity analyses show that different cultivars have quite different responses to changes in ambient air temperature, ambient CO2 concentration and rainfall. Because crops reach maturity earlier under...

When averaged across the three growing seasons of the study, regression analyses indicated that 25R47 had maximum yield at ~1,320,000 seeds/acre, close to the recommended rate of 1,400,000 seeds/acre (Table 1). In contrast, 25R62 had a maximum yield at ~ 1,030,000 seeds/acre, about 400,000 seeds/acre less than the current recommended rate (Table 1). Furthermore, this variety did not respond to ...

The aim of this study is to estimate the green, blue and grey water footprint of wheat in a spatially-explicit way, both from a production and consumption perspective. The assessment is global and improves upon earlier research by taking a high-resolution approach, estimating the water footprint of the crop at a 5 by 5 arc minute grid. We have used a grid-based dynamic water balance model to ca...

TESAŘOVá, M., KUDLIČKA, P., POSPÍŠILOVá, L., KALHOTKA, L., HRABĚ, f.: Comparison of mineralisation and humification of postharvest residues of cereals in conventional and organic cropping. Acta univ. agric. et silvic. Mendel. Brun., 2006, LIV, No. 1, pp. 121–126 Yearly inputs and transformations of above – and underground plant residues of winter wheat and spring barley were followed in „intens...

A potential application of the normalized difference vegetation index (NDVI) is to monitor crop yields over large areas. The study concentrated on the spring Mheat areas of North Dakota and South Dakota for several years (1989-1992). The NOAA AVHRR data was carefully analyzed to minimize processing and sampling errors. Sums of biweekly NDVI county averages over an eight week period from heading...

this research aims at determining and evaluating the water productivity indexes in astan-ghods-razavi companies for different crops during 2007-2008 growth season. required field data were collected during several field surveys. these data consisted of crop yields and crop consumptive water that is irrigated by distinct agriculture well. with regard to collected data, four water productivity in...

Superoxide dismutase (SOD) acts as first line of defense against oxidative and genetic stress. Manganese superoxide dismutase (MnSOD), found in mitochondria or peroxisomes, contains Mn(III) at the active site. Therefore, it is of interest to study MnSOD from bread wheat (a grain crop). However, a structure model is not yet solved for bread wheat MnSOD. Hence, we describe the structure model of ...

It is a common practice to grow winter wheat (Triticum aestivum L.) as a dual-purpose crop in the U.S. Southern Great Plains to decrease production risk and to increase profit margin through cattle (Bos taurus) production. Crop management of the dual-purpose wheat is complex because of the tradeoffs between beef production and wheat grain yield. A wheat grazing model helps in making optimal dec...