Maize-soybean relay cropping increases soybean yield synergistically by extending the post-anthesis leaf stay-green period and accelerating grain filling

Relay cropping of Poaceae and Fabaceae promotes high yield and land-use efficiency by allowing a double harvest.However,it is difficult to increase yield synergistically because of the reduced photosynthetic abilities of legume leaves under the shade of graminoids.Leaf photosynthetic capacity in relay cropping systems is associated with ecological niche differentiation and photosynthetic compensation after restoration of normal light.We conducted a field experiment in southwest China in 2020–2021 to evaluate the effects of three cropping patterns:maize–soybean relay cropping(IMS),monoculture maize(MM),and monoculture soybean(SS),and N application levels:no N application(NN:0 kg N ha^(−1)),reduced N(RN:180 kg N ha^(−1)),and conventional N(CN:240 kg N ha^(−1)).Compared to monocropping,relay cropping increased the stay-green traits of maize and soybean by 13%and 89%,respectively.Relay cropping prolonged the leaf stay-green duration in the maize and soybean lag phase by almost 4 and 8 days,respectively.Relay cropping maize(IM)increased the leaf area index(LAI)by 79.4%to 88.5%under NN and 55.5%to 148%under RN.Relay cropping soybean(IS)increased the LAI from 115%to 437%at days 40 to 50 after anthesis.IM increased yield by 65.6%.IS increased yield by 9.7%.HI and system yield were at their highest values under RN.In the relay cropping system,reduced N application extended green leaf duration,increased photosynthesis inside the canopy at multiple levels,ultimately increases soybean yield synergistically.

Development of Spraying Devices for Interplantation in Forest

Honghuagang District,Zunyi City,Guizhou Province,develops the characteristic industry of crispy peaches,and at the same time develops the forest economy and promotes the model of planting soybeans in peach orchards to promote rural revitalization.However,due to the different pests and diseases occurring in peach trees and soybeans,the control drugs used are also different,and the existing technology for spraying and controlling peach or soybean seedlings is operated separately and cannot be sprayed together at the same time.This study,based on the actual situation of forest land,develops a spraying device for interplantation in forest(peach tree and soybean)from the aspects of technical solutions,working principles and beneficial effects,in order to solve the problem of low spraying efficiency of spraying control of peach tree or soybean seedlings in the existing technology.

Nitrogen use in double cropping soybean with non-fertilized winter oilseed crops

Sustainable intensification of cropping systems is a strategy to increase productivity and reduce disservices of conventional agroecosystems.Camelina[Camelina sativa(L.)Crantz]and field pennycress(Thlaspi arvense L.)are winter annual oilseed crops well suited to fill the fallow period between corn(Zea mays L.)and soybean[Glycine max(L.)Merr.]in the U.S.northern Corn Belt,but their inclusion may be limited by resource use limitations.A 2-year study was conducted from 2015 to 2017 in the U.S.upper Midwest to evaluate the effect of double cropping on winter oilseed crops and soybean productivity and economic performance.Treatments included relay-and sequential-cropped soybean with winter camelina and field pennycress,and monocrop soybean as control.Biomass and grain yield of winter oilseed crops were not affected by cropping system.Averaged over years and cropping systems,winter camelina resulted in more biomass,nitrogen(N)uptake and grain yield by 240,186 and 139% respectively,compared to field pennycress.Soybean biomass,N uptake and yield were higher in relay relative to sequential cropping.Relay soybean resulted in similar total grain yield(soybean+winter oilseed crop)compared to monocropped soybean.Double cropping soybean could maintain net return compared to monocropped soybean.Results indicate that double cropping winter oilseed crops with soybean can be economically viable in the U.S.upper Midwest.Yet,research aimed at optimizing yield through N and water use while improving ecosystem services is needed.