| China is a large agricultural country,rice as a main crop,its planting area in Heilongjiang Province is larger than other provinces.A large amount of water and phosphorus nutrients are needed during the process of rice planting.However,in the face of the basic national conditions that China's total water resource and phosphate resource are relatively scarce,Therefore,the growth and development of rice,phosphorus?P?absorption and accumulation,and available Ps content of soil under different irrigation modes and different P application levels were compared and analyzed comprehensively in Heilongjiang Province,so as to obtain a more reasonable P application level under different irrigation modes.It can reduce the risk of environmental pollution caused by a large amount of residual phosphate fertilizer in the soil on the basis of maintaining stable yield or even increasing yield.The experiment was carried out in the Rice Irrigation Experiment Center Station of Qing'an county,Heilongjiang Province.In this experiment,two different irrigation modes?F:flood irrigation,C:controlled irrigation?and six different P application rates(P0:0 kg·hm-2,P1:15kg·hm-2,P2:30 kg·hm-2,P3:45 kg·hm-2,P4:60 kg·hm-2,P5:75 kg·hm-2)were set up,a total of 12treatments.The effects of different water and P management modes on plant height,tiller number,root morphology at heading stage,dry matter accumulation,yield and its components,P accumulation in grains and plants,P utilization efficiency,P absorption efficiency,partial productivity of P,available P content in surface soil and apparent P balance were studied.The main findings of this experiment are as follows:?1?With the increase of P application rate,the plant height,tiller number,root morphological indexes of heading time,dry matter accumulation of aboveground part,yield,water consumption and water use efficiency?WUE?increased first and then decreased,however,the harvest index showed a trend of decreasing first and then increasing.The controlled irrigation mode increased the plant height at the tillering and jointing stage,root length,root length density,and specific root length compared to the flooding irrigation mode.Compared with flood irrigation,controlled irrigation increased the plant height at the milky and mature stages,the peak tiller number and the water consumption.Plant height,peak tiller number,root morphological indexes of heading time,dry matter accumulation of aboveground part,yield,water consumption and WUE of CP2 and FP3reached the maximum values,harvest index reached the minimum value under two irrigation modes with different P application levels.Correlation analysis showed that there was a significant positive correlation between yield and root length,root dry weight,root surface area,root volume,root tip number,average diameter,effective panicle number and dry matter accumulation of aboveground part?P<0.01?,a significant positive correlation between yield and peak tiller number?P<0.05?,and a positive correlation between yield and plant height,thousand grain weight,seed setting rate,number of grains per panicle,WUE?P>0.05?.There was a significant negative correlation with harvest index?P<0.05?.?2?With the increase of P application rate,P concentration and P accumulation increased first and then decreased;the P harvest index and P utilization efficiency decreased first and then increased;the absorption efficiency and partial productivity of P fertilizer showed a downward trend.Compared with flood irrigation,controlled irrigation increased P concentration,grain P accumulation,and P harvest index.Compared with controlled irrigation,flood irrigation increased the P uptake per unit root length and P dry matter utilization efficiency.P concentration and P accumulation of CP2 and FP3 reached the maximum values,P harvest index and P utilization efficiency reached the minimum value under two irrigation modes with different phosphorus application levels.Correlation analysis showed that there was a significant positive correlation between P accumulation and yield,aboveground dry matter accumulation?P<0.01?,and a significant positive correlation with root dry weight and root length density?P<0.05?.The concentration showed a very significant positive correlation?P<0.01?and a significant negative correlation with the P utilization efficiency?P<0.05?.?3?With the increase of P application,the soil available P content after harvest and the apparent P surplus of the soil showed an increasing trend and the apparent P deficit of the soil showed a decreasing trend.The increase of soil available P in CP2 and FP3 treatments reached the minimum values under the two irrigation modes and different P application levels.Correlation analysis showed that the increase of soil available phosphorus was significantly positively correlated with soil apparent P profit and loss?P<0.01?;the amount of P application was positively correlated with soil available P increase?P>0.05?.In summary,P2 is the best P application rate under the control irrigation mode,P3 is the best P application rate under the flood irrigation mode,and there is no significant difference in rice yield between CP2 and FP3 treatments?P>0.05?,the partial P productivity of CP2 was significantly higher than that of FP3 treatment?P<0.05?.Therefore,CP2 treatment was the best water and P management mode in this experiment.A suitable water and phosphorus management mode could create good root morphology,plant height at each growth stages,tiller number,dry matter accumulation on the aboveground and P accumulation in rice,and it will be more conducive to improving yield and P fertilizer utilization efficiency,and reduce the increment of soil available P.This study provides a theoretical basis for understanding the differences in physiological index and P fertilizer utilization under different water and phosphorus management strategies,and for guiding the practice of high-yield and high-efficiency rice cultivation in cold and black soil regions. |
PDF Full Text Request