Crop yield gaps in Bangladesh Yield gaps exist in different crops of Bangladesh. To evaluate the yield gap in boro rice, a study was conducted by BRRI in Rajapur village of Bhanga upazila of Faridpur and Meghdubi village of Gazipur districts (Alam, 2006). Under farmer’s practice, the yields of boro rice were 4.47 t/ha and 3.67 t/ha, while the potential yields with better management were 5.90 t/ha and 4.73 t/ha at Rajapur and Meghdubi villages, respectively. The yield gaps were thus 1.43 t/ha and 1.06 t/ha which were 24.24% and 22.41% of the potential yield at Rajapur and Meghdubi, respectively. Roy (1997) reported yield gaps of 44.44 and 60.00% in aus and aman, respectively.
Depicts yield levels and yield gaps in other economic crops of the country, such as wheat, potato, sweet potato, mustard, groundnut, sesame, lentil, chickpea, tomato, radish, and jute. A yield gap study was carried out by OFRD on wheat (var. Kanchan) at the MLT site Palashbari, Rangpur (OFRD, 2003- 2004). It was observed that the better managed plot gave higher yield of 2.56 t/ha whereas the average managed farmers’ plot yield was 1.87 t/ha indicating a yield gap of 27%. A similar study was undertaken at the MLT site, Atgharia upazila of Pabna district to evaluate the yield gap in mustard using the variety BARI Sharisha-13 (OFRD, 2008-2009). Better managed plots gave higher yield (1366 kg/ha) than farmers’ practice (894 kg/ha) with an yield gap of 35.03%. Yield gaps of groundnut and sesame were found to be 26.66% and 33.33%, respectively (ORC, BARI, 2002). In Potato and sweet potato, yield gaps were 44.72 and 64.01%, respectively, between demo and farmers’ average. Yield gap study was also conducted by OFRD with chickpea (var. BARI Chola-5).The study revealed yield gap of 31.43% in chickpea (OFRD 2003-2004). Likewise, yield gaps of 32.35% and 19% were found in potato, sweet potato, lentil, and jute, respectively. A study was also undertaken to assess yield gap in tomato (var. Ratan) and radish (var. Tasaki sun). The yield gaps were found to be 36.68% and 40.28%, respectively. It is thus evident from Table 3 that yield gaps in different crops varied from 19% to 64%.
It depicts the yield levels and yield gaps in other economic crops of the country, such as wheat, potato, sweet potato, mustard, groundnut, sesame, lentil, chickpea, tomato, radish, and jute. A yield gap study was carried out by OFRD on wheat (var. Kanchan) at the MLT site Palashbari, Rangpur (OFRD, 2003- 2004). It was observed that the better managed plot gave higher yield of 2.56 t/ha whereas the average managed farmers’ plot yield was 1.87 t/ha indicating a yield gap of 27%. A similar study was undertaken at the MLT site, Atgharia Upazila of Pabna district to evaluate the yield gap in mustard using the variety BARI Sharisha-13 (OFRD, 2008-2009). Better managed plots gave higher yield (1366 kg/ha) than farmers’ practice (894 kg/ha) with a yield gap of 35.03%. Yield gaps of groundnut and sesame were found to be 26.66% and 33.33%, respectively (ORC, BARI, 2002). In Potato and sweet potato, yield gaps were 44.72 and 64.01%, respectively, between demo and farmers’ average. A yield gap study was also conducted by OFRD with chickpea (var. BARI Chola-5). The study revealed yield gap of 31.43% in chickpea (OFRD 2003-2004). Likewise, yield gaps of 32.35% and 19% were found in potato, sweet potato, lentil, and jute, respectively. A study was also undertaken to assess the yield gap in tomato (var. Ratan) and radish (var. Tasaki sun). The yield gaps were found to be 36.68% and 40.28%, respectively. It is thus evident from Table 3 that yield gaps in different crops varied from 19% to 64%.
Crop yield gaps in other countries Yield gaps in crops were also observed in other countries, especially those of Asia region. Table 4 illustrates the rice yield gaps in India, Nepal, Thailand, etc. While it was only 3.38% in China, yield gap in other countries varied from 17 to 50 % (Tran, 2000). Yield gaps in wheat (100-800 kg/ha), mustard (500-640 kg/ha), and cotton (790-1220 kg/ha) were also observed in different states of India.
Factors Causing Yield Gaps in Crops Several factors can cause yield gaps in crops. In general, factors causing yield gaps can be classified as follows (RAP, 1999)
Biological factors Variety, soil fertility, management practices (fertilizer, water, pests management, etc.
Socio-economic factors Social and economic status of farmers, family size, farm holding, knowledge and education level of farmers, contact with extension agents.
Climatic factors Flood, drought, salinity, etc. caused by climatic changes. Institutional/government policy related factors Input/ output price, availability of inputs, credit supply, tenancy, etc. The price of produces and fertilizers could influence the rate of fertilizer use by farmers and thereby yield. Factors promoting technology transfer Research-extension linkage, training of extension personnel on the new technology, their knowledge and education level about the technology, demonstration of the technology, field visits and monitoring, etc. by extension.
Strategies for Minimizing Yield Gaps: Promotion of integrated crop management- Yield gaps caused by biological, socio-economic, and institutional constraints can be effectively addressed through integrated crop management (1CM) practices. Transfer of the practices through extension agents could effectively help farmers minimize yield gaps. Timely planting, irrigation, weeding, plant protection, and timely harvesting could account for more than 20% yield increase (Siddiq, 2000). However, input/output prices and employment opportunities influence farmers’ decision on the level of inputs to be applied.