| Cherry radish?Raphanus sativus L.var.Radculus pers?,a kind of four-season radish,has the characteristics of short growth cycle,high nutritional value,and considerable economic benefits.It is one of the root vegetables widely planted in China.At present,there are many researches on the irrigation technology of cherry radish,little on the relationship between soil moisture and cherry radish.Therefore,in this study,two years pot water-controlled experiments with various negative pressure irrigation?NPI?treatments and conventional irrigation?CI?were carried out on cherry radish.By analyzing soil moisture,and agronomic traits,photosynthesis,root-to-shoot ratio,water use efficiency?WUE?,nutrient uptake and other traits of cherry radish,and then explore the effect of soil water on cherry radish growth and water use efficiency under negative pressure irrigation.The results are as follows:1.Cherry radish pot experiment in 2018:?1?The average volume of soil water content through the full experiment treated with CI,NPI1?-5 kPa?,NPI2?-9 kPa?,NPI3?-14 kPa?were 12.60%,12.63%,10.07%,and 8.47%,respectively.NPI1 and NPI2 were sorted to weak temporal variation,while NPI3and CI were sorted to moderate temporal variation.?2?In the range of soil water content from 8.47%to12.63%under NPI,agronomic traits,SPAD value,yield and dry matter quality of cherry radish in the mature stage all increased with the increase of soil water content;When soil water content was basically the same?CI and NPI1 treatment?,agronomic traits,photosynthetic rate,dry matter quality and WUE of cherry radish treated with NPI1 were all higher than CI.?3?Compared with CI,cherry radish treated with NPI1 and NPI2 had higher plants,larger leaves,higher SPAD value and higher net photosynthetic rate.Besides,yield and dry matter mass of cherry radish treated with NPI1 were the highest,which were34.92 g·plant-1 and 4.63 g·plant-1,respectively;WUE of yield and biomass in NPI2 treatment were the highest,which were 1.20 g·kg-1 and 2.43 g·kg-1,respectively.2.Cherry radish pot experiment in 2019:?1?The average volume of soil water content through the full experiment treated by NPI1?-2 kPa?,NPI2?-5 kPa?,NPI3?-8 kPa?,CI1?80%-90%FC?,CI2?70%-90%FC?and CI3?60%-90%FC?were 35.38%,25.02%,23.75%,24.71%,23.26%,and 21.80%,respectively,of which NPI1,NPI2,and NPI3 were sorted to weak temporal variation.?2?In the range of soil water content from 23.26%to 25.02%under NPI,compared with CI1 and CI2,cherry radish treated with NPI2 and NPI3 had good canopy potential,high net photosynthetic rate,transpiration rate,leaf water use efficiency,and good fruit morphology.Compared with CI1,the yield,dry matter quality and water use efficiency of cherry radish under NPI2 were significantly increased by 34.63%,42.86%and45.82%,respectively;Compared with CI2,the yield,dry matter quality and water use efficiency of cherry radish under NPI3 were significantly increased by 94.18%,62.86%and 74.47%,respectively.?3?In the negative pressure water supply treatment,the nitrate content of NPI3 treated fruits was lower,the reducing sugar content was higher,and the nutrient absorption was higher.Compared with CI2,the nitrate content in fruits treated with NPI3 decreased by 29.50%,and the total absorption of Nitrogen?N?,Phosphorus?P?and Potassium?K?increased by 47.57%,78.86%and 19.27%,respectively.In summary,the soil water content and irrigation methods affect the growth and yield formation of cherry radishes together.When the average soil water content is basically the same,the weak time-variable soil moisture under NPI can promote plant growth and development,and significantly improve cherry radish yield,nutrient absorption and water use efficiency.Under the conditions of this experiment,the irrigation pressure of-5?-9 kPa is suitable for the growth of cherry radish throughout the growth period. |
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