Fakkar, A.A.; A.E. Ismail and Nadia M. Hemeid( 2016). Influence of NPK Fertilization and Wild Oat (Avena fatua) Densities on Wheat CropJ. Soil Sci. and Agric. Eng., Mansoura Univ., Vol. 7 (4): 299 - 310, 2016
Abstract: Two field experiments were conducted at Shandaweel Agricultural Research Station, Sohag Governorate during two growing winter seasons 2013/2014 and 2014/2015. The objective of this work was to study the effect of NPK fertilizer levels and wild oat competition on wheat productivity. Each experiment included eighteen treatments which were the combination of three
NPK fertilizer levels being 50 kg N-10 kg P2O5 -12 kg K2O fed-1, 75 kg N-15 kg P2O5 -24 kg K2O fed-1 and 100 kg N-20 kg P2O5 -36 kg K2O fed-1 and six of wild oat densities i.e., zero, 5, 10, 15, 20 and 25 wild oat plant m-2. A split plot design, with four replications was used. Results revealed that increasing NPK rates increased significantly the studied wheat growth parameters,
yield and its components in both seasons. Application of N75P15K24 and N100P20K36 fertilizer levels increased grain yield by 8.7 and 17.4 %, respectively in the first season and 10.1 and 19.2 %, respectively in the second season compared to the lowest (N50P10K12) fertilizer rate. Also, increasing NPK fertilizer rates had significant effect on most of N, P and K % of both wheat and wild oat plants at 30, 60 and 90 days after sowing (DAS). N, P and K % decreased with growth in both wheat and wild oat plants and were higher with wild oat than wheat in N % showing that wild oat plants is a great competitor with wheat plants for N nutrient. Moreover, the addition of NPK fertilizer levels significantly affected N, P and K %, NPK uptake and protein % in wheat grain. Application of N75P15K24 and N100P20K36 increased protein % in grain wheat by 9.7 and 12.9 %, respectively in the first season and 9.5 and 11.2 %, respectively in the second season compared to the lowest (N50P10K12) fertilizer rate. In contrary, increasing wild oat density m-2 caused adverse effect on wheat growth, yield and its components in both seasons. Increasing number of wild oat plants from 5 to 25 m-2 reduced the grain yield by 6.1 to 25.0 %, in the first season and 8.5 to 28.3 %, in second season compared with wild oat free treatment. Positive significant effects were detected for wild oat density m-2 on N, P and K percentage of both wheat and wild oat plants at 30, 60 and 90 DAS as well as wheat grain contents of N, P, K and protein in both seasons. Increasing wild oat plants from 5 to 25 m-2 decreased grain protein % from 0.9 to 17.4 %, in 2013/14 and from 2.4 to 8.9 %, in 2014/15 compared with wild oat free plots. The interaction between N100P20K36 fertilization rate and zero wild oat plants m-2 gave the highest wheat grain yield (22.93 and 24.23 ard.fed-1) in the1st and 2nd seasons, respectively compared with N50P10K12 fertilization rate and 25 wild oat plants m-2 (15.10 and 15.03 ard.fed-1) in the1st and 2nd seasons, respectively. From this study, we can conclude that the integration between N100P20K36 fertilization and zero wild oat plants m-2 gave the highest wheat grain yield and protein.
Keywords: (NPK fertilization, wild oat density, wheat, growth, yield , yield components .)
