جستجوی مقالات مرتبط با کلیدواژه « disk » در نشریات گروه « کشاورزی »

Purple nutsedge is one of the most problematic weeds of onion fields. To investigate the management practices of this weed, an experiment was conducted in the Agricultural and Natural Resources Center in Southern Kerman in 2017-2018 as a randomized complete block design with three replications. Treatments included twice disk + glyphosate, heavy plow + disk, metribiuzin, pendimethalin (Stomp), hand weeding, soil solarization, soil solarization + glyphosate, Control (no control), pendimethalin (Prowl), three times plowing, and twice disk + two times glyphosate. The results showed that the effect of different treatments was significant on shoot and underground dry weight and density, neck diameter, number of leaves and yield of onion. Twice disk + twice glyphosate decreased shoot and underground dry weight and density by 86, 87, and 87.2 %, respectively, and yield of onion increased 83 %. Therefore, combination of disk and glyphosate was desired in purple nutsedge control and this treatment is recommended.

In order to evaluate the growth characteristics, yield components and yield of sweet corn affected by different tillage operations, planting densities and planting patterns, a field experiment was conducted as factorial of 2×3×3 treatments based on a randomized complete block design with three replications at university Putra Selangor, Malaysia during growing season of 2007-2008. The factors were three tillage methods including, (moldboard plow and disk harrow (T1), disk plow and disk harrow (T2), and rotary cultivator (T3) only as control), three plant densities (of 63000 (D1), 41600 (D2), and 31500 (D3) plants ha-1 only as control) and single row as control (P1) and double row (P2) planting patterns. The traits of dry weight of root, plant height, ear corn height, cob corn dia, stem dia, ear dia, kernel depth, fresh weight husked, row length of kernel, number of kernel per row, number of row, fresh weight husked, ear dia dehusked and yield were investigated. The results revealed that the main effect of tillage operation was significant (p≤0.01) on growth characteristics and yield of sweet corn. Interaction effects of plant densities × planting pattern were significant on yield at 5 percent level. The maximum corn yield attributed to the plots plowed with disk plow followed by disk harrow (T2) with 12503.3 kg.ha-1. Corn yield in P2 was 41% greater than P1 planting pattern. With decreasing plant densities of 63000 to 41600 and 31500, the average corn yield decreased to 36% and 76%, repectively. Maximum and minimum of corn yield obtained to 1443.87 and 7268.89 kg ha-1 from P1D2 and P1D3, respectively. In overal, in order to improve the production and yield of sweet corn as a valuable cereal under Malaysia climatic conditions, disk plow, two-row planting pattern and density of 63,000 plants ha-1 could be recommended.

To study the effects of tillage methods on yield and its components of wheat cv. N-80-9، an experiment was conducted using randomized complete block design with four treatments including moldboard + disk، disk، chisel + disk and rotivator + disk with four replications in Aliabad- Katool in Golstan Province in two cropping seasons (2009-2010). Yield and yield components were affected by tillage methods، significantly. The highest yield was obtained in moldboard + disk and rotivator + disk in 2009 and moldboard + disk and two time disk and rotivator + disk in 2010. Whereas، common tillage (moldboard + disk) in comparison with preservative tillage methods not only consumed high energy and additional time، but also caused more erosion using mechanical tools and consequently led to more expense، the conservational methods are recommended instead of costume tillage methods.

Fagus orientalis Lipsky accounted for 24 percent of stem number and 30 percent of total volume in northern forests of Iran. The aim of this research is finding the regularity in frequencies of diameter increment, determining the relationship between tree age and fluctuations in radial increment of beech trees. Several hypotheses including stationary, secular trend, cyclic and random variations in data series of the beech tree increment, were examined to find out the main effective factor on variations. Four sound beech trees with mean diameter of 10 cm and maximum age of 350 years were selected. One disk was prepared at breast height from each sample tree. Then rings width was measured and data processed with the Time Series analysis. Results showed that there is more than one trend (model) in radial increment diagram of the sample beech trees. Positive correlation was calculated between tree age and radial increment up to the age of 120 years, where as this correlation turns to negative after this age. The mean and distribution of radial increment differ in periods of tree life. Radial increment of the beech trees is fitted with cubic model along the two age periods. Volume trend of annual increment always is positive and is not inversed. Autocorrelation diagrams show one year periodicity for the fluctuations of radial increments. The other periodicities are irregular and the alterations are not statistically significant.