Mechanisms Of Nitrogen Competition And Utilization In Spring-sown Maize And Summer-sown Maize Relay-planting Systems And Its Effects On Yield And Quality

In order to learn the nitrogen competition and utilization in different maize cultivarsrelay-planting and its effects on yield and quality and their mechanisms under differentnitrogen application and root partition, field experiment, pool experiment and physiological &biochemical test were carried out from 1999 to 2003. The results were as follows:1 High yield, high quality and high benefit of different maturity maize cultivarsrelay-planting system Compared with mono-cropping, relay-cropping prolongs the growth period, whichmakes two crops a year possible. In spring-sown maize and summer-sowing maizerelay-planting system, the yield was up to 18000 kg, the benefit was near to 20000 yuan, andat the same time 20000 kg high quality feed straw was get. Different maize cultivarsrelay-planting improved the use of land, and increased the income of peasant, which was veryimportant in the region of North China.2 nitrogen competition and utilization in different maize cultivars relay-planting andits effects on yield and quality2.1 difference of nitrogen competition and utilization in relay system Relay-planted with same late maturity or early maturity spring-sown maize, the yearlynitrogen absorption quantity of summer-sown late maturity maize YD13 was highest, thoseof summer-sown middle maturity maize were middle, and those of summer-sown earlymaturity maize were lowest. While relay-planted with middle maturity, the yearly nitrogen VII春夏玉米套作氮素竞争利用及对产量品质的影响机理研究absorption quantity of summer-sown late maturity maize YD13 was highest, those ofsummer-sown early maturity maize were middle, and those of summer-sown middlematurity maize were lowest. Relay-planted with different spring-sown maize, the yearlynitrogen absorption quantity of relay-planted with spring-sown early maturity maize washighest, those of relay-planted with spring-sown middle maturity maize were middle, andthose of relay-planted with spring-sown late maturity maize were lowest. Due to the samenitrogen fertilization quantity, the higher yearly nitrogen absorption were, the higher thenitrogen from soil will be. Relay-planted with the same spring-sown maize, the quantity ofnitrogen absorption of late maturity summer-sown maize was highest, but their nitrogen useefficiency was lowest, which because most the nitrogen absorbed were left in organs exceptgrain. The trend of soil nitrogen use efficiency was same to that of nitrogen use efficiency.2.2 Effect on yield and quality The results indicate that relay-cropping with summer-sown different maturity maizecultivars, there are no obvious effects on biomass, grain yield, and nutritive values (crudeprotein yield, crude fiber yield, crude fat yield) of the same spring-sown maize cultivars.But relay-cropping with spring-sown different maturity maize cultivars can obviouslyaffect the biomass, grain yield, and nutritive values of the same summer-sown maizecultivars. The order of biomass, grain yield, and nutritive values of the samesummer-sown maize cultivars are: relay-cropping with spring-sown LD14>relay-cropping with spring-sown YD22> relay-cropping with spring-sown YD13. Judgedfrom the grain yields of the whole year, YD22/YD13 is the highest treatment. Butaccording to biomass, grain yield, and crude protein yield, crude fiber yield, crude fatyield of the whole year, the better ones are: YD13/YD13, YD13/YD22, and YD22/YD13.2.3 Effects on paste properties and starch contents It showed that relayed with different maturity summer-sown maize, the paste propertiesand starch content and its compositions of the spring-sown maize could not be affectedobviously. But those of the summer-sown maize were affected remarkably. YD13/YD22 wasthe best relay-planting mode in which starch content and paste properties of both spring-sownand summer-sown maize cultivars were higher.3 Effects of different nitrogen applied level on nitrogen...