Study On Yield Effect And Mechanism Of Different Corn And Wheat Intercropping Patterns In Jilin Corn Belt

In recent years,Chinese corn production is excessive and overall prices have fallen.Jilin Province is a great province of corn cultivation.So it want to improve economic efficiency,it needs to be restructuring.Intercropping development will be long-term production practice and considered to be a test to find the best economic and ecological benefits for the purpose of modern agricultural production.The study was conducted at the experimental station in Lishu County,Jilin Province.Five treatments were set up,they are 4:2?four ridge corn two ridge wheat?,3:2?three ridge corn two ridge wheat?,2:2?two ridge corn two ridge wheat?and corn,wheat mono-cropping.After two years of experiments,the growth and development of crops,the accumulation of dry matter mass yield status,inter-specific competition,water use efficiency and photosynthetic eco-physiology characteristics and regularities under intercropping and mono-cropping were studied.To provide a theoretical basis to exploring the best intercropping model for the increase of benefits under the condition of ensuring corn production in Jilin corn belt.Preliminary results from this study are as follows:1.Intercropping can increase crop yield and land equivalence ratio.The grain yields were significantly higher in the intercropped than in monoculture.Intercropping wheat production increased by 12.1%²1.1%?2016?,7.1%¹8%?2017?,Intercropping maize production increased by7.8%¹1%?2016?,3%¹3.6%?2017?,The spikelet number were more than mono-cultured wheat.No significant difference in the thousand seed weight compared with mono-cropping.The intercropping pattern had a great influence on ear number,ear weight and hundred seed weight.The intercropping significantly increased the number of effective panicles but decreased the number of panicles.In terms of100-grain weight,the inter-season trends were inconsistent.Compared with other treatments,the yield of 2:2 treatment was the highest.The LER varied from 1.06 to 1.17,indicating wheat//maize intercropping improved the land use efficiency.2:2 intercropping system has the highest land equivalence ratio.2.Intercropping can increase the nitrogen use efficiency of maize,but it will reduce the nitrogen utilization efficiency of intercropping wheat.Intercropping wheat has no significant increase in the grain N content,the grain N uptake,plant N uptake in intercropped wheat were higher than in mono-cultured wheat.The grain N content and NHI were higher in intercropped maize than in mono-cultured maize.At plant level,the IE of intercropped maize(49.95⁵7.70 kg·kg^-1)and wheat(21.31²1.63kg·kg^-1)were higher than that of mono-cultured.At system level,the nitrogen absorption equivalent ratio?NER?is greater than 1,indicating the maize//wheat intercropping used N higher efficiently than the mono-cultures.In the three intervening modes,2:2 processing is the best.3.Intercropping model promotes the growth and development of crops,improve crop dry matter accumulation amount.The plant height,stem diameter,and dry matter accumulation of intercropping wheat and corn were significantly higher than those of mono-cropping crops.In the whole growth period,the plant height of maize continued to increase to a stable trend,while the stem diameter appeared to increase first and then decrease to a stable trend.Among them,the 2:2 model crop is the best in agronomic traits.The commensal wheat competition was stronger than that of corn.After wheat was harvested,the recovery effect of intercropping maize was significantly higher than that of mono-cropping.The principle of competition-recovery production is one of the important mechanisms for increasing production between crops with short growth periods and long growth periods.Under the intercropping pattern,wheat and corn showed a clear competition.Intercropping wheat is in a competitive position with respect to maize,and with the growth period of wheat growing,it first increases and then decreases,among which 2:2intercropping wheat is the most competitive compared to other treatments.After wheat was harvested,the growth and development of intercropping maize was restored.The relative growth rate?RGR?of three intercropping treatments was significantly higher than that of mono-cropping maize,and the recovery effect of 2:2 intercropping was the best.4.Intercropping System Improves Crop Water Absorption and Utilization.The maize//wheat intercropping system can significantly increase crop water consumption.The water content competition ratio?CRwm?of wheat relative to corn was significantly different among the treatments,among which CRwm>1 in the 2:2 treatment.The maize//wheat intercropping system can significantly increase crop water use efficiency.Compared with mono-cropping,intercropping wheat increased by 4.8%¹7.2%,intercropping maize increased by1.1%¹1.1%.Intercropping can make full use of water resources.The dislocation of the distribution of water use efficiency of wheat and corn is the basis of efficient utilization of water resources in maize//wheat intercropping.5.The intercropping pattern significantly increased the net photosynthetic rate?Pn?and transpiration rate?Tr?of wheat and corn.During the crop growth cycle,the intercropping system increased the chlorophyll content?SPAD?of wheat leaves and reduced the SPAD value of corn.During the jointing and filling stages of wheat,intercropping wheat had higher utilization efficiency of light energy than mono-cropping and had a higher net photosynthetic rate Pn(15.20¹6.80 umol·m^-2·s^-1;11.40¹2.10umol·m^-2·s^-1)and transpiration rate Tr(4.89⁵.66 umol·m^-2·s^-1;5.23⁵.91 umol·m^-2·s^-1);during the symbiotic period,early wheat growth was developed earlier The plant height is higher than that of corn,so it spatially interferes with corn intercropping.The light absorption of intercropping corn leaves was affected,and photosynthetic performance was reduced.The photosynthetic performance of corn was recovered to a certain extent after wheat harvest.Pn and Tr of intercropping maize after tasseling period were higher than those of monoculture maize.It is proved that intercropping can increase the crop's full use of light energy resources.