To feed a growing population Pakistan needs increased, sustainable food production.
Understanding fluctuations in production for the major aromatic rice production area of Pakistan, the Punjab rice-wheat system, will help in reaching this goal.
New knowledge from collaborations between CSIRO through the Sustainable Development Investment Portfolio (SDIP) and the University of Agriculture, Faisalabad (UAF) has revealed some of the causes of production gaps in the rice-wheat system.
Using the cropping systems model APSIM, which was tested with data from five years’ worth of farmer grain yields, rice-wheat yields were modelled for 35 years. Model outputs revealed that nitrogen deficiency was the major driver for the large production gaps, with low topsoil carbon contributing to this outcome. In the model simulations the modelled farmer crops were not significantly constrained by water under existing nitrogen applications, or by high or low temperatures.
Unwillingness to take risks due to the unreliability of the irrigation water supply may be a factor in how farmers apply nitrogen or low nitrogen application rates may mask the fact that one or more soil micronutrients may be limiting, resulting in a lack of crop growth response to increased nitrogen.
Current seed sowing dates were also found to be important in yields. Optimum rice sowing dates were up to one month later and optimum wheat sowing dates were one month (or more) earlier than those currently used.
Further investigation is needed into optimising the farming system, with better nutrient management, increased soil carbon levels, and shorter season high-yielding rice varieties likely to be the keys to increased productivity. The research team is now using the APSIM model to investigate and develop new cropping system adaptation options to maximise several different variables: farmer profit, water productivity and land productivity. These will be tested in the field with on-farm trials for demonstration to farmers and to gain their feedback. This information and insights will also inform basin scale modelling scenarios to explore local management options in a system management perspective.
The collaboration between CSIRO, UAF and Sindh Agriculture University (SAU) continues to build understanding of agricultural water demand and yield gaps and add to the information and evidence available for policy making that integrates both agriculture and water considerations, particularly in the Punjab and Sindh.
This work is part of a portfolio of investments supported by the Australian Government addressing the regional challenges of water, food and energy security in South Asia.
The SDIP Phase 2 aims to improve the integrated management of water, energy and food in the Himalayan river basins, addressing climate risk and the interests of women and girls. It seeks to: