Crop yield analysis

This analysis has demonstrated that pesticide use in the world could be reduced by approximately 50% without any reduction in crop yields (in some cases increased yields) or the food supply. This effort would require applying pesticides only-when-necessary plus using various combinations of the nonchemical control alternatives currently available (34). Although food production costs might Increase slightly (0.5% to 1%), the added costs would be more than offset by the positive benefits to public health and the environment (15). 

One common example of qualitative analysis is the examination of the conditions of a particular environment. Farmers, for example, may have soil samples examined for mineral content to determine any necessary steps for producing a better crop yield. Qualitative analysis is also employed in detecting the presence of pollutants in rivers or other bodies of water, or in the land or air. Those who use water from wells may periodically have those wells tested for toxic substances such as lead. Again, although most people only see the results of the analysis as a positive or negative finding for some chemical or element, the rigorously developed procedures of qualitative analysis have still been applied. 

Increased knowledge about secondary nutrients and micronutrients, including plant requirements, nutrient sources, and methods of application, has resulted in th increased use. Improvements In soil testing and plant analyses have provided more knowledge about plant needs and the unde variations in plant responses to these nutrients. Higher crop yields and the use of h h-analysis NPK fertilizers also have resulted in increased needs for these nutrients. 

Present research, together with practical observation, points to the fact that the mere evaluation of crop yields in terms of tons of forage or bushels of grain produced per acre is not enough. Neither does a standard food analysis (a proximate analysis) tell the whole story. Rather, there is a direct and most important relationship between the fertility of the soil and the composition of the plant. 

We conclude, therefore, that the atmospheric effects of the many fires started by the nuclear war would be severe. For the war scenario adopted in this study, it appears highly unlikely that agricultural crop yield would be sufficient to feed more than a small part of the remaining population, so many of the survivors of the initial effects of the nuclear war would probably die of starvation during the first post-war years. This analysis does not address the additional complicating adverse effects of radioactivity or synergism due to concomitant use of chemical and biological warfare weapons. 

Reduction of 17a-EthynyI to 17a-Ethyl °° A solution of 5 g of 17a-ethynyl-androst-5-ene-3j9,17j5-diol in 170 ml of absolute alcohol is hydrogenated at atmospheric pressure and room temperature using 0.5 g of 5 % palladium-on-charcoal catalyst. Hydrogen absorption is complete in about 8 min with the absorption of 2 moles. After removal of the catalyst by filtration, the solvent is evaporated under reduced pressure and the residue is crystallized from ethyl acetate. Three crops of 17a-ethylandrost-5-ene-3) ,17j9-diol are obtained 3.05 g, mp 197-200° 1.59 g, mp 198.6-200.6° and 0.34 g, mp 196-199° (total yield 5.02 g, 90%). A sample prepared for analysis by recrystallization from ethyl acetate melts at 200.6-202.4° [aj, —70° (diox.). 

The o-dichlorobenzene extracts were combined and analyzed by GLC. Four peaks were observed under standard GLC conditions in the 10 to 15 min retention time range which is characteristic of hexachloro-dibenzo-p-dioxins (sample 1 in Table IV). The mixture was fractionally sublimed (120° to 175°G/1 mm). The major crop was harvested at 175 °G and recrystallized from anisole. Analysis of this material by GLG indicated that two isomeric hexachlorodibenzo-p-dioxins were present (sample 2). Overall yield (1.5 grams) of the product was 1-3% at 99+% purity, as determined by GLG and mass spectrometry. 

Notably, however, any comparison of biodiesel vs. bioethanol should be done with great caution, because analysis of an industry such as that related to biofuels is a very complex task and all conclusions are country dependent. It may be interesting, however, to compare the energy balance and environmental impact in producing biodiesel from oilseed rape and bioethanol from wheat crops [4], Table 9.3 reports this comparison. The energy balance for bioethanol is more positive than for biodiesel, in particular when straw is utilized, mainly due to the higher yield... 

The biofuel yield of different crops is differs, but a more correct analysis also requires consideration of the (fossil) energy inputs needed to seed, harvest, and process the crops, etc. Clearly, the results depend significantly on regional and technology details, but an overall comparison of net energy yield factors is given in Fig. 1. 

The solid was recrystalhzed from chloroform-methanol to yield brown needle-Uke crystals. The filtrates were concentrated to dryness and the resulting residue was recrystallized from chloroform-methanol. This was repeated a third time and the three crops of catalyst combined to yield 5.102 g (78.2 % isolated yield assuming 98 % pure). The crystals were analysed by carbon and proton NMR and elemental analysis. 

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