EFFECT OF SOWING DATE, INTRA-ROW SPACING AND BIOPESTICIDE ON THE PRODUCTIVITY OF COWPEA UNDER STRIGA INFESTATION IN KATSINA, SUDAN SAVANNA OF NIGERIA.

Abstract

A field experiment was conducted during the cropping seasons of2015 and 2016 at the Teaching and Research Farm of College of Agriculture, Hassan Usman Katsina Polytechnic, Katsina, Sudan savanna of Nigeria. The study area lies between Latitudes 12° to12.98° N and Longitudes 7.36° to7.60° E, 619 m above sea level. The objective of the research was to evaluate the performance of cowpea under Striga infestation as affected by sowing dates (SD), intra-row spacings (SP) and bio-pesticides (B). The experiment was laid out in Split-Split Plot Design with three sowing dates (SD1: 2ndJuly, SD2:23rd July and SD3: 13thAugust) allocated to the main plot, three intra-row spacings (SP1: 75 x 20 cm, SP2: 75 x 30 cm and SP3: 75 x40 cm) allocated to the sub-plot and bio-pesticides to the sub-subplot. The treatments were replicated three times. Each plot consisted of 6 ridges of 6 m long and 4.5 m wide. All agronomic practices for successful cowpea production were observed. Data collected were subjected to the analysis of variance and significant means were compared using LSD at 5 % level of probability. The physical and chemical analysis of the soil identified the soil as sandy loam with very low organic carbon (< 4 g kg-1), total nitrogen (< 0.6 g kg-1) and low available phosphorus (3-7 mg kg-1). Lower Striga counts were observed on cowpea sown on SD3 (126.81) per cm-2which was significantly different (P ≤ 0.01) from SD1 (335.42) and SD2 (238.31)which were statistically similar. The result of the effect of intra-row spacing showed that highly significant (P≤ 0.01) Striga counts were obtained in SP2 (236.56) but were statistically at far with SP1(236.06). The least Striga count was obtained in SP3 (227.92). The area under Striga number progress curve (ASNPC) showed that there was up to 6 and 5.8 Striga density per m2. This implies that there is possibility of 60 and 58% cowpea yield reduction during2015 and 2016, respectively. Managements which involve early soil testing (prior to sowing) and use of Striga resistant variety could give a better control strategy in the study area.