Responses To Fertilizers And Nutrients Requirement Of Dwarf Winter Rape

Rapeseed is one of the important oil crops in China,with various uses and wide planting area.Understanding the nutrient requirements of rapeseed is an important way to achieve high yield,but the traditional winter rapeseed is high and prone to lodging,which limits the further improvement of yield.Therefore,it is of great significance to study and understand the growth and nutrient absorption of rapeseed and its response to fertilizer for guiding efficient fertilization management of rapeseed.In this study,two selected dwarf rape materials YF675 and YF705 were selected as the research subjects,and the local traditional rape varieties(Mianxian: Shaanxi You 28 and Yangling: Qin You 7)were used as the control.The field trials were conducted in Huangsha and Yangling agricultural stations in Mianxian County,Shaanxi Province from 2020 to 2021,representing two different ecological areas in southern Shaanxi and Guanzhong.In this experiment,a two-factor split plot experiment design was adopted,with rape varieties as the main treatment and "3414" fertilizer as a secondary treatment.At the same time,the planting density of control rape was 25,000 plants/mu,and the planting density of short-stem compact rape was 40,000 plants/mu.The main results are as follows:(1)The dry matter accumulation from sowing to seedling stage,seedling to flowering stage and flowering stage to maturity stage in southern Shaanxi showed a slow-fast-slow trend,and nitrogen application significantly increased the dry matter accumulation in the upper part of winter rape field.The main stages of nitrogen absorption in winter rape were seedling stage and moss budding stage,and the main stages of phosphorus and potassium absorption in WINTER rape were YF675 and YF705.YF675 and YF705 had more absolute nitrogen and potassium absorption than CK,and their nutrient demand and nutrient accumulation accounted for more in the early stage.The effective branch number and silique number of YF675 and YF705 were lower than those of CK,and the number of grains per silique was relatively higher.The average yield of CK,YF675 and YF705 were 3646.5 kg/ha,4151.7 kg/ha and 3439.0 kg/ha,respectively,and the highest nitrogen application rates of CK,YF675 and YF705 were 264 kg/ha,216 kg/ha and 268 kg/ha,respectively.YF675 is recommended to be planted.Meanwhile,potassium fertilizer should be increased for YF675 and YF705.(2)The dry matter accumulation from sowing to seedling,seedling to flowering,and flowering to maturity in Guanzhong area showed a slow-fast-fast trend,which was related to the suppression of rape growth by low temperature and drought.The seedling stage was the main stage of nitrogen absorption in winter rape,and the nitrogen accumulation was higher in the seedling stage of YF675 and YF705,and the phosphorus absorption was mainly in the seedling stage and flowering stage of YF705.Compared with CK,YF675 and YF705 had higher demand for potassium fertilizer,but lower demand for nitrogen fertilizer and phosphorus fertilizer.YF675 and YF705 were significantly lower than CK in effective branch number,silique number and seed number per Angle,but 1000-seed weight was significantly higher.Plant height and first effective branch height of YF675 were not significantly affected by nitrogen level,which was conducive to mechanical harvesting.The average yield of YF675 and YF705 was significantly lower than that of CK.Under the recommended fertilization level,the average yield of CK,YF675 and YF705 were 3658.6 kg/ha,3338.6kg/ha and 2632.9 kg/ha,respectively.The maximum nitrogen application rates of CK,YF675 and YF705 were 225kg/ha,237kg/ha and 226 kg/ha,respectively.The p and k fertilizer effect of YF705 was obvious.The results showed that there were significant differences in fertilizer absorption and utilization between the dwarf rod and the tall rod,which were affected by air and rainfall.Therefore,YF675 and YF705 were not suitable for planting in Guanzhong area,and YF675 with low fertilizer input was recommended to be planted in southern Shaanxi area.The original recommended nitrogen application rate should be increased for rapeseed planting in southern Shaanxi and Guanzhong,and the input of potassium fertilizer should be appropriately increased for rapeseed planting.