عنوان مقاله [English]
Inefficient management of strawberry fields is one of the important factors in significantly reducing the strawberry fruit yield and quality. Nowadays application of polyethylene soil mulch is widely considered in the cultivation of fruits and vegetables, with various purposes such as improving quality, increasing yield and reducing weeds. The thermal and light environment around the plant due to the use of polyethylene mulch, can affect the quality and yield of strawberry fruit.
Material and Methods
In this study, In order to investigate the effect of colored polyethylene mulch on fluorescence parameters, leaf chlorophyll and strawberry fruit yield (cv. Camarosa), an experiment was carried out as completely randomized block design with four experimental treatments including; colored polyethylene mulch (black, red, white) and control (traditional cultivation without mulch) in three replication in the Caspian Sea region, Iran during the 2016-17 and 2017-2018 years. The experimental plots were 5 m long and 1.5 m wide, with 4 planting rows separated by 30 cm in each plot. Then polyethylene mulch was laid on the ridge and the plants were planted at a distance of 20 cm in a row (1 October). Three harvest times (170, 185 and 200 days after planting) were determined to assess the characteristics of harvested fruits.
Result and Discussion
Based on the results, the effect of mulches color on fruit yield was significantly (P ≤ 0.01). Considering fruit yield at the first harvest (175 DAP) and the second (185 DAP), red mulch showed the highest fruit yield and the lowest was observed in the control treatment. While at the third harvest time (200 DAP), it was the black and white mulches that resulted in the largest amount of yield. The effect of colored polyethylene mulch on the acidity (pH) and titratable acid (TA) of the fruit was not significant, but the amount of soluble solids (TSS) of the fruit at different harvest times showed a significant difference between the experimental treatments. So that in the first harvest time (170 DAP) and the second (185 DAP), the highest amount of soluble solids was observed in treatments with colored polyethylene mulch. The results also showed that colored polyethylene mulches effect on fluorescence parameters and leaf chlorophyll content was significant (P ≤ 0.05). The results showed that mulch color had a significant effect on Fv/Fo ratio, Fo and leaf chlorophyll content. During the both years, the highest Fv/Fo ratio, Fo and leaf chlorophyll were related to colored polyethylene mulches, and the lowest was observed in the control treatment, while colored mulches did not affect the Fv/Fm ratio. In fact, it can be explain that the plant's response to the colored polyethylene mulches, compared to the control treatment, improves fruit yield and increases the strawberry photosynthetic system.
Comparison of the average effect of polyethylene mulch on strawberry fruit yield during the growing season in both years, showed similar results. Polyethylene mulches can increase yields by increasing soil temperature, increasing nutrient availability, increasing root uptake in nutrients and increasing the efficiency of soil microorganisms. Based on the results, in the first harvest time (170 DAP), second harvest time (185 DAP) and third harvest time (200 DAP), the yield of strawberry fruit in both growing season showed that the highest yield was related to treatments with The colored polyethylene mulch and the lowest yield was observed in the control treatment. Red mulch had the highest fruit yield during the first and second harvests, but gradually decreased during the third harvest. It seems that red color, in addition to increasing yield, has also caused early ripening of the fruit. The amount of soluble solids (TSS) of the fruit at different harvest times showed a significant difference between the experimental treatments. During the first harvest (170 DAP) and the second (185 DAP), the highest amount of soluble solids was observed in treatments with colored polyethylene mulch. Based on the findings, the effect of colored polyethylene mulch on fluorescence parameters and chlorophyll content of leaves indicated that the color of polyethylene mulch had a significant effect on the amount of Fo and chlorophyll content of leaves. Therefore, the use of polyethylene mulch due to the increase in yield and quality of strawberry fruit compared to its traditional cultivation method seems very beneficial.