جستجوی مقالات مرتبط با کلیدواژه « کاشت مستقیم » در نشریات گروه « زراعت »

In order to study the effects of various tillage methods on some soil physic-chemical properties, soil moisture maintain and sunflower performance, in Kalpoush dryland region of Miami, this project conducted as Randomize Complete Block Design (RCBD) with four replications in wheat rotation. Treatments were included, 1- moldboard plowing + disk harrow (CT), 2- reduced tillage with disk harrow (RT1), 3- reduced tillage with chisel plowing (RT2), 4- reduced tillage with chisel packer (RT3) and 5- direct seeding or no-tillage (NT). The results showed that at depths of 0-15 cm, soil moisture storage in conservation tillage was higher than the conventional tillage (P<0.05). In the first and third years of the experiment, in the conventional method, compared with the no-tillage, the yield of sunflower was higher. In the final year (2016), the result was reverse. Combined analysis of 3-years on sunflower yield showed that conventional tillage and direct seeding were in the same class. In low precipitation year (2016), sunflower grain yield decreased in the conventional method but it increased a little in direct seeding method. In addition, soil moisture saving and precipitation use efficiency in direct cultivation was more than conventional method. Results of research showed that, after several years, grain yield of the sunflower has increased in conservation method and this may be an appropriate alternative to the conventional tillage method.

In order to evaluate the effect of seed priming on lodging-related characteristics in direct seeding method, a study was conducted in a factorial randomized complete block design with four replicates in the research field of Rice Research Institute of Iran (Rasht) for two years. The first factor consisted of two rice cultivars (Khazar and Hashemi) and the second one consisted of ten levels of seed conditions encompassing, eight priming treatments including hydropriming, ascorbic acid, salicylic acid, CaCl2, cold, cold heat, seed coating, and non-primed dry seed, all sown with seed tap technology along with linear direct seeding of germinated seeds and transplanting (25-days-old seedlings). Agronomic and morphological characteristics and resistance to lodging indices were measured. The results showed that there were significant differences between two cultivars and ten levels of seed conditions in morphological traits and lodging resistance indices. Mean comparisons and correlation analyses showed that grain yield (5142 kgha-1), resistance to fracture in third and fourth internodes (549 and 704 Newton, respectively) in Khazar were higher than those of Hashemi. There was a significant difference between planting methods (direct-seeded and transplanting) in terms of lodging resistance. Maximum indicators in the third and fourth internode bending momentum (1060 and 1708 gcm-1) were observed in the transplanting method. Hydropriming treatment had significant effect on fourth internode thickness in cultivar Khazar. Priming treatments appeared to leave significant effect on resistance to lodging in different planting methods in a cultivar-specific manner.

In this experiment، seed rates in direct seeding methods of rice (cv. Hashemi) were compared and lodging related traits were evaluated in split plot lay out based on randomized complete block design with three replications and four seeding methods as main plots and three seeding rates (60، 80 and 100 kgha-1) as sub plots at Rice Research Institute of Iran، Rasht، Iran. Seeding methods consisted of drum direct seeding، hill wet seeding، broadcasting and pre-geminated seeding in puddle field. The maximum grain yield (2753 kgha-1)، internodes length، internodes fresh weight، third and fourth internode cross-section area (4. 43 and 7. 12 mm2، respectively)، third and fourth bending moment (493. 04 and 581. 93 gcm، respectively) and breaking resistance of third and fourth node (947. 24 and 1651. 89 gcm، respectively) were obtained in hill wet seeding method. The maximum grain yield (2486 kgha-1) was obtained in 100 kgha-1 seed rate. Increase in seeding rate resulted in decrease of internodes length، internodes fresh weight and bending moment of third and fourth internodes. Stepwise regression analysis showed that internode cross section area and internode flattening had highly significant effect on breaking resistance (verified 56% and 59% of breaking resistance، respectively). It seems it may possible to prevent the lodging problems in Hashemi rice production to a large extent by direct seeding of pre-germinated seeding in conditions of the intended region.

Direct seeding of canola after summer crops has not proved to be suitable, because of low establishment. This experiment was carried out in order to compare of direct seeding and transplanting methods of canola hybrid Hayola 308 in Khuzestan agricultral research center during 2002 and 2003 cropping cycles. A strip plot arrangement in randomized complete block design was used, with 5 planting dates (Oct, 10 and 20, Nov.1, 10and 20) as horizontal plots and two direct seeding and transplanting methods as vertical plots. Means comparision showed that 40 days delay in sowing date lead to increasing of 3.5 days of sowing to germination interval and 11.4 and 33.0 days in flowering and maturity respectively. It also decreaed pods per plants by 35.9, grains per pods by 2.7, grain yield to 1762.5 kg/ha and oil yield to 938 kg/ha. The transplanting method increased duration to flowering by 1.9 days, pods per plant 57.2 and grains per pod by 1.4, grain yield by 492 kg/ha and oil yield by 162.6 kg/ha. The interaction between sowing dates and planting methods showed that there are significant differences interactions between direct seeding and transplanting methods specially in late sowing dates. Considering economic yield, planting date of canola is recommended from Oct.10 to Nov. 1. Using transplanting method Nov. 10 until Nov. 20 would be suitable. In addition, transplanting method of canola is recommended for recovering the no or low established patches in the field.