Nutrient management in integrated nursery stock production

Abstract

Integrated production systems mean using low inputs of herbicides, pesticides and fertilizers to achieve emission levels that are environmentally acceptable, while ensuring good economic performance. Two prototype nurseries (one for forestry and hedging plants, the other for ornamental conifers and shrubs) were started in 1991 in the Netherlands, to see if these goals could be attained via crop rotation, mechanical weed control, integrated pest management, the use of nematode-suppressing green manures which can replace chemical soil disinfection, and integrated nutrient management. A strategy was developed to adjust fertilizer application to plant growth. The methods used were row fertilization and split applications, based on the actual nitrogen availability during the growing season as measured by soil sampling. One aspect of this management is fertilizing with manure. The organic matter can reduce nutrient leaching by increasing the buffer for nutrients and water in the soil. It was studied whether the chosen strategy reduced the loss of nutrients to acceptable levels. For three years the nitrogen balance for the two prototypes in the growing season was worked out and checked against the amount of available nitrogen. The research indicated that the nitrogen uptake of nursery stock is relatively low. Under laboratory conditions, high potential mineralization rates were measured. These two factors explain why nitrogen accumulated in the top soil. This available nitrogen subsequently leached out, either later — as measured in the dry summer of 1992 — or sooneras measured in the wet summer of 1993. No leaching occurred in systems with high plant densities and in crops with high nitrogen demands. Concluded is that fertilizer use could be reduced by taking the amount of mineralized nitrogen into account. In nursery stock production, the loss of nutrients by leaching can be reduced to acceptable levels if organic matter low in available nutrients is applied.