North-western Indo-Gangetic Plains Research Articles

Long term effect of conservation agriculture in maize rotations on total organic carbon, physical and biological properties of a sandy loam soil in north-western Indo-Gangetic Plains

Maize-based crop rotations are advocated as alternate to rice-based systems in South Asia due to better suitability for diverse ecologies, higher yields with less water use and more palatable maize fodder compared to rice, and increased demand of maize from piggery and poultry industries. Alternate tillage and crop establishment practices are important management strategies for tackling the issues of soil health deterioration and over exploitation of underground water resources, particularly in rice based intensive crop rotations. The conservation agriculture (CA) based tillage and crop establishment practices such as zero tillage (ZT) and permanent raised beds (PB) hold potential to enhance soil organic carbon (SOC), physical and biological properties for sustainability of soil health. Therefore, a long term study was conducted to evaluate the twelve combinations of tillage practices (03) and irrigated intensive maize based crop rotations (04) on organic carbon, physical properties and microbial biomass and enzymatic activities of a sandy loam (Typic Haplustept) soil in north-western India. The tillage practices consisted of ZT, PB and conventional tillage (CT) in main plots and four diversified intensive maize based crop rotations (MWMb: Maize-Wheat-Mungbean, MCS: Maize-Chickpea-Sesbaina, MMuMb: Maize-Mustard-Mungbean, MMS: Maize-Maize-Sesbania) in sub plots. In this study we analysed the SOC, physical and biological properties of soil at various depths after 7 years of continuous ZT, PB and CT in diversified maize rotations. Compared to CT plots, the soil physical properties like water stable aggregates (WSA)>250μm were 16.1-32.5% higher, and bulk density (BD) and penetration resistance (PR) showed significant (P<0.05) decline (11.0–14.3 and 11.2–12.0%) in ZT and PB plots at 0–15 and 15–30cm soil layers. The soil organic carbon (SOC) increased by 34.6-35.3% at 0–15cm, and 23.6-26.5% at 15–30cm soil depths with conservation agriculture (ZT and PB) based crop establishment techniques over CT. Similarly, the soil microbial biomass carbon (MBC) under CA based systems increased by 45–48.9% in 0–30cm profile depth of a sandy loam (Typic Haplustept) soil. Significant (P<0.05) improvement in soil enzymatic activities i.e., Fluorescein diacetate, dehydrogenase, β Glucosidase and Alkaline phosphatase was also recorded in the CA based treatments. Significant (P<0.05) synergistic effects of summer legumes (mungbean and Sesbania) with winter legume/cereal in crop rotations were observed on SOC,WSA, BD, PR and Ksat at 0–15 and 15–30cm depths. Interaction between tillage and crop rotations were significant (P<0.05) for soil organic carbon, physical properties and enzymatic activities. Thus our long-term study suggests that CA based crop management with selected diversified maize based rotations (MCS and MWMb) can be advocated as sustainable intensification strategy in light textured soils of north-western India and other similar agro-ecologies of South Asia.

Conservation agriculture in a rice-wheat cropping system on an alluvial soil of north-western Indo-Gangetic plains: Effect on soil carbon and Nitrogen pools

Improving soil organic carbon (SOC) and nitrogen (N) in arable soils is one of the important strategies to enhance soil quality for sustainable crop production and to mitigate climate change. Hence, we investigated the changes in SOC and N under conservation agriculture (CA) in an alluvial soil of the north-western Indo-Gangetic Plains (IGP) after two years of rice (Oryza sativa L.)-wheat (Triticum aestivum L.) rotation. The treatments were: Puddled transplanted rice followed by conventional-till wheat (TPR-CTW), TPR followed by zero-till wheat (TPR-ZTW), Direct-seeded rice followed by ZTW (DSR-ZTW), DSR-ZTW with rice residue retention in ZTW (DSR-ZTW+RR), DSR-ZTW with Sesbania brown manuring (DSR+BM-ZTW), DSR+BM-ZTW+RR, DSR-ZTW with ZT summer mungbean (greengram) (Vigna radiata) as a relay crop and mungbean residues retained on rice fields as in-situ green manuring (MBR+DSR-ZTW-ZTMB) and MBR+DSR-ZTW+RR-ZTMB. Results indicated that plots under CA (MBR+DSR-ZTW+RR-ZTMB) had significantly higher Walkley-Black C, KMnO4-C and very labile SOC compared with TPR-CTW in surface (0–15 cm) soil. Interestingly, addition of residues with mixed C:N ratios (legume and rice residues) failed to register improvement in soil mineral N, owing possibly to greater portioning of N towards soil microbial biomass (SMB) and particulate organic matter (POM) associated pools. Fascinating results could be expected in the present experiment with the passage of time.

Quantifying changes to the global warming potential of rice wheat systems with the adoption of conservation agriculture in northwestern India

Field trials were conducted in Haryana representing the northwestern Indo-Gangetic Plains (IGP) to assess the changes brought about by management, including conservation agriculture (CA) practices, in the global warming potential (GWP) of conventional rice–wheat systems. Conservation agriculture is an approach to managing agro-ecosystems for improved and sustained productivity, by way of minimal soil disturbance, permanent soil cover with organic matter or cover crops and crop rotation. Methane (CH4) and nitrous oxide (N2O) fluxes were measured using static chambers. Experiments involved four cropping system scenarios with different CA components, and different N rates. In addition, emissions of CH4 and N2O fluxes were measured in farmers’ fields to establish baselines. The dynamics of CH4 emissions were controlled by floodwater levels, and fertilizer N had no effect. On the other hand, N application rates and timing in relation to soil water status determined the N2O emissions in rice fields. Nitrous oxide fluxes could be avoided by applying N fertilizer to wet soil or by irrigating the field not later than 1 day after N application. Applying crop residues on soil surface had no significant effect on the seasonal CH4 and N2O emissions. It was estimated that switching rice crop establishment method from conventional to CA-based practices in Haryana could reduce GWP for rice by 23% or by 1.26 Tg CO2 eqyr−1. An intensive CA-based rice–wheat and maize–wheat system reduced GWP by 16–26% or by 1.3–2.0 Tg CO2 eqyr−1 compared with the conventional rice–wheat system. However, this reduction in GWP would be from a decrease in diesel and electricity consumption and not from direct emissions of CH4 and N2O, which were higher in the maize–wheat system than in the rice–wheat system.

Status of nutritional practices for domestic cows in rural ecology of north-western Indo-Gangetic plains

Data congregated on 150 households from 15 ecosystems in rural area of Baghpat district of north-western Indo-Gangetic plains. The overall body weight of cows was 376.1 ± 8.8 kg and overall daily milk yield was 4.76 ± 0.08 kg. On an average, a cow requires 9.4 ± 0.09 kg dry matter daily; whereas, only 8.46 ± 0.07 kg dry matter could be supplied leaving a 10 % deficiency of dry matter, which was significantly affected by the lactation order. The daily digestible crude protein (DCP) availability to a cow were 0.47 ± 0.008 kg and 0.43 ± 0.005 kg indicating a deficiency of 0.04 kg DCP/ day/ cow. The requirement as well as availability of DCP for cows was affected significantly by lactation order. The requirement and availability of total digestible nutrients (TDN) were 4.47 ± 0.10 kg and 3.96 ± 0.05 kg/day for cows, showing a deficiency of 8.85 %. The lactation order and herd size affected significantly the requirement as well as the availability of TDN for cows.

Impacts of laser land leveling in rice–wheat systems of the north–western indo-gangetic plains of India

We assessed the impact of laser land leveling technology in rice-wheat (RW) systems of north-west India using data collected from household surveys in 2011. We compared crop yield and total irrigation time required per season between laser leveled (LLL) and traditionally leveled (TLL) fields. Laser leveling in rice fields reduced irrigation time by 47–69 h/ha/season and improved yield by approximately 7 % compared with traditionally leveled fields. In wheat, irrigation time was reduced by 10–12 h/ha/season and yield increased by 7–9 % in laser leveled fields. Our analysis showed that laser land leveling is a scale neutral technology, not biased towards large farmers. Farmers benefited by an additional USD 143.5/ha/year through increased yields in RW systems and reduced electricity used in laser leveled fields compared to traditionally leveled fields when estimated by using the electricity tariff equivalent to the average subsidized tariff for agricultural use. This benefit became much larger when estimated by using an electricity tariff equivalent to the average cost of its supply. Hence, assuming an average electricity tariff equivalent to the average cost of its supply in the year 2010–11 in the country, the net benefit of shifting from TLL to LLL in RW systems in the study area was USD 194 per ha per year. This large difference in benefits indicates the loss due to market distortions by subsidy in electricity and hence, is a matter of policy concern requiring further scrutiny. The RW system in a hectare of laser leveled field required 754 kWh less electricity for irrigation per year compared to a traditionally leveled field. Furthermore, if 50 % of the area under the RW system in Haryana and Punjab states were laser leveled, this would provide an additional production of 699 million kg of rice and 987 million kg of wheat, amounting to USD 385 million/year. Thus, laser leveling contributes to food security and economical use of water and energy resources.

Chemical fractions and bioavailability of nickel in alluvial soils

The present study was undertaken to sequentially fractionate nickel (Ni) in soils of divergent physicochemical char acteristics and evaluate the contribution of different fractions towards plant uptake. For this, fifteen bulk surface (0–15 cm) soil samples were collected from the cultivated fields of northwestern Indo-Gangetic alluvial plains. A pot experiment was conducted with these soils to assess the contribution of soil Ni fractions to plant uptake using soybean as test crop. Results showed that residual Ni was the most dominant fraction in soil constituting 3.19–63.6% of total Ni. The water soluble plus exchangeable Ni accounted for only 0.70–4.04% of total soil Ni. Organically bound Ni varied from 1.60–6.85% of total Ni; these values are relatively lower as compared to those reported for temperate soils. Correlation studies showed that the free iron oxide (Fe 2 O 3 ) and soil organic carbon correlated with various fractions of Ni in soil. Water soluble plus exchangeable and organically bound are the dominant fractions which contributed positively and manganese oxide (MnO 2 ) bound and residual fractions contributed negatively towards the phytoavailability of Ni in soil.

Rice Productivity and Profitability Under Different Crop Establishment Methods, Plant Densities and Weed Control in North-Western Indo-Gangetic Plains

The experiments were conducted at Students’ Research Farm, Department of Agronomy, Punjab Agricultural University, Ludhiana during summer seasons of 2009 and 2010 to study the yield and economics of rice under different establishment methods, plant densities and weed control methods. Rice was directly sown with different drills or broadcasting technique and manual transplanting. For weed control, alone pre-emergence application of pendimethalin 0.75 kg ha1 and sequential application of bispyribac sodium 0.025 kg ha−1/azimsulfuron 0.02 kg ha−1 was done along with one weed free treatment. Grain yield did not vary significantly among establishment methods and the highest benefit:cost ratio (B:C) was obtained when rice was direct seeded with the help of drills. The maximum grain yield (71.06 q ha−1) was recorded in weed free treatment which was statistically at par with sequential use of pendimethalin 0.75 kg ha−1 with bispyribac 0.025 kg or azimsulfuron 0.02 kg ha−1 applied 30 DAS. The B:C ratio increased as seed rate increases from 20 kg to 50 kg ha−1 and it was more for closer spaced direct seeded rice crop.

ASSESSMENT OF IMPACT OF CLIMATE CHANGE ON POTATO AND POTENTIAL ADAPTATION GAINS IN THE INDO-GANGETIC PLAINS OF INDIA

India is the second largest producer of potato in the world. The Indo-Gangeticplains (IGP) is the main potato growing region accounting for almost 85% of the1.8 Mha under the crop in India where it is grown as an irrigated crop during thewinter season. Since IGP is in sub-tropical plains, duration of the thermally suitablewindow is the main determinant limiting yields. Hence the impact of climatechange on potato in the IGP was assessed using MIROC HI.3.2 A1b and B1,PRECIS A1b, A2, B2 scenarios and estimated the potential adaptation gains. Thepotato crop duration in the IGP is projected to decrease due to climate change. Theevapotranspiration (ET) is projected to increase while the water use efficiency(WUE) for potato yield is projected to decline in future climates as a consequenceof low threshold temperatures for decline in WUE and yield than the ET. Resultsindicate that the upper threshold for ET decrease is ~23 oC while that for WUE is15 oC. The optimal temperatures for tuber yield is ~17 oC and thus the reduction inWUE in future climates is discernable. Climate change is projected to reducepotato yields by ~2.5, ~6 and ~11% in the IGP region in 2020 (2010-2039), 2050(2040-2069) and 2080 (2070-2099) time periods. Change in planting time is thesingle most important adaptation option which may lead to yield gains by ~6% in2020 and its combination with improved variety or additional nitrogen may be required to adapt to climate change leading to positive gains by ~8% in 2020 andby ~5% even in 2050. However, in 2080 adoption of all the three adaptationstrategies may be needed for positive gains. Intra-regional differences in the impactof climate change and adaptation gains are projected; positive impact in northwestern IGP, gains in Central IGP with adaptation and yield loss in eastern IGPeven with adaptation.

Chemical weed management effects on productivity and profitability of gladiolus (Gladiolus hybridus) in north-western Indo-Gangetic Plains

A field experiment, involving ten weed control treatments laid out in a randomized complete block design with three replications, was undertaken at the Indian Agricultural Research Institute, New Delhi during the winter seasons, 2011-12 and 2012-13. The objective was to evaluate the effects of different combinations of herbicides, particularly pre-emergence tank-mix herbicides applications on weeds, and flowering, corm yield and benefit-cost economics of gladiolus (Gladiolus hybridus Hort.). It was observed that all herbicidal treatments resulted in significantly lower density of monocot and dicot weeds, and total weed dry weight compared to weedy check, which had the highest two- year mean density of monocot (165/m2) and dicot (364/m2) weeds and total weed dry weight (171 g/m2). Among herbicide treatments, atrazine 1.0 kg/ha pre-emergence followed by rice residue @ 5 tonnes/ha at 2 days after atrazine application caused the greatest reduction in density and dry weight of weeds. All herbicidal treatments, except butachlor 1.0 kg/ha pre-emergence, were equally effective as this treatment against weeds. The herbicides and their doses adopted in this study did not pose any phytotoxicity to gladiolus plants. The tank-mix pre-emergence applications were usually more effective than the single herbicide application. The tank-mix pre-emergence application of pendimethalin 0.75 kg/ha + metribuzin 0.3 kg/ha resulted in significantly greater two-year mean gladiolus plant height (116 cm), cut-flower yield (172 500 spikes/ha), corm yield (3.82 tonnes/ha) and net returns (` 243 100/ha) compared to weedy check and most other treatments, and was most remunerative.

Reprint of “Optimizing intensive cereal-based cropping systems addressing current and future drivers of agricultural change in the Northwestern Indo-Gangetic Plains of India”

Increasing scarcity of resources (labour, water, and energy) and cost of production, along with climate variability, are major challenges for the sustainability of rice–wheat system in the northwesten Indo-Gangetic Plains (IGP). We hypothesized that adopting the principles of conservation agriculture together with best crop management practices would improve system productivity and overall efficiency, resulting in a higher profitability. To test this hypothesis, we evaluated the performance of four cropping system scenarios (treatments), which were designed to be adapted to current and future drivers of agricultural changes. The treatments including farmers practices varied in tillage and crop establishment methods, residue management, crop sequence, and crop management. Zero-tillage direct-seeded rice (ZT-DSR) with residue retention and best management practices provided equivalent or higher yield and 30–50% lower irrigation water use than those of farmer-managed puddled transplanted rice (CT-TPR). Overall, net economic returns increased up to 79% with a net reduction in production cost of up to US$ 55ha−1 in ZT-DSR than CT-TPR. Substituting rice with ZT maize was equally profitable but with 88–95% less irrigation water use. Avoiding puddling in rice and dry tillage in maize with residue retention increased yield (by 0.5–1.2tha−1) and net economic returns of the succeeding wheat crop. Inclusion of mungbean in the rotation further increased system productivity and economic returns. In summary, our initial results of 2-year field study showed positive effects of CA-based improved management practices on yield and system efficiencies with greater benefits in the second year. There is a need of longer term monitoring to quantify cumulative effects of various interventions and to eventually make recommendations for wider dissemination.

Optimizing intensive cereal-based cropping systems addressing current and future drivers of agricultural change in the northwestern Indo-Gangetic Plains of India

Increasing scarcity of resources (labour, water, and energy) and cost of production, along with climate variability, are major challenges for the sustainability of rice–wheat system in the northwesten Indo-Gangetic Plains (IGP). We hypothesized that adopting the principles of conservation agriculture together with best crop management practices would improve system productivity and overall efficiency, resulting in a higher profitability. To test this hypothesis, we evaluated the performance of four cropping system scenarios (treatments), which were designed to be adapted to current and future drivers of agricultural changes. The treatments including farmers practices varied in tillage and crop establishment methods, residue management, crop sequence, and crop management. Zero-tillage direct-seeded rice (ZT-DSR) with residue retention and best management practices provided equivalent or higher yield and 30–50% lower irrigation water use than those of farmer-managed puddled transplanted rice (CT-TPR). Overall, net economic returns increased up to 79% with a net reduction in production cost of up to US$ 55ha−1 in ZT-DSR than CT-TPR. Substituting rice with ZT maize was equally profitable but with 88–95% less irrigation water use. Avoiding puddling in rice and dry tillage in maize with residue retention increased yield (by 0.5–1.2tha−1) and net economic returns of the succeeding wheat crop. Inclusion of mungbean in the rotation further increased system productivity and economic returns. In summary, our initial results of 2-year field study showed positive effects of CA-based improved management practices on yield and system efficiencies with greater benefits in the second year. There is a need of longer term monitoring to quantify cumulative effects of various interventions and to eventually make recommendations for wider dissemination.

Double no-till and permanent raised beds in maize–wheat rotation of north-western Indo-Gangetic plains of India: Effects on crop yields, water productivity, profitability and soil physical properties

Excessive pumping of groundwater over the years to meet the high water requirement of flooded rice crop and intensive tillage have threatened the sustainability of irrigated rice–wheat system (RWS) in the Indo-Gangetic plains (IGP) of South Asia. Replacement of rice with less water requiring crops such as maize in the RWS and identification of effective strategies for alternate tillage systems will promote sustainable cropping systems in the IGP. To this effect a 3-year field experiment was established with annual maize–wheat rotation in the north-western IGP of India to evaluate the effect of 3 tillage systems (conventional flat, CTF; no-till flat, NTF; permanent raised beds, NTB) on crop production, water use efficiency, economic profitability and soil physical quality. Grain yield of maize was highest (8.2–73.4%) under NTB followed by NTF and CTF across the years. Wheat yield was significantly higher under NTF during the 1st year while tillage practices had non-significant effect in the succeeding two years. On average, maize planted on NTB recorded about 11% lower water use and 16% higher water use efficiency compared to CT. The NTB and NTF required 24.7% and 10.8% less irrigation water than CTF system, respectively with 11.5% higher system productivity and demonstrated higher water productivity. The NTB and NTF systems provided similar net returns (averaged over 3 years) in maize–wheat system (MWS), which were US$ 281ha−1 higher compared to CTF system. The CTF system had higher bulk density and penetration resistance in 10–15 and 15–20cm soil layers due to compaction caused by the repeated tillage. The steady-state infiltration rate and soil aggregation (>0.25mm) were higher under NTB and NTF and lower in the CTF system. Similarly, mean weight diameter (MWD) of aggregates was higher under NTF and NTB compared to CTF. The study reveals that NTB and NTF systems could be more viable options for MWS in order to save input costs and enhance profitability; however, the long-term effects of these alternative technologies need to be studied under varying agro-ecologies.

English

&nbsp; Rice production in Punjab has increased 23 times in the past seven decades, mainly due to increased grain yield rather than increased planting area. This increase has come from the development of high-yielding varieties and improved crop management practices, such as optimum transplanting time, nitrogen fertilization, improved weed and irrigation management. However, sustainability of rice cultivation in Punjab is at risk due to receding water table and degradation of natural resource base. As the population of India rises, it will pose more pressure on Punjab to produce more rice (about 20%) by 2030 to meet the domestic needs, due to less arable area, less water, global climate change, labour shortage and increasing consumer demand for high quality rice (which often comes from low yielding varieties). The major problems confronting rice production in Punjab are excessive use of fertilizers and pesticides, receding water table, degradation of soil health, and oversimplified crop management. Despite these challenges, good research strategy can lead to increase in rice production in Punjab. These include the development of new varieties with high yield potential, resilience to climate change and tolerance to major abiotic stresses such as drought and heat, and the establishment of integrated crop management and new crop establishment method, namely direct seeded rice. &nbsp; Key words:&nbsp;Rice sustainability, Punjab, North-western Indo-Gangetic Plains (IGP), rice productivity, food security.

Resource Scarcity Gradients and Agricultural Technologies

The green revolution converted the Indo-Gangetic Plains (IGP) into South Asia's cereal basket. The recent slowdown in cereal productivity growth and continuing poverty in the IGP pose a major challenge to agricultural research and development. In addressing this challenge, it is useful to revisit the resource scarcities that farmers face across the vast IGP. A scoping study using village surveys in 12 clusters along an agro-ecological gradient in the Indian IGP and secondary data suggest some marked gradients in factor ratios and factor prices. Labour–land factor ratios and price ratios alone, however, can be misleading as they fail to capture the increasingly important role of capital in the post-green revolution setting. Relative to other IGP regions, the green revolution heartland is relatively capital-abundant, explaining the advent of both land-saving and labour-saving technologies in the north-western IGP. Further downstream, the densely populated eastern IGP are particularly capital-scarce. Agricultural innovations emerging from either area are unlikely to be directly adequate for the other, calling for more investment in adaptive agricultural research to develop innovations in line with the prevailing resource scarcities.

Farmers’ Perceptions about Constraints in Sustainability of Rice-Wheat Cropping System in Haryana

Rice-wheat (RW) is the most important cropping system of irrigated areas and widely practiced in the Gangetic plains in Haryana. Stagnation in land productivity, particularly of the RW system, has been observed over the past few years in the northern and northwestern Indo-Gangetic Plains. A survey was undertaken in Haryana, covering the RW system in Karnal, Kurukshetra, Ambala and Kaithal districts. Using the multistage random sampling, 160 RW growing farmers were selected covering small, medium and large land owners. Data were collected by using personal interview method during 2011. The farmers perceived erratic power supply, non-availability of labour, non-availability of seeds of newly released variety, increasing incidence of insect, pest and diseases and lack of knowledge among farmers about newly released technology as the major constraints in sustainability of RW cropping system. Rice and wheat productivity in Haryana can be increased by making some policy decisions like providing regular power supply during crop growth period, good quality seed, fertilisers, pesticides and educating the farmers on latest technologies.

Performance and Water-use Efficiency of Rice Relative to Establishment Methods in Northwestern Indo-Gangetic Plains

Gains or losses in grain yield and water-use efficiency of aerobic direct-seeded rice (Oryza sativa L.) must be considered before promoting this technology in areas where this is not common. In the northwestern Indo-Gangetic Plains (IGP) of South Asia, irrigation water for rice production is becoming scarce because of depleting surface and groundwater resources. The objective of this study was to compare the crop performance and water-use efficiency of 10 selected rice cultivars between aerobic direct-seeded rice (ADSR) and conventional puddled transplanted rice (CPTR) on a sandy loam soil in Punjab Agricultural University (PAU), Ludhiana, India. Grain yields were similar between ADSR and CPTR for cultivars PR-120, Punjab Mehak 1, Fang-ai-zan, and RH-664. Grain yields of the other cultivars decreased significantly in ADSR compared with CPTR. PAU-201, a medium-duration cultivar, had the highest grain yields in each crop establishment method, followed by PR-120. Water-use efficiency (WUE) values for Fang-ai-zan, RH-257 (hybrid), PAU-201, and PR-120 were significantly higher than the WUE of any other cultivar, and they also had high values for stress-tolerance index (STI). Averaged across cultivars, WUE was similar in ADSR and CPTR as yield reduction in ADSR overweighed the benefit of water saving. We recommend that for more economic water use in the northwestern part of IGP, growing cultivars such as Fang-ai-zan, RH-257, PR-120, and PAU-201 in ADSR because of their lower water requirement, yield maintenance, and relatively higher STI. Correlation coefficients between STIs revealed that STI, mean productivity (MP), and geometric mean productivity (GMP) were the best criteria for the selection of high-yielding cultivars under ADSR and CPTR.

Optimizing Seed Rate to Suppress Weeds and to Increase Yield in Aerobic Direct-seeded Rice in Northwestern Indo-Gangetic Plains

Weed infestation is a major constraint to widespread adoption of aerobic, direct-seeded rice (Oryza sativa L.). Higher than optimum initial seeding density for obtaining more panicles/m2 is often accompanied by reduced panicle size and 1,000-grain weight, and high rate of spikelet sterility. On the other hand, weeds in plots with a lower seeding rate have a better chance to emerge, grow and build up a strong population and thus pose a serious crop-weed competition. Experiments were conducted during kharif (rainy season) 2008 and 2009 to determine the optimum seed rate that can substantially reduce rice-yield loss caused by weed competition under aerobic conditions. A factorial-treatment arrangement was used with factors consisting of five seed rates (15, 30, 60, 120, and 240 kg/ha) and two weed-pressure treatments (weedy-check and weed-free). Weed pressure caused a significant reduction in yield; there was up to 36.2% reduction in yield for weedy check as compared with the weed-free treatment. Seeding rat...

Weed Management in Aerobic Rice in Northwestern Indo-Gangetic Plains

Aerobic rice systems, wherein the crop is established via direct seeding in non-puddled, non-flooded fields, are among the most promising approaches for saving water and labor. However, aerobic systems are subject to much higher weed pressure than conventionally puddled transplanted rice (CPTR). Experiments were conducted for two years to develop effective and economical methods for managing weeds in aerobic rice grown by direct seeding rather than by conventional transplanting method. The proportion of mean grass-weed dry matter was 28.3% more in aerobic direct-seeded rice (ADSR) as compared to CPTR. Both weed density and dry weight were negatively correlated with rice grain yield. ADSR treatment produced yield similar to CPTR treatment when weeds were controlled effectively. Post-emergence application of bispyribac Na 25 g/ha and penoxsulam 25 g/ha could effectively control all the weeds in ADSR. Irrigation water productivity remained statistically the same in both ADSR and CPTR under the weed-free situation or when bispyribac Na herbicide was applied as post-emergence because of effective weed control in ADSR. The variation in net profitability between the ADSR and CPTR decreased with herbicide treatments, viz., Bispyribac Na, followed by penoxsulam and sequential application of pretilachlor and metsulfuron.

Economics of Custom Hiring of Combine Harvesters in North-Western Indo-Gangetic Plains of India - A Case Study

Combine harvesters were introduced in the North-Western Indo-Gangetic plains of India due to labour shortage particularly on harvesting season and uncertain weather conditions. Now, these are being popularized and adopted by all categories of farmers. The custom unit managers who are involved in the business were selected for this study, which was conducted in 7 districts of North-Western plains of U.P. and one district of Tarai region of Uttaranchal during the year 2001-02. The North-Western Indo-Gangetic Plains were classified in three intensity zones based on crop harvesting index i.e. high intensity zone (greater than 60%), medium intensity zone (30-60%) and) low intensity zone (less than30%). A total of 30-unit managers (10 unit managers from each intensity zone) were selected randomly for the present study. The data were collected from these selected unit managers/owners on a pre-structured and well-tested proforma. About 90% of combine harvesters on the farms were of local made. The area of coverage of combine harvester was about l49.8lha in Kharif season and 261.81ha in Rabi season. The field capacity of commercial combine was 0.86 hath in Rabi season and 0.66 hath in Kharif season. Combine owners reported that the business of combines on custom hiring had become highly competitive.

Energetics, productivity and weed control in different rice (Oryza sativa) establishment methods in North-Western Indo-Gangetic Plains

A field experiment was conducted at Punjab Agricultural University, Ludhiana (Punjab) during the rainy (kharif) season of 2009 and 2010, to study the effect of various establishment methods and weed-control treatments on weeds, crop growth, yield attributes and yield of rice (Oryza sativa L.). The experiment was laid out in a split-plot design with 5 establishment methods, i.e. dry-seeding with 3 different drillszero till drill, modified furrow drill, con- ventional seed-cum-fertilizer drill in unpuddled soil, wetseeding or manual broadcast in puddled soil and manual transplanting in puddled soil, and 4 weed-control treatments, viz. pre-emergence application of pendimethalin 0.75 kg/ha, sequential application of pendimethalin 0.75 kg/ha and bispyribac 0.025 kg/ha or azimsulfuron 0.02 kg/ha and weed-free in 4 replications. Weed biomass at harvesting, effective tillers and grain yield did not vary signifi- cantly among different establishment methods. At 60 days after sowing, 27% more plant height, 5.6% more num- ber of tillers and 49% more crop biomass were recorded under direct seeding methods than transplanting method. More net returns ( 36,660/ha) and energy output: input ratio (5.04) were recorded under dry seeding methods than wet seeding ( 28,792/ha and 4.24) and puddled transplanted method ( 27,305/ha and 4.47). The maximum grain yield (6.7 t/ha) was recorded under weed-free treatment which was statistically at par with sequential use of pendimethalin 0.75 kg/ha with bispyribac 0.025 kg (6.6 t/ha) or azimsulfuron 0.02 kg/ha (6.5 t/ha). Sequential ap- plication of pre- and post-emergence herbicides resulted in more benefit: cost ratio (1.66) and energy output: input ratio (5.32).