فصلنامه اکوفیزیولوژی گیاهان زراعی
پیاپی 22 (تابستان 1391)

To evaluate beneficial effect of intercropping based on replacement and additive methods to sustainable agriculture, two experiments were conducted at the Agricultural Research Station of University of Tabriz in 2005 and 2006, to study the effect of intercropping potato and pinto bean by using these two methods. The experiments carried out using randomized complete block design with three replications and 16 treatments. The treatments, consisted of: eight treatments of replacement intercropping with 2:1 and 3:1 proportions of potato and pinto bean (with densities of 4.7 and 5.3 plants m-2 for potato and 45 and 55 plants m-2 for pinto bean), four treatments of additive intercropping (with densities of 4.7 and 5.3 plants m-2 for potato and 5.3 and 10.6 plants m-2 for pinto bean), two sole croppings of potato (4.7 and 5.3 plants m-2) and two sole croppings of pinto bean (45 and 55 plants m-2). Maximum tuber yield per plant, tuber yield of potato per unit area, tuber size, mean tuber weight, number of leaves and branches per plant were obtained from replacement intercropping treatments. Maximum grain yield of pinto bean per unit area was obtained from the replacement intercropping treatments; Maximum grain yield per plant, number of pods per plant, number of leaves and branches, plant height, dates of emergence, flowering, poding and ripening were obtained from the additive intercropping treatments. To evaluate the beneficial effect of intercropping, land equivalent ratio (LER) was more than one, and the maximum amounts for two years (1.25 and 1.27, respectively) belonged to replacement intercropping of 1:2 treatment (66% potato with 5.3 plants per m2 34%pinto bean with 55 plants per m2). This treatment, therefore, can be recommended to be the best intercropping pattern for sustainable agriculture.

To evaluate the effect of sowing dates on yield, yield components and some agronomic characteristics of four winter wheat cultivars and also their phenological changes, a factorial experiment based on randomized complete block design with three replications was carried out at the Agriculture Research Station of Ardabil (Iran) during 2009 growing season. First factor consisted of four wheat cultivars (Azar2, Sabalan, Sardari and Zagros) and second factor consisted of four sowing dates (1st, 10th, 20th and 30th of September). The results showed that sowing date had significant effect on the number of spikes, the number of seed per spike, 1000-seed weight, germination percentage, days to spike appearance, days to ripening, growing degree days, biological yield, seed yield and harvest index. The highest and lowest seed yields of wheat were obtained from sowing date of the September the first (4616 kg/ha) and sowing date of September 30th (2197 kg/ha) respectively. Delaying planting decreased the number of spikes per m2 and 1000-seed weight. Cultivars had significant effect on all of the traits measured, except leaf number, fertile and non-fertilie tillers. The highest and the lowest seed yields were obtained from Sabalan (4750 kg/ha) and Zagros (2757 kg/ha) cultivars respectively. Interaction of sowing date and cultivar were significant on all of traits measured, except stem height, the leaf number, the number of spikes, 1000-seed weight and seed yield (P

To evaluate the effect of herbicides and biofarm (Pseudomonas spp.) as biological fertilizer on weeds and yield components of canola, a factorial experiment based on randomized complete block design with three replications was conducted at Agricultural Research Center of East Azarbaijan in 2009. The treatment factors consisted of herbicide (factor A) at 4 levels (application of trifloralin, Treflan, at 2.5 l/ha as pre-planting, chlopyralid, Lontrel, at 0.8 l/ha when canola plants were at 2-4 leaf stage, metazachlorꫨꞙ, Butizan star, at 2.5 l/ha at cotyledonous stage of canola, and not controlling the weeds as check. Biological fertilizer (factor B) at 2 levels, using or not using the biofarm. Wild mustard (Sinapis arvvensis) and tansy mustard (Descurainia sophia), being in same family with canola, were the dominant weeds in the field. Traits like number of species and biomass of weeds, biomass and yield of the crop were recorded to evaluate the effects of the treatments. The statistical analysis indicated that Botizan star and Treflan, compared with control, significantly reduced the number and biomass of wild mustard. In spite of non significant effect of the herbicide on number of tansy mustard and total weed, Botizan star and Treflan significantly reduced their biomasses. Application of biofarm and its interaction with herbicides did not influence the evaluated traits significantly. The herbicides, also, did not have significant effect on biomass and yield of the crop.

To study the effect of vermicompost and biological fertilizers on seed yield and yield components of basil, an experiment based on complete randomized block design with three replications was conducted in Mashhad during cropping season of 2009-2010.The treatments were: vermicompost, nitroxin (Azotobacter and Azospirillum), bio phosphorus(Pseudomonas and Bacillus), vermicompost nitroxin, vermicompost bio phosphorus, nitroxin bio phosphorus, vermicompost nitroxin bio phosphorus, chemical fertilizer (N.P.K), and control (no fertilizer). The results showed that the highest of plant height (57.66cm), lateral branch in plant (17.6 branch), number of flower per plant (38 flower), number of flower cycle per plant (231.6 cycle), number of seed per flower cycle (16 seed), 1000 seed weight (1.89 g) and seed weight per plant (10.22 g) were obtained with vermicompost nitroxin treatment. But, the difference of this treatment with vermicompost nitroxin bio phosphorus treatment, except lateral branch per plant, was not significant. The highest of seed yield (1939.1 kg/ha) and biological yield (15183.3 kg/ha) obtained by using vermicompost nitroxin bio phosphorus treatment. This study showed that the effect of biological fertilizer combined with vermicompost on seed yield and yield components of basil was higher than chemical fertilizer and control (no fertilizer).

To study the effects of end season drought stress on yield, yield components and drought stress indices in barley, a split plot experiment arranged in randomized complete block design with three replications was conducted at the Agricultural Research Center of Birjand in 2008-2009 crop years. Drought stress, in 2 levels, consists of control (complete irrigation) and stopping irrigation at the 50% of heading stage, and 20 promising genotypes of barley were the treatments of the experiment. Results revealed that stopping irrigation lead to declining of 14.64 and 8.12 percent of seed and forage yields against control condition, respectively. Using stress susceptibility index (SSI) indicated that genotypes 2, 3, 7, 9, 10 and 15; using STI and GMP indices, genotypes 5, 8, 18 and 20 using MP, genotypes 8, 18 and 20, and TOL, genotypes 2, 3, 7, 9, and 10, were the most drought tolerant genotypes. Correlation between seed yield and stress evaluation indices showed that MP, GMP and STI are the best indices to be used in selection and introducing drought tolerant genotypes of barley. Considering all indices, and given that the best genotypes are those with high yield under normal condition and minimum yield reduction under drought stress, No. 18 and 20 could be introduced as the most tolerant barley genotypes to drought.

To assess the effects of management factors on nitrogen nutrition and seed yield of rapeseed farms in Gorgan areas, an experiment was conducted as a nested model arranged in a randomized complete block design (RCBD) with three replications in 2010. Fifteen canola fields were classified at three levels of management (optimum, medium, minimum) studied at four growth stages. Questionnaires were filled out by farmers for the quantification of agricultural management levels during the experiment. The results showed that levels of management for nitrogen nutrition index, plant density, dry matter yield, seed yield and harvest index were different significantly (p

In order to evaluate the performance of spring sweet corn (Zea mays var saccharata) at different planting dates under plastic cover, a split plot experiment based on RCBD with three replications was conducted in Gachsaran, in southwest of Iran, during 2009-2010 growing season. Four sweet corn hybrids (Merit, Challenger, Chase and Basin) were used as main factor and five sowing date (15th and 25th Jan, 4th, 14th and 24th Feb) as sub factor. The results showed that hybrid effect was significant on the days to tassel and ear emergence, days to harvest, ear harvest index, ear length, number of row per each ear, wet biological yield and 1000 grains weight, at 1%, and ear wet yield and grain yield harvest index at 5% probability levels. Also the effect of sowing date was significant on the days to tassel and ear emergence, days to harvest, ear wet yield, ear harvest index, ear diameter, ear length, biological yield, and 1000 grains weight at the 1% probability level. 'Basin' and 'Chase' hybrids were determined to have highest and lowest ear wet yield (17.09 and 15.13 t.ha-1) respectively. The highest and the lowest wet ear yield (16.81 and 15.06 t.ha-1) belonged to 15th Jan. and 24th Feb. respectively. 'Basin' hybrid and 'Challenger' with 8.39 and 7.59 t.ha-1 grain yield were found to be highest and lowest yields. The highest and the lowest grain yield (8.41 t.ha-1 7.45 t.ha-1) were recorded for 15th Jan. and 24th Feb. respectively.' Merit' and 'Chase' hybrids were determined to have longest and shortest days to ear harvest (94.3 and 86.2 days). Longest and shortest days to ear harvest (101.5 and 82 days) were recorded in 4th Jan. and 24th Feb. Sowing date and hybrids interaction effects showed that the longest and shortest days to ear harvest (104.7 and 78.3 days) were calculated in 4th Jan. of Merit and in 24th Feb. for Chase. Based on these results, it can be concluded that 'Basin' hybrid Feb. 24 is the most suitable cultivar to be produced in Gachsaran.

Eighteen promising clones of potato along with four commercial cultivars (Savalan, Agria, Marfona and Lady-Rozeta) in randomized complete block design with three replications were evaluated at Agricultural and Natural Resources Research Station of Ardabil during 2010 and 2011. Prior to and after harvest, traits like main stem number per plant, plant height, tuber number and weight per plant, total and marketable tuber yield, dry matter percentage, baking type, hollow heart, tuber inner ring and discoloration of raw tuber flesh after 24 hours were measured. Combined ANONA for quantitative traits showed that there were significant differences among promising clones and their interactions with year as to total and marketable tuber yield, tuber number and weight per plant, plant height, tuber average size, main stem number per plant and dry matter percentage. The results also showed the clones 397003-7, 396151-27, 397045-100 and Savalan (check) produced higher total and marketable tuber yield, tuber number and weight per plant, plant height, main stem number per plant, tuber size average and stable tuber yield. These clones produced high and mid-uniform tuber, yellow skin and flesh color, oval round, shallow eyes, very little hollow heart, tuber inner crack and tuber inner ring, mid-late maturity and mid and high dry in comparison to those of check. Based on results of this experiment, the clones 397003-7, 396151-27 and 397045-100 could be selected for Ardebil region.