Agronomic assessment of phosphorus efficacy for potato (Solanum tuberosum L) under legume intercrops

• Published in: Journal of plant nutrition 2020-04, Vol.43 (6), p.864-878
• Main Authors: Gitari, Harun I., Shadrack, Nyawade, Kamau, Solomon, Karanja, Nancy N., Gachene, Charles K. K., Schulte-Geldermann, Elmar
• Format: Article
• Language: English
• Subjects: Agronomy; Beans; Cropping systems; Dry matter; Intercropping; Lablab purpureus; Legumes; Leguminous plants; Peas; Phaseolus vulgaris; Phosphorus; phosphorus harvest index; phosphorus partial balance; phosphorus partial factor productivity; phosphorus uptake; phosphorus uptake efficiency; Pisum sativum; Potatoes; Solanum tuberosum
• ISSN: 0190-4167; 1532-4087
• DOI: 10.1080/01904167.2019.1702202

Phosphorus (P) is an essential element and its efficient use is of global importance. This study evaluated the effect of growing potato under legume intercrops on P uptake and use efficiency indices: P harvest index (PHI), P uptake efficiency (PuPE), P partial factor productivity (PPFP) and P partial balance (PPB). The experiment was carried out for four consecutive seasons with treatments comprising potato cultivated under legume intercrops: none (T1), dolichos (Lablab purpureus L) (T2), peas (Pisum sativum L) (T3) and beans (Phaseolus vulgaris L) (T4). Across the seasons, the mean haulm P uptake for T2 (6.7 kg P ha −1 ), T4 (5.5) and T3 (4.5) were 6%, 23% and 36% lower than that observed in T1 (7.1 kg P ha −1 ), respectively. On the other hand, tuber P uptake was highest in T1 (21.8 kg P ha −1 ) and T2 (21.3 kg P ha −1 ) and were significantly higher than 13.2 kg P ha −1 in T3 and 15.1 kg P ha −1 in T4. This had a profound effect on PuPE, which was equally highest in T1 (0.26 kg total P uptake kg −1 P supply) and T2 (0.25) and lowest in T3 (0.16) and T4 (0.18). Similarly, PPFP, PHI and PPB followed a similar trend, with highest values in T1 (57 kg tuber dry matter yield kg −1 P supply, 76.4 kg tuber P uptake kg −1 total plant's P uptake and 0.20 kg tuber P uptake kg −1 P supply, respectively). Among the tested legume intercrops, dolichos competed least for P with the main crop (potato) hence it can be integrated into potato-based cropping systems without compromising potato tuber yield.