Some Aspects of Yield Physiology Research in Soybean

The paper reviews the factors and mechanisms involved in the regulation of seed growth,discusses the roles of source sink relationship in yield formation and effects of climate change and canopy photosynthesis on groth and yield in soybean.

Coupling Effect of Water and Fertilizer on Soybean Yield and Nutrient Absorption

Soybean cultivar Bei 92-28 was tested in this experiment in 2000 to study the coupling effect of water and ferilizer on soybean yield.The results showed that the effect of irrigation varied among the levels of fertilizer application,and vice versa;pods per plant,seeds per pod.and 100-seed weight had positive correlations with soybean yield,but the degrees of correlations of different treatments were various;LAI and dry matter accumulation could be significantly increased when watered and applied fertilizer with different levels,but high fertilizer application treatment didn't obtain the highest yield;watering could increase the absolute absorption amount of N,P,K in seeds,but the accumulation rates were various.

Year-to-Year and Maturity Variation in Rainfed Soybean Yield by Planting Dates

The interactions on rainfed soybean yield among planting date, maturity, and year-to-yearclimate change were studied using CROPGRO-soybean model. Simulations were based on 19 plantingdates, maturity groupsⅢ, ⅣandⅤ, 30 years recorded weather data from Corbin, Suffolk,West Point in Virginia, USA. Yield was similar on early plantings and went down with lateplantings. Both grand and year-to-year variation of soybean yield declined linearly withplanting date. Year-to-year climate variation was dominant yield variation source inrainfed soybean production. Interaction occurred between planting date and maturity.Optimal planting dates for different sites lied within 130th-170th day of a year.Irrigation is recommended for profitable crops, especially in Corbin and West Point.

Influences of mechanized tillage and sowing modes on soil physical properties,soybean yield and economic benefits in mollisols region of Northeast China

Appropriate mechanized straw returning and tillage sowing techniques were effective means to optimize soil physical properties and enhance agricultural productivity,as well as important measures for the conservation and restoration of mollisols region in Northeast China.Under the condition of full-scale maize straw returning,four mechanized tillage and sowing modes were set,including plough tillage and sowing(PTS),combined tillage and sowing(CTS),no-tillage and sowing(NTS),and no-tillage and sowing with straw mulching(NTSM).In 2020 and 2021,the study investigated the effects of different mechanized tillage and sowing modes on soil physical properties,soybean yield and economic benefits.The results showed that during the pod-setting and pod-filling period of soybean,the NTS and NTSM treatments exhibited better effects on deep soil insulation and shallow soil moisture retention,the soil physical structure of PTS and CTS treatments were relatively ideal.Compared with PTS and CTS treatments,NTS and NTSM treatments significantly increased soil gravimetric water content(SWC)by 2.35%to 7.98%in the 5-15 cm soil layer and increased soil temperature(ST)by 3.94%to 10.42%in the 25-35 cm soil layer(p<0.05),significantly increased soil bulk density(SBD)by 2.98%to 6.72%and significantly reduced soil total porosity(STP)by 3.88%to 6.53%in the 5-25 cm soil layer,and significantly reduced soil gas phase ratio by 8.26%to 6.27%at the 15-25 cm soil layers,which caused soil three-phase ratio(STPR)of PTS and CTS treatment in 15-25 cm soil layer were relatively ideal.The soybean yield of NTSM treatment in 2020 was not significantly different from PTS and CTS treatment(p>0.05),the soybean yield of NTSM treatment in 2021 significantly increased by 7.30%and 5.84%over PTS and CTS treatments,respectively.And the average annual profit per unit area of NTSM treatment increased by 12.84%,12.41%and 8.57%compared with PTS,CTS and NTS treatments,respectively.Therefore,it was recommended to combine NTSM technique with PTS or CTS technique in a maize-soybean rotation system in mollisols region.The research results provided reference for the selection of appropriate mechanized tillage and sowing techniques in Northeast China’s mollisols region and had important guiding significance and practical value for the construction of rational plow layers and the implementation of conservation tillage.