Effect of Organic, Bio and Mineral Fertilization with Weed Control on Weed Species, Herbicides Residues, NPK Uptake by Potato Tubers and Crop Productivity.

Both proper fertilization and integrated weed management are major components for improving potato (Solanum tuberosum L.) yield productivity.  So, two field experiments were conducted during the two successive winter seasons of 2013/2014 and 2014/2015, Sakha Agricultural Research Station, Kafrelsheikh  Governorate.  Each experiment consisted of  forty two treatments in split plot design with four replicates were used. The main plots included seven fertilizers combination between  organic and mineral fertilizers with or without bio-fertilizer  and  the sub-plots contained  six weed control treatments (Gesagard and  Sencor as soil-acting herbicides each applied alone or combined with hand hoeing, hand hoeing twice and un-treaated check). The existed weed species in the two experimental potato fields were  Chichorium endivia, Medicago hispida Gaertn and  Chenopodium album as broad leaf weeds,  Phalaris minor Retz. as annual grassy weed and Cyperus  rotundus as perennial like-grass weed. The main findings indicated that all farmyard manure fertilizers application FYM at 20m³/fed + (100 kg N, 30 kg P and 45 kg K /fed) plus bio-fertilizer combination gave the highest potato tuber yield (ton/fed) with increasing NPK uptake/ fed  by 23.8, 34.0 and 26.1 % as compared with standard NPK at 200 kg N, 60 kg  P  and 90 kg K/fed treatment, respectively. Both Gesagard at 0.75 L/fed and Sencor at 0.2 kg/fed each plus hand hoeing  once and hand hoeing twice gave  the highest controlling  percentage on weeds density by 90.48, 94.12 and  90.19%,   and dry weight  by 93.63, 90.37 and 88.09 %, respectively, at 70 days  assessment,   and the same trend was observed  at 95 assessment increasing N, P   and K % and their uptake (kg/fed) in potato tubers than un-weeded check. The effects of interaction between fertilizer and weed control treatments     show that number of tubers /plant, tubers yield grade A%, tubers yield (g/plant) and tubers yield (ton/fed) were  increased  significantly by adding  20 m³ farmyard manure and 100 kg N, 30 kg P and 45 kg K/fed with bio-fertilizer and (Sencor at 0.2 kg /fed or Gesagard at 0.75 kg/fed ) plus hand hoeing packages. There were no residues of herbicides (Gesagard at 1.0 L/fed and Sencor at 0.3 kg/fed)  were detected in potato tubers at harvest. Thus, it can be concluded from this study that combination of  20 m³ farmyard manure plus  NPK [100 kg N, 30 kg  P  and 45 kg K/fed] + bio-fertilizer with spraying (Gesagard at 0.75 L/fed  or  Sencor at 0.2 kg/fed) followed by one  hand hoeing, which recorded  highest reduction on density weeds accompanied    with increasing of  NPK uptake and  potato tubers yield (ton/fed), without any    effect in potato tubers at harvest..