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

Abstract

Phosphorus (P) is an essential element and its efficient use is of globalimportance. This study evaluated the effect of growing potato under leg-ume intercrops on P uptake and use efficiency indices: P harvest index(PHI), P uptake efficiency (PuPE), P partial factor productivity (PPFP) and Ppartial balance (PPB). The experiment was carried out for four consecutiveseasons with treatments comprising potato cultivated under legume inter-crops: none (T1), dolichos (Lablab purpureus L) (T2), peas (Pisum sativum L)(T3) and beans (Phaseolus vulgaris L) (T4). Across the seasons, the meanhaulm 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. Onthe 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 T3and 15.1 kg P ha 1 in T4. This had a profound effect on PuPE, which wasequally 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 followeda similar trend, with highest values in T1 (57 kg tuber dry matter yieldkg 1 P supply, 76.4 kg tuber P uptake kg 1 total plant’s P uptake and0.20 kg tuber P uptake kg 1 P supply, respectively). Among the tested leg-ume intercrops, dolichos competed least for P with the main crop (potato)hence it can be integrated into potato-based cropping systems withoutcompromising potato tuber yield.