Effects Of RDI On Growth And Production Of Soybean

Heilongjiang Province is located in the black soil region of Northeast China,which has made significant contributions to the national food security as a province with large output.However,due to the long-term unreasonable human activities and the unequa l spatial and temporal distribution of water resources,agricultural water shortage,and seasonal drought occur from time to time,which seriously restrict the sustainable development of agricultural production.It is imperative to seek technical ways of e fficient utilization of agricultural water resources.T herefore,in Harbin,Heilongjiang Province,in 2017,a pot experiment was conducted to study the effects of different water deficit regulation treatments on soybean growth,yield and water use efficien cy,taking soybean as the primary field crop in Heilongjian g Province as the research object,in order to provide a basis for water management of soybean in Heilongjiang Province.Twenty-three different RDI treatments(T₁-T₂₃)were set up in the experiment.The whole growth period of soybean was divided into six stages: seedling,branching,flowering,bearin g pod,filling and maturing.I n T₁ to T₂2 treatments,the field water holding capacity varied from the lowest 55% to the highest 8 5%,and the full irri gation treatment T₂₃?90-100% of field capacity?was added.T he conclusions of the present conducted experiment are as follows:?1?The plants subjected to T₁ expressed the utmost growth in height during the seedling stage?4.50 cm?,regarding the plant height during growth at the seedling stage,subjected to T₂₃ RDI treatment?90-100 % of field capacity?was minimum?1.50 cm?due to excessive soil moisture.Once the plants were re-watered the plant height started recovering during the branching and flowering stage.T he plants subjected to T₃ to T 18 RDI treatments expressed the highest change in the height of the plants,respectively,but the plants subjected to T₂₃ RDI treatment?90-100 % of field capacity?were still affected due to excessive soil moisture.T he plant height increased slowly but gr adually at bearing pod stage by showing utmost gro wth?73.6 cm?at T₁₄ RDI treatment.?2?The plants subjected to T₁ RDI treatments expressed the utmost growth?8.30 cm2?in the total leaf area of the plant at seedling stage.While the plants leaf area of the plants subjected to T₂₃ RDI treatments?90-100 % of field capacity?was reduced to?2.3 cm2?due to excessive soil moisture,and T₂0 RDI treatment?60-70 field capacity %?showed slight change with almost same leaf area.While the plants subjected to T₁ to T₃ and T₇ to T 18 RDI treatments expressed the highest difference in the leaf area of the plants during the stages branching,flowering,bearing pod,seed filling and m aturity.T he plant leaf area increased till the branching stage by showing utmost growth?133.80 cm2?at T₁ to T₃ and T₇ to T 18 RDI treatments.?3?The total number of pods,total seed-weight,100-seed weight and grain yield of soybean plant was affected at various regimes of RDI.T he plants subjected to T₂₃ RDI treatments?90-100% field capacity?expressed the utmost average number of pods?86?and total seed weight?270.1 0 g?.While the plants subjected to T₂0 RDI treatment?60-70% field capacity?showed the least number of pods?42?and total seed weight?24.6 0 g?,but the 100-seed weight was almost similar in all the water regime with a maximum weight?29.50 g?and minimum?22.80 g?.The T₂₃ RDI treatment?90-100% field capacity?exhibited the highest number of pods,total seed weight and also expressed highest grain yield?5.34 gm-2?comparatively other applied water regimes.?4?There was no remarkable difference in total water consumption among the different RDI?regulated deficit irrigation?and the total water consumption of other adjustment deficit irrigation with the highest being?97.97 kg?for T₂ and lowest?54.03 kg?for T19 which was irrigated at 55-65% field capacity in all the growth stages.The highest water use efficiency of T13 RDI treatment was?1.64 g/kg?indicating that the use of 75-85% field capacity in the whole growth period can greatly increase the water use efficiency?WUE?;While the WUE of T₂₃ RDI treatment is the lowest,which is?0.36 g/kg?,indicating the effect of using 90-100 % of water on WUE was maximum,and the water use efficiency of other treatments was below?1.50 g/kg?,which indicates that water shortages in different periods all have a certain impact on WUE.