To obtain detailed information of sowing density and DEFOLIATION INTENSITY under more controlled conditions on herbage production and seed yield, Paraggio medic was grown on raised-beds located outdoors at the Waite Agricultural Research Institute. A split randomized block design was used. Treatments comprised three sowing rates (densities): Low (3 kg/ha), Medium (15 kg/ha) and High (75 kg/ha) (based on pure germinating seed which gave 75, 375 and 1875 seedlings/m2 respectively); four DEFOLIATION intensities: Control (undefoliated), Low (6 cm from ground level), Medium (4 cm) and High (2 cm) to simulate different grazing pressures and two DEFOLIATION systems of continuous (DEFOLIATION from June 1) and deferred (DEFOLIATION from June 29). The total combination for experimental blocks was: Main plots, DEFOLIATION systems (2) x Sub plots. Sowing densities (3) x Sub-sub plots DEFOLIATION intensities (4) x Blocks (4) = 96 micro plots. The continuous DEFOLIATION system produced significantly higher (P<0.05) available forage as well as total pasture production (P<0.05) than the deferred. High sowing rate increased (P<0.01) forage availability and total pasture production. Medium and high DEFOLIATION intensities significantly (P<0.01) reduced available forage and total pasture production in the deferred DEFOLIATION system. Seed production was adversely affected by DEFOLIATION INTENSITY.

In order to evaluate the effects of time (20, 40, 60 and 100 days after sowing) and INTENSITY of DEFOLIATION (0, 33, 66 and 100%) on a corn cultivar (three way cross 647), a complete randomized block design with split plot arrangement and three replications was conducted in Experimental Field of Faculty of Agriculture Ferdowsi University of Mashhad. The main plots were consisted of DEFOLIATION time and the sub plots were consisted of DEFOLIATION INTENSITY. For this purpose leaves were defoliated at 33, 66, and 100% and at the end of experiment, different morphologic and physiologic criteria such as number of leaves per plent, total dry matter and plant components dry matter, seed yield and yield components and also harvest index were evaluated. Results indicated that DEFOLIATION at the early stage of crop growth (20 and 40 days) and at the end of crop growth (100 days) showed no effects on most of criteria measured. However at the middle of growth period, DEFOLIATION reduced these parameters. INTENSITY of defoliatin up to 66% had no effects, but 100% reduced all those parameters. Therefore, it appears that by DEFOLIATION up to more the 50% of plant leaves, plants could recover and appears as a normal plant, but with 100% DEFOLIATION this was not happened. DEFOLIATION at early stages had no negative effects, because regrowth of leaves could have compensated for this type of damage. At the end of growing season, plant cycle was completed and so DEFOLIATION had no negative effects on growth and development, while at the middle stage (60 and 80 days) the negative effect was due to the fact that plants could not recover completely from DEFOLIATION.

The effect of DEFOLIATION on root yield and quality of sugarbeet (Beta vulgaris L.) was examined in a field study in Research Station of Faculty of Agriculture, Ferdowsi University of Mashhd during 2005 growing season. The experiment was conducted as a split plot on the basis of randomized complete block design with three replications. Time of DEFOLIATION (May 16th, May 31th, June 18th, July 9th, July 31th, and August 20th) were allocated to main plots and DEFOLIATION severity (0, 30, 60, and 100%) were assigned to subplots. Results showed that root yield, shoot and root dry weight and sugar yield were influenced by DEFOLIATION time. However, DEFOLIATION time had no significant effects on sugar white content and white sugar yield. Effects of DEFOLIATION on plant growth was more pronounced in mid season when about 1500 degree days was accumulated, compared to early or late season. DEFOLIATION INTENSITY resulted in a significant decrease in root yield, shoot fresh weight, root and shoot dry weight, sugar and white sugar content, and white sugar yield compared with undefoliated control, but molass sugar was increased in all DEFOLIATION intensities. Sugar and white sugar percent were significantly affected by DEFOLIATION time x INTENSITY interaction. Complete DEFOLIATION (100%) on July 30th and Auguat 19th led to 18 and 21% reduction in sugar and 29 and 28% in white suagar, respectively. However, 100% DEFOLIATION in July 8th resulted in 6 and 8% increase in sugar and white sugar, respectively.

To evaluate the effect of artificial DEFOLIATION INTENSITY at different growth stages on the root yield and quality of sugar beet (Beta vulgaris L.) a field experiment was carried out at Miyandoab Agricultural Research and Natural Resources Field Station in 2007 growing season. Experimental treatments were arranged as factorial (4×5) in RCBD with three replications. DEFOLIATION were practice at four growth stages (S) of sugar beet including: plant establishment to 10% ground cover (S1), from 10 up to 70% ground cover (S2), from the S2 to root maturity (S3), and from the S3 to harvest time (S4). Five levels of DEFOLIATION intensities (I) were: blade removal up to 25% (I1), 50% (I2), 75% (I3), 100% (I4) and no DEFOLIATION as check (I5). At final harvest, sugar beet roots were harvested and root yield, sugar content, white sugar content, white sugar yield and extraction coefficient of sugar were determined. Results showed that the main effect of growth stage was significant on quality traits of sugar beet such as sugar content, white sugar content and sugar extraction coefficient, however, its effect on agronomic traits such as root yield was not significant. However, different levels of DEFOLIATION affected both quality and quantitative traits of sugar beet. At the 100% DEFOLIATION level, root yield reduced by 36% as compared to no DEFOLIATION (47.49 t. ha-1). In the meantime the least root yield (23.90 t. ha-1) was recorded at S2 with 100% DEFOLIATION (S2I4). The interactions between DEFOLIATION INTENSITY × growth stages were significant (P<0.01) for sugar content and white sugar content. At the 25% DEFOLIATION (I1) at final growth stage (S4), sugar content decreased by 4.65 units whic was 22% of no DEFOLIATION (sugar content of 21.50%). In conclusion, any DEFOLIATION during the growing season may increase sugar losses in the sugar factory.

In order to determine the effect of DEFOLIATION INTENSITY at different reproductive stages in sunflower (Helianthus annus L.) on seed and oil yields, and determining the most sensitive reproductive stages to DEFOLIATION, a field experiment was conducted at Tarbiat Modares University Research field using a split plot arrangement in a RCBD with four replications in 2007 cropping season. Main plots consisted of DEFOLIATION at four reproductive stages including: star shape of inflorescence stage (R1), pollination stage (R5), seed setting initiation (R6), and end of grain filling (R7), while five DEFOLIATION intensities (0% as an undefoliated control, 25%, 50%, 75% and level removed 100%) were arranged in sub-plots. The results indicated that DEFOLIATION time and intensities had significant effects on all traits. The interaction of two factors significantly (P<0.01) reduced the grain yield, thousand seeds weight, unfilled seed and oil content. The most variation resulted from DEFOLIATION effect on number of filled seed per area and1000 seed weight, at R1 and R5 stages, consequently reduced grain and oil yields. On the bases of these results it could be concluded that sunflower crop that lost 100% of its leaves would be economically unprofitable and it is more logic to be replaced with a suitable crop adapted to the region.

In order to investigate the effect time and INTENSITY of DEFOLIATION under use of amino acid condition, a factorial experiment was conducted based on randomized complete block design with three replications in Ali Abad Katoul, Golestan Province during growing season 2016-17. The first factor included the INTENSITY of DEFOLIATION at three levels of 0, 50 and 100%, the second factor included the time of DEFOLIATION in five levels (V1, V3, V5, V7, and R1), and the third factor was the application and non-application of amino acids. The results showed that the effect of amino acids, the time and INTENSITY of DEFOLIATION, and the interaction between times in INTENSITY of DEFOLIATION were significant on oil yield. Application of amino acid resulted in an increase of 98. 9% of oil yield compared to the non-application treatment. The highest oil yield was observed in the DEFOLIATION of 50% leaf in V1 stage with a mean of 867. 5 kg/ha, which was 10. 5% higher than to the control treatment. Comparing the mean interactions effects of times in INTENSITY of DEFOLIATION, the highest grain protein yield was observed in DEFOLIATION of 50% leaf in V5 stage with 1296. 17 kg/ha, which increased 17. 33% compared to the control treatment. DEFOLIATION of 100% of leaves resulted in the lowest weight of 100 seeds, and the absence of leaf DEFOLIATION and the DEFOLIATION of 50% of the leaf had the highest mean of this trait. Application of amino acids increased 12. 28% of grain yield compared to the non-application. In the interaction of the times in INTENSITY of DEFOLIATION, the highest grain yield associated with 50% DEFOLIATION of leaf in stages V1 and V5 were 3681. 9 and 3696. 3 kg/ha respectively, which was 2. 46 and 2. 84% higher than to the control treatment, respectively. In general, leaf DEFOLIATION in late stages of growth (especially reproductive growth) with 100% INTENSITY was reduced the quantitative traits (yield and yield components) and qualitative traits (oil and protein content of grain). On the other hand, the application of amino acids, by increasing the mean of measured traits, moderated the effect of DEFOLIATION stress. DEFOLIATION of 100% of leaves resulted in the lowest weight of 100 seeds, and the absence of leaf DEFOLIATION and the DEFOLIATION of 50% of the leaf had the highest mean of this trait. Application of amino acids increased 12. 28% of grain yield compared to the non-application. In the interaction of the times in INTENSITY of DEFOLIATION, the highest grain yield associated with 50% DEFOLIATION of leaf in stages V1 and V5 were 3681. 9 and 3696. 3 kg/ha respectively, which was 2. 46 and 2. 84% higher than to the control treatment, respectively. On the other hand, the application of amino acids, by increasing the mean of measured traits, moderated the effect of DEFOLIATION stress. DEFOLIATION of 100% of leaves resulted in the lowest weight of 100 seeds, and the absence of leaf DEFOLIATION and the DEFOLIATION of 50% of the leaf had the highest mean of this trait. Application of amino acids increased 12. 28% of grain yield compared to the non-application.