Early Transplanting of Rainfed Rice Minimizes Irrigation Demand by Utilizing Rainfall

Abstract

BackgroundRainfall is the key contributor to provide soil moisture for wet season rice (T. Aman) cultivation. Erratic rainfall often causes water shortage resulting negative impact on plant growth and grain yield. The study aimed to determine suitable transplanting window that utilized maximum rainfall for long duration (145 days) rice cultivar. Firstly, three years field experiment conducted in Kushtia, Bangladesh in T. Aman season from 2013 to 2015, and then the findings were implemented for another two adjacent locations, Panba and Rajshahi. The field experiment considered six transplanting dates of popular cultivar BR11 at 7 days interval starting from 10 July up to 14 August. The CROPWAT 8.0 model was used to calculate crop water requirement (CWR), effective rainfall and irrigation demand (ID) from collected weather data in each growth phase of rice. A suitable transplanting window was selected considering minimum ID at reproductive phase and the maximum grain yield. ResultsT. Aman rice received enormous rainfall and accounted no irrigation at vegetative phase in all three tested years in all locations. The early transplanting received more rainfall in reproductive phase than late planting practice. Thus, Irrigation demand increased at reproductive phase with delay transplanting in moderate drought prone Kushtia, Pabna and Rajshah. A significant relationship (R2 = 0.71) observed between ID at reproductive phase to grain yield, while grain yield responded weakly with the ID at ripening phase. Based on yield performance 10-24 July found suitable transplanting window for BR11 in Kushtia. Applying ID vs yield relationship, 10-17 July and 10-24 July considered the best transplanting window in Pabna and Rajshahi, respectively. ConclusionsDelay in transplanting demanded more irrigation and reduced yield. Consequently, early transplanting utilized maximum rainfall, reduced ID in reproductive stage and ensured desired grain yield.

Cropping System Intensification: An Approach to Increase Yield, Water Productivity, and Profitability in North-West Bangladesh

“…Usually, the northwest and middle parts of the county receive around 1500 mm of rainfall while the northeast and southeast parts get more than 3000 mm of rainfall annually [16]. ough June-September is considered the rainy season in Bangladesh, the rainfall occurrence has shifted to April-mid August [17]. During the monsoon, 70-90% of rainfall accumulated in April-August, and only 10% occurred in the late monsoon.…”