Effects Of Environmental Stresses(Waterlogging,Salt,Heat)on Grain Yield And Associated Traits Of Wheat Under Application Of Controlled Release Nitrogen Fertilizer

Wheat(Triticum aestivum L.)is the staple food worldwide,especially in Asia.The increasing population puts pressure on wheat production with increased demand of 2%every year.The world population is 7.9 billion,which is a considerable number to feed.The agricultural practices,fertilization,introduction of genetically modified seeds,pesticides,and mechanization have significantly increased wheat production.Despite all these efforts,vast land areas call attention as these are affected by salts,waterlogging,or chemical contaminants that are unsuitable for crop production.Moreover,in many regions of the world,the climate factor,high temperature,and disrupted rainfall patterns cause considerable economic losses.With a proper release time,control fertilization,such as sulfur-coated urea(SCU),can be a potential strategy to minimize the damage.The current study analyzed the effect of two fertilizers,SCU1(release time of 120 days)and SCU2(release time of 160 days),on wheat production under different environmental stresses(waterlogging,salt and heat).The main results are as follows:1.The high-water content(waterlogging)in the soil causes hypoxia to wheat plant roots,hampering the overall plant growth.It was observed the same in our study,but after applying SCU2,plant growth was restored close to the control.Data revealed that SCU2 at a rate of 130 kg of N/ha maintained the number of tillers to 12 under waterlogging stress from germination to the overwintering stage(35-40 days),which was the same as control.The leaf area in SCU1 was?5500 cm2,slightly reduced under waterlogging stress with SCU1,while it was just?3000 cm2 in control.The spike length was 12 cm in control while it was?11.4 cm in the case of SCU2 under stress conditions;more or less,the same trend was observed for all other growth parameters as well.The same was observed in the crop yield cases,like 66.6 g/pot in control,45.83 g/pot in the case of waterlogging(SCU1),and 51.62 g/pot in waterlogging(SCU2).Growth,spike length,yield,and physiological restrictions significantly correlated with nitrogen in the soil,while nitrogen-related indicators were positively associated.Fertilizer provided enough nutrients for the plant growth at the required time.In this case,the particular wheat variety Yangmai 25 built an extensive root network under waterlogging stress that is a key to plant survival.Urea fertilizers coated with secondary minerals,such as "S," improved urea's nitrogen release ability to meet plants' nitrogen requirements.As a result,it is suggested to use SCU with a longer release time of about 160 days to provide nitrogen until the harvesting stage of the wheat crop.2.The application of both fertilizers was seen as effective in the salt stress while using NaCl as a source of salt stress,but SCU2 was more effective than SCU 1.Salt stress damaged the plant cells,as depicted by the results of MDA,CAT,PPO,and POD but fertilizer application significantly reduced the damage to the wheat plant.As a result,an increased crop yield was observed.Principal component analysis(PCA)plots showed that SPAD value,ear weight,and plant length were the most significant parameters affecting wheat yield.SCU2 showed a better crop yield than SCU 1.The data showed that SCU2 maintained a SPAD value of approximately 53 at a rate of 130 kg N/ha,near to the control.The net photosynthetic rate of leaves was 16.38?mol CO2 m-2s-1,and the salt stress treatment increased until the flowering stage.The panicle length was 12 cm in control and 11.6 cm in the case of salt stress under SCU2.The crop yield was 66.6 g/pot in control,53.1 g/pot under salt stress(SCU2),and 41.56 g/pot in SS(SCU1).This study demonstrates that SCU2 can be an environmental friendly option for wheat under salt stress conditions.3.Both of the fertilizers were ineffective in the case of heat stress.Heat stress disturbed the plant proteins,enzymatic mechanisms,and soil microbiology.As a result,the plant could not survive under heat stress even after the ample availability of fertilizers in the soil.Data revealed that SCU2 at a rate of 130 kg of N/ha maintained the SPAD value of 53 in control and?12 under heat stress in the case of both fertilizers.The average dry weight of the plant was 10 g in the case of SCU1 and 12 g in the case of SCU2 under heat stress.The same was depicted as a crop yield of 66.6 g/pot in control,while?28 g/pot in both cases of SCU1 and SCU2 under heat stress.Since the heat stress was given after the flowering period in a cryogenic room,heat stress was the most intolerable to the plants.In the case of heat stress,when nitrogen application is based on SCU1,the yield of soil peroxidase increases.Since soil peroxidase is a vital oxidase involved in the degradation of plant litter and organic matter,it can be reasonably predicted that the high temperature in summer will rapidly accelerate the degradation of dead roots and soil organic matter in creeping wheat systems that receive low nitrogen rates.It also corresponds to the yield results,where heat stress showed the lowest grain yield of?28 g/pot in both cases(SCU1 and SCU2),which is far from the control.4.The combined stress was applied to the Yangmai 25 to mimic the harsh climatic conditions such as hot deserts with salt-affected lands.Data revealed that SCU1 at a 130 kg of N/ha rate maintained the SPAD value nearly the same as control under waterlogging and salt stress conditions up to the flowering stage.The net leaf photosynthetic rate was 15.58 ?mol CO2 m2s-1,while it was similarly improved in all stress treatments until the flowering stage,especially in the case of SCU2.The crop yield was most negatively affected,from 66.6 g/pot in control to 17.53 g/pot in the case of SCU1 and 19.18 g/pot in the case of SCU2.It is suggested that use more advanced fertilizers for heat and combined stresses.Moreover,SCU having a release period of about 160 days can be adequate for salt and waterlogging stress alleviation.Also,screening should be done in soil,not potting mix,as adverse effects are more pronounced in vertosol(high content of clay minerals)soil and more representative of the actual farm situation.5.Comparing the Fourier transform infrared spectrum characteristics of Wheat Leaves under different stress conditions,it showed that the wheat produces a series of protein substances(stress proteins)to deal with the effects of different stresses,and there are differences in the composition of substances produced in response to different stresses.The results can point out the way for developing different biochemical agents(regulatory substances)to deal with different stresses in production.6.Studying soil properties with and without added fertilizers provides sustainable solutions for increasing yields.The fertilizer has a critical role in the growth of plants and in improving the physical and chemical states of the soil.The present study showed that SCU2 treatment in salt stress cases significantly increased cation exchange capacity,phosphorus,and K2O content.Adding SCU2 to high-saline soils can reduce the adequate water capacity.EC increases soil bulk density,total porosity,and soil aggregate stability.Therefore,SCU2 can be used as a source of essential nutrients for plants and helps enhance the soil's physical and chemical properties.Current research results indicated that SCU2 might help reduce the salinity of land affected by salinity and increase the proportion of soil aggregates.In the case of heat stress,when nitrogen application is based on SCU1,the yield of soil peroxidase increases.Since soil peroxidase is a vital oxidase involved in the degradation of plant litter and organic matter,it can be reasonably predicted that the high temperature in summer will rapidly accelerate the degradation of dead roots and soil organic matter in creeping wheat systems that receive low nitrogen rates.However,the fertilizer has been proved to be the most effective for studying the actual situation of the crop.Therefore,it will endorse the present findings and lead toward these fertilizers' effectiveness and efficiency.