Growth, yield components and micronutrient nutrition of field-grown maize (Zea mays L.) as affected by nitrogen fertilization and plant density
Growth and yield components in field-grown maize (Zea mays L.) were enhanced by nitrogen fertilization ranging from 50 to 200 kg N ha−1. Ear diameter, kernel depth, grain: stover ratio, number of ears plant−1, plant height and dry matter production increased as N fertilization rate was increased up to 100 or 150 kg N ha−1. Tasselling in maize was hastened by N fertilization. Increasing plant density from 25000 to 75000 plants ha−1 increased plant height, dry matter production and delayed tasseling but reduced ear diameter, kernel depth, grain: stover ratio and number of ears plant−1. Increased N supply and plant density had no influence on the concentrations of Mn, Zn, Cu, and Fe in ear leaf; except that Mn concentration increased as N fertilization rate was increased up to 150 kg N ha−1. Nitrogen × plant density interactions on the concentrations of the micronutrients in maize ear leaf were not significant.
THE ORGANIC MATTER CONTENT OF THE SAVANNA SOILS OF WEST AFRICA
Summary 
 
Published and unpublished data on the amounts of organic matter and nitrogen in the surface soils of the West African savanna are reviewed. In general, amounts are small; the mean carbon content of soils from 605 well-drained sites was 0.68 per cent. 
 
 
 
Two important factors governing amounts of organic matter in well-drained soils appear to be the clay content and a moisture factor related to the length of the wet season and represented here by mean annual rainfall. Multiple linear regression on soil clay content and rainfall accounted for 46.5 per cent and 57.2 per cent, respectively, of the observed variability of soil carbon and nitrogen contents. These findings suggest that the low levels of organic matter in savanna soils arise from their predominantly sandy nature and from the relatively low rainfall. In poorly drained soils organic matter levels are higher but are less significantly related to clay content and rainfall. The influence of human interference and of parent material and altitude on organic matter is demonstrated in the context of geographically limited areas within the savanna for which more detailed information was available.
Livestock Aspects of Feed Grain Policy
It is a signal event that our topic should be included on this program. In recent years, the livestock and poultry economy has scarcely been considered in the making of price and income policy for feed grains. It has been disregarded by pragmatic policy makers. It has been almost equally bypassed by theoretical economists, who usually kibitz freely. Policy for support and target prices for corn, grain sorghums, and other feed grains has been made with an eye almost exclusively fixed on the producers of those crops. The target price has been set relatively high in order to protect crop farmers' income. The latest (and current) loan rate policy has been to hold the rate low. Although a low rate facilitates moving grain into livestock and poultry consumption when crops are abundant, it does nothing to provide buffer stocks for years when crops are short. In addition, a couple of years ago it became administrative policy to dispose of the stocks inherited from an earlier period, even subsidizing their sale abroad. But the foremost example of one-sidedness is the attitude toward release prices. In all the rhetoric heard recently about the peril of holding corn or sorghums in reserve, the scold has been that release prices would not be set high enough. What group can the spokesmen have had in mind? Feed producers, of course! Not feed consumers, that is, livestock and poultry men. It has been a one-sided consideration of a two-sided issue. If all groups are to have equal voice in policy making, how can livestock and poultry interests be so ostracized? The one-sidedness has more impact now that so much livestock and poultry production has become detached from feed supply on individual farms. The livestock-poultry economy is therefore more sensitive to the availability and price of feed. It is in fact a contradiction that historically, livestock and poultry got more attention when they were still closely connected with feed production on the farm. In the early years of farm programs, the "ever-normal granary" was consciously designed to level out the supply and price of feed for livestock and poultry. Now that livestock and poultry have become more commercial and more vulnerable to a volatile feed situation, feed price stabilization has been progressively removed from the councils of farm policy. And the ultimate contradiction is that the alleged price-depressing perils of a feed reserve have been proclaimed in disregard of the fact that the main defense of feed grain producers' incomes is the target price-direct payment mechanism, not support prices. If grains on reserve should cause market prices to be reduced below target level, producers would get bigger direct payments, that is, producers with a base on their farm are protected in that way. Admittedly, production outside such a base would not be eligible for payment.