جستجوی مقالات مرتبط با کلیدواژه « تراکم کشت » در نشریات گروه « زراعت »

The large fluctuations of the final yield of greenhouse cucumber are of great importance in Iran due to its very large cultivated area, so that 76.47% of all greenhouses in the country are under cucumber cultivation. In order to investigate the effect of crop density and variety in the production of greenhouse cucumber (Cucumis sativus), a factorial experiment was conducted in the form of a basic design of randomized complete blocks in 3 replications during 2016 and 2017. Based on this, single-flowered, double-flowered, medium-flowered and multi-flowered cucumber cultivars were cultivated in different planting densities of 37, 42 and 47 cm. The results of the research showed that the highest production productivity was achieved in the planting density of 42 cm between the plants and the selection of    multi-flowered cultivars with a maximum yield of 270 tons per hectare, and the lowest yield was obtained in single-flowered cultivars with a planting density of 37 cm. meter and numerical value of 197 tons per hectare was obtained. Therefore, the main reason for the decrease in cucumber yield in Tehran province was the selection of low-flowering cultivars with inappropriate planting density.

In this study, the Aquacrop model was evaluated to predict the crop yield and the water use efficiency of tomato in climatic conditions Kahriz region, and use mulch cover was modeling. The research was carried out at split plot factorial experiment based on randomized design. The factors of between-row spacing (100 and 120cm), in-row spacing (30 and 40cm) and black plastic were studied. The treatment of black plastic were: full ridge and half furrow were covered by mulch; full furrow and half ridge were covered by mulch and control (no mulch). Every plot was irrigated separately. The model was calibrated by the use of first year’s data, and as a result on the base of R2 (0.99) and NRMSE (0.19). Efficiency parameters, it is obvious that Aquacrop appropriately simulates the crop yield, WUE and soil water content of the root zone for tomato under different planting densities and three types of mulch.

This experiment was conducted as factorial base on randomized complete blocks design with three replications at Agriculture and Natural Resources Research Station, Samian, Ardabil in 2015. The first factor included three canola cultivars (Hyola 308, Hyola 401 and R.G.S 003), second factor was three row distances (20, 30 and 40 cm) and the third factor comprised of plant distances on row (5 and 10 cm). Results showed that the effect of cultivar was significant on traits of growth and reproductive periods, total growth period, and the number of pods per plant. Effect of cultivar and row spacing interaction was significant on seed oil, thousand seeds weight and seed yield. Also, interaction between cultivar, row spacing, and plant distances was significant on all traits except for oil yield. Spring rapeseed, Hyola 308 cultivar showed the highest seed yield (2.55 t ha-1), the highest pod per plant (338.89), and seed per plant (9536) in combination treatment of 20 cm row spacing and plant distance of 5 cm. Also, the highest oil yield (899.05 kg ha-1) was achieved by Hyola 308 planted in 20 and 30 cm row spacing. Having total period of vegetative and reproductive growth of 103 days, Hyola 308 cultivar was determined as the earliest growing cultivar. Generally, results showed that the Hyola 308, as early growing and high yielding cultivar, gained the highest oil and seed yield in combination treatment of plant spacing of 5 × 20 cm for this region.

Planting density and weight of minituber are the factors influencing on the yield and yield components on seed tuber production in potato. In order to study the effect of distance and the weight of minituber on quantity and quality traits of seed tubers of potato cv. Savalan, the experiment was designed as a factorial experiment in randomized complete block design with three replications. In this research, minitubers with five different weights (<5, 5-10, 10-15, 15-20 and >20 g) in three intra rows spacing of 15, 20 and 2 cm and 75 cm inter row spacing were studied. The number of tuber in 1 m2, weight and number of tuber in each plant, total yield, the percentage of tubers with the size <35, 35-55 and >55 mm and tubers diameter were recorded. Results showed that the effect of distance and minituber weight on the average of number of tuber per m2, weight and number of tuber in each plant and the total yield were statistically significant (p≤0.01). In this study, other traits such as the percentage of tubers with the size <35 and 35-55 mm than the minituber weight and density did not respond. Number of tuber in each plant, total yield and diameter of tubers increased with increasing the minituber weight, so the caltivation of minitubers with >20 g compared to cultivation of minitubers <5 g, increased 20.8 ton ha-1 the total yield. With increasing the distance of minitubers, the average of number of tuber in m2 and the total yield increased but the weight and number of tuber in each plant decreased. In this experiment, the maximum of total yield of tubers (71.1 ton ha-1) was obtained from minitubers >20 gram with 15 cm within-rows spacing. In this research, tuber yield showed a positive and significant correlation with weight and number of tuber in each plant and tuber diameter. So that for achivement of the greatest yield indexes of Savalan cultivar in Mashhad climate conditions, caltivation of minitubers >20 g with 15 cm within-rows spacing is recommended.

In order to investigate yield, yield components and quality traits of P. ovata and P. psyllium under water stress and plant density, two experiments were conducted at the Agriculture Research Field, University of Tehran, Karaj, in April 2005 and 2006. Two Factorial experiments based on randomized complete block design with three replications were used. The treatments were three levels of water stress including water witholding at flowering (Severe stress), water withholding at flowering with complementary irrigation at grain filling (Medium stress) and control, three levels of plant density (low, medium and high density), and two plantago species. Combined analysis results showed that seed yield, biological yield, mucilage percentage and mucilage yield significantly different in two years experiments. In both years, water stress significantly decreased seed thousand weight, biological and mucilage yield per hectare. Water stress also significantly increased mucilage percentage and swelling seed in both species. The highest seed yield (765 kg.ha-1) and biological yield (4079 kg.ha-1) observed in medium and high plant density, respectively. Totally, results of this experiment showed that seed yield and mucilage yield per hectare were higher in P. ovata in compared to P. psyllium. The highest mucilage yield observed in medium drought stress and plant density of 100 and 70 plants per square meter in P. ovata and P. psyllium, respectively.