جستجوی مقالات مرتبط با کلیدواژه "پلیمر" در نشریات گروه "زراعت"

The function of a growth substrate is to provide an ideal medium for plantlet emergence which allows for the optimal development of plants during the time they stay in the container. A high-water storage capacity is necessary due to the limited volume available in growth substrate. There is a large variety of materials available for substrate elaboration, and their selection depends on the plant species to be propagated, season, propagation system, price, substrate availability and proper features. Compost seems to be an excellent alternative to peat. Also, the fresh material presents a high carbon: nitrogen ratio (C: N) and it may contain substances that are toxic to the plants, such as phenols, resins and tannins. Choosing the suitable planting bed for ornamental plants is one of the problems for most greenhouse managers. In this regard, in order to investigate the possibility of using liquorice residue compost as a by-product of the medicinal plant industry, in growth medium, the effect of peat moss, coir and liquorice root residue compost on the growth of African violet tested in an experiment.  
 
The experiment was done with 7 treatments and 5 replications in a completely randomized design. Experimental treatments included: 60% (volumetric) peat moss, 60% coir, 60% liquorice root residue compost, 30% peat moss + 30% coir, 30% peat moss + 30% liquorice root residue compost, 30% coir + 30% liquorice root residue compost. Each treatment was mixed with 40% perlite. According to the results of a pre-test on the low water retention capacity of liquorice compost, a treatment was also performed using liquorice compost with superabsorbent polymer (Aquasorb made by SNF) at a rate of 5g/kg mixed medium.
 
Experiment results in African violet showed that in shoot fresh weight, leaf number, root fresh weight, leaf area and relative leaf water content of 30% peat + 30% coir treatment and shoot dry weight, flower number and chlorophyll a were the best in 30% peat moss + 30% liquorice root residue compost treatment. The highest amount of chlorophyll b and total chlorophyll were observed in 60% liquorice root residue compost + superabsorbent polymer, the highest carotenoid content in 60% peat treatment, and the highest root dry weight and proline content in 60% liquorice root residue compost treatment. In general, according to the obtained results, by using licorice root residue compost with peat, it is possible to achieve favorable growth results, and it is recommended to use it up to 50% of the required organic matter in the bed of African violets. Based on the results of this study, licorice root resigue compost with peat moss can achieve favorable growth results and it can be used up to 50% of the required organic matter in African violet bed. The effects of licorice compost on morphological and physiological parameters of plants may be due to its effects on increased water content and soil aeration. Because there is a strong relationship between RWC and plant biomass. That also suggests that plants having greater biomass can maintain higher water content in their leaves.
 
Presence of nutrient elements increased the overall fertility, and functionality of the tested media, leading to maintain better plant growth. RWC is a measure of plant water status, which reflects metabolic activity in plant tissues and is one of the most important indicators to identify differences in substrate conditions.

Pulses have great contribution in human nutrition and agriculture due to having high protein content (nearly 2-fold more than cereals) and ability to biological nitrogen fixation. Pulses cultivation in dry lands requires some management issues like using superabsorbent and best nutrition managements in dry farming conditions. Superabsorbent are materials that absorb and hold water several times more than their weight, therefore they could increase plant available water and consequently could increase plant water potential. Due to importance of polymers in improving soil water holding capacity, present study was conducted with the aim of study the effect of phosphate Barvar-2 biofertilizer, iron nano-chelate and superabsorbent on qualitative and quantitative yield of chickpea (Cicer arientinum L.) under dry farming conditions.

Present study was conducted during 2015-2016 cropping year in a land located in Pole-Hero village, Khorram Abad town. The aim of this study was to evaluate the effect of phosphate Barvar-2 biofertilizer, iron nano-chelate and superabsorbent on qualitative and quantitative yield of chickpea (Cicer arietinum L.) under dry farming conditions. The study was conducted as factorial based on completely randomized design with three factors and three replications. The first factor was superabsorbent at two levels including S1 (without application) and S2 (80 kg/ha), the second factor was iron nano-chelate in three levels including F1 (foliar application of distilled water), F2 (1/1000) and F3 (2/1000) and third factor was phosphate Barvar-2 in two levels including B1 (non-application) and B2 (100 g/ha). At the end of growth season traits including sheath per plant, grain per plant, 100-grain weight were measured. Biological yield and grain yield, harvest index and grain protein percent (using NIR device) were measured, as well. Data were analyzed using MSTAT-C and mean comparisons were conducted via Duncan multiple range test and graphs were plotted using Excel software.

Results of mean comparisons of the triple effects of treatments showed that there were significant differences between treatments in terms of grain yield and yield components, leaf chlorophyll index, grain protein yield (excluding harvest index and 100-grain weight). Superabsorbent via maintaining soil moisture and preventing nitrogen leaching, iron nano-chelate via providing iron required for nitrogen metabolism and phosphate Barvar-2 through affecting nitrogen fixation caused increase in grain protein and chickpea chlorophyll index. It can also be stated that co-application of superabsorbent and foliar application of iron nano-chelate and phosphate Barvar-2 through alleviating the decrease in soil moisture and keeping soil water and providing sufficient nutrients by increasing secondary branches and spikes number per plant and grain number per plant could increase grain yield. The highest and lowest grain yield obtained in S2F3B2 and S1F1B1 treatments by 1623 and 950 kg/ha, respectively. According to the results, S2F2B2, S2F3B2, S1F3B2 and S1F2B2 had no significant difference in terms of grain yield and the highest and lowest grain yield by 1623 and 950 kg/ha obtained in S2F3B2 (superabsorbent, iron nano-chelate foliar application 2/1000 and phosphate Barvar-2) and S1F1B1 (control), respectively. Results showed that highest grain protein content by 21.86 percent was related to S2F3B2 (superabsorbent, iron nano-chelate foliar application 2/1000 and phosphate Barvar-2) and the lowest content was in S1F1B1 by 19.36 percent. The role of combined application of treatments in the study could be attributed to increase in water availability in soil and consequently higher water holding capacity in plant tissues, especially leaf tissues. This causes increase in plant photosynthetic ability and consequently grain protein yield which is a function of grain yield.

Foliar application of iron nan-chelate and also phosphate Barvar-2 biofertilizer and superabsorbent significantly affected qualitative and quantitative traits of chickpea such as grain yield, biological yield, leaf chlorophyll and grain protein content and highest levels of studied treatments (S2F2B2) resulted to highest amounts of studied traits. It could be said that application of treatments, in addition to alleviating drought stress and reducing application of chemical phosphorous fertilizers, resulted to increase in qualitative and quantitative traits and decreasing environmental pollution and increase in some nutrients concentration in soil.

In order to investigate the possibility of decreasing forage sorghum (Sorghum bicolor L. var speedfeed) water requirements applying of superabsorbent (SAP), without decreasing the dry matter yield and increasing the water use efficiency, and also to investigate the economic efficiency of applying superabsorbent (SAP), this experiment was conducted in Dashtak region of Zahedan during 2013 and 2014 seasons in a split-split plot with four irrigation regimes, providing 40, 60, 80 and 100% of the water requirements of sorghum, calculated from pan evaporation as main plots, four amounts of SAP )0, 75, 150 and 225 kg ha-1( as subplots and cutting as sub-subplots based on a completely randomized block design with three replications. The results indicated that the effect of irrigation regimes, SAP levels and their interaction effects of the two factors on dry matter yield, water use efficiency, and economic efficiency were significant. The regression models estimated showed that applying SAP in 100% ETc treatment had no effect on this trait but in the other irrigation treatments caused an increased the dry matter yield and water use efficiency. Therefore, applying 75 kg SAP per hectare along with 20% decrease in the sorghum’s water requirement in arid regions, the dry matter yield and water use efficiency is maintained similar to 100% sorghum’s water requirement. Also the greatest economic efficiency of applying SAP was secured at 75 kg SAP per hectare SAP level and 80% of sorghum’s water requirement.

In order to investigate the possibility of decreasing sorghum water requirements with application of SAP and to investigate the relationship between the accumulation of proline and soluble sugars with leaf relative water content (RWC) and forage yield in sorghum variety Speedfeed this experiment was conducted in Dashtak region of Zahedan during 2013 and 2014 seasons in a split plot with four irrigation regimes, providing 40, 60, 80 and 100% of the water requirements of sorghum, calculated from pan evaporation as main plots, four amounts of SAP )0, 75, 150 and 225 kg ha-1( as subplots based on a completely randomized block design with three replications. The results indicated that the effect of irrigation regimes, SAP levels and interaction effects of two factors in all measured traits were significant. The regression models estimated for two years showed that although applying SAP in 100% ETc treatment had no effect on this trait in 2 seasons but the other irrigation treatments reduced the accumulation of proline and soluble sugars and increased the RWC and dry matter. Therefore, applying 75 kg SAP per hectare along with 20% decrease in the sorghum’s water requirement produced a dry matter yield Similar to 100% water treatment.