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.

Maize is one of the most important grains in the world. The leaves play an important role in providing grain reserves in cereals by performing ‎photosynthesis. The leaf is known as the source and the seed is known as the sink. Removing part of ‎the leaf can decrease the amount of photosynthetic material produced by the plant. A C4 plant, maize has been widely cultivated as a summer plant in western  ‎Iran in recent years. Utilizing maize for both grain and forage can reduce the amount of woody ‎residues left by this plant in the soil while providing part of the forage for livestock. Field and laboratory experiments were conducted to investigate the effect of defoliation and nitrogen on seed yield and germination characteristics of seeds derived from the maternal plant. Defoliation intensities (removing none, half of the leaves, or all of the leaves per plant) and nitrogen rates (zero and 100 kg ha-1) were among the variables examined. Nitrogen and defoliation as two source manipulations were used. The results demonstrated a significant decrease in the number of seeds per ear row and column, cob length and weight, and seed yield upon complete defoliation during the tasselling stage. Germination features of generated seeds were also affected by the maternal plant environment. Under removal of all leaves per plant, seed germination percentage, seed vigor, and seedling weight were reduced. Harvesting of the half-green leaves prior to the ripening of the seeds did not result in a decrease in seed yield or ‎germination characteristics of the generated seeds. Nitrogen had less application of an impact on the analyzed maize features than defoliation. In conclusion, half of the green leaves in maize can be harvested before seed maturity without reducing seed yield and seed germination.

In order to study the effect of defoliation and stand reduction on grain yield and yield components in sunflower, an experiment was conducted in Agricultural Research Station, Faculty of Agriculture, University of Tabriz in 2000. Two varieties namely Azargol (CMS19x R46) and Golshid (CMS31 xR46) were used in this study. The leaves were removed at the time of beginning of anthesis (R5) and the treatments consisted of five levels including check (no leaves removed), removal of one third upper leaves, removal of one third middle leaves, removal of one third lower leaves, and removal of all leaves of the plant. The experiment was carried out in randomized complete block design with three replications. Each plot consisted four 4 m long rows spaced 0.75m apart with 25cm between plants on each row. With the exception of plant height and stem diameter, head diameter, filled achene percent, 1000 grain weight, harvest index and grain yield was reduced as a result of partial or complete leaf excision when compared with the undefoliated check. Middle leaves showed maximum effect on filling of grains due to their largest surface and more photosynthetic activity. Grain yield was minimum at treatment with all leaves removal as reflected by less 1000 grain weight and filled achene percent.

The date of planting and defoliation of sunflower have some effects on the amount of the damage that is caused by birds. To determine these effects an experiment was done in 2008. in Tazeshahr area, of Salmas. Expriment carried out as factorial experiment arrenged in RCBD with four replications. The first factor of the experiment was the date of planting that was done five times in a year, on 24th April, 9th and 24th May and 8th, 24th June. The second factor was leaf cutting that was done in three forms. In the first one, there was not any leaf cutting. The second form was based on cutting of three terminal leaves after the end of pollen dispersion period and in the third one there was not leaf cutting and it included covering of leaf. The final results showed, the first factor had effects on attributes of diameter of flower, amount of seeds, the yield of seeds, harvest index, biological yield, oil percentage, oil yield and productivity index. Also the leaf cutting had effects on the attributes of seeds yield, harvest index, oil yield and percentage of birds' damage. The date of third planting had the average of 532.3 gram seeds in one square meter. It was the highest yield of seeds. The date of fifth planting had the average of 304.9 gram seeds in one square meters. It was the lowest operation of seeds. The cutting of three terminal leaves could lessen sixty percent of birds' damage; however cutting of the leaves had no effect on the yield of seeds.

In order to determine the effects of yield and yield components on corn planting and defoliation, an experiment was carried out in a randomized complete block design with three replications in Agricultural Resource Research Station of Khoy. In this experiment, planting pattern in four (20×75, 20×51, 14×75 and 17× 60) as the main plot and defoliation at three levels (no cutting the leaves, cutting the leaves off the top third, cutting alternating leaves) were considered as sub plots. According to the test results, pattern significantly affected on all traits except grain weight and harvest index. The highest yield of planting patterns 20×51 which had the lowest planting density (66000 plants per hectare) was obtained. 20×51 and 17×60 inter-planting statistically showed significant difference. The highest seed weight with an average of 6/301g belonged to non-cutting treatment of the leaves. Of course, the treatment of non cutting leave and cutting off the top third of vegetation was not significantly different. interactive planting and cutting leaves, the highest seed weight of 319g of planting 20×75 with treatment continuation of the leaves and the highest grain yield of 15000kg per hectare of planting 20×51 cell treatments belonged to cutting off the top third of the canopy.