Improving Nitrogen Use Efficiency By Maize Through The Pigeon Pea-Groundnut Intercrop-Maize Rotation Cropping System In Malawi

EXTENDED ABSTRACT

A study was initiated in the 2011/12 cropping season with a parallel experiment mounted along side in the second season to investigate the possibility of improving nitrogen use efficiency (NUE) by the maize crop in a pigeon pea groundnut intercrop-maize rotation cropping system at Chitedze Agricultural Research Station in Malawi. The parallel experiment was conducted to compare the performance of legumes over two cropping seasons. The experiments involved the planting of two pigeon pea varieties, namely; long (ICEAP 04000) and medium duration (ICEAP 00557) and groundnut (CG 7) as monocultures or as intercrops. The main experiment had eight treatments; 1) Sole maize (control); 2) Medium duration pigeon pea; 3) Long duration pigeon pea; 4) Sole groundnut; 5) Medium duration pigeon pea + groundnut; 6) Long duration pigeon pea + groundnut; 7) Medium duration pigeon pea + groundnut (biomass not incorporated in season two); and 8) Long duration pigeon pea + groundnut (biomass not incorporated in season two). All the treatment plots except treatment plot number one were treated with 25 kg P ha-1 . The parallel experiment had ten treatments; 1) Long duration pigeon pea; 2) Medium duration pigeon pea; 3) Sole groundnut; 4) Sole groundnut + 25 kg P ha-1 ; 5) Medium duration pigeon pea 25 kg P ha-1 ; 6) Long duration pigeon pea + 25 kg P ha-1 ; 7) Long duration pigeon pea + groundnut; 8) Long duration pigeon pea + groundnut + 25 kg P ha-1 ; 9) Medium duration pigeon pea + groundnut; and 10) Medium duration pigeon pea + groundnut + 25 kg P ha-1 . Both experiments were laid in a randomized complete block design replicated three times. Key parametres assessed during the experiment included; legume biomass and grain yield, soil nitrate nitrogen (NO3 - ‒N), maize stover, and rachids yields; nitrogen and phosphorus partitioning both for the legumes and maize NUE.