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.
Nitrogen, phosphorus, potassium, magnesium, and sulphur requirements for maize grain production
Abstract Nitrogen, phosphorus, potassium, magnesium, and sulphur requirements for maize grain production were investigated at 7 sites selected in the Waikato, Bay of Plenty, and Poverty Bay to provide a range in soil nutrient status. High grain yields were achieved without pre-plant or starter fertiliser in Poverty Bay and using only 20–25 kg of Nand P as starter in the Waikato and the Bay of Plenty. It was concluded that no pre-plant P is required if the Olsen P test is 15 or above, and no pre-plant K is required if the K soil test is above 4. No evidence was found to support Mg or S applications to maize. The influence of soil N on the chemical composition of the maize plant, and its implications in diagnosis of nutrient deficiencies using tissue analysis, is discussed.
Keeping Farmers on the Land: Adding Value in Agriculture in the Veneto Region of Italy
Italy's relatively small area, high population density, and high land and labor costs have created the challenges of ensuring profitably for agricultural producers, slowing urban encroachment onto arable land, and keeping farm families on land that has been handed down within the families for generations. As part of the solution to these issues, the European Union is enacting policies to reduce producer dependence on direct subsidies while increasing the competitiveness of agricultural products and returns to producers, reinvigorating rural communities, and encouraging environmentally sound production methods. These regulations provide incentives for producers to add value to their products by obtaining legal recognition of typical products, participating in agritourism, and helping to promote traditional products for regional food systems. This paper examines how E.U. and national policies are encouraging farmers in the Veneto region of Italy to adopt an agricultural production model that encourages limited production of high-quality, high-value products and more diversified land use.