Effect of Biofumigation on Typical Weeds of Strawberry Fields

Abstract

This research was conducted to evaluate the effect of biofumigation using fresh organic matter on typical weeds present in strawberry fields of southern Spain. Field experiments consisted of biofumigation (BF) treatment over 45 days, at two locations, with hen droppings or horse manure at a dose of 3 kg m-2, alone or in combination with solarization (BF+S) in an experimental randomized block design. Results showed good control of the main weed species, Poa annua, Portulaca oleracea and Lolium rigidum, with comparative populations of the three species under BF/BF+S of 42/4/8, 18/9/12, and 15/0/1 plants m-2 respectively. In addition, 20 seeds each of several weeds were sown inside cloth bags and were submitted to the treatment. The efficiency of biofumigation combined with solarization in the control of P. oleracea, Cynodon dactilon and Echinochloa crus-galli was 77/0, 50/15, and 30/2, as a percentage of germination of control/BF+S. Laboratory experiments consisted of simulating field conditions using a mix of soil, water and different fresh organic matter in a plastic bag, into which different seeds were sown and kept under controlled conditions over 30 days at 27ºC. Fresh organic matter used was whole strawberry plants, horse manure, hen droppings, and combinations of these. Best results were obtained with hen droppings, which showed effective control of Malva parviflora, Medicago sp., E. crus-galli, Amaranthus retroflesuxus, Chenopodium album and P. oleracea, while strawberry residues and horse manure were not useful as herbicides, sometimes even less so than the solarization treatment. Biofumigation with fresh hen droppings and solarization showed promising results in preliminary experiments.