Interaction between black plastic mulch, irrigation interval and bio-fertilizers on weeds biomass and yield of naked-seeds pumpkin

In order to study the effect of black plastic mulch and bio-fertilizers on weed biomass and yield of naked-seed pumpkin under different irrigation regimes, a field experiment was conducted at the research station of Bu-Ali Sina University (Hamedan region of Iran). The experiment was carried out in a randomized complete block design with a split-factorial arrangement of treatments and three replications. The main plots included two irrigation intervals (7 and 12 days), and the subplots included covered with black plastic and un-matched, and four fertilizer regimes (25% chemical fertilizers + bio-fertilizers, 50% chemical + bio-fertilizers, 75% chemical + bio-fertilizers and 100% chemical fertilizers). Different traits including the seed yield and yield components of naked-seed pumpkin, total biomass of all weed species and weed density were investigated. Also leaf, stem, inflorescence and plant weight of redroot pigweed as a dominant weed species were all measured. Results indicated that seed yield and components were affected by a three-way interaction of factors. The highest seed yield (1559 kg ha-1) was obtained with a 12-day irrigation interval, using black plastic mulch and application supplying 75% of plant requirements from chemical sources + bio-fertilizers. This treatment led to a 67% increment compared to a 7-day irrigation interval in un-mulched plots which received 100% of plant requirements from chemical sources. Using mulch at a 12-day irrigation interval and reduced chemical fertilizers replaced by bio-fertilizers led to a considerable reduction in total weed biomass. In general, a 12-day irrigation interval, using black plastic mulch and the application of 75% of plant requirements from chemical sources + bio-fertilizers is recommended. Under the circumstances of this treatment, chemical fertilizer could be decreased by 25% and weeds controlled non-chemically and a high seed yield could be produced with lower water input.