Mitigating nitrate accumulation in potato tubers under optimum nitrogen fertilization with K-humate and calcium chloride. (20th June 2020)

• Record Type: Journal Article
• Authors: Abdo, Ahmed I.; Elrys, Ahmed S.; Abdel-Fattah, Mohamed K.; Desoky, El-Sayed M.; Huitong, Li; Wang, Linquan
• Is Part Of: Journal of cleaner production. Volume 259(2020)
• Publication Date: 2020-06-20
• Subjects: Nitrogen -- K-humate -- Calcium chloride -- Nitrate accumulation -- Potato; Factory and trade waste -- Management -- Periodicals; Manufactures -- Environmental aspects -- Periodicals; Déchets industriels -- Gestion -- Périodiques; Usines -- Aspect de l'environnement -- Périodiques; 628.5
• DOI: 10.1016/j.jclepro.2020.121108
• Languages: English
• ISSNs: 0959-6526

Abstract

Abstract: Producing safe food under excessive fertilization strategies is a serious issue; thus, this study introduced a novel approach combining K-humate and calcium chloride under nitrogen (N) fertilization for maximizing potato ( Solanum tuberosum L.) yield and improving quality by reducing nitrate (NO3 − ) accumulation in tubers. A two-season field experiment during the 2017 and 2018 growing seasons was conducted in a farm field with a sandy loam texture. The experiment followed a modified Box-Behnken design with 13 treatments, which combined ammonium sulfate (N-AS), K-humate (KH) and calcium chloride (CC) alternately using their maximum rates (370 kg N ha −1 for Z, 8.0 kg kH ha −1 for X, and 1.20 kg Ca ha −1 for Y) and subdividing. A three-level, three-variable central composite model (TCCM), integrated with regression modeling, was interpreted to illustrate the combined effects of AS, KH and CC on all the variables under investigation. The results indicated a remarkable increment in tuber yield and nitrate accumulation with the N-AS inputs, while KH and CC had minor impacts; however, the later decreased the nitrate concentration to some extent. The maximum soil N content (25 mg kg −1 ), tuber N content (18 g kg −1 ) and nitrate accumulation (450.5 mg kg −1 ), which exceeds the acceptable limit (200 mg kg −1 ) for human consumption, was recorded under the application of 370 kg N ha −1 as the ammonium sulfate fertilizer with the conventional farming practices used. The response surface combined with regression models showed that the N rate (246 kg N ha −1 ), when combined with KH (1.33 kg ha −1 ) and CC (0.2 kg ha −1 ) representing T8 (66.6% N-AS + 16.6% KH + 16.6% CC), could reduce the NO3 − content in tubers to an acceptable level (170 mg kg −1 ) and at the same time resulted in the highest tuber yield (58.8 Mg ha −1 ). The regression models accurately predicted the changes in nitrate accumulation in tubers, soil N and plant attributes under different N rates as related to KH and CC. Generally, when using these models under similar soil conditions worldwide, it can be concluded that using 222, 2.5, and 0.2 kg ha −1 of ammonium sulfate, potassium humate, and calcium chloride, respectively, would achieve a proximal yield (56 Mg ha −1 ) while simultaneously decreasing nitrate accumulation in tubers to a very safe level (160 mg kg −1 ). Graphical abstract: Producing maximum tubers yield (TY) with lowest nitrate accumulation in tubers (T.NO3 ) by combining N-AS (ammonium sulfate), KH (potassium humate) and CaCl2 (calcium chloride). S.NH4 is soil NH4 (mg kg −1 ), S.NO3 is soil NO3 (mg kg −1 ) and NR is nitrate reductase (μmol NO2 mg protein −1 h −1 . Image 1 Highlights: Toxic levels of nitrate in potato tubers under excessive use of nitrogen fertilizers. Optimizing potato yield with minimum nitrate content using low levels of ammonium sulfate with K-humate and CaCl2 . Calcium chloride augments nitrate reductase activity and K-humate reduces nitrogen losses from soil.