Short term effects of manure and irrigation application on soil nutrients content, water use efficiency and maize productivity in Chitwan, Nepal

A field experiment was conducted at Chitwan, Nepal to evaluate the effects of manure and irrigation application on soil nutrients content, water use efficiency and maize productivity. The experiment was laid out in a factorial complete randomized block design with three replications. The treatments were consisted of two manure levels: no manure and manure with fertilizer based on 120 kg ha-1 nitrogen recommended. Similarly, another factor was irrigation water application with five levels which were control (no irrigation) and irrigation applications of 300, 600, 900 and 1200 mm during growing period. The manure application significantly affected the total nitrogen (0.13%) and available phosphorus (37.5 kg ha-1) content in the soil. Interestingly, different irrigation treatments enhanced soil nutrient content differently except soil nitrogen. Similarly, the highest grain yield was observed on 1200 mm irrigation which corresponded to 169% increment over control irrigation treatment but not significant with 600 and 900mm irrigation. The 1200 mm irrigation showed the lowest irrigation water use efficiency (IWUE) (5.96 kg ha-1 mm-1), while 300 mm irrigation showed maximum (18.37 kg ha-1 mm-1) followed by 600 mm irrigation (7.04 kg ha-1 mm-1) based on grain yield. In conclusion, it seems that 600 mm irrigation treatments are quite suitable for the maize production in spring season with benefits of increasing IWUE and saving water around 50% of water which will help in growing more areas and in managing the limited water resources in Chitwan, Nepal.