Effects Of Rhamnolipid And Nano Silicon Fertilizer On Salt Tolerance Of Cotton

Rhamnolipid and nano silicon fertilizer,as a new type of microbial fertilizer,have a certain application prospect in agricultural production.They can improve the soil environment,promote the absorption of nutrients by plants,and reduce the harm of soil salinization to cotton growth.However,the influence mechanism of rhamnolipid and nano silicon fertilizer on the changes of soil ion content in salinized cotton field and the physiological growth characteristics of cotton under drip irrigation without film is not clear.Therefore,in this paper,three types of soil salinization(conductivity is 2000 μS/cm、5000 μS/cm and 8000μS/cm),three concentrations of rhamnolipid(100,300 and 500 mg/L)and nano silicon fertilizer(100,300 and 500 mg/L)were set up to illustrate the effects of rhamnolipid on soil salt ions and cotton growth in non film drip irrigation cotton field and nano silicon fertilizer on improving the antioxidant effect of cotton.The main conclusions are as follows:In this study,the combination of drip application of rhamnolipid(concentrations of 100 mg/L,300mg/L and 500 mg/L)and drip irrigation technology was applied to low salt treatment(2000 μS/cm),medium salt treatment(5000 μS/cm)and high salinity treatment(8000 μS/cm),the effects of rhamnolipid as soil curing agent on soil salt ions in cotton field and cotton growth under film-free drip irrigation were studied;Spraying treatment(with concentrations of 100 mg/L,300 mg/L and 500 mg/L)is set to spray nano silicon fertilizer and clean water,and spray it in low salt treatment(2000 μS/cm)and high salinity treatment(8000 μS/cm)two kinds of salinization degree of film-free drip irrigation on cotton leaves in cotton field,to study the antioxidant effect of spraying nano silicon fertilizer as modifier on cotton leaves.The main conclusions are as follows:(1)Rhamnolipid can effectively reduce the contents of Cl-,SO42-,K+,Na+,Ca2+ and Mg2+ in soil.After dropping rhamnolipid,the change of salt ions in soil is obvious,and each treatment has the best effect on reducing the content of Na+ in 0 ~ 20 soil layer.Among them,the low salt treatment has the lowest Na+content,that is,rhamnolipid can effectively improve the low salt saline alkali land,so as to alleviate the harm of excessive soil salt ion content to cotton growth.At the same time,drip application of rhamnolipid also had a significant effect on the stem diameter and plant height of cotton treated with different salts.For the stem diameter of cotton,under the three salt treatments,the drip treatment increased by 3.33% ~ 9.05%,2.14% ~ 10.70% and 3.59% ~ 8.98% respectively compared with the clear water control treatment;For cotton plant height,under the three salt treatments,the drip treatment increased by 3.75% ~ 14.43%,6.98%~ 20.35% and 11.42% ~ 23.41% respectively compared with the clear water control treatment.(2)Spraying nano silicon fertilizer had a significant effect on improving the indexes of chlorophyll,photosynthesis and antioxidant enzymes of cotton leaves under film-free drip irrigation in saline soil.At the seedling stage of cotton,which was most affected by salt stress,the chlorophyll content of cotton leaves increased by 2.26% ~ 16.51% and 2.17% ~ 18.68% respectively under the two salt treatments;Under the two salt treatments,the CAT activity of cotton leaves increased by 5.46% ~ 12.61% and 1.86% ~ 18.31%respectively;Under the two salt treatments,the content of SOD activity in cotton leaves increased by5.16% ~ 12.24% and 3.35% ~ 12.55% respectively;Under the two salt treatments,the POD activity of cotton leaves increased by 3.82% ~ 16.14% and 11.04% ~ 23.96% respectively.(3)Spraying nano silicon fertilizer has a significant effect on improving the growth and yield of cotton under film-free drip irrigation in saline soil.For the stem diameter of cotton,under the two salt treatments,the spraying treatment increased by 1.77% ~ 6.67% and 1.40% ~ 7.29% respectively compared with the water control treatment;For the plant height value of cotton,under the two salt treatments,the spraying treatment increased by 4.50% ~ 21.12% and 3.66% ~ 33.14% respectively compared with the water control treatment;Under the two salt treatments,the aboveground dry matter accumulation of cotton increased by2.82% ~ 10.42% and 2.26% ~ 6.61% respectively;For the seed cotton yield of cotton,under the two salt treatments,the spraying treatment increased by 5.39% ~ 15.91% and 1.89% ~ 34.58% respectively.