Effects Of Plant Density And Nitrogen Rate On The Silage Yield And Quality Of Foodstuff Maize

A field experiment was carried out in rain fed semi arid environments to investigate theimpact of plant density, including4.5×10⁴plants ha^-1（T1）,5.25×10⁴plants ha^-1（T2）,6×10⁴plants ha^-1（T3）,6.75×10⁴plants ha^-1（T4）, and nitrogen application, including0kgha^-1（N1）,100kg ha^-1（N2）,200kg ha^-1（N3）,300kg ha^-1（N4）, on the dynamics of dry, andfresh matter accumulation, leaf area index, crude protein, NDF, and ADF in leaf, stem, andgrain of dual-purpose maize under ridge-furrow mulching systems. The main results areconcluded as follows:1. Leaf area and leaf area index of dual-purpose maize increased with crop growth,reached maximum at filling, and then declined, under different plant density and nitrogenapplication. Leaf area of maize per plant decreased with plant density increasing, whileleaf area index increased with plant density increasing. Nitrogen application had positiveeffects on leaf area and leaf area index, i.e. improved nitrogen application significantlyimproved leaf area and leaf area index of dual-purpose maize. Among treatments,application of300kg ha^-1had greatest leaf area and leaf area index.2. Fresh weight of above ground parts of maize displayed an “S” curve under differentplant density and nitrogen applications, while dry matter accumulation exhibited a “Z”curve, in which both fresh and dry matter increased with plant density and nitrogenapplication. Fresh and dry matter of maize under different plant density was in an order ofT4>T3>T2>T1, and under different nitrogen applications in an order of N4>N3>N2>N1.Grain yield under a plant density of5.25×10⁴plants ha^-1was significantly greater thanthat of6×10⁴and6.75×10⁴plants ha^-1. It achieved the highest grain yield under nitrogenapplication of300kg ha^-1.3. Plant density and nitrogen applications had significant effects on forage quality ofpurpose maize, plant density increased crude protein, NDF, and ADF in stem and grain,namely, was in an order of T4>T3>T2>T1. Improved nitrogen applications increasedforage quality of dual-purpose maize, in which crude protein in stem and grain increasedwith nitrogen applications, while NDF and ADF declined, exhibiting an order ofN4>N3>N2>N1.To sum up, under different plant density,5.25plants ha^-1achieved the highest grain yield, and6.75plants ha^-1greatest fresh weight for above ground parts of maize. Under differentnitrogen applications,300kg ha^-1achieved the highest grain yield and fresh matter weight.Additionally,300kg ha^-1also resulted in lower contents of NDF and ADF. In the presentstudy, although6.75plants ha^-1had highest fresh weight, its forage quality wassignificantly reduced. Thus, it was recommended that the optimal plant density andnitrogen application was5.25plants ha^-1and300kg ha^-1for semi arid rain fed land underridge-furrow mulching systems.