Effect of Ridging and Mulching on Soil Moisture, Rainwater use Efficiency and Maizeyield in Lundazi, Zambia
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Agricultural practices that conserve soil moisture are inevitable in the face of erratic rains and constant droughts. Mulching can improve water productivity through increase in water retention and reduction in surface evaporation. The study was conducted in Lundazi District of Eastern Province of Zambia (latitude: 12.8S longitude: 35.18 E and 1080m above sea level). The objective of the study was to evaluate the effects of ridging and surface soil mulching on maize growth and rain-water use efficiency (RWUE). The specific objectives were to determine the effect of ridging and mulching on rain-water use efficiency, root-zone soil moisture regime and yield in maize (ZeaMays L). The experimental design was a Randomized Complete Block Design (RCBD) with three replications and four treatments andmaize as the test crop.The treatments were:(i) Ridged field without mulch, (ii)ridged field with mulch, (iii) flat field without mulch and (iv) flat field with mulch. Hyperrhenia grass (Hyperrheniahirta) was used as mulch, a common grass species in the study site. The aboveground biomass varied from9.5 to 12.3 tons/ha with an average of 11.1 tons/ha. There were nosignificant differences in aboveground biomass among the treatments (p>0.05) of either mulching orridging. The stove rbiomass varied from5.9 to 7.8 tons/ha with an average of6.8 tons/ha. Stover biomass was significantly (p<0.05) affected by both mulching and ridging. The significant differences in stove rbiomass was observed between flat field with mulch,flat field with ridges when compared with flat field without mulch and ridged field with mulch. The grain yield varied from3.5 to 4.8tons/ha with an average yield of4.3 tons/ha. Significant differences (p<0.05) were observed among the treatments. The ridged field with mulch was significantly higher compared with flat field with mulch. The harvest index (HI) varied from36.2%to 44.1%with an average of39.3%.There were significant differences in HI among the treatments (p<0.05). The rain-water use efficiency (RWUE) of the grain varied from4.5 to 6.0 kg DM mm-1ha-1. The significant differences were observed between ridge field without mulch and flat field with mulch. Soil moisture storage in the root-zone varied from 129.1mm to 236.8mm with an average of 181.5mm. However, there were no significant differences among the treatments in soil moisture storage.The results showed that ridging greatly improved yield during the studied season which had normal rainfall,hence farmers benefited from ridging as it helped to drain excess water and and improved aeration in the root zone. On the other hand, mulching would be useful in seasons with water stress conditions. In view of climate change and variability, it can be said that water scarcity will be a burning problem for the future and its most probable solution can be use of mulching and ridging for quality agricultural production.
The University of Zambia
- Agricultural Sciences