JOURNAL OF CROP PRODUCTION RESEARCH (ENVIRONMENTAL STRESSES IN PLANT SCIENCES)
Year:2014 | Volume:6 | Issue:2|Papers Count:6

This study was carried out at the research farm of Agriculture faculty, Bu- Ali Sina University, in 2009, to evaluate the effects of allelopathic plants in two plant density for weed management in potato as compared to chemical weed control. The experiment was done as completely randomized blocks design with three replications. The trial included of ten treatments consists of chemical control and control (no cover crop and no chemical control), rye, barley, triticale and oilseed rape each one with common and triple planting density. The results showed that rye and barley with triple plant density produced 1503.5 and 1392.2 g/m2, respectively and were prior to the other treatments. Cover crop treatments showed significant different weeds control of potato at 3 time (15, 45 and 75 day after germination) compare to control treatment. Residues mixed to soil of rye and oilseed rape with common plant density had the most inhibition affects on summer weeds. These treatments, average weeds biomass decreased 41 and 31 percent respectively, in compare to chemical control. The was a significant correlations of weeds plant population, weeds dry matter, average tuber weight and number of large potato tubers with potato tuber yield. The treatments, oilseed rape and rye with common plant density in compare to chemical control increased tuber yield of potato 25 and 22 percent, respectively. These treatments, increased the number of large potato tubers (More than 70 mm diameter) 44 and 39 percent, respectively in compare with chemical control.

In order to evaluate the effects of different nitrogen amounts and potassium silicate foliar application on agronomic traits and seed yield of rice Tarom cultivar, an experiment was conducted as split plot based on completely randomized blocks design with four replications at Neka in 2014. In this experiment the main factor was nitrogen in 3 levels (0, 50 and 100 kg/ha) and the sub factor were three levels of potassium silicate foliar application (0, 1 and 2 L/ha). Nitrogen application was at baseline, tillering and before heading and silica consumption was at tillering stage. The results showed that the effects of nitrogen and potassium silicate on plant height, number of tillers, panicle length, number of seeds per panicle, seed weight, seed yield and biological yield were significant. The highest seed yield was observed by 2 L/ha application of potassium silicate and 100 kg/ha nitrogen consumption. The recent treatment effect was significant for all studied traits and is recommended for getting maximum yield.

Drought stress is one of the main causes for crop yield reduction in the majority of agricultural regions of the world. Ascorbic acid (ASA) and sodium nitroprusside (SNP) are the substances that make plants resistant to biotic and abiotic stresses. In this study, the effect of drought stress, ascorbic acid and sodium nitroprusside foliar sprays was examined on the qualitative characteristics in summer squash plants. The experimental design was done as split plot factorial based on completely randomized blocks design with 3 replications at research field of Zabol University, in 2011. Irrigation regimes in 2 levels (Irrigation at 75% FC and 25% FC) as main factor and sodium nitroprusside (SNP) at three levels (0 and 50 mol) and ascorbic acid at three levels (0, 10 and 20 mmol) foliar application at flowering stage were considered as subplot. Deficit irrigation reduced the number of seeds per fruit, one-thousand seed weight, seed yield, fruit size and fruit weight. Also delay irrigation decreased fruit yield. Ascorbic acid spraying increased, seed yield, fruit yield, fruit size, fruit weight and number of fruits per plant, but number of empty seeds decreased with the use of ascorbate. The results demonstrated that use of 20 mM of ascorbic acid and 100 M of sodium nitroprusside achieved the greatest lateral branches per plant, seed weight, seed yield, fruit weight and fruit size.

This experimental was done as split plot in the basis of completely randomized blocks design with tree replication in Mazandaran province in 2009. Main factor was sowing date (August 16, 24, 31 and 7 September) and sub factor was row spacing (65, 75 and 85 cm). The results showed that the maximum plant height and plant dry weight were obtained on August 16 and most of the ear diameter, grain number per row, grain number per ear, grain weight, green ear yield and harvest index were conducted on August 24. Most of the plant height, ear length and plant dry weight were gained at rows space 65 cm and the maximum grain number per row, grain weight, green ear yield and harvest index were obtained at row space of 75 cm. Maximum of the plant height and plant dry weight were obtained on interaction effect of the 16 August and rows space 65 cm. The most amounts of green ear yield and grain yield were obtained in the August 24 and rows space 75 cm. Sowing date 24 August introduced the best treatment, because in this sowing date increased ear diameter, grain number per row, grain number per ear, grain weight, green ear yield and harvest index that introduce as the most important traits of sweet corn. The Rows space 75 cm determined as the best because in this treatment grain weight, green ear yield and harvest index increased.

In order to investigation the effect of planting densities and patterns on agronomic and physiological traits in basil (Ocimum basilicum L.), an experiment was done as spilt plot based on completely randomized blocks design with three replications at Qazvin region in 2013. Planting  patterns as main plot in two levels included one row (30 cm) and two rows (60cm) and planting density as sub - factor in three levels (40, 60 and 80 plant in square meter) were considered. The results showed that single effect of planting densities and patterns were significant on plant height, stem diameter, number of leaf per plant and leaf area index. Also single effect of planting density was significant on leaf chlorophyll, stem fresh weight and total fresh weight in plant. The greatest amounts of studied traits obtained in 40 and 80 plant in square meter. Interaction effects were no significant about any one studied characters.

Due to study the effect of different planting dates on yield and yield components of advanced mungbean lines in shoushtar region an experiment was done as split plot based on completely randomized blocks design with 4 repetitions at shushtar in summer of agronomical year 2008. The experimental Factors were consisted of three dates of plantation 1th, 10 th and 20th of July as main factor and the advanced mungbean lines included VC6153B-20G, VC6372 and VC6173A. Moreover, the Parto cultivar was taken as the control. The results of this experiment indicated that the effect of plantating dates and varities were significant (p≤0.01) on pod number in plant, seed number in pod, 1000 seed weight and seed yield. The greatest seed yield (3575 kg/ha) was obtained through both plantating date 20 julyth and the variety VC6153B-20G. It seems that among yield components, the pod number in plant and the seed number in pod had greater role in seed yield achievement and this traits is more affected by planting date. So in more cases delay in plant cultivation, decreased all correlated characters of mungbean growth and development and consequently seed yield decreased.