Average Yield Increase Research Articles

Sugarbeet Root Maggot Resistance of Hybrids with a Maggot Resistant Pollinator

Sugarheet root maggot (Tetanops inyopaeforinis) is a major insect pest of sugarheet (Beta vulgaris) throughout much of North America. Host plant resistance is a potential alternative to the few chemical insecticides currently being used to control the root maggot. Gerniplasm lines with root maggot resistance have been identified but only minimal information about the resistance of hybrids created by crossing these lines with a susceptible ems parental line is available. This study compared the performance of four hybrids with a maggot resistant pollinator. F1015, and a susceptible commercial hybrid, with and without insecticide. With insecticide, the yield of the susceptible commercial hybrid was 7.8 Mg ha' greater than the root yield without insecticide. In contrast, the average root yield increase attributable to the application of insecticide for the four hybrids with F1015 as the pollinator was only 0.8 Mg ha* With insecticide, the root yield of the susceptible hybrid was equal to or greater than the root yield of the four resistant hybrids with insecticide; however, without insecticide, the yield of the susceptible hybrid was significantly lower than all the hybrids except one that also had a relatively low yield when insecticide was applied. These root yield and similar sucrose yield patterns indicated that when F1015 was used as a pollinator the resulting hybrid would have substantial root maggot resistance. The results

Role of Crop Residue Management in Sustainable Agricultural Development in the North China Plain

ABSTRACT Crop residue, the largest product of agricultural harvests, contains large amounts of assimilated carbon (C) and nutrients such as nitrogen (N), phosphorus (P), and potassium (P); these elements must be recycled for the sustainable development of agriculture. Crop residue management should serve a double function, both confronting global warming and food security by increasing carbon sequestration in agriculture and increasing grain yields. Historically, the North China Plain has experienced different crop residue management practices. While direct burning in the field remains an environmental problem in the region, crop residue amendment triggers benign cycling of C and nutrients in agriculture. Data showed that soil organic carbon (SOC) in topsoil increased by 0.174 to 1.74 g kg−1, with an average of 0.79 g kg−1 after wheat residue amendment collected from 35 sites in the North China Plain. The average increase in grain yield achieved by wheat residue amendment in the region is 260 kg ha−1 year−1 for wheat and 310 kg ha−1 year−1 for maize, for a total of 570 kg ha−1 year−1. At the same time, the available potassium (K2O), the available phosphorus (P2O5), and total nitrogen in soil increased, significantly or not. With the development of the economy, technology, and supporting policy, crop residue management can play an increasingly important role in sustainable agricultural development.

Effect of temperature and rainfall on wheat yield in south western region of Punjab

A study was conducted to evaluate the effect of temperature and rainfall on historical wheat yields in south western region of Punjab. The technology trend at Bathinda indicated that over the past 25 years wheat yields have increased at the rate of 82.1 kg ha-1 year-1. Maximum, minimum temperature and rainfall from December to March for each pentad years 1977-81 to 1997-2001 were analyzed.Temperatures during February and March revealed significant effects on wheat yield. The maximum temperature of 25.6 OC and minimum temperature of 10.8 OC during grain filling period resulted in highest yield of wheat. Compared to first pentad, the percent increase in average yield during second, third, fourth and fifth pentad was 9.7, 20.3, 49.4 and 60.3 percent, respectively. The grain yield revealed positive correlation with minimum temperature but no trends were observed for other parameters. The regression models are in good agreement between the observed and predicted values of wheat yield.

Model‐Based Approach to Quantify Production Potentials of Summer Maize and Spring Maize in the North China Plain

The North China Plain (NCP) belongs to the major maize (Zea mays L.) growing areas in China. Maize yields have increased steadily since the 1980s, but in recent years average yields have stabilized around 5000 kg ha−1. The objective of this study was to quantify the production potential of summer and spring maize in the NCP. For this purpose the CERES‐Maize model was calibrated and validated. The variability caused by climate was considered by using up to 30 yr of weather data from 14 meteorological stations across the NCP. Simulations were carried out for five different soil texture. Results were linked to a Geographic Information System (GIS). The results of the model calibration and validation showed a good fit between simulated and measured yield. Average simulated grain yield for summer maize was 4800 kg ha−1 and for spring maize was 5700 kg ha−1. Yields of summer maize were limited by the duration of the growing period. In order to increase spring maize yields, two strategies were developed. The first approach was to sow spring maize at a time when water deficit was least likely to occur during the late vegetative, flowering, and grain‐filling stages. A delay in sowing of 30 d shifted maize development closer to the rainy season and increased average yield by 13%. In a second test the use of a variety with a later flowering date as a result of a longer vegetative growth led to an average increase in yield of 15%.

The yield pattern considering the distance to flow accumulation lines

Precision agriculture techniques imply a spatial management of fields and to do so a good understanding of the spatial and temporal variability of yield is needed. Average yield data from seven irrigated maize fields were used to study the yield pattern considering the distance of plants to flow accumulation lines. It was found that there is a significant correlation between average yield and distance to flow accumulation lines (DFL). This correlation is best represented by a polynomial function. The most common shape of the yield pattern curve considering the distance to flow accumulation lines shows that there is an increase in average yield with DFL from 0 to 12.5–17.5 m. Near the flow lines the average yield presents lower values due to drainage problems causing plant growth problems. It was also observed higher yield variability near the flow lines. For higher distances from the flow lines there is a continuous decrease in average yield due to less water availability and other variations of soil properties.

A Novel Approach to Perform Gate-Level Yield Analysis and Optimization Considering Correlated Variations in Power and Performance

Increasing levels of process variation in current technologies have a major impact on power and performance and result in parametric yield loss. In this paper, we develop an efficient gate-level approach to accurately estimate and optimize the parametric yield, defined by leakage power and delay limits, by finding their joint probability distribution function. We consider inter-die variations, as well as intra-die variations, with correlated and random components. The correlation between power and performance arises due to their dependence on common process parameters and is shown to have a significant impact on the yield, particularly in high-frequency bins. We then propose a new heuristic approach to incrementally compute the gradient of yield with respect to gate sizing and gate-length biasing in the circuit with high efficiency and accuracy. We show how this gradient information can be effectively used by a nonlinear optimizer to perform yield optimization. The proposed yield-analysis approach is compared with Monte Carlo simulations and shows high accuracy, with the yield estimates achieving an average error of 2%. The proposed optimization approach is implemented and tested, and we demonstrate an average yield increase of 40% using gate sizing (as compared to a deterministically optimized circuit). Even higher improvements are demonstrated when both gate sizing and gate-length-biasing techniques are used.

Fertiliser N and P applications on two Vertosols in north-eastern Australia. 1. Comparative grain yield responses for two different cultivation ages

Nitrogen (N) and phosphorus (P) are the 2 most limiting nutrients for grain production within the northern grains region of Australia. The response to fertiliser N and P inputs is influenced partly by the age of cultivation for cropping, following a land use change from native pasture. There are few studies that have assessed the effects of both N and P fertiliser inputs on grain yield and soil fertility in the long term on soils with contrasting ages of cultivation with fertility levels that are running down v. those already at the new equilibrium. Two long-term N × P experiments were established in the northern grains region: one in 1985 on an old (>40 years) cultivation soil on the Darling Downs, Qld; the second in 1996 on relatively new (10 years) cultivation on the north-west plains of NSW. Both experiments consisted of fertiliser N rates from nil to 120 kg N/ha.crop in factorial combination with fertiliser P from nil to 20 kg P/ha.crop. Opportunity cropping is practiced at both sites, with winter and summer cereals and legumes sown. On the old cultivation soil, fertiliser N responses were large and consistent for short-fallow crops, while long fallowing reduced the size and frequency of N response. Short-fallow sorghum in particular has responded up to the highest rate of fertiliser N (120 kg N/ha.crop). Average yield increase with fertiliser N compared with nil for 5 short-fallow sorghum crops was 1440, 2650, and 3010 kg/ha for the 40, 80, and 120 kg N/ha, respectively. Average agronomic efficiency of N for these crops was 36, 33, and 25 kg grain/kg fertiliser N applied. This contrasts with relatively new cultivation soil, where fertiliser N response was generally limited to the first 30 kg N/ha applied during periods of high cropping intensity. Response to P input was consistent for crop species, VAM sensitivity, and starting soil test P level. At both the old and new cultivation sites, generally all winter cereals responded to a 10 kg P/ha application, and more than half of long-fallow sorghum crops from both sites had increased grain yield with P application. At the old cultivation site, average yield gain for 10 kg P/ha.crop treatment was 480 kg/ha for all winter cereal sowings, and 180 kg/ha for long-fallow sorghum. Short-fallow sorghum did not show yield response to P treatment.

The Economics of Atrazine

It is often claimed that atrazine is of great economic benefit to corn growers, but support for this claim is limited. Some cost-benefit studies have assumed that atrazine boosts corn yields by 6%; an extensive review found a 3%-4% average yield increase; other research suggests only a 1% yield effect. Syngenta, the producer of atrazine, also makes mesotrione, an alternative herbicide that does about the same amount for corn yields as atrazine. Italy and Germany both banned atrazine in 1991, with no decrease in corn yields or harvested area. Even if atrazine leads to 6% more corn production, it is not certain that this would justify its continued use; a 1%, or perhaps zero, change does not warrant large-scale exposure of humans and the environment to this potentially hazardous chemical.

Water Saving for Paddy Cultivation Under the System of Rice Intensification (SRI) in Eastern Indonesia

The System of Rice Intensification (SRI) developed in Madagascar in 1980s is a revolutionary new idea for paddycultivation to increase yields with reduced external resources. Basic idea of SRI originally proposed (Basic SRI) is to applycombination of (a) transplanting of young seedlings with wider spacing and (b) intermittent irrigation during vegetativegrowth period Further, application of organic fertilizers without use chemicals has practiced as "Organic SRI" as an idealapproach to improve soil and to produce high quality rice. Over the past fIVe years, a Japan-funded irrigation project inEastern Indonesia executing by the Directorate General of Water Resources, the Ministry of Public Works has introduced SRIand assessed it's potential to reduce demandfor irrigation water while rewardingfarmers with higher production and incomes.This paper reports on on-farm comparative evaluations conducted over 9 seasons between 2002 and 2006 across 8 provincesunder DISIMP. It summarizes the results of 12,133 comparison trials that covered a total area of 9,429 hectares. Averageyield increase was 78% (3.3 tlha) with reductions of 40% in water use, 50% in fertilizer applications, and 20% in the costs ofproduction. As a conclusion, SRI practices can achieve significantly higher output of rice with a reduction in inputs, enhancingsimultaneously the productivity of the resources (land, labor, water and capital) used in irrigated rice production. Theeconomic attractiveness of SRI methods is very great, giving farmers strong incentive to accept water-saving as new norm forirrigated rice production.

Integrated Nutrient Management for Sustainable Sugarcane Production in Different Agro-ecological Zones of Bangladesh

A field experiment was conducted to study the effects of integrated plant nutrition system (IPNS) on sugarcane yield and economic return at Ishurdi (High Ganges River Floodplain), Thakurgaon (Old Himalayan Piedmont Plain), Sreepur (Madhupur Tract) and Jaipurhat (Tista Meander Floodplain). The combined use of organic and inorganic fertiliser gave significantly higher sugarcane yield and economic benefit in all locations under study. Results revealed that average yield increase was 13.0 per cent higher for combined application of press mud/ cowdung at 12.5 tonnes per hectare along with inorganic fertilisers over use of only inorganic fertilisers in case of both MYG and HYG. In situ incorporation of dhaincha (Sesbania aculeata) as green manure increased sugarcane yield and contributed about 42-46 kg N per hectare in soil. Keywords: Integrated nutrient, management, sugarcane, sustainable, production.

Impacts locaux attendus de l'augmentation du CO2 dans l'atmosphère sur la productivité de l'eau du maïs dans la Drôme, France

AbstractThis study was conducted to assess local impacts of doubling of the rate of atmospheric CO2 (660 ppm) on irrigation demand and maize crop water productivity in the Drôme valley (SE France). This region is characterised by severe water shortages in the summer season. A comparison of historical records, between the periods of 1990–2001 and 1960–89, shows that in July, the mean temperature increased by 2 °C and the river stream flow diminished by 16%. At peak periods, the maize irrigation requirements represent 80% of the seasonal irrigation demand. The ARPEGE‐CLIMAT atmospheric model, regionalised at high resolution on the Rhône catchment, was used to calculate monthly climate variations. For a doubled rate of CO2, in July, an increase of 4 °C in average temperature and a decrease of 30% of rainfall are expected. Monthly climate variations were introduced into the stochastic weather generator LARS‐WG to simulate local daily climate scenarios for present (1 × CO2) and future (2 × CO2) climates. Then, the STICS crop model was applied to simulate the direct and indirect effects of increasing atmospheric CO2 on irrigation demand and maize crop production. Several simulation conditions, such as soil types, sowing dates and water stress levels, were studied for current climate and future climate scenarios. Principal results show that global warming increases water irrigation demand by 14%; lowers the maize cultivation cycle by 20%; and reduces the yield by 15%. On the other hand, a direct increase in CO2 concentration induces an average yield increase of 18%; these opposite effects balance the maize yield. The maize crop water productivity increases by 13% but it depends greatly on the water stress level. Similarly, earlier sowing dates allow earlier irrigation and a reduction of the water application depth by 40 mm in peak water demand periods and low water availability. Copyright © 2007 John Wiley & Sons, Ltd.

Comparisons of Three Recurrent Selection Methods in the Improvement of Maize Populations

Abstract The maize population Csyn 4 was improved for three cycles with three recurrent selection methods MS1, MS1-HS, and MHSRRS in northern China. A total of 40 NC II testcrosses were made by four testers with Csyn 4 and 10 improved populations, which were evaluated in four environments in the cropping season of 2005. Analysis of variance indicated a significant progress ( P<0.05) in yield and other chief agronomic traits in the improved populations and testcrosses. demonstrating that the three recurrent selection methods were effective for increasing grain yield of testcrosses and improvement of general combining ability in maize population. The average grain yield increase of population Csyn 4 in MS1, MS1-HS, and MHSRRS recurrent selections was 266.7 kg ha −1 (5.3%), 288.0 kg ha −1 (5.7%), and 231.3 kg ha −1 (4.6%) per cycle, while the grain yield of S1 progeny of population for Csyn 4 was increased by 420.0 kg ha −1 (10.9%), 376.0 kg ha −1 (9.8%), and 414.7 kg ha −1 (10.8%) per cycle in MS1, MS1-HS, and MHSRRS recurrent selections, respectively. Linear responses (b) in the MS1, MS1-HS, and MHSRRS recurrent selections were the same as the realized responses of the selection (G) for grain yield increase of Csyn 4 and S1 progeny of the populations. The grain yield of testcrosses increased by 3.3-5.2% on average per cycle. The value of heterosis did not display any differences amongst the different cycles of selections. The GCA for yield component traits of population Csyn 4 was improved significantly by means of three selection methods, whereas the GCA for plant height, ear height, days to silking, and days to pollen did not show significant increase in the recurrent selections. GCA for the number of tassel branches were decreased in the selections, while GCA for the number of plant leaves were increased, but the difference was not significant.

Effects of the nitrification inhibitor dicyandiamide on soil mineral N, pasture yield, nutrient uptake and pasture quality in a grazed pasture system

AbstractRecent lysimeter studies have demonstrated that the nitrification inhibitor, dicyandiamide (DCD), can reduce nitrate (NO) leaching losses from cow urine patches in grazed pasture systems. The objective of this study was to quantify the effects of fine particle suspension (FPS) DCD on soil mineral N components, pasture yield, nutrient uptake and pasture quality under grazed pasture conditions. A field study was conducted on the Lincoln University dairy farm, Canterbury, New Zealand, from 2002 to 2006. FPS DCD was applied to grazed pasture plots at 10 kg ha−1 in early May in addition to applied cow urine patches at a nitrogen (N) loading rate of 1000 kg N ha−1, with DCD reapplied in early August. Soil mineral N levels in the urine patches were monitored. Pasture yield, N and cation concentrations and uptake were measured in treatment urine patches and inter‐urine areas of the pasture. Comparisons were made with control plots which did not receive DCD. NO levels under the DCD‐treated urine patches (0–7.5 cm) were in the order of 10 kg N ha−1 compared with 40–80 kg N ha−1 under untreated patches, and soil ammonium (NH) levels were consistently higher under the DCD‐treated patches. The DCD significantly and consistently increased pasture yield in both the urine patches, and inter‐urine areas of the pasture in all 4 years of the trial. Mean annual dry matter (DM) yields over 4 years were inter‐urine areas, 10.3; inter‐urine + DCD, 12.4; urine, 12.4 and urine +DCD 16.0 t DM ha−1, representing an average DM yield increase of 20 and 29% in inter‐urine and urine patch areas, respectively. On a whole paddock basis, the increase in annual DM yield resulting from DCD application was estimated to be 21%. N, calcium (Ca), magnesium (Mg) and potassium (K) concentrations in pasture were unaffected by treatment with DCD; however, total annual uptake of these nutrients by pasture was significantly higher in all years where DCD had been applied. Pasture DM, protein, carbohydrate, metabolizable energy and fibre levels and sward clover content were not affected by treatment with DCD. The results demonstrate the agronomic value of the DCD treatment in addition to the environmental benefits in a grazed pasture system.

Impact of elevated CO 2 and temperature on rice yield and methods of adaptation as evaluated by crop simulation studies

Impact of elevated CO 2 and temperature on rice yield in eastern India was simulated by using the ORYZA1 and the INFOCROP rice models. The crop and weather data from 10 different sites, viz., Bhubaneswar, Chinsurah, Cuttack, Faizabad, Jabalpur, Jorhat, Kalyani, Pusa, Raipur and Ranchi, which differed significantly in their geographical and climatological factors, were used in these two models. For every 1 °C increase in temperature, ORYZA1 and INFOCROP rice models predicted average yield changes of −7.20 and −6.66%, respectively, at the current level of CO 2 (380 ppm). But increases in the CO 2 concentration up to 700 ppm led to the average yield increases of about 30.73% by ORYZA1 and 56.37% by INFOCROP rice. When temperature was increased by about +4 °C above the ambient level, the differences in the responses by the two models became remarkably small. For the GDFL, GISS and UKMO scenarios, ORYZA1 predicted the yield changes of −7.63, −9.38 and −15.86%, respectively, while INFOCROP predicted changes of −9.02, −11.30 and −21.35%. There were considerable differences in the yield predictions for individual sites, with declining trend for Cuttack and Bhubaneswar but an increasing trend for Jorhat. These differences in yield predictions were mainly attributed to the sterility of rice spikelets at higher temperatures. Results suggest that the limitations on rice yield imposed by high CO 2 and temperature can be mitigated, at least in part, by altering the sowing time and the selection of genotypes that possess higher fertility of spikelets at high temperatures.

Nitrogen efficiency of dairy cows as affected by diet and milk yield

Abstract The aim of this study, which was part of the EU-financed project Life Ammonia, was to evaluate the effects of dietary components and milk production on nitrogen efficiency of dairy cows. The study included examining the effects of decreased crude protein (CP) concentration in a grass-clover silage based diet and results of mixing whole-crop barley silage (WCBS) with grass-clover silage in the diet, on feed intake, milk production and nitrogen efficiency. Rations were formulated and milk production data were registered individually each month for 42 cows of the Swedish Red Cattle breed during four indoor periods from 1999 to 2003. The range in nitrogen efficiency by the cows, 11 to 398 days in milk, was 18 to 40%, when fed a diet containing 135 to 184 g CP/kg DM, 44 to 56% of NDF as rumen degradable fibre (RDF) and milking 13 to 57 kg of ECM daily. The average CP concentration of the diet, containing mainly grass-clover silage and concentrate, was decreased from 168 g/kg DM (170 g in early lactation) in the control treatment period to 160 g/kg DM (163 g in early lactation) during the following treatment period. The CP concentration was 170 g/kg DM (171 g in early lactation) during the third treatment period, when the grass-clover silage was fed in a mixture with WCBS. Using the whole data set ( n = 284 for primiparous, n = 440 for multiparous cows based on measurements each month) resulted in models, in which total DM intake, ECM yield, dietary CP concentration and RDF were the most important factors affecting nitrogen utilisation of primiparous and multiparous cows. Increases in both average DM intake and milk yield by multiparous cows and no changes in average intake and milk yield by primiparous cows fed the low CP diet or the normal CP diet containing WCBS, compared to cows fed the normal CP diet, resulted in similar nitrogen efficiencies among the treatments. Hence, dietary CP concentrations of 160 to 170 g/kg DM can be used for cows in early lactation in commercial herds to improve nitrogen utilisation without causing a simultaneous decrease in milk yield.

Effect of supplementary irrigation and variety on yield and some agronomic characters of sunflower grown under rainfed conditions in Northern Syria

Sunflower is an important edible oil crop. Its yield on dry lands of West Asia-North Africa is low due to limited rainfall at the time when this crop is in full growth during May-June, thus supplementary irrigation (SI) must be used. However, this region lacks river/canal water and irrigation, when possible, is from underground water storages, which, due to their quantitative scarcity, have to be used judiciously. This trial was conducted to assess the minimum SI application needed to produce optimum economic yields. The study was made for three years (1995-1997) at Tel Hadya, ICARDA, in northern Syria, on a soil characterized as fine clay (montmorillonitic, thermic Calcixerollic Xerochrept) with a pH around 8.0. We tested two open pollinated varieties, HO-1 and Record, and three water level treatments, rainfed, 50% of crop water requirement and 100% of crop water requirement. Effects of environment (years), variety and water level were observed on plant height, head and stem diameter, 200-seed weight, leaf area and sunflower grain yield. The results show that plant height, head diameter, stem diameter and leaf area differed significantly due to year effects while seed weight and yield differed non-significantly. The cultivars were significantly different only regarding seed weight and stem diameter. Grain yield obtained under rainfed conditions was highly significantly lower than those obtained under SI, with both lower and higher quantity of irrigation water. The average yield increase with 50% SI was 150% and with 100% SI was 312%. However, the yield difference between the two irrigation levels was 66%. This trial showed that 50% SI irrigation level can increase the yield substantially and economically, and can be resorted to in the absence of water for full irrigation.

A review of on-farm evaluations of system of rice intensification methods in Eastern Indonesia.

Abstract The system of rice Intensification (SRI) developed in Madagascar has been controversial in some agronomic circles, in part because there have been no large-scale, long-term evaluations of the impact of the alternative methods recommended. This review reports on on-farm comparative evaluations conducted over nine seasons between 2002 and 2006 across eight provinces in Eastern Indonesia under a major irrigation project (SSIMP-DISIMP), with project management by a Nippon Koei consultant team. It summarizes the results of 12 133 comparison trials that covered a total area of 9429 ha. Average yield increase was 78% (3.3 t/ha) with reductions of 40% in water use, 50% in fertilizer applications and 20% in the costs of production. While the controversy will not be resolved by any single evaluation, these results support the previous reports that SRI practices, when used in combination, can achieve significantly higher output of rice with a reduction in inputs, enhancing simultaneously the productivity of the resources (land, labour, water and capital) used in irrigated rice production.

Productivity of crops grown on raised beds on duplex soils prone to waterlogging in Western Australia

Waterlogging of duplex soils in Western Australia has long been recognised as a major constraint to the production of agricultural crops and pastures. The work described in this paper examines the application of raised beds to arable land that is frequently waterlogged for the production of crops such as wheat, barley, field peas, lupins and canola. Raised beds are 138 cm wide, seed beds separated by 45 cm wide furrows 183 cm apart. These beds were made with a commercial bed former. Seven sites were selected across the south-eastern wheat belt of Western Australia with the experimental areas varying in size from 10 to 57 ha. These large sites were used to accommodate commercial farm machinery. Each site had raised beds formed with a commercial bedformer. The production from the bedded areas was compared with crops grown conventionally on flat ground under minimum tillage as the control. The experiments were established in 1997 and 1998 and the sites were monitored for a maximum of 5 years. In 11 of the 28 site-years of the experiments, grain yields on the raised beds were statistically significantly higher than the yield from crops grown on the control, with an average yield increase of 0.48 t/ha. Across the whole dataset, growing crops on raised beds did not produce significantly lower yields. Below average rainfall was received for much of the experimental period at several sites. Growing season rainfall had a large effect on grain yield and high rainfall over a period of 40 days after seeding significantly increased the grain yield difference between the raised bed and the control. These data indicate that the use of raised beds lead to higher grain yields when seasonal conditions are appropriate.

The Happy Seeder enables direct drilling of wheat into rice stubble

Lack of suitable machinery is a major constraint to direct drilling into combine-harvested rice residues due to the heavy straw load, and the presence of loose tough straw deposited by the harvester. Therefore, most rice stubbles are burnt in the mechanised rice–wheat systems of south Asia and Australia, as this is a rapid and cheap option, and allows for quick turn around between crops. As well as loss of organic matter and nutrients, rice stubble burning causes very serious and widespread air pollution in the north-west Indo-Gangetic Plains, where rice–wheat systems predominate. A novel approach with much promise is the Happy Seeder, which combines the stubble mulching and seed drilling functions in the one machine. The stubble is cut and picked up in front of the sowing tynes, which engage bare soil, and deposited behind the seed drill as mulch. Evaluation of the technology over 3 years in replicated experiments and farmers’ fields in Punjab, India, showed that establishment of wheat sown into rice residues with the Happy Seeder was comparable with establishment using conventional methods (straw burnt followed by direct drilling or cultivation before sowing) for sowings around the optimum time into stubbles up to 7.5 t/ha. For late sowings, plant density declined significantly at straw loads above 5 t/ha. The mulch also reduced weed biomass by ~60%, and reduced soil evaporation. Yield of wheat sown around the optimum time into rice residues, using the Happy Seeder, was comparable with or higher than yield after straw removal or burning, in replicated experiments and farmers’ fields, for straw loads up to 9 t/ha. In farmers’ fields there was an average yield increase of 9 and 11% in 2004–05 and 2005–06, respectively, compared with farmer practice. For sowings after the optimum time, yield declined significantly at straw loads greater than 7.5 t/ha. The Happy Seeder offers the means of drilling wheat into rice stubble without burning, eliminating air pollution and loss of nutrients and organic carbon due to burning, at the same time as maintaining or increasing yield.

Potato Yield Increases Due to Fungicide Treatment in Argentinian Early Blight (Alternaria solani) and Late Blight (Phytophthora infestans) Field Trials During the 1996-2005 Seasons

The effect of fungicides on potato yields in separate early blight and late blight trials during the 1996 to 2005 growing seasons at the INTA Balcarce experimental station was determined. Potato cultivars Pampeana INTA were used for early blight trials while Kennebec ones were used for late blight trials. A randomized complete block design with four replications was used in all trials. The fungicides Folicur 25EC at 0.5 liter/ha and Brestan 60WP at 0.5 kg/ha were tested in early blight trials while Dithane M80WP at 2.5 kg/ha and Ridomil Gold 68WP at 1.25 kg/ha were tested in late blight trials. Early blight infections were rated using a 0 to 50 a rating scale. Late blight severity was rated using a disease index of 0 to 5. Potatoes were graded into two categories, marketable (&gt; 60 g) and undersize tuber “seeds” (&lt; 60 g), and then weighed. Data was subjected to analysis of variance. Early and late blight symptoms were present every season. In early blight trials, the efficacy of the systemic fungicide Folicur 25EC was greater than that of the non-systemic Brestan 60WP. The average yield increase due to fungicide treatment during the ten-year period was 22.4% for marketable and 17.9% for total yield. In late blight trials the efficacies of Dithane M80WP and Ridomil Gold 68WP were similar. The average yield increase due to fungicide treatment during the study was 41.23% for marketable and 33.85% for total yield. Accepted for publication 23 October 2006. Published 2 February 2007.