| The intensive planting model reduces crop diversity in farmland ecosystems,and inter-crop intercropping achieves the advantage of yield and the efficient use of nutrients by increasing the crop diversity and taking advantage of the difference in temporal and spatial niche between crops.Most of the previous researches were intercropping of crops,and there are few studies on intercropping of different varieties of the same crop.In this study,corn was used as the research object,and 8 varieties with different plant heights and growth periods were selected:Tiannong 9(A),Dongnong 259(B),Xianyu 335(C),Jingke 968(D),Jiulong 19(E),Lihe 1(F),Jiudan 57(G),Jinghua 8(H),set single crop(Mono),2 varieties of intercropping(Mix2),4 varieties(Mix4),6 varieties(Mix6),8 varieties of mixed crops(Mix8)a total of 17 treatments,through the field plot test,preliminary exploration of the impact of different maize varieties on the yield and nutrient use efficiency,and analyze the time stability of 2017-2019 three consecutive years of production,To provide new ideas for increasing maize production through genetic diversity cultivation,the main results are as follows:(1)Intercropping of different varieties of corn significantly affects the plant height and ear height of the corn,but has no significant effect on the stem thickness.The plant height and ear height of high-stalk corn varieties A,C,D,and F were significantly higher than those of medium-stalk varieties B,E,G,and H.The tall-plant corn varieties showed stronger competitiveness during intercropping.(2)The chlorophyll content SPAD value of the high-stalk corn varieties A,C,D,and F during intercropping with other varieties in this experiment were higher than their corresponding monocropping treatments;meanwhile,the net photosynthetic rate Pn and transpiration rate of the high-stalk corn varieties were Tr The values are higher than their corresponding monocropping,in which the E/F and C/F intercropping combinations increase significantly;while the photosynthetic parameters of the mid-stalk corn varieties are lower than those of the monocropping,of which the compact plant type G and H varieties have There was no significant difference between the treatments.(3)The analysis of nutrient accumulation data of nitrogen,phosphorus and potassium shows that high-stalk corn varieties have higher nutrient advantages,among which high-stalk corn variety Xianyu 335(C)and middle-stalk variety Dongnong 259(B)During intercropping,LERN=1.07,which significantly improves nitrogen absorption.When intercropping C and Ligan No.1(F),nitrogen(LERN),phosphorus(LERP),and potassium(LERK)were 1.09,1.10,and 1.08,respectively.,Indicating that C/F intercropping significantly increased the absorption of nutrients by crops.(4)In this experiment,LER>1 for B/C,C/F,E/F,and Mix6 intercropping treatment has the advantage of intercropping yield.Among them,C/F and B/C intercropping yield yield advantages are significant,respectively Increased by 14%,8%.A/B,F/H,Mix8 three intercropping treatments have a LER<1,which has no intercropping yield advantage;D/E,Mix4 intercropping treatment has a LER=1,and the intercropping yield advantage is not significant.This shows that the selection of mixed cropping between different maize varieties with different growth periods and heights can increase the yield of corn,and the effects of mixed cropping between different varieties on the yield advantage are different;through the analysis of yield components and the correlation of inter-mixed species diversity on yield The yield was significantly positively correlated with the ear height and the number of grains per ear.Therefore,the yield contribution rate of the high-stalk corn varieties in the inter-mixing treatment was greater than that of the medium-stalk varieties,and the yield advantage reached the maximum in the Mix2 treatment.As the number of intermixed works increases,the yield advantage gradually decreases.(5)The analysis of production data for 2017-2019 shows that the time stability of the output of each inter-crop treatment is higher than that of the single crop,and the other inter-crop treatments except Mix8 have achieved significant significance compared to the single crop for three consecutive years in 2017-2019.Difference(P<0.05).When analyzing the three-year average data,the time stability of yield has the maximum value under Mix4 treatment,which is an increase of 112%compared to single cropping,indicating that mixed cropping between different corn varieties has higher planting productivity stability than the corresponding single crop corn,but when When the number of mixed works increases,the time stability of production will show a downward trend.Therefore,the rational choice of varieties and variety diversity when mixing between different varieties has an important impact on maintaining the long-term productivity stability of the system. |
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