Person: Hobbs, P.R.
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- Wheat in the cotton-wheat farming systems of the punjab: implications for research and extension(PARC, 1986) Akhtar, M.R.; Byerlee, D.; Qayyum, A.; Majid, A.; Hobbs, P.R.The cotton-wheat area constitutes the most important cropping system in Pakistan. Taking those districts in which cotton is grown on at least half of the Kharif irrigated area, 2.2 million ha of wheat are grown in the cotton-wheat cropping system. However, current research and extension recommendations do not differentiate between wheat sown after cotton and wheat sown in other rotations. A diagnostic survey of wheat was conducted in the district of Multan in the 1948-85 crop cycle. The major objectives of this survey were to delineate major sources of variation in the area, identify factors limiting productivity and plan an on-farm experimentation/extension programme. An informal survey a team of agricultural economists and agronomists was conducted in March 1985. This was followed by a formal survey of wheat production practices and yields at harvest time in 150 randomly selected fields. Production practices were recorded in the short interview with farmers in their fields and yields were measured by harvesting and threshing three to five plots of dimension 1m2 located randomly in the field. Wheat after cotton was a major crop rotation in the area. About 50 percent of wheat fields were planted after cotton, and 30 percent planted after fallow. Average cropping intensity was about 130 percent. The prolonged harvesting of cotton is the major conflict in the cotton-wheat cropping system, resulting in late planting of wheat. Wheat after cotton was planted on an average 19 days later than wheat after other Kharif crops or fallow. Indeed, nearly 70 percent of wheat following cotton was planted after December 15th reducing potential yields substantially. The farmers appear to rationally weigh up the benefits of an additional cotton picking with the loss from later wheat planting. The results show that even taking into account high picking cost for the late picking, benefits of extra cotton pickings are likely to outweigh the loss in wheat yields due to late planting. The majority of farmers (60%) used non-recommended wheat varieties. Variety WL-711 which is banned because of susceptibility to leaf rust is the most common variety (39% of fields) in the area. Only 15 percent of farmers planted new recommended varieties (Punjab 81, Pak 81, Bahawalpur 79 etc). The rest (24%) used Sonalika/Bluesilver. The problem of slow uptake of new varieties reflects an inadequate distribution system for: certified seed as well as farmers' lack of awareness of the danger of a rust epidemic from using banned varieties. Chemical fertilizer was used by 95 percent of the sampled farmers. Most farmers are aware of the need to apply both nitrogenous and phosphatic fertilizers, although fertilizer application rates are well below recommended rtes. The most important nutrient explaining variation in wheat yields was phosphorous. Farmers on average applied 95-46 kg N-P2O5/ha. Crop rotations, size of farm, access to irrigation and use of farm yard manure all influenced the quantity of fertilizer applied by farmers. Weeds were not a major problem in the area. Broadleaf and wild oats were a problem in some fields but did not significantly affect wheat yields. To some extent weeds were controlled by crop rotations (after berseem). None of the farmers used herbicide to control weeds in wheat. Salinity Fifteen patches salinity yields of was found is becoming a bigger problem in the area. Fifteen percent of fields were rated as having a few of salinity and five percent had a substantial problem resulting in an average reduction in about 17 percent in those fields. No farmer who applied gypsum. Irrigation is provided by perennial (57 percent) and seasonal (43 percent) canals, supplemented by tubewells. Because of lack of electricity in many villages, diesel tubewells are much more widely used despite the fact that they are more costly to operate. About 21 percent of the farmers reported saline tubewell water. High cost of diesel, load-shedding and canal closure were the major irrigation problems in the area. Delayed harvesting well beyond maturity was a common practice, especially among large farmers who depend on hired labour for harvesting. The harvest index declined from 30.2 percent in early harvested fields to 27.4 percent in late harvested fields. This, in part, reflects the fact that late harvested fields were also late planted and hence subject to more heat stress. Farmers pay about one third of their wheat production or 13.2 kg per 40 kg. for harvesting, threshing and marketing costs. The net value of the wheat standing in the field that should be used in calculating the profitability of an innovation was Rs. 42.5 per 40 kg of wheat after subtracting harvesting and post harvest costs. The average measured wheat yields from the 150 samples were 2.3 t/ha. One third of fields yielded less than 2.0 t/ha and only 13 percent yielded above 3.0 t/ha. The characteristics of the high yielding fields were a) wheat after fallow, b) access to tubewell water and perennial canal system, c) better land preparation, d) use of new recommended varieties e) planted before November 30th and harvested before April 26th f) more irrigations and g) application of 40 percent more phosphorous. Conversely, low yielding fields had usually been planted after cotton, used banned varieties and were planted after November 30th. Multiple regression analysis of yields confirmed most of these factors as significantly affecting yields. The net returns of low (<1.84 t/ha) and average (2.29 t/ha) yielding fields only barely covered variable costs and were not high enough to cover land rent and give a reasonable return on capital to farmers. The net returns in high yielding fields (>2.64 t/ha) were positive but not high enough to give a reasonable return on capital to farmers. These results reflect the importance of cost reducing technologies if wheat is to compete with alternative crops such as sunflower. The cotton-wheat areas represent the major irrigated wheat growing areas of Pakistan and justifies a major allocation of measures for research and extension. A realistic yield gap exists in the area of 30% that can be reduced by developing recommendations for more homogeneous groups of farmers. These recommendation domains should be based on crop rotation and access to irrigation water. Major problems exist with late planting of wheat, use of rust susceptible varieties, fertilizer efficiency, irrigation water efficiency, broad leaf weeds and harvesting costs. An on-farm experimental research program is suggested to overcome these problems.
Publication - Increasing wheat productivity in the context of Pakistan's irrigated cropping systems: A view from the farmers' field(PARC, 1986) Byerlee, D.; Hobbs, P.R.; Khan, B.R.; Majid, A.; Akhtar, M.R.; Hashmi, N.I.Over 85 percent of wheat area in Pakistan is now sown to high yielding varieties and the national average fertilizer application for wheat is nearly 90kg/ha of nutrients. Further increases in wheat yields will come about largely through improved cultural practices which exploit the genetic potential of available varieties. This will have to be done within an economic environment tending to reduce price incentives in wheat production. This report summarizes findings from three years of research on wheat production in farmers' fields in three irrigated cropping systems the Punjab rice/wheat area and cotton/wheat area and the NWFP maize-sugarcane/wheat area. A farming systems research approach has been used in which a) wheat has been viewed as an integral part of a cropping system and changes have been evaluated in terms of the productivity of the system, b) constraints on wheat production and opportunities for change have been analysed at the farm level for well defined groups of farmers and c) a multidisciplinary team of wheat scientists and social scientists have collaborated in analysing farmers' problems. A diagnostic survey has been conducted in each area using informal and formal survey techniques, to provide an understanding of the system and farmers' production practices. This has been followed by experiments in farmers' fields to test promising opportunities for improving productivity. The results reported are based on interviews with nearly 1000 farmers and the outcome of nearly 200 on farm experiments. In each of the three areas a dominant crop rotation prevails with wheat sown after rice, cotton or maize (according to the area) in half or more of the fields surveyed. These sequential double cropping patterns have led to widespread late planting of wheat (70% of fields were planted after December 1st in the cotton/wheat area). Late planting leads to an average decline in yields of 30-40kg for every day's delay in planting. Breeding emphas±s needs to shift to developing varieties which perform well over all planting dates, and particularly for late planting, which represents the "norm" in many areas. Recent evidence indicates that newly released "full season" varieties, especially Pak81, perform better in late planting than the early variety, Sonalika, which is currently recommended. The trend toward double cropping is continuing and will place greater pressure on the wheat crop. Many fields, especially in the rice/wheat area, are sown to a single cropping pattern year-after-year. The continuous sowing of wheat in Rabi cycle has led to an increase in weed and probably other pest problems and a decline in yields. Research is needed to establish more productive long term rotations in this area. In 1984, 80 percent of farmers planted banned or other rust susceptible wheat varieties such as Sonalika, and the Pakistan wheat harvest is again at risk of a rust epidemic. Less than 20 percent of farmers planted newly released varieties such as Pak8l and Punjab 81. The adoption of these newer varieties has accelerated over the last two seasons but the pace of change is too slow to prevent a rust epidemic. Pak 81, in particular, has consistently outyielded 6ther varieties by 20% or more in onfarm trials and greater efforts are needed in extension and seed distribution to speed up the adoption of this variety, especially in stripe rust areas. Farmers in the three areas commonly used one bag/acre each Gf Urea and DAP. This is well below the recommended levels but evidence is presented that fertilizer recommendations need to be tailored to farmers' needs by a) adapting recommendations to particular crop rotations, soil types, irrigation access etc. and b) basing recommendations on sound economic analysis of response curves and taking into account farmers' costs and scarcity of capital. The major issue in land preparation and planting is the difficulty experienced in obtaining a good seed bed for wheat after rice. The use of a specially designed drill for direct drilling with zero tillage has shown promise of a breakthrough in this area. Direct drilling has produced a good st~nd of wheat, reduced turnaround time from rice to wheat and eliminated land preparation costs. The major weed control method used by farmers, especially for grassy weeds is crop rotation. However, significant yield losses occur due to grassy weeds in the rice/wheat area and broadleaf weeds in the maize/wheat area. Herbicide control of broadleaf weeds is highly profitable in the NWFP maize/wheat area but more work is needed to find economic means for controlling grassy weeds in the rice/wheat and practical area. Irrigation practices are very variable depending on crop rotation, soil type and access to water. Little research is available to guide farmers to utilize water efficiently under their particular circumstances. Wheat yields varied from 1.8t/ha in the rice/wheat area to 2.8t/ha in the NWFP maize/wheat area. Official yield statistics are grossly in error for NWFP. At current, prices, wheat production provides negative economic returns in all areas except the maize/wheat area. Multiple regression analysis of farmers yields' shows, that the main factors responsible for differences in yields are - variety, nitrogen or phosphorous depending on the area, irrigation and especially crop rotation. Weed problems are also a significant yield reducing foetor in each area. However, the yield gap between farmers' yields and an economic potential yield is only 30-40%, much low~r than widely reported. In addition, yield differences between small and large farmers are not significant except in the rice/wheat area. Opportunities for technology transfer and research to sustain future increases in wheat production are identified. Technology transfer should focus on dissemination of newly released varieties in all areas, use of direct drilling in the rice/wheat area, and broad leaf weed control by herbicides in the maize/wheat area. Many of the issues analysed in the report are identified for further onfarm research especially fertilizer and water use efficiency. In addition, long term research on rotations is needed. Finally, the data base generated can serve as a ~aluable starting point for analysis of key policy issues such as fertilizer subsidies or the comparative advantage of wheat and oilseeds. The report concludes with implications for organizing research to sustain increased wheat production. These emphasise a multidisciplinary approach to solving farmers' pro~uction problems with priority on onfarm research. Decentralization of production research to specific locations representing major cropping systems and reorientation of extension priorities are also recommended.
Publication - Wheat and rice in the mid-hills of Nepal: a benchmark report on farm resources and production practices in Kavre District(CIMMYT, 1999) Adhikary, C.; Adhikary, B.; Rajbhandari, N.P.; Hooper, M.; Upreti, H.K.; Gyawali, B.K.; Rajbhandari, N.K.; Hobbs, P.R.This benchmark survey involved a random sample of 54 farmers from the Naldung area, grouped by altitude class, ethnicity, land type, and several farm-level categories to characterize sample variability for production practices and yield. The study identified soil fertility, crop establishment, and weed and pest management as key factors for maintaining high rice and wheat yields in the mid-hills of Nepal. Results are available in the form of an easily accessible database, and will allow researchers and policy-makers to track changes in farmers' resources, production practices, and system productivity
Publication - Wheat in the rice-based farming system of the Punjab: implications for research and extension(CIMMYT, 1984) Byerlee, D.; Sheikh, A.D.; Aslam, M.; Hobbs, P.R.The planting of wheat after rice is a major cropping pattern in the Punjab, occupying 0.5 million ha. in the Districts of Sheikhupura and Gujranwala alone. In this irrigated area, however, wheat yields remain low and research is urgently needed to find ways of increasing productivity in this important region. As part of NARC's outreach program, a diagnostic survey of wheat was conducted in the Districts of Sheikhupura and Gujranwala in the 1983/84 crop cycle in order to delineate major sources of variation in the area, identify major factors limiting productivity and plan an on farm experimentation/extension program. An informal survey by a team of agricultural economists and wheat agronomists was conducted in February, 1984. This was followed by a survey of wheat production practices and yields at harvest time in 152 fields. Production practices were recorded in a short interview with farmers and yields measured by harvesting and threshing a sample of the crop. Wheat after Basmati rice was the dominant crop rotation in the area, followed by wheat after IR-6 rice. Wheat was produced on two major soil types (based on soil survey classifications) imperfectly drained days and well drained loams and clay loams. Seedbed preparation for wheat was often very poor reflecting the difficulties of preparing land after rice, especially in heavy soils. After Basmati rice these problems were greater because of the limited time available for land preparation and the greater rice residue problem. As a result of poor land preparation, stand establishment was often poor and weed growth was encouraged. These factors combined to produce low wheat yields especially in heavy soils and after Basmati rice. The majority of farmers used banned wheat varieties, especially Yecora (58%). Only 16 percent used approved varieties released in the last 5 years. An inadequate seed distribution system and poor extension of information on newer varieties were the major factors constraining use of newer varieties. Since Yecora is susceptible to both leaf and stripe rust, there is a real danger of a serious rust epidemic. Late planting of wheat in December and into January occurs in over half of the wheat fields. This is particularly true when wheat follows Basmati rice. The later harvest of Basmati and the need to obtain a suitable moisture condition for land preparation for wheat often leads to late planting. The majority of farmers now use 80kg/ha of nitrogen and 57kg/ha of phosphorus (i.e. 1 bag/acre each of urea and diammonium phosphate). In better prepared fields and fields with better access to irrigation water, fertilizer rates are somewhat higher leading to higher yields. The most important element explaining variation in yields was nitrogen. Most farmers appear to apply adequate phosphorus. Phalaris minor is a serious weed problem in a quarter of all fields leading to an average reduction in yield of about 25 percent in these fields. Broadleaf weeds are also a problem in some fields but with less yield damage. Farmers control Phalaris to some extent through crop rotation, especially by planting berseem. The survey showed that very few fields of wheat after berseem in the previous year were infested with Phalaris. Herbicides are used by only a handful of farmers. The high cost of herbicides in relation to returns, equivalent to 500kg of wheat/ha or 27 percent of average yields at the recommended dose, is an important obstacle to wider herbicide use. 9. Irrigation practices vary substantially depending on access to canal and tubewell water. Many farmers who obtain water from publicly owned tubewells faced serious water shortages due to mechanical breakdowns in these tubewells. The effect on yields in 1983-84 was not large due to timely rains. Harvesting, threshing and transport costs account for over 25 percent of the total value of wheat harvested. While the official price of wheat is R 1600/ton (64 R for 40 kg) the net price that should be used in calculating the profitability of an innovation is about R l,100/ton (R42 per 40 kg) when harvesting and post-harvest costs are deducted. Average yields from the 152 samples were 1.8t/ha but quite variable. Twenty percent of fields yielded under 1.0 t/ha and only 7 percent yielded over 3.0 t/ha. The characteristics of the high yielding fields were: (a) lighter soils (b) wheat after maize or other non-rice crops, (c) sown with a newer variety (e.g. Punjab 81), (d) better land preparation, (e) earlier planting (f) 50 percent more nitrogen and (g) more irrigations. Conversely, low yielding fields had usually been planted continuously to wheat in the rabi cyde, usually followed Basmati and were seriously infested by Phalaris weed. Multiple regression analysis of yields confirmed most of these factors as significantly affecting yields. Overall, the regression analysis explained half of the variation in wheat yields. There is an urgent need to stratify the farmers in the area into more homogeneous groups (i.e. recommendation domains) for the purpose of formulation of recommendations. Major delineations should be based on soil type and access to irrigation water. Research and extension should direct efforts to evaluating and promoting newer varieties of wheat, finding economic means for controlling weeds and seeking solutions to the problem of poor stand establishment. A series of experiments/verifications to meet these objectives in both the should and longer run are proposed. This research should be conducted in farmers fields within the 61elineated recommendation domains. There is also a need for rice and wheat researchers to integrate efforts to develop appropriate cropping systems that increase total productivity of the cropping system.
Publication - Population densities of rice root nematodes (Hirschmanniella spp.) in long-term fertility experiments in Nepal(Istituto per la Protezione delle Piante (IPP), 2004) Pokharel, R.P.; Hobbs, P.R.; Regmi, A.P.Long-term soil fertility experiments at Bhairahawa (rice-wheat-rice), Tarahara (rice-wheat), and Rampur (rice-wheatmaize) were sampled to assess the densities of rice root nematodes Hirschmanniella spp. Nematode densities in roots and soil samples were determined by the blender-cum-modified Baermann trays and sieving-cum-modified Baermann trays techniques, respectively. The rice root nematodes, Hirschmanniella oryzae and H. mucronata, were common and observed in most of the rice samples collected, although the population varied greatly among the samples. In wheat crops, rice root nematodes were observed at low densities only in the soil samples, not in roots. Significantly higher numbers of nematodes were observed in the plots receiving N and P fertilizers as compared to those receiving N alone. Potassium fertilizer, up to 50 kg/ha, had no effect on rice root nematode populations, but significantly lower nematode populations were observed in plots fertilized with 100 kg/ha potassium as compared to the control. Also, significantly lower nematode populations and higher rice yields were observed in fields where farmyard manure was applied annually for 16-17 years. Incorporation of rice stubble and Dhaicha before flowering had no effect on nematodes.
Publication - International Wheat Improvement: Highlights from an Expert Symposium(CIMMYT, 2008) Reynolds, M.P.; Hobbs, P.R.; Ortiz, R.; Pietragalla, J.; Braun, H.J.Wheat is grown on 217 million hectares worldwide, accounting for some 620 million tons of grain and providing one-fifth of the world’s total calorific input. In regions like North Africa, Turkey, and Central Asia, wheat provides fully half of total dietary calories. Half the world’s wheat area is found in developing countries, where steady increases in productivity since the Green Revolution, associated with improved yields, resistance to diseases, adaptation to abiotic stresses, and better agronomic practices, are now under serous threat. Challenges include increased demand, scarcity of water resources, unpredictable climates, increased urbanization and loss of quality farmland, and decreased public investments in agriculture. To meet the rising demand for wheat in a sustainable way, farmers need a new generation of improved cultivars, along with resource-conserving practices to grow them. In March 2006, with support from the Australian Centre for International Agricultural Research (ACIAR), CIMMYT brought together 160 scientists from over 30 wheatproducing countries to discuss how to increase wheat production sustainably. Their presentations and discussions are being assembled in the proceedings International Symposium on Wheat Yield Potential: Challenges to International Wheat Breeding, to be published by CIMMYT in March 2008. The volume will include articles from the symposium already published in 2007 in special issues of Euphytica (volume 157:3) and the Journal of Agricultural Science (volume 145:1-3), as well as other papers from the meetings: Reports of the workshop “Stakeholder priorities for internationally-coordinated wheat research” involving representatives of major wheat producing countries on all continents whose remit was to develop a list of priorities for future wheat research that could best be tackled in a globally-coordinated fashion, and outlines of activities that would serve as templates for future project development for selected priorities. The summary of field day presentations by groups of collaborating scientists in attendance, illustrating the continuum between national, regional, and internationalcenter-based research activities. Reports of a pre-symposium survey soliciting statistics on wheat production and constraints to productivity and research from 19 countries in Latin America, sub-Saharan Africa; Central and West Asia and North Africa; and South and Southeast Asia. Collectively these countries account for over 100 million hectares of wheat and around 90% of the wheat production in the developing world. The data were also used to prepare a general summary of the constraints to productivity and research across the above-mentioned regions.
Publication - Wheat and rice in Karnal and Kurukshetra Districts, Haryana, India: farmers practices, problems, and an agenda for action(CIMMYT, 1993) Harrington, L.W.; Fujisaka, S.; Morris, M.L.; Hobbs, P.R.; Sharma, H.C.; Singh, R.P.; Chaudhary, M.K.; Dhiman, S.D.Two diagnostic surveys conducted during the rice and wheat seasons in 1992 in Kamal and Kurukshetra Districts of Haryana, India, helped develop a preliminary assessment of both near-term and potential longer-term problems in the area's rice-wheat cropping pattern. The surveys obtained information on farmers' rice and wheat crop management (crops and cropping patterns, water and soil fertility management, pest and disease management, and practices from sowing to harvest). Information on interactions between rice and wheat cultivation and other enterprises in the farming system was obtained as well. The major problems affecting wheat are (in order of importance) weed competition. declining soil health, poor groundwater quality, low plant popUlation, and late planting. [n rice. insect pests and diseases were identified as problems. Leaf folder and white-backed planthopper were the most severe. followed by blast, stemborer. foot rot, and bacterial leaf blight. Increased weed pressure and changing weed species were problems that also affected rice. Problems of declining soil fertility and soil health, poor groundwater quality, and groundwater depletion are longer-term problems that have implications for the sustainability of the rice-wheat pattern. Suggested. actions to address these problems include additional diagnosis. monitoring to assess the longer-term effects of fanners' practices and alternative technologies, research on alternative solutions 10 problems that are thought to be well understood, extension. and research on policy implications.
Publication - Irrigated wheat in North West Frontier Province: A synthesis of On-farm research results 1983-86(CIMMYT, 1990) Razzaq, A.; Khan, B.R.; Khan, B.; Hobbs, P.R.; Hashmi, N.I.; Heisey, P.W.This paper presents the data obtained from on-farm experiments on tillage, variety, weed control, and fertilizer in the irrigated areas of Mardan, Peshawar, and Swat Districts of NWFP. More emphasis is given to Mardan District, the major irrigated area of the province. The study was conducted jointly from 1983-86 by the Wheat Program, NARC, CIMMYT, and the outreach program at the Cereal Crops Research Institute, Pirsabak, NWFP. From 1983-84 to 1985-86, 127 experiments were conducted on different aspects of crop management (tillage, variety, weed control, and fertilizer). Fields were selected where the previous crop was either maize or sugarcane. Trials were mostly researcher managed and designed to obtain quantitative data on potential yields in the area. Most of the trials were unreplicated. Based on 14 experiments, deep primary tillage gave 10.6% more yield than traditional farmers' practices. Although the cost of deep plowing was double that of traditional methods, it gave higher net benefits. In the varietal trials, Pirsabak-85 and Pak-81 (both Veery lines) were higher yielding than the other two varieties tested, Sarhad-82 and Sarhad-83, and also showed good stripe and leaf rust resistance. Broadleaf weeds were a serious problem in the area but could easily and economically be controlled by the Phenoxy-type herbicides like Buctril-M, 2,4-0 and MCPA. Dicuran-MA proved to be the best herbicide for controlling the grassy weeds, Avena fatua and Phalaris minor. Application of herbicides mixed with sand and broadcast was as effective as spraying, provided the chemicals were uniformly broadcast Based on economic analysis of fertilizer response curves, the recommended doses for wheat after maize were 106-38 kg/ha of N-P205 and for wheat after sugarcane, 107-65 kg/ha. Nitrogen doses from 80 to 170 kg/ha and phosphorus from 30 to 130 kg/ha were economical, depending on how much the farmer can afford.
Publication - Wheat in the rice-wheat cropping system of the Punjab: A synthesis of On-farm research results 1984-1988(CIMMYT, 1989) Aslam, M.; Majid, A.; Hobbs, P.R.; Hashmi, N.I.; Byerlee, D.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.
Publication - Wheat production and yields in Rawalpindi District of the Punjab from 1983 to 1986(CIMMYT, 1989) Hobbs, P.R.; Razzaq, A.; Hashmi, N.I.; Khan, B.R.; Khan, B.This study is based on surveys undertaken during wheat harvest in the rainfed (barani) areas of Rawalpindi district of Pakistan's Punjab from 1983 to 1986. Wheat yields were estimated by crop cut and related to farmers' management practices in the same plots. Differences in yields and practices were analysed in terms of farm size, cropping pattern, land type and socioeconomic factors. Visual observations of field problems were also taken and related to yield. The area surveyed has an average annual rainfall between 500-750 mm. One third of this rain falls in the wheat season. The four years of study had variable rainfall with 1983 and 1986 above and 1984 and 1985 below average. Soils in the study area are composed of loess deposits and sedentary materials and range in texture from sandy loam to silty clay loam. Soil available moisture varies from 50 to 200 mm to a depth of 1.5 metres.
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