Wheat in the rice-wheat cropping system of the Punjab: A synthesis of On-farm research results 1984-1988
This report presents the results of five years of on-farm studies on wheat production in the rice-wheat zone of the Punjab. The work was started in 1983-84 with an informal diagnostic survey and a formal survey at harvest time to explore farmer production practices and causes of low wheat yield in this cropping system. On the basis of the findings of that survey, an on-farm experiment program was developed to seek ways to improve the productivity of wheat in this area. The following is a summary of the work conducted from 1984-88. 1. The surveys indicated that the low yield of wheat sown after rice was associated with 1) late planting of wheat, 2) poor crop stands, 3) weeds (especially Phalaris minor), and 4) imbalanced fertilizer use. 2. To find solutions for the above issues, 136 on-farm experiments were conducted over 51 locations in the rice-wheat zone from 1984 to 1988, covering tillage methods, variety, chemical weed control, and fertilizer (NPK) responses. 3. The fields selected for experiments were those where the previous crop was either IR-6, Basmati-370, or Basmati-385 rice. 4. Most experiments were researcher managed and designed to obtain quantitative data on the potential yields of wheat sown after rice. Most experiments were non-replicated within locations. Data for individual sites were combined for analysis across locations: 5. Tillage methods were studied with an eye toward reducing land preparation costs and ensuring the timely planting of wheat after the rice harvest. In a series of experiments on large plots at 42 sites over 4 years, zero tillage was found to reduce land preparation costs by 100% and total planting costs for wheat by 87% relative to conventional tillage methods. While zero tillage resulted in only 6% higher yields than conventional methods when crops under both treatments were planted at the same time, wheat planted under zero tillage immediately after the rice harvest produced 24% higher yields than wheat planted under conventional tillage. This difference is due to the nearly 24-day post-harvest period required for conventional tillage/planting operations and to improvements in several other yield related factors in wheat under zero tillage: 16% more tillers, 19% better germination, and 43% less weeds. 6. Wheat varieties are developed and recommended for specific planting dates (early, normal, and late). Managing cultivars with different recommended planting dates is difficult for farmers. Two groups of varieties were tested from 1984- 88 to identify varieties that are suitable for a wider range of planting dates. Group one included Pak-81, Kohinoor, and Punjab-85, which are recommended for early-to-optimal planting. The second group included Blue Silver, Faisalabad-83, and Faisalabad-85; all recommended for late planting. In a pooled analysis of all varieties when planted at the recommended time (mid-November), varieties from group one showed significantly higher grain yields than those from group two. Pooled analysis of all the varieties under a late (mid-December) planting showed non-significant differences in yield between the two groups. Kohinoor, Punjab85, and Pak-81 (the first group) obtained respective yields of 4.0, 4.0, and 4.1 t/ha when planted at the recommended time, and 3.3, 3.6, and 3.1 t/ha when planted late. Blue Silver, Faisalabad-83, and Faisalabad-85 (the second group) obtained respective yields of 3.1, 3.5, and 3.7 t/ha when planted at the recommended time, and 2.9, 3.0, and 3.2 t/ha when planted late. This demonstrates that some late maturing varieties with high yield potential can be used by farmers at early, normal, and late planting dates. 7. Phalaris minor was the most important weed identified in the rice-wheat area and reduced yields by an average 400-500 kg/ha in heavily infested fields. Several herbicides were tested at 14 locations over the 1984-87 period. In the pooled results, the use of Dicuran-MA increased average yield almost 1 t/ha (34%) over that of treatments where no herbicide was used. Dicuran-MA gave promising results even when broadcast in a urea or sand mixture, and was also effective at 50% and 75% of the recommended dose. Broadleaf weeds--Chenopodium album and Rumex acetosella--were important in some fields, but were controlled effectively with Dicuran MA. 8. Fertilizer trials were conducted to obtain N, P, and K response curves for wheat following rice. Four points on the response curve were obtained with treatments varying from 0 to 210 kg/ha for nitrogen, from 0 to 150 kg/ha for phosphorus, and from 0 to 150 kg/ha for potash. Forty-three fertilizer experiments were conducted in farmers' fields over the 1984-88 period. The data were pooled for regression analysis using year, planting time, weed control, and tillage methods as dummy variables. The results show that nitrogen fertilizer has a significant effect on wheat yields, and phosphorus or potash no effect. Late planting (after November 15) reduced yields by 30 kg/day/ha. Weed control increased yields by a significant amount (279 kg/ha). Fertilizer efficiency under zero tillage was less than that under conventional methods, apparently because the fertilizer is not incorporated into the soil under zero tillage, resulting in losses by denitrification. The economics of fertilizer use in the experiments was also analyzed at different marginal rates of return. Results at MRR=0.5 suggest an optimal dosage of 124 kg/ha of nitrogen on wheat sown after rice. The report ends with a discussion of the implications of these results for technology transfer, and suggestions are given for future research. Five major near term research topics are Identified: Delayed and sub-optimal plant stand establishment. Inadequate plant nutrients. Inadequate soil/water management. Losses to pests/diseases/weeds. Low profitability. Long term issues discussed include the effects of nutrient depletion and specific biotic constraints (pests/diseases) on sustainability.
| Main Authors: | , , , , |
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| Format: | Report biblioteca |
| Language: | English |
| Published: |
CIMMYT
1989
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| Subjects: | AGRICULTURAL SCIENCES AND BIOTECHNOLOGY, RICE, NPK FERTILIZERS, VARIETIES, PHALARIS, EXPERIMENTATION, CROPPING SYSTEMS, ZERO TILLAGE, WHEAT, TECHNOLOGY TRANSFER, WEED CONTROL, TILLAGE, INTERCROPPING, FOOD PRODUCTION, |
| Online Access: | http://hdl.handle.net/10883/1122 |
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