Sheep Wool as Fertiliser for Vegetables and Flowers in Organic Farming

摘要

The availability of fertilisers for organic farming is often limited and not standardised. In Germany, high amounts of uncleaned sheep wool are available. Because of the high amount of nutrients - especially nitrogen -, sheep wool pellets could be used as multi-functional fertiliser in vegetable and flower cultivations. Four sheep wool pellet types with a total nitrogen content of 10 to 11% DM and different supplements (10% cellulose, 20% potato starch, 20% casein) have been tested in open and protected cultivation. Tomatoes (Lycopersicon esculentum L.) were cultivated in greenhouse using substrate culture with perlite, bark compost and sheep wool slabs, respectively, and sheep wool pellets as fertiliser. Kohlrabi (Brassica oleracea var. gongylodes L.) and iceberg lettuce (Lactuca sativa var. capitata nidus Jagg.) were cultivated in the field comparing the effect of mineral and organic fertilisers (sheep wool pellets, lupine and ricinus wholemeal). In flower pot cultivation, different amounts of pellets were investigated with poinsettia (Euphorbia pulcherrima Willd.). In most experiments, a stimulating effect of the pellets on growth and yield could be determined in comparison with mineral and other organic fertilisers. In cultivation of iceberg lettuce, the best results in all quantitative and qualitative parameters were obtained when using pellets as a fertiliser. In kohlrabi, however, the yield in the treatment with pellets was up to 50% lower than with mineral or other organic fertilisers. Best growth and highest yield for tomatoes were obtained using pine bark and perlite as substrate, both fertilised with sheep wool pellets. In poinsettia pot cultivation, the addition of 1, 2, 5, and 10 g pellets L~(-1) substrate resulted in a correlation between pellet concentration and plant development. Based on analyses of the nutrient content in plants it seems that sheep wool pellets can, for some plant cultures, successfully substitute mineral fertilisers.