Impact of Bio- and Organic Fertilizers on Potato Yield, Quality and Tuber Weight Loss After Harvest

This study was conducted to assess whether organic fertilization alone or with bio-fertilization could replace mineral fertilization in potato production with no adverse effect on quantity or quality. Therefore, two field experiments were conducted at Maba Farm, Cairo—Alexandria Desert Road in Egypt to evaluate the impact of mineral, organic, and bio-fertilizers on a sandy soil on yield, quality, and weight loss after harvest of potato tubers. Control plots were treated with recommended rates of mineral fertilizer + 11.9 t ha⁻¹compost and the other treatments were 23.8 t ha⁻¹compost, 23.8 t ha⁻¹compost + bio-fertilizer, 11.9 t ha⁻¹compost + bio-fertilizer, 50% of mineral fertilizers + 23.8 t ha⁻¹compost, 50% of mineral fertilizers + 23.8 t ha⁻¹compost + bio-fertilizer, 50% of mineral fertilizers + 11.9 t ha⁻¹compost + bio-fertilizer, and 35.7 t ha⁻¹compost. There were significant increases in the total and marketable yield of potato crops from plots treated with 50% of the recommended mineral fertilizers plus 23.8 t ha⁻¹compost with or without bio-fertilizer as well as from plots that received compost at the rate of 35.7 t ha⁻¹, compared with plots treated with full dose of mineral fertilizer plus 11.9 t ha⁻¹compost (control). Compost at 23.8 t ha⁻¹+ bio-fertilizer resulted in a significant increase in marketable yield. Nevertheless, total yield obtained from plots treated with compost at 23.8 t ha⁻¹alone or plus bio-fertilizer did not differ significantly from the conventional control treatment. Compared with conventional fertilizer treatment, plots receiving compost at 23.8 t ha⁻¹alone or at 11.9 t ha⁻¹plus 50% mineral fertilizers and bio-fertilizer showed a lower nitrate content in potato tubers. Bio-fertilizer + organic fertilizer at a rate of 11.9 t ha⁻¹reduced marketable yield by 11.8% and total yield by 9.2%, compared with using organic fertilizer at a rate of 23.8 t ha⁻¹compost. So, for export of organic potato, which is characterized by 2–3-fold higher product prices, bio-fertilizer in the present study could not be an alternative to organic fertilizer. The highest nitrate content of tubers was obtained in control plots and plots that received 35.7 t ha⁻¹compost. Conventional fertilizer showed significantly higher weight loss of potato tubers during cold storage than all other treatments. Tuber K content was low in organic potato, whereas no effect was recorded on tuber N, P, or starch content. Hence, these results suggest that organic production of potato (at the level of 23.8 t ha⁻¹compost) could be an alternative to conventional production without significant reduction in yield, and with low nitrate content and better storability.