Use Of Straw Mulch Research Articles

Control measure of sweet potato weevil (Cylas formicarius Fab.) (Coleoptera: Curculionidae) in endemic land of entisol type using mulch and entomopathogenic fungus Beauveria bassiana

Abstract Sweet potato weevil Cylas formicarius (Fab.) is the main obstacle for sweet potato production in various countries. Root damage caused by C. formicarius larvae reduced root yield up to 100%. The aim of this study is to test the measures using mulch and entomopathogenic fungus Beauveria bassiana for controlling C. formicarius in endemic land of entisol type. The control measure tested was the use of straw mulch and plastic mulch as well as the application of the entomopathogenic fungus Beauveria bassiana. The research was conducted at the experimental station at Indonesian Legumes and Tuber Crops Research Institute, Malang from July to December 2018. The results showed that the measure for controlling C. formicarius using straw or plastic mulch combined with the entomopathogenic fungus B. bassiana produces root yields between 17 and 26 t/ha. Using plastic mulch as a cover for mounds with the application of the fungus B. bassiana is more effective and efficient in controlling C. formicarius than the insecticide deltamethrin. Plastic mulch can physically inhibit the process of laying eggs and the formation of C. formicarius larvae, while B. bassiana is toxic to eggs, larvae, and adults of C. formicarius. The efficacy of control measure using plastic mulch and the application of B. bassiana can reduce yield losses by up to 96.76%. Technological innovation using plastic mulch to cover the mound with the application of the entomopathogenic fungus B. bassiana can be recommended to control C. formicarius on land endemic to the entisol type.

Pengaruh Macam Mulsa terhadap Pertumbuhan dan Hasil Tanaman Bawang Merah

This study aims to determine the type of mulch that is effective for suppressing weed growth and the effect of using mulch on the growth of shallots (Allium ascalonicum L.). The research was carried out from September 2021 to December 2021 in the village of Central Jlko, Plosorejo, Matesih, Karanganyar Regency with an altitude of 380 meters above sea level and soil of the brown Litosol type. This research method used a Completely Randomized Block Design (RAKL) method consisting of one factor (single factor) and repeated 6 times with the following levels: A1: Without mulch, A2: Use of straw mulch, A3: Use of silver black plastic mulch, and A4: Use of husk mulch. The research results were analyzed using ANOVA or 5% variance. If it is significantly different, then continue with the Duncan's Multiple Range Test (DMRT) which shows that the type of mulch has a significant effect on shallot yields and has no significant effect on shallot growth. Silver black plastic mulch treatment (A3) was better than treatment without mulch (A1), straw mulch (A2), and rice husk mulch (A4) in inhibiting weed growth.

Influence of the best management practices on performance of dual-purpose baby corn (Zea mays) under eastern Himalayas

A field experiment was conducted during the winter (rabi) season of 2013–15 at the ICAR–Research Complex for North-Eastern Hill Region, Nagaland Centre, Jharnapani, Medziphema, Nagaland, to evaluate the effect of mulching, liming and integrated nutrition for maximizing the productivity of recently introduced crop baby corn (Zea mays L.) in the region. The results revealed that, use of straw mulches significantly increased the yield attributes of baby corn. Significantly higher yields of green baby cob (10.8 t/ha), baby corn (1.84 t/ha) and green fodders (34.65 t/ha) were recorded with application of 1.0 t lime/ha but was on a par with 0.5 t lime/ha. Similarly, higher yields of green baby cob (10.56 t/ha), baby corn (2.02 t/ha) and green fodder (34.95 t/ha) were noted with application of 100% recommended dose of fertilizer through inorganic sources (RDF (IN) + 25% RDF through organic sources (ON). Hence, use of straw mulch integrated with application of lime in furrow @ 1.0 t/ha along with 100% RDF (IN: N-P-K-S-Zn: represents 150-80-60-30-10 kg/ha) + 25% RDF (ON) may be adopted and promoted to achieve the maximum crop productivity of baby corn under the foot-hill condition of eastern Himalayas.

Effect of integrated weed management on turmeric under mid hill conditions of Himachal Pradesh

A field experiment was carried out on silty clay loam soil, acidic in reaction, high in available phosphorus, medium in available potassium and low in available N during kharif 2017 at the Research Farm of Department of Agronomy, CSKHPKV, Palampur to study effective weed control strategy for this important crop. The results revealed that Alternanthera philoxeroides was the major weed constituting 16% of the total weed flora. This was followed by Cynodon dactylon and Echinochloa colona with 14 and 12% of total weed population, respectively. The count of Echinochloa colona, Alternanthera philoxeroides, Commelina benghalensis, Digitaria sanguinalis and Ageratum conyzoides was maximum at 120 DAP and there after it gradually decreased. All herbicide treatments brought significant reduction in the count on Echinochloa, Alternanthera and Ageratum over weedy check. The lowest count of these weeds was recorded in metribuzin fb straw mulch fb hand weeding and the maximum count was in case of weedy check. All the weed control treatments significantly reduced the total weed count and dry weight of weeds as compared to the weedy check. Amongst different herbicide treatments application of metribuzin @ 0.70 kg/ha fb straw mulch fb hand weeding resulted in significantly lowest weed count at all stages of observation as well as at harvest though this treatment was at par with metribuzin @ 0.70 kg/ha fb two hand weedings and treatments in which atrazine 0.75 kg/ha and hand weedings were applied with or without the use of straw mulch resulted in significantly lower dry matter accumulation by weeds as compared to other herbicide treatments. Weed index calculated at 120 DAP was highest with use of metribuzin @ 0.70 kg/ha and atrazine @ 0.75 kg/ha used along with straw mulch and one or two hand weedings proving effective as compared to other herbicides tested. From the present study it seems that mulching must be included in any effective weed management strategy for turmeric. Also among different herbicides metribuzin and atrazine are effective and their integration with mulching and/or hand weeding gave good control of weeds in turmeric.

Earthworm Abundance Changes Depending on Soil Management Practices in Slovenian Vineyards

Earthworms are key indicators of soil quality and health in vineyards, but research that considers different soil management systems, especially in Slovenian viticultural areas is scarce. In this investigation, the impact of different soil management practices such as permanent green cover, the use of herbicides in row and inter-row areas, use of straw mulch, and shallow soil tillage compared to meadow control for earthworm abundance, were assessed. The biomass and abundance of earthworms (m2) and distribution in various soil layers were quantified for three years. Monitoring and a survey covering 22 May 2014 to 5 October 2016 in seven different sampling dates, along with a soil profile at the depth from 0 to 60 cm, were carried out. Our results showed that the lowest mean abundance and biomass of earthworms in all sampling periods were registered along the herbicide strip (within the rows). The highest abundance was found in the straw mulch and permanent green cover treatments (higher than in the control). On the plots where the herbicide was applied to the complete inter-row area, the abundance of the earthworm community decreased from the beginning to the end of the monitoring period. In contrast, shallow tillage showed a similar trend of declining earthworm abundance, which could indicate a deterioration of soil biodiversity conditions. We concluded that different soil management practices greatly affect the soil’s environmental conditions (temperature and humidity), especially in the upper soil layer (up to 15 cm deep), which affects the abundance of the earthworm community. Our results demonstrated that these practices need to be adapted to the climate and weather conditions, and also to human impacts.

The Use of Straw Mulches to Mitigate Soil Erosion under Different Antecedent Soil Moistures

Straw mulch cover is one of the most important soil erosion control measures applied to reduce runoff and soil loss in cultivated areas. However, in developing countries such as Iran, without a clear tradition or knowledge about soil erosion control measures, the use of straw mulch is rare, and its impact in the most extended crops is not well understood. We investigated the separate and combined effects of colza (Brassica napus L.) and corn (Zea mays L.), to mitigate the activation of soil loss and runoff in sandy-loam soils, under different antecedent soil moisture conditions, in a rainfed plot in Northern Iran. Under laboratory conditions, we used a rainfall simulator device. The experiments were performed by using a rainfall intensity of 50 mm h−1, with a duration of 10 min and an inclination of 30%, with three replications. These conditions were used to evaluate the soils under extreme meteorological and topographical conditions. Two types of straw mulch, colza and corn, separated and combined with three different cover levels (25, 50 and 75%) and four distinct antecedent soil moisture conditions (0, 15, 20 and 30%), were used. The results showed that the applied straw mulches had significant effects on the reduction of soil loss and sediment concentration, by almost 99%. The maximum reduction of soil loss and sediment concentration was observed for the treatments with 0% moisture and 75% of corn, colza + corn and colza, with a reduction of 93.8, 92.2 and 84.9% for soil loss, respectively, and 91.1, 85.7 and, 60.7% for sediment concentration, respectively. The maximum reduction of runoff was also obtained with 0% soil moisture and a cover of 75%, reducing 62.5, 48.5 and 34.8% for colza, colza + corn and corn, respectively. The corn straw mulch showed the highest effectivity on reducing soil loss and sediment concentration toward colza treatment. But the colza straw mulch showed the best results on reducing runoff toward corn treatment. We conclude that the application of straw mulch is affordable and useful in reducing soil loss and runoff, instead of bare soils.

Integrated use of straw mulch with nitrogen fertilizer improves soil functionality and soybean production

Mulching can effectively maintain and improve soil health and functionality. The mechanisms, however, have not been fully elucidated. Therefore, the effects of temperature on the biogeochemical properties of soil were investigated in the present study in relation to nitrogen management and soil functionality. The results of the 3-year field experiments showed that integrated straw mulch (S) and nitrogen fertilizer (N) treatments enhanced the activities of soil urease, invertase, alkaline phosphatase, and catalase by >1.8, 2.1, 2.0 and 1.4 fold, respectively, compared with the control treatment. Furthermore, these treatments increased soil available N by 28%, phosphorus by 45%, and potassium by 55%. In general, the soil organic carbon, dissolved carbon and labile organic carbon content in the treated plot were approximately 1.2–2.9 folds greater than in the control plot. These improvements in soil fertility and carbon indices increased the biomass and grain yield of soybean (67 and 75%, respectively) during the three-year study period. During 2015–2017, the straw mulch and nitrogen fertilizer treatment increased the soil moisture (23%) and decreased the soil temperature (8%) in comparison to the control in the 0–0.2 m soil depth and, therefore, improved soil enzyme activities, nutrient availability, and carbon stocks, and ultimately, soil functionality and sustainability, in the semiarid region.

The potential of straw mulch as a nature‐based solution for soil erosion in olive plantation treated with glyphosate: A biophysical and socioeconomic assessment

AbstractFifty paired plots under simulated rainfall showed that the use of a cover of straw mulch of 50% (1 mg ha−1) in olive orchards results in a reduction of soil erosion. An economic survey based on interviews shows that the use of straw mulch in olive plantation would cost €174.7 ha−1, from which €54.7 ha−1 is needed for the application work, €52.3 ha−1 for the purchase cost, and €67.7 ha−1 for the transport of 20‐kg bales. The cost of the straw is 22.5% of the total income of the farmers. We found that their perception was negative about the use of straw mulch, as the tradition is to keep the soil clean from any weed or cover, except the crop. However, farmers would use it if they would be subsidized with a minimum of €267 ha−1, which is €92 ha−1 more than the costs estimated on the basis of the surveys. We conclude that soil erosion can be controlled with the use of straw mulch but that to convince farmers to adopt this management strategy, it needs to be subsidized.

Straw mulch as a sustainable solution to decrease runoff and erosion in glyphosate-treated clementine plantations in Eastern Spain. An assessment using rainfall simulation experiments

In many Mediterranean areas, citrus orchards exhibit high soil loss rates because of the expansion of drip irrigation that allows cultivation on sloping terrain and the widespread use of glyphosate. To mitigate these non-sustainable soil losses, straw mulch could be applied as an efficient solution but this has been poorly studied. Therefore, the main goal of this paper was to assess the use of straw mulch as a tool to reduce soil losses in clementine plantations, which can be considered representative of a typical Mediterranean citrus orchard. A total of 40 rainfall simulation experiments were carried out on 20 pairs of neighbouring bare and mulched plots. Each experiment involved applying 38.8 mm of rain at a constant rate over 1 h to a circular plot of 0.28 m2 circular plots. The results showed that a cover of 50% of straw (60 g m−2) was able to delay the time to ponding from 32 to 52 s and the time to runoff initiation from 57 to 129 s. Also, the mulching reduced the runoff coefficient from 65.6 to 50.5%. The effect on sediment transport was even more pronounced, as the straw mulch reduced the sediment concentration from 16.7 g l−1 to 3.6 g l−1 and the soil erosion rates from 439 g to 73 g. Our results indicated that mulching can be used as a useful management practice to control soil erosion rates due to the immediate effect on high soil detachment rate and runoff initiation reduction in conventional clementine orchards on sloping land, by slowing down runoff initiation and by reducing runoff generation and, especially, sediment losses. We indirectly concluded that straw mulch is also a sustainable solution in glyphosate-treated citrus plantations.

Growth and yield of patchouli (Pogostemon cablin, Benth) due to mulching and method of fertilizer on rain-fed land

The drought stress that occurs during growth results in a drastic reduction in growth and yield. This study was aimed to study the effect of mulching and method of fertilizer application in reducing the impact of drought stress on patchouli plants. The experiment was conducted from July to December 2016 using a split plot design into three replications with two treatment factors. The first factor was mulch factor with three levels, i.e. M0 (without mulch), M1 (rice straw mulch) and M2 (silver black plastic mulch). The second factor was the method of fertilizer application consisting of three stages: C1 (once), C2 (twice), C3 (three times). The parameters included plant height, number of branches, number of leaves, root length, wet weight of plant, root canopy ratio, total of chlorophyll, soil temperature and soil moisture content. The results showed the use of straw mulch reduce the impact of drought stress on patchouli plants. Two times fertilizer application gave better growth and yield. The use of straw mulch produced lower temperature degrees and maintained soil moisture content.

The immediate effectiveness of barley straw mulch in reducing soil erodibility and surface runoff generation in Mediterranean vineyards

Soil and water loss in agriculture is a major problem throughout the world, and especially in Mediterranean areas. Non-conservation agricultural practices have further aggravated the situation, especially in vineyards, which are affected by one of the highest rates of soil loss among cultivated lands. Therefore, it is necessary to find the right soil practices for more sustainable viticulture. In this regard, straw mulching has proven to be effective in other crop and fire affected soils, but, nonetheless, little research has been carried out in vineyards. This research tests the effect of barley straw mulching on soil erosion and surface runoff on vineyards in Eastern Spain where the soil and water losses are non-sustainable. An experiment was setup using rainfall simulation tests at 55mmh−1 over 1h on forty paired plots of 0.24m2: twenty bare and twenty straw covered. Straw cover varied from 48 to 90% with a median value of 59% as a result of the application of 75g of straw per m2. The use of straw mulch resulted in delayed ponding and runoff generation and, as a consequence, the median water loss decreased from 52.59 to 39.27% of the total rainfall. The straw cover reduced the median sediment concentration in runoff from 9.8 to 3.0gL−1 and the median total sediment detached from 70.34 to 15.62g per experiment. The median soil erosion rate decreased from 2.81 to 0.63Mgha−1h−1 due to the straw mulch protection. Straw mulch is very effective in reducing soil erodibility and surface runoff, and this benefit was achieved immediately after the application of the straw.

Effects of soil deformation and surface mulching on soil physical properties and soybean response related to weather conditions

A field experiment was conducted on Haplic Luvisol developed from loess to assess the effects of soil deformation and straw mulch on soil water status (matric potential), temperature, penetration resistance, soybean growth, seed yield and yield components including straw, protein and oil in 2006–2008. Water use efficiencies related to the amount of rainfall during the growing seasons were calculated for seeds and total above ground biomass. The soil deformation levels (main plots) comprised the following trials: non-compacted (NC, 0 tractor pass), moderately compacted (MC, 3 passes), and strongly compacted (SC, 5 passes). A uniform seedbed in all plots was prepared by harrowing before planting. The main plots included sub-plots without and with surface wheat straw mulch (0.5kgm−2) and the corresponding trials were NC+M, MC+M, SC+M. The amount and distribution of rainfall during the growing season differed among the experimental years with extended drought at bloom-full seed (R2-R6) stages in 2006, good water supply in 2007, and alternative periods with relatively high and low rainfalls in 2008. The effect of soil deformation on matric potential was influenced by weather conditions, soybean growth phase, mulching and depth. The differences were greatest in 2007 and 2008 at R7-R8 growth stages. With increasing deformation level from NC to SC matric potential for 0–15cm depth during these stages significantly decreased from −401 to −1184kPa in 2007 and from −1154 to −1432kPa in 2008. On mulched soil, the corresponding ranges were from −541 to −841kPa and from −748 to −1386kPa, respectively. In the dry summer 2006, the differences were smaller and less consistent. Irrespective of soil deformation level, mulching reduced soil temperature in most growth phases but most pronounced initially. Most yield components increased from NC to MC during the experiments which could be attributed to enhanced root water and nutrient uptake rates and decreased from MC to SC due to high soil strength that restrained root growth down to deeper depth. The yields of seeds, straw, protein and oil as well as water productivity of soybean seed and biomass were improved by mulching in 2007–2008. This improvement was more pronounced in 2007 when the mean yield of seeds, protein and oil were significantly greater by 16, 29 and 11%, respectively and was attributed to positive alterations in soil water retention. These results indicate the possibilities of improvement in soybean performance by identifying allowable amount of traffic and mulching practices at planting depending on weather fluctuations during the growing season. Since rainfall and air temperature distribution in 2007 are close to those averaged over a long period of time, the use of straw mulch may positively affect soybean performance and yields excluding anomalously dry years. The positive effect of straw mulch can be enhanced by moderate soil deformation combined with seedbed loosening before planting to avoid constraining effect of soil structure on crop establishment.

Influence of mulches on urban vegetation construction in coastal saline land under drip irrigation in North China

In order to generate information for reclaiming coastal saline sandy-loam soil for urban vegetation construction around Bohai Bay in North China, a field experiment combined with drip irrigation and setting a gravel–sand layer beneath the saline soil but above the water table was conducted to study the effect of mulches on irrigated water amount, soil salt control and willow (Salix babylonica L.) growth, and construction costs were also estimated during 2012 and 2013. The three mulch treatments were control treatment with no mulch (C1), black shading net mulch (C2) and straw mulch (C3). In order to leach salts in the soil profile, irrigation was triggered by the soil matric potential threshold at 20-cm soil depth of −5kPa in the early stage, and this was changed to −10kPa until the end of the first growing year, and to −20kPa for the second year. The results showed that (1) the straw mulch consumed the least irrigation water, followed by the black shading net mulch and the control treatment. Compared to the control treatment, the amount of irrigation for the straw mulch had decreased by 12% in 2012 and 27% in 2013. (2) The salinity reduction was mainly related to rainfall and the strategy of drip irrigation; and the mulches, especially straw mulch, decreased the risk of salt accumulation in early spring. (3) The best growth characteristic of plants and the optimal investment cost were for straw mulch, and the high investment cost in 2012 was due to soil preparation cost and the willows, gravel and sand cost was high and then it had decreased by 90% in 2013. From the combined points of water saving, plant growth and investment cost, the use of straw mulch with drip irrigation could aid in urban vegetation construction on coastal saline land in North China.

Septoria leaf spot in organic tomatoes under diverse irrigation systems and water management strategies

The objective of this study was to analyze the temporal progress of septoria leaf spot of tomato, caused by Septoria lycopersici, in different irrigation systems. The experiment was carried out in an organic farming system, in a randomized block design with three replicates. Six irrigation systems were evaluated: GO1L: one drip-line per row of plants; GO2L: two drip-lines; SU: furrow; MIsub: microsprinkler below plant canopy; MIalta: microsprinkler above plant canopy; AS: overhead sprinkler irrigation. Water management strategies varied with soil moisture tensions. Irrigation by drip systems was carried out when soil water tensions reached 15-30 kPa (high moisture), whereas for SU the trigger soil tension was 30-60 kPa (moderate moisture). All other systems were conducted at both soil water tension ranges. One additional treatment was conducted with overhead sprinkler, high soil moisture and straw mulch (ASpalha). The disease manifested itself by natural infection, and quantification was carried out weekly from the onset of symptoms. Disease severity was estimated at the halfway point (Y50) and at the end (Ymax) of the time-course of the epidemics, and the area under the disease progress curve was also calculated (AUDPC). Disease progress analysis was done after fitting severity data to the Gompertz model. Highest Ymax (30-35%) values were found in the AS systems, while the lowest severities were associated with MI (6-10%), GO and SU (4%), indicating that the smaller the water drop size, the lower the disease severity. To a lesser extent, higher frequencies of irrigation in the AS and MI systems also favored higher disease levels. The use of straw mulch (ASpalha) significantly reduced Y50 and AUDPC, when compared to AS.

The Effects of Straw Mulching on Post-Wildfire Vegetation Recovery in South Eastern British Columbia

Following the severe wildfire season of 2007 in southeastern British Columbia, straw mulching was used to stabilize soil on burned hillslopes and to reduce the risk of debris flows and flooding after the fires. The effects of the straw mulch on vegetation recovery and the introduction of invasive species were studied in two elevation classes over 2 years following the fires. The study measured percent of live vegetation cover including native, non-native, and invasive species in mulched and untreated control plots in highseverity burns. Total percent vegetation cover was not significantly different between treatments in either elevation class. A slightly slower rate of vegetation growth in mulched sites may suggest that mulch inhibits growth. Invasive species were present prior to mulching in both elevation classes. In the lowelevation class, the invasive species cover increased in both treated and control plots and in both years of the study. High-elevation plots showed a decrease in invasive species in the second year. Non-native species introduced with the mulch did not increase after the first year in either elevation class. This study shows that the use of straw mulch as an erosion control treatment has minimal effects on vegetation growth, but considerable effort should be taken to access mulch that does not contain seed to prevent the introduction of invasive species.

Impact of Straw Mulch on Populations of Onion Thrips (Thysanoptera: Thripidae) in Onion

Development of insecticide resistance in onion thrips, Thrips tabaci Lindeman (Thysanoptera: Thripidae), populations in onion (Allium spp.) fields and the incidence of the T. tabaci transmitted Iris yellow spot virus have stimulated interest in evaluating alternative management tactics. Effects of straw mulch applied in commercial onion fields in muck areas of western New York were assessed in 2006 and 2007 as a possible onion thrips management strategy. In trials in which no insecticides were applied for thrips control, straw mulch-treated plots supported significantly lower T. tabaci populations compared with control plots. In both years, the action thresholds of one or three larvae per leaf were reached in straw mulch treatments between 7 and 14 d later than in the control. Ground predatory fauna, as evaluated by pitfall trapping, was not increased by straw mulch in 2006; however, populations of the common predatory thrips Aeolothrips fasciatus (L.) (Thysanoptera: Aeolothripidae) were significantly lower in straw mulch plots in both years. Interference of straw mulch in the pupation and emergence of T. tabaci was investigated in the lab and their emergence was reduced by 54% compared with bare soil. In the field the overall yield of onions was not affected by the straw mulch treatment; however, the presence of jumbo grade onions (>77 mm) was increased in 2006, but not in 2007. These results indicate that populations of T. tabaci adults and larvae can be significantly reduced by the use of straw mulch without compromising overall onion yield. The use of this cultural practice in an onion integrated pest management program seems promising.

On the Use of Shallow Basins to Restore Cutover Peatlands: Plant Establishment

Abstract Since the early 1990s, restoration techniques have been developed for milled and cutover peatlands in eastern Canada. These techniques are based on the active reintroduction of peatland plant diaspores, blocking drainage, and the use of straw mulch to improve surface conditions. This study examines the effectiveness of using shallow (20 cm deep) basins of various widths to improve the success of current peatland restoration techniques. It comprises three different experiments, each spanning three or four growing seasons and combining both small‐scale manual and large‐scale mechanized plant reintroductions. Cover data recorded in two of the experiments were regressed against a series of environmental factors to determine how Sphagnum establishment success was related to abiotic variables such as moisture, water ponding, surface roughness, and mulch cover. Results of these experiments demonstrate that shallow basins were generally effective at promoting Sphagnum establishment and that this effect extends beyond the positive impact that basins have on hydrological conditions. Basins of various widths were equally successful. Soil‐moisture content (linear positive effect) and duration and severity of flooding events (quadratic effect) were shown to be determinant of plant recovery. Other factors such as the density of straw cover (positive effect) and surface roughness (negative effect) were also instrumental in explaining local variation in Sphagnum cover. Plant cover after three and four growing seasons averaged 20–25% in mechanical reintroductions and 40–60% in manual reintroductions, demonstrating the overall effectiveness of the restoration techniques used.

Evaluation of improved management technologies and linseed (Linum usitatissimum) cultivars in salt-affected soils under rainfed condition

Eight and twelve on farm trials were conducted during the winter (rabl) season of 2001-2002 and 2002-2003, respectively, to evaluate the improved management technologies and promising linseed (Linum usistatissimum L.) cultivars in salt-affected soils under rainfed condition. lmproved management technologies consisting of line or seed drill sowing, application of FYM @ 2 tonneslha a month before sowing and use of straw mulch after sowing proved superior to traditional practices adopted by the farmers. 'Padmini' variety followed by 'SWeta' and vice-versa proved superior to 'Bijuri Local' with improved management technology in comparison to farmers' practices. 'Padmini' having markedly higher dry matter, number of branches and capsuleslplant with dwarf plants utilized soil moisture more efficiently under rainfed condition and showed better tolerance to salts compared to 'Sweta' and 'Bijuri Local'.

Interaction of Mulch and Bacillus thuringiensis subsp. tenebrionis on Colorado Potato Beetle (Coleoptera: Chrysomelidae) Populations and Damage in Potato

The use of straw mulch and no-mulch, a synthetic pyrethroid (esfenvalerate, Asana XL) and a bioinsecticide, Bacillus thuringiensis subsp. tenebrionis, were compared for their main and interactive effects on Colorado potato beetle, Leptinotarsa decemlineata (Say), populations in potato, Solanum tuberosum L. Numbers of Colorado potato beetle adults and egg masses were not significantly different in mulch versus no-mulch plots. There were fewer adults and egg masses in Asana-treated plots than in plots treated with B. thuringiensis (Mtrak) or the control (untreated). Significantly fewer small (1st and 2nd instars) and large (3rd and 4th instars) larvae were recorded in mulch treatments than in no-mulch treatments, and significantly fewer small and large larvae in Asana-treated plots compared with M-trak or untreated plots. However, the M-trak plots had significantly fewer large larvae than the untreated plots. Defoliation levels were significantly greater in no-mulch plots than mulch plots. Defoliation levels were significantly lower in Asana plots compared with M-trak or untreated plots. There was a significant interaction between mulch plus M-trak. This combination had numbers of large larvae, defoliation levels and yields as low as the Asana treatment. M-trak had its greatest effect on 1st instars and neonates, and did not affect natural enemies.

MODELING POTENTIAL IMPACTS OF LAND DEVELOPMENT ON SEDIMENT YIELDS

To assist land-use managers in addressing the problem of erosion, a computer simulation model (SEDCAD) can be used to determine the effectiveness of well-applied erosion-control practices in reducing the loss of soil from actively developing sites. The program includes procedures based on a modified version of the Universal Soil Loss Equation, which is widely used by water resource managers to estimate soil erosion rates over a range of spatial scales. For a construction site in northeastern Ohio, the computer program SEDCAD was used to estimate the changes in off-site sediment delivery that occur when the soil on the site is completely exposed as a result of clearing, grading, and other construction activities. Assuming application of erosion-control best-management practices, ranging from the use of straw mulch to the use of a sediment basin, SEDCAD simulation results indicate that proper management practices can reduce sediment delivery to wetlands adjacent to this site to pre-development levels. This ...