JOURNAL OF CROP ECOPHYSIOLOGY (AGRICULTURE SCIENCE)
Year:2019 | Volume:13 | Issue:2 (50) |Papers Count:10

To study some growth indices of soybean under moisture stress by replacing nitrogen with phosphorus, a field experiment was conducted at the Research Station of Bu-Ali Sina University during the 2017-2018 growing season. The experiment was carried out in a split-factorial arrangement of treatments based on randomized complete block design with three replications. The main plots consisted of three levels of irrigations (irrigating after 60, 90 and 120 mm evaporation from class A evaporation pan). Two levels of nitrogen replacement with phosphorus and without replacement and two levels of phosphorus replacement and without phosphorus replacement assigned to subplots. The results showed that simultaneous replacing of nitrogen and phosphorus in all irrigation levels increased physiological growth indices of leaf area index, dry matter accumulation, crop growth rate, relative growth rate and net assimilation rate. Moisture stress reduced growth rate of the crop significantly. Results also showed that crop growth rate increased 35 to 45 days after planting and reached to its maximum level after 65 days after planting date. After this period, the crop growth rate of soybean decreased and reached to zero about 95-100 days after planting. The highest dry matter accumulation and crop growth rate were obtained from irrigation after 60 mm evaporation and nitrogen-phosphorus simultaneous placement application. According to the results, simultaneous replacing nitrogen and phosphorus, reduced the negative effect of moisture stress on soybean growth indices. Nitrogen replacement with phosphorus increased grain yield by 11. 4% as compared to non-replacement of nitrogen with phosphorus and yielded 3855. 88 kg. ha-1. In this research, nitrogen replacement with phosphorus under irrigation after 90 mm evaporation prevented significant oil yield loss as compared to irrigation after 60 mm evaporation.

The use of salicylic acid in the nutrition of medicinal plants under moisture stress conditions has a considerable role in reducing the effects of water stress and improving plant yield. To this purpose, a factorial split plot experiment with three replications based on randomized complete block design was conducted at the Research Farm of Faculty of Agriculture, Zabol University, Iran during 2013-2014 cropping years. Drought stress consisted of three levels (irrigation at 90, normal, 60 and 40 percent of field capacity) as main factor, and salicylic acid spraying wiyh three levels (0, control, 2. 5 and 5 mM) and three cultivars (Isfahan, Hamedan and Nahavand) minor factors, respectively. The investigasted traits were plant height, number of umbels per plant, number of umbellate per umbel, number of seeds per umbellate, root length, number of lateral branches, stem diameter, fresh weight of plant, grain and final plant yield, 1000 seed weight, chlorophyll a, b, total chlorophyll, carotenoids, anthocyanins, soluble sugars and proline. The results showed that drought stress decreased the traits under study. Salicylic acid spray caused an increase in some parameters such as the final height of the stem, the number of umbels, number of seeds per umbellate, root length, fresh weight of plant, seed and plant yield, chlorophyll a, b, soluble sugars and proline. Given the results of trilateral interaction effects, the greatest yield of grain was obtained from 5 mM spraying and Isfahan cultivar under irrigation conditions of 90% of the field capacity. Considering trilateral effects, the best cultivar in terms of grain yield was Isfahan cultivar with 5 mM spraying under complete irrigation conditions.

Mineral mulches, such as pumice, increase water retention of soil, reduce evaporation and optimum water consumption. Use of pumice, thus, can be effective in improving the performance and growth of plant under water stress condition. This research was performed in completely randomized block design with three replications, four levels pumice, without its use (as control), and use of 30, 60 and 90 tons of pumice per hectare and three levels of irrigation (at 50% severe stress, at 70% moderate stress and at 100% without stress, evaporation from class A evaporation pan to evaluate the effect of treatment on some physiological traits of corn (modified hybrid of Maxima). Physiological traits of corn, was affected significantly by pumice and irrigation. The highest and lowest chlorophyll index, leaf relative water content, stomatal conductance and dry and fresh weight biomass, were obtained from pumice treatment of 90 tons per hectare and the control. The highest and lowest leaf temperature was also obtained from treatments of control and 90 tons per hectare. Chlorophyll index of 90 tons treatment per hectare in comparison with control and 30 tons per hectare of pumice amounted to 52 and 26% respectively. Stomatal conductance of irrigation at 50% evaporation from evaporation pan in comparison with treatments 70 and 100% decreased by 42 and 23% respectively. Thus it can conducted that the use of the 60 tons per hectare of pumice and irrigation at 70% evaporation from evaporation pan would be effective and will significantly affect plant vegetative characteristics and yield of corn.

To evaluate the effects of plant growth promoting bacteria and irrigation levels on some physiological traits and yield of flax, a split-plot experiment was conducted based on randomized complete block design with three replications at the research farm of Agricultural Faculty of Shahrekord University in 2015. The main factor was three irrigation levels (100 % of full irrigation as control, 75 and 50 % of full irrigation) and the sub-factor was seven levels of plant growth promoting bacteria (no inoculation as control and inoculation with Bacillus SP. strain1, Bacillus SP. strain2, Bacillus amyloliquefaciens, Azotobacter Chroococcum, Pseudomonas putida and Azospirillium lipoferum). The interaction effect of irrigation and bacterial inoculation on relative water content, cell membrane stability, chlorophyll a, b and carotenoid content, chlorophyll a/b ratio, water use efficiency, number of capsules per plant, 1000 grain weight and seed yield were significant but non significant on seed number per capsule. The highest amounts of measured traits in each irrigation level were related to the bacterial treatments. The highest seed yield (with 62% increase) was obtained from Bacillus sp. strain1 in treatment and 100% of full irrigation as compared to that of control. According to the results of main effect of irrigation on number of seeds per capsule, full irrigation treatment resulted in highest number of grain per capsule as compared to the other levels. Among bacterial treatments, B. Amyloliquefaciens had the highest significant number of seeds per capsule, as compared with no inoculation treatment. The effects of treatments of Bacillus SP. strain1, B. amyloliquefaciens and A. Chroococcum treatments were more pronounced as compared to other bacterial treatments traits studied under normal and stress conditions. According to the results of this research, flax seed treatment with plant growth promoting bacteria is recommended flax seed production under water deficit conditions.

To evaluate variation of agronomic traits and chlorophyll fluorescence in rice genotypes using subirrigation, as randomized completely block design with three replications was conducted in 2013-2014. During the growth of seedlings in the treasury, the main plot was prepared according to the experimental design in the plots. Transplantation was carried out after 4-3 leaves with the selection of healthy and uniform seedlings on June 20th. In the method of flood irrigation, the land was prepared as usual. To prepare subirrigation treatments, each plot was removed to a depth of 40 cm and porous clay capsules were used. The irrigation system consisted of three main pipelines (the number of irrigation treatments), one valve head and one volume meter installed on each main pipe. The main tubes were spread along the floor and the water needed for each treatment was taken using 16 mm tubes at the beginning of each plot. By placing the pressure gauge at the beginning of the pipelines, the system pressure was modulated in the subirrigation irrigation system. Significant differences detected between genotypes in all traits at 1% probablity. HHZ1-DT3-Y1Y1, HHZ 22-Y3-DT1-Y1, HHZ 6-DT1-LI1-LI1, IR14L110 and HHZ 23-DT16-DT1-DT1 had the highest grain weight. These genotypes in terms of chlorophyll fluorescence parameters, it is evident that these genotypes are in terms of parameters such as Y (II), ETR, qP, qL, NPQ, Fm, Fv / Fm and F'v / F'm were high and were low in terms of qN, NPQ and Fo parameters. High yield genotypes and high photosynthetic potency can be used to cultivation and breeding programs in subirrigation stress areas. Therefore, these genotypes can be of further studies to be used as genotypes with low water requirements.

To compare morphological and physiological responses of three salicornia species to NaCl concentrations, a greenhouse experiment was carried out. The factors consisted of five levels of NaCl concentrations (5, 100, 200, 400 and 600 mML-1) and three Salicornia species (Salicornia persica، Salicornia perspolitana and Salicornia bigelovii ). The results showed that, simple effects of salinity and species on proline, glycinebethein, carbohydrates, chlorophyll a, chlorophyll b, relative water content, osmotic potential in shoots, dry and fresh weights were significant. Interaction effects between salinity and species on proline, glycine betaine, carbohydrates, chlorophyll a, chlorophyll b, osmotic potential in shoots, dry and fresh weight were also significant. Carbohydrates concentration increased by 70-80% at 400 mM and then decreased from 5% to 13% at 600 mM concentration. Increasing salt concentration up to 600 mM, increased proline and glycine betaine contents. Osmotic potential was also increased by 3 to 4 times with increasing salinity levels. The chlorophyll a and chlorophyll b contents decreased at 600 mM. At 200 mM NaCl concentration, wet and dry weights were significantly increased 2 to 3 times as compared control in all of three species while at 600 mM, it was decreased by 60% to 65%. It can be concluded that with increasing salt concentration all three species tolerated higher salt concentrations throught proline and glycine-betaine accumulation and reduction of osmotic potential. S. bigelovii had the highest Na+ accumulation at 600 mM of NaCl and least accumulation of K+, Ca2+ and Mg2+. On the other hand, S. perspolitana at 600 mM NaCl concentration, had the highest accumulation of potassium, calcium and magnesium, and was superior to other species in terms of dry weight yield under salinity.

To evaluate AquaCrop and Cropsyst models for simulating yield and water use efficiency (WUE), this research was performed at the Research Station in ChaharTakhteh, Shahrekord, during 1998-1999, by considering water stress amount at five levels (E0, E1, E2, E3, and E4 indicating 100, 85, 70, 50, and 30 percent of crop water needed according to lysimeter data, respectively) in three periods during potato production (T1, T2, and T3 indicating 50, 100, and 150 days after sowing, respectively) and 15 data in each year. First year data was used to calibrate and the second year was used to validate AquaCrop. The highest and lowest differences between observed and AquaCrop simulated yield were 3. 15 (E1T2) and 0. 3 (E1T3) ton. ha-1, respectively, and the highest and lowest WUE were 0. 53 (E3T2) and 0. 03 (E4T2) kg. m-3, respectively. The highest and lowest differences between observed and Cropsyst were 2. 34 (E3T3) and 0. 35 (E1T2), ton. ha-1, respectively. Corresponding results for WUE were 0. 32 (E3T2) and (E1T1) kg. m-3, respectively. NRMSE results for Yield were 0. 9 (AquaCrop) and 0. 7 (CropSyst) for calibration periods and 0. 5 (AquaCrop) and 0. 9 (CropSyst) for validation periods. EF values for yield were 0. 99 and 0. 95 for AquaCrop and 0. 90 and 0. 79 for CropSyst in calibration and validation periods, respectively. Both models had good precision; however, AquaCrop had better efficiency for simulating yield. Based on results, it is recommended to use AquaCrop in low water stress (since it is water-driven model and simulates water response to water accurately) and apply Cropsyst in high water stress (since it is radiation-driven model). In addition, using Cropsyst in T2 is better than AquaCrop.

To investigate the effect of foliar application of micronutrients on chlorophyll and protein content and yield of alfalafa populations and evaluate economics obtain cost-effect, an experiment was carried out in split split plot by time with four replications using a randomized complete blocks desighn at the Shahid Zendeh-Ruh Agricultural Research Center of Kerman. Experimental treatments were micronutrients with five levels: Fe, Zn, Mn, Fe+Zn+Mn and control (without nutrient applications), bacterial inoculation, with three levels: Rhizobium melilloti, Rhizobium legumenasarum and without inoculation. Foliar application had a positive significant effect on all traits under study and increased chlorophyll and protein contents, and alfalfa forage yeild. The highest fresh forage yield belonged to second cutting (71 t. ha-1) by using combined micronutrient foliar application and to third cutting (68 t. ha-1) by using Rhizobium leguminosarum. The highest protein rate was observed in Mn foliar application and Rhizobium meliloti inoculation at second cutting by 50%. Based on the results obtained it can be concluded that foliar application of micronutrients and inoculation with Rhizobium bacteria improves morphological characteristics of Bami population of alfalfa in Kerman region.

To evaluate the effects of two herbicides mixures, of Oxadiargyl and Rimsulfuron on weed control and potato yield and its components, a randomized complete block design experiment with 3 replications was conducted at the Research Field of Mohaghegh Ardabili University. The factors include Rimsulfuron in 0, 12. 5, 25, 37. 5 and 50 gr a. i/ha and the Oxadiargyl in 0, 0. 2, 0. 4, 0. 6 and 0. 8 lit a. i/ha in 5 herbicide mixture percentage two by two (include: 0: 0. 8, 12. 5: 0. 6, 25: 0. 4, 37. 5: 0. 2 and 50: 0) and the second factor is different time of application of these herbicides include (preplant and potato emergence). The statistical analysis showed that interaction effect of two herbicides mixture percentage and time of application had significant effect on reduction percentage of density of Commen Lambsquare, Redroot Pigweed and Field Bindweed. In order to results herbicide mixture application improved the efficacy of each herbicide on weed control, wherby these herbicide mixture percentages reduce density of Commen Lambsquare in 75% Oxadiargyl + 25% Rimsulfuron, Redroot Pigweed in 25% Oxadiargyl + 75% Rimsulfuron and Field Bindweed in 100% Rimsulfuron lonely recpectively 100%, 94. 67% and 59. 67% in preplant stage. Interaction effect of herbicide mixture percentage on time of application had significant effect on mean of tuber weight, yield of per plant and total tuber weight. The results of total yield showed that treatment of 25% Oxadiargyl + 75% Rimsulfuron in potato emergence application by 69. 16% increasment in comparison to weedy was the best recommended treatment of experiment. Also the results showed that despite increasment in enzyme activity of Catalase, this increasment hadn’ t destructive effect on yield of potato, so conclude application of this herbicide mixture hadn’ t any destructive effect on potato.

To investigate the response of corn varieties with different maturity groups to low dose applications of nicosulfuron herbicide, a split plot experiment with a randomized complete block design with three replications was carried out in Barekat Jovain Agricultural Company (Sabzevar, Razavikhorasan province) in 2017. Factors were: corn hybrids (early maturing (single cross hybrid 260, medium maturing (single cross hybrid 400) and late maturing (single cross hybrid 704) varieties as main plot and subplots five herbicide low dose applications (0, 25, 50, 75 and 100% recommended dose (50 g. ha-1 a. i. nicosulfuron) and with one weed free treatment. The results showed that, the late maturity hybrid had higher plant height, ear weight, number of rows per cob, number of seeds per row, cob weight, and seed number in cob, economic yield, biological yield, weed density and weed dry weight than other hybrids. Increasing doses of herbicide increased plant height (0. 64%), ear weight (39. 45%), number of rows per cob (8. 93%), number of seeds per row (30. 15%), seed weight (10. 68%), number of seed per cob (40. 63%), economic yield (41. 82%), biological yield (14. 95%)and decreased weed density (70. 88%)and weed dry weight (82. 17%) as compared to that of weedy condition. Although use of herbicide to reduce weed dry weight in late maturing hybrids was more than early and medium maturing hybrids but the use of the recommended herbicide dose had the same effects on weed control. 75% of the recommended dose in all three varieties produced the same yield as compared to the recommended dose. But in the late maturity hybrid, 50% reduction in recommended doses could be similar to the recommended dosage. In general, it can be said that increasing the length of the plant growth period allows the use of lower doses of herbicide than the recommended dose.