Document Type : Full Paper
Authors
1 Agricultural Engineering Research Department, Hamedan Agricultural and Natural Resources Research and Education Center, AREEO, Hamedan, Iran.
2 Horticulture Crops Research Department, Hamedan Agricultural and Natural Resources Research and Education Center, AREEO, Hamedan, Iran.
3 Sahar Food Industry, Hamedan, Iran
Abstract
Keywords
Main Subjects
Extended Abstract
Introduction
Usually, to increase the yield of cucumber the farmers in different regions of Hamedan use 10 tons per hectare of poultry manure before planting, and regardless of the soil test, urea fertilizer consumes in the amount of 150 to 200 kg per hectare in two stages of planting time and secondary stem formation, through injection in irrigation water or top dressing. This method of fertilizing cucumber is far from the standard and optimal principles of cucumber nutrition and will cause problems for its sustainable production. Poultry manure as an organic fertilizer is rich in nitrogen and has an adequate quantity of other elements. Nevertheless, indiscriminately use of it without conducting a soil test can be destructive and leads the soil to be out of nutrition balance. For the sustainable production of cucumbers, the nutritional program should be optimized based on the soil test and fertilizer recommendations. Therefore, in this research, the effects of different combinations of poultry manure and chemical fertilizers on the quantity and the quality of cucumbers were investigated according to soil test results, to provide sufficient and optimal nutritional requirements in cucumbers.
Materials and Methods
This research was carried out in 2018 at the Hamedan Agricultural and Natural Resources Research and Education Center, located in the west of Iran at longitude 48°32'01" E and latitude 34°52'48" N at 1729 meters above sea level. Cucumber cultivars, Hike and Royal, were planted as a strip factorial experiment based on a randomized complete block design with three replications in separate experiments. Factors included harvesting time, poultry manure, and chemical fertilizer. Cucumbers were harvested at three dates (the first, middle, and last growing periods), and poultry manure was consumed at 0, 6, and 12 tons per hectare. Chemical fertilizers used at four levels consisting of 50 kg urea without considering a soil test (regional custom); 109 kg ammonium sulfate without considering a soil test; urea, phosphorus, potassium as well as micronutrients (according to the soil test); and ammonium sulfate, phosphorus, and potassium sulfate as well as micronutrients (according to the soil test). Micronutrients were applied, using the foliar spraying method. Cucumbers were planted in rows with a distance between the rows and plants of 0.4 × 1.5 meters. The length of the planting row in each treatment and the corresponding repetition was considered 15 meters. Cucumbers were irrigated by drip method, using 16 mm pipes with a distance of 30 cm between the droplets. The amount of poultry manure, based on each treatment was evenly distributed and mixed with the soil at a distance of 10 cm from the planting site of the seedlings. Yield, moisture content, color index, nitrate, and tissue firmness were measured for every cultivar at each harvesting date. For measuring yield, cucumbers with a length of 6 to 10 cm were harvested continuously (every two days) during 35-40 days after planting and weighed.
Results and Discussion
The results showed that the application of six tons per hectare of poultry manure in combination with urea, phosphorus, potassium, and complete micronutrient fertilizers based on soil test results, caused a significant increase in total yield. With increasing poultry manure, nitrate accumulation increased, but the nitrate content of all treatments was below the allowed threshold. The cucumber tissue firmness in the first and second harvests was higher than in the third harvest and decreased with more nitrogen application. In the Hike cultivar with chemical fertilizer treatments, chlorophyll accumulation in the first and third harvests was higher than the second. In the Royal cultivar, increasing in ammonium sulfate consumption led to an increase in the green color index of cucumbers. The consumption of six tons of poultry manure and chemical fertilizers, based on soil tests and foliar application of micronutrient fertilizers, improved the yield and quality of cucumber. The addition of poultry manure combined with chemical fertilizers by soil test, compared to without soil test, increased cucumber yield significantly. Increase of yield and quality of the cucumbers is not feasible, only by using poultry manure as a rich source of soil nutrition. Indeed, it needs chemical fertilizers for better growth and more yield. As there is no significant difference between 6 and 12 tons poultry manure, therefore the consumption of 6 tons per hectare of poultry manure is sufficient. Among the chemical fertilizers, ammonium sulfate is absorbed by cucumbers faster than urea, due to the low energy for absorption. Using ammonium sulfate and poultry manure at 6 tons per hectare causes the reduction of nitrate content in the plant. In most treatments, the firmness of the cucumbers was higher in the first and second harvests, compare with the third harvest, which is due to fruiting and an increase in the rate of absorption and use of photosynthetic substances in these stages of cucumber plant growth. The inverse linear relationship between the firmness of cucumbers and their moisture content showed that poultry manure and chemical fertilizers consumption, especially ammonium sulfate used with a soil test increase the osmotic potential of cucumbers, notably in the Royal cultivar. Increasing both of the fertilizers has a conspicuous effect on the moisture content of the cucumbers.
Conclusion
In general, the use of poultry manure at two levels of 6 and 12 tons per hectare caused a significant increase in cucumber yield, compared to not using poultry manure. The treatments of chemical fertilizer application based on soil tests in combination with foliar spraying of complete micronutrient fertilizer caused a significant increase in cucumber yield, texture firmness, and green color intensity, compared to the one-time use of urea fertilizer without any soil test. The effect of harvesting time on the amount of chlorophyll accumulation in both cultivars in the second harvest, when the plant had the highest number of flowers and fruits, was lower than in the first and third harvest stages.
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