Effect of Nitrogen Addition and Weed Interference on Soil Nitrogen and Corn Nitrogen Nutrition

摘要: Weeds cause crop loss indirectly by reducing the quantity of resources available for growth. Quantifying effects weed interference on nitrogen (N) supply, growth, and N nutrition may assist in making both management decisions. Experiments were conducted to quantify effect addition soil nitrate-N (NO3N) over time dependence corn growth NO3-N availability, determine index (NNI) at anthesis, evaluate if relative chlorophyll content can be utilized as a reliable predictor NNI. Urea was applied 0, 60, 120 kg N/ha establish treatments. Season-long weedy, weed-free, five treatments established delaying control from planting V3, V6, V9, V15, or R1 stages development. Soil ranged 20 without 98 with added early season, but reduced 10 anthesis. Weed presence up 50%. Average explained 29 40% variation shoot mass maturity. biomass NNI 24 69%. Lack also 13 46%, only 11 23%. Nondestructive measures predicted 65 85% accuracy. Although competition factors other than major contributor reduction, meter useful diagnostic tool assessing overall negative weeds productivity. Further research could develop practices guide supplemental applications response competition. Nomenclature: Corn, Zea mays L. ‘DK589RR’.