Yield And Competitiveness Response In Maize/pea Intercropping System Under Different Nitrogen System

Due to the excessive demand of neitrogen fertilization on achieving high yield, disordered N fertilizermanagement in practices and inefficient use of potentially saving N fertilizer, an intensive reseach wasconducted to make a comprehensive and accurate assessment on the advantages of cereal/legume intercroppingsystem. This study investigated the effects of symbiotic growth on competition and complementarity of Nfertilizer in maize and pea intercropping and the recovery of N utilization after pea harvesting. The purposewas to provide new theoretical basis and technical approach for the efficient management of nitrogen resourcesin cereal/legume intercropping systems. The main findings are as follows:1Systematic N application significantly affected competition during symbiosis and complementarity afterpea harvesting of maize/pea intercropping. The competitiveness of maize relative to pea is the smallest throughthe whole growth period under N1, and that would benefit the rescovery potential of intercropped maize. Themean competitiveness of maize relative to pea through the growth period were all less than0, indicating thatthe competition of pea was greater than corn. Relative competitiveness under N3was the greatest, which wasincreased by26%,48%and50%as compared to N1, N2and N0, respectively. The relative competitiveness wassignificantly influenced by systematic N application. With the nitrogen levels increasing, the competitivenessof pea was decreasing. The averaged competitiveness of other nitrogen systems by remove N fertilizerapplication to later stages was the maximum. Comparative analysis of the dry matter accumulation rate ofintercropping system showed that maize monoculture enhanced the dry matter accumulation rate by2%-40%during symbiosis. While after pea harvesting, the dry matter accumulation rate of intercropped maize wassignificantly improved, which was increased by20%-120%compared to sole maize. Therefore, the growthof intercropped maize was rather slowly than maize during early symbiotic period. However, during the laterperiod of maize/pea intercroping, especially after pea was harveated, growth of intercropped maize wassignificantly recovered over monoculture maize.2The land equivalent ratio (LER) of maize/pea intercropping systems was ranged from1.20to1.41,indicating that intercropping increased the efficiency of land use and capacity of yield productivity. On average,the economic yield of intercropped pea was increased by33%-59%over sole pea. Similarly, intercroppedmaize increased the economic yield by12%-41%compared to sole maize. By remove N fertilizer applicationto later stages, the intercropping achieved a comparatively higher economic yield (maize and pea) than N1.Additionally, biomass yield of intercropped maize was enhance by34%-75%compared to maize monoculture,and27%-56%was increased by intercropped pea over monoculture pea, which indicating that intercroppingcontributed to improving crop biomass production. Generally, intercropping system and monoculture maizeobtained the highest biomass yield under N2, while monoculture pea under the N3system.3Conic correlation between yield and competitiveness was revealed in this research. A significantnegative correlation between competitiveness of maize relative to pea at pea branching and pea bud was alsofound. However, the relative competitiveness of maize to pea at pea flowering had a significantly positiveinfluence on yield of intercropping, and the positive correlation between competitiveness and yield was alsosignificant. In the present study, nitrogen fertilizer shift system after pea flowerings achieved the maximummaize relative to pea competitiveness, which ensured the yield advantage of the formation. Dry matteraccumulation rate of maize grain filling stage and the composite yield production had a significantly positivecorrelation, indicating that corn grain filling period could be used as a major regulatory period to meet theyield advantages. Nitrate content of soil and the corn dry matter accumulation rate after pea harvesting had apositive and significant correlation, indicating that an appropriate increase in the formation of soil nitratecontent would help restore the effect of corn after pea harvesting. 4An area weighted mean value of the two monoculture was used as a control, maize/pea intercroppingunder N1, N2and N3made the NUE increased by1%to10%, showing a great advantage of intercroppingsystem. There were no significant differences on NUE between intercropping system under N1and N2, whileboth were significantly higher than N3. Intercropping, in addition, significantly improved agronomic efficiencyand physiological efficiency. Under different nitrogen systems, agronomic efficiency was improved by36%-250%compared to monoculture pea, and119%-268%compared to monoculture maize. An area weightedmean value of the two monoculture was used as a control, physiological efficiency of maize/pea intercroppingunder N1, N2and N3was respectively increased by1%,13%and9%as compared to the correspondingmonoculture. Intercropping revealed great advantages on physiological efficiency.