水文学: 現在の研究

Dry Season Irrigated Rice Yields Response to Water Saving Techniques in Tolon District of Northern Region, Ghana

Abstract

Shaibu Abdul Ganiyu*, Naoko Oka and Seiji Yanagihara

Dry season irrigated rice production in northern Ghana is often hampered by lack of sufficient water in dams and reservoirs to meet the crop and irrigation water requirements under continuous flooding. In some years, rice farmers are forced to change their cropping repertoire and move to vegetable production. This situation calls for development of efficient water application and saving methods on the field. The objective of this study was to assess the effects of different water saving irrigation applications to improve over continuous flooding used on dry season rice fields. Two years of experiments were conducted using a randomised complete block design with 4 replications at golinga irrigation scheme in 2017/2018 and 2018/2019 dry seasons, respectively. The treatments were as follows: Alternate Wetting and Drying (AWD 10) at 10 cm water-table drop below the soil surface; AWD 15 at 15 cm drop of water-table below soil surface; Continuous Flooding (CF) from 2 to 10 cm depth of water above soil surface, used as control; Intermittent Flooding (IF) at 5 cm of water-table drop below the soil surface and System of Rice Intensification (SRI). A 115 days maturity rice variety Gbewaa (i.e. Jasmine 85) was used for the experiments. Seedlings were transplanted at spacing of 20 cm × 20 cm at one seedling per stand in 27 m² plots. Data were collected on plant height, number of tillers, days to 50% heading, yields and yields related parameters. The results showed that all the parameters with the exception of maximum tiller count, showed significant difference between SRI and the rest of the treatments. AWD 10 and IF are recommended as most suitable for adoption by rice farmers in the Northern Region of Ghana.