• Authors:
    • Sarma, K. K.
    • Debnath, M. C.
    • Borah, B. K.
    • Das, B.
  • Source: Insect Environment
  • Volume: 15
  • Issue: 4
  • Year: 2010
  • Summary: Gram pod borer, Helicoverpa armigera Hubner is the most important pest on chickpea. The present study was undertaken to study the effect of different intercrops on the incidence of gram pod borer on chickpea. The experiment was conducted at Regional Agricultural Research Station, Shillongani, Nagaon (North-east India) in rabi season, 2007-2008. Seven crops were used as intercrops viz., linseed, marigold, wheat, mustard, fennel, coriander and garlic. The chickpea variety, PantG-186 was sown in 5 x 4m size plots and the ratio with intercrop was 4:1, except the sole crop which was used as check. Each intercrop was replicated thrice in RBD. Recommended package of practices were followed. For observation of larvae, ten plants were selected randomly from each plot and their count was recorded weekly. Similarly, for pod damage, ten plants randomly selected were uprooted at harvest and per cent pod damage was assessed by counting all the pods.
  • Authors:
    • Oliveira, O. L. P. de
    • Melo, G. W. B. de
    • Botton, M.
    • Onzi, I.
  • Source: ACTA SCIENTIARUM-AGRONOMY
  • Volume: 32
  • Issue: 4
  • Year: 2010
  • Summary: The use of cover crops is an important strategy to reduce erosion and improve chemical and physical soil properties. In this work, we evaluate the effect of cover crops to reduce Brazilian ground pearl Eurhizococcus brasiliensis (Hemiptera: Margarodidae) infestation in vineyards. In the first experiment, glyphosate was sprayed each three months to avoid cover crops. This treatment was compared with naturally occurring vegetation during the year and the use of Avena sativa in the winter. In a second experiment, Stizolobium aterrimum was cultivated during the summer compared with naturally occurring vegetation. Brazilian ground pearl population was higher in glyphosate sprayed areas than where cover crops were maintained during the year. No differences in inssect infestation were observed between naturally occurring vegetation and A. sativa during the winter. Scale infestation where S. aterrimum was cultivated during the summer was similar to naturally occurring vegetation. S. aterrimum is registered for the first time as a host of E. brasiliensis.
  • Authors:
    • Wang, J.
    • Jolliffe, P.
    • Kimmins, J.
    • Cao, F.
  • Source: Agroforestry Systems
  • Volume: 79
  • Issue: 3
  • Year: 2010
  • Summary: Ginkgo ( Ginkgo biloba L.) is a multi-value deciduous tree species grown for the production of nuts, timber and foliage for medicinal products. Understanding the ecological and biological basis for Ginkgo agroforestry systems is essential for the design of optimum Ginkgo-crop species combinations. We established two greenhouse replacement series to examine interactions between Ginkgo and wheat ( Triticum aestivum L.); and Ginkgo and broad bean ( Vicia faba L.). The results showed that crop species were more competitive than Ginkgo at low Ginkgo density, but less competitive than Ginkgo at high Ginkgo density. Ginkgo: wheat ratio 5:1 and Ginkgo: broad bean ratio 5:1 had relative yield total (RYT) and relative land output (RLO) values of more than one and the largest total land output (TLO) values in respective mixtures. Therefore, these two ratios might be considered optimum Ginkgo: crop ratio for enhancing the combined biomass of the Ginkgo and crop in respective mixtures. Broad bean and wheat were more competitive than Ginkgo, which was less affected by wheat than by broad bean. However, there were compensatory interactions between Ginkgo and wheat, and Ginkgo and broad bean. There was significant belowground competition for soil N between Ginkgo and the two crop species in the Ginkgo/crop mixtures. The two mixtures outperformed monocultures of the individual species when comparing the mixtures with the crop monoculture system.
  • Authors:
    • Conte, O.
    • Levien, R.
    • Trein, C.
    • Cepik, C.
  • Source: REVISTA BRASILEIRA DE ENGENHARIA AGRICOLA E AMBIENTAL
  • Volume: 14
  • Issue: 5
  • Year: 2010
  • Summary: No tillage implies keeping the soil surface covered with crops or crop residues, which might influence planter performance. Using fixed shanks as furrow openers to place fertiliser is an alternative to minimize compaction, as it mobilizes the soil in the sowing line. The aim of this research was to evaluate the effect of different amounts of winter cover crop residues evenly distributed on the soil, the effect of the shanks working depth and quantity of planter lines on power demand, cross sectional furrow area and total volume of soil mobilized in the lines and corresponding wheel slippage in distrophic red Argisol. During winter, black oats and black oats plus turnip were used as cover crops before maize and beans, respectively. Increasing the working depth showed an increase in power demand, as measured directly at the shanks (three lines for maize and five for beans). There was also an effect of residue, increasing power demand on the shanks, but only measurable with the planter operating with three lines in maize sowing. Soil mobilization in the sowing lines was influenced by the amount of residues, the working depths of shank and the quantity of planter lines. Wheel slippage was higher with larger amounts of soil cover residues and when power demand was higher.
  • Authors:
    • Vieira, F. C. B.
    • Flores, J. P. C.
    • Anghinoni, I.
    • Souza, E. D.
    • Costa, S. E. V. G. A.
    • Martins, A. P.
    • Ferreira, E. V. O.
  • Source: Soil & Tillage Research
  • Volume: 109
  • Issue: 1
  • Year: 2010
  • Summary: The distribution of phosphorus in the soil profile as a function of soil tillage, fertilizer management system and cultivation time is strongly related to root distribution. As the dynamics of this process are not well understood, long-term experiments are useful to clarify the cumulative effect through time. The study evaluated an 18-year-old experiment carried out on Rhodic Paleudult soil, located in Rio Grande do Sul state - Brazil, with cover crops (black oat and vetch) in the winter and corn in the summer. In the 0- to 20-cm layer, the amounts of clay, silt and sand were 22, 14, and 64 g kg -1, respectively. This layer had a mean slope of 3%. The mean local annual rainfall is 1440 mm. The climate is subtropical with a warm humid summer (Cfa), according to the Koeppen classification. The treatments consisted of three soil managements (conventional tillage, no tillage and strip tillage) and three application modes (broadcast, row and strip) for triple superphosphate and potassium chloride fertilizers. Data for phosphorus and root distribution in the soil from the 1989/90, 1999/00 and 2006/07 growing seasons were used. Phosphorus stratification occurred through time, irrespective of soil and fertilizer management, mainly in the 0- to 5-cm layer. The tillage and fertilization systems promoted significant differences in the Pi and Pt fractions up to a depth of 20 cm. For the Po fraction, significant differences were found only in the 0- to 5- and 15- to 20-cm layers. Inorganic phosphorus accumulated in the fertilized zone (0-10 cm), with higher intensity in the no-tillage system under row fertilization with values around 150 mg dm -3. Root distribution presented a strong positive relationship with phosphorus distribution, exhibiting redistribution in the soil profile through time. This redistribution was accompanied by increases in organic phosphorus and total organic carbon content. Corn grain yield was not affected by long-term tillage systems.
  • Authors:
    • Hoffmann, A. A.
    • Penfold, C. M.
    • Sharley, D. J.
    • Thomson, L. J.
    • Danne, A.
  • Source: Environmental Entomology
  • Volume: 39
  • Issue: 3
  • Year: 2010
  • Summary: Indigenous cover crops have the potential to promote an increase in natural enemies providing fortuitous control of pest species and other ecosystem services. We test this idea in a vineyard in south eastern Australia, where reduced water availability because of drought coupled with increased temperatures has generated interest in sustainable alternatives to the exotic perennial cover crops commonly planted. Three endemic perennial cover crops, comprising the grasses Austrodanthonia richardsonii and Chloris truncata and a mix of two saltbushes ( Atriplex semibaccata and Atriplex suberecta) were established as cover crops and compared with introduced oats ( Avena sativa). Abundance of a range of predators and parasitoids was higher in vines with native cover crops compared with the oat control. In addition, predation levels of sentinel eggs of a common vineyard pest, light brown apple moth ( Epiphyas postvittana), were increased in the native cover crops. However, the native cover crops also increased the abundance of some potential pest species. Native plants therefore have potential to increase abundance of beneficial invertebrates that assist in pest control, but need to be used carefully to ensure that they do not increase local pest problems.
  • Authors:
    • Karmakar, R.
    • Das, S. K.
    • Das, I.
  • Source: SATSA Mukhaptra Annual Technical Issue
  • Volume: 14
  • Year: 2010
  • Summary: In India, rice-wheat cropping system (RWCS) has contributed and will continue to contribute largely towards food security. Well-planned steps are necessary to make it sustainable and more productive without any adverse effects on the natural resources and the environment. Past studies indicate that sustainability of RWCS in the Indo-Gangetic Plains is at risk mainly due to decline in groundwater levels, soil organic matter content and nutrient availability, increased soil salinization and pest incidence. Practices for sustainable management diversified crop rotations that enhance soil cover and fertility, and accelarated adoption of resource conserving technologies like zero-tillage, bed planting, laser leveling, surface seeding, intercropping of high value crops, furrow irrigated raised bed planting technique, etc., all of which have been briefed in the present paper.
  • Authors:
    • Conte, O.
    • Trein, C. R.
    • Levien, R.
    • Debiasi, H.
    • Kamimura, K. M.
  • Source: PESQUISA AGROPECUARIA BRASILEIRA
  • Volume: 45
  • Issue: 6
  • Year: 2010
  • Summary: The objective of this work was to evaluate the effect of soil winter covers and soil mechanical loosening on soybean and corn yield, in no-tillage system. Two experiments were carried out in Rio Grande do Sul state, Brazil, in a compacted Argissolo Vermelho (Haplic Acrisol), in the 2005/2006 and 2006/2007 crop seasons. The first experiment was carried out in a complete block design, with a split plot arrangement. The treatments were two theoretical working depths of a driller chisel-type furrow opener (0.06 and 0.12 m, split plot), and three soil winter covers (main plot): fallow, black oat ( Avena strigosa), and black oat+common vetch ( Vicia sativa). In 2006, the soil cover black oat+common vetch was replaced by oilseed radish ( Raphanus sativus). In the second experiment, in a complete block design, the soil was chiseled and treatments consisted of black oat or oilseed radish as winter cover crops. Cover crops reduced soil superficial (0-0,06 m) compaction compared to fallow and, in the 2005/2006-crop season, under low water availability, provided higher soybean and corn yields. In the 2006/2007-crop season, when water availability was higher, the same did not happen. Increasing working depths of the chisel-type furrow opener did not affect soybean or corn yields. Soil chiseling reduced soybean and corn yields in comparison to the continuous no-tillage system.
  • Authors:
    • Chen, L.
    • Sun, Q.
    • Li, H.
    • Fang, S.
  • Source: Agroforestry Systems
  • Volume: 79
  • Issue: 2
  • Year: 2010
  • Summary: The importance of agroforestry systems in CO 2 mitigation has become recognized worldwide in recent years. However, little is known about carbon (C) sequestered in poplar intercropping systems. This study aims compare the effects of three poplar intercropping designs (configuration A: 250 trees ha -1; configuration B: 167 trees ha -1 and configuration C: 94 trees ha -1) and two intercropping systems (wheat-maize cropping system and wheat-soybean cropping system) on biomass production and C stocks in poplar intercropping systems. The experiment was conducted at Suqian Ecological Demonstration Garden of fast-growing poplar plantations in northwestern Jiangsu, China. A significant difference in C concentration was observed among the poplar biomass components investigated ( P≤0.05), with the highest value in stemwood and the lowest in fine roots, ranging from 459.9 to 526.7 g kg -1. There was also a significant difference in C concentration among the different crop components ( P≤0.05), and the highest concentration was observed in the maize ear. Over the 5-year period, the total poplar biomass increased with increasing tree density, ranging from 8.77 to 15.12 tonnes ha -1, while annual biomass production among the crops ranged from 4.69 to 16.58 tonnes ha -1 in the three configurations. Overall, total C stock in the poplar intercropping system was affected by configurations and cropping systems, and configuration A obtained the largest total C stock, reaching 16.7 tonnes C ha -1 for the wheat-soybean cropping system and 18.9 tonnes C ha -1 for the wheat-maize cropping system. Results from this case study suggest that configuration A was a relative optimum poplar intercropping system both for economic benefits and for C sequestration.
  • Authors:
    • Miao, G.
    • Gao, Z.
    • Guo, C.
  • Source: Acta Agronomica Sinica
  • Volume: 36
  • Issue: 4
  • Year: 2010
  • Summary: Shading post flowering, caused by cloudy weather and the surrounding protective trees, often occurs in some wheat ( Triticum aestivum L.) area in north China. In general, wheat yield is negatively influenced by shading post flowering, but the effect on grain quality is reported discrepantly. This study aimed at disclosing the effects of post-flowering shading on photosynthesis of leaf and yield and quality of grain in wheat, accordingly, giving suggestions to wheat production. Three treatments were designed with shading of 20%, 50%, and 80% for 30 d, respectively. The normal condition was taken as the control. The results showed that shading treatments had significant influences on photosynthetic characteristics of flag leaf. The shading treatments increased the number of sterile spikelet and reduced the grain weight per spike and the 1000-grain weight. As a result, the grain yield of the three shading treatments significantly decreased by 27.6%, 49.0%, and 60.2% compared with the control. In the shading treatments, the contents of the chlorophylls a and b increased, whereas the ratio of chlorophyll a to chlorophyll b decreased. Moreover, the net photosynthetic rate, the stomatal conductance, and the transpiration rate were also significantly reduced, but the intercellular CO 2 concentration was promoted. The shading depression on net photosynthetic rate became smaller in the process of grain filling, with the largest effect at early stage of grain filling and the smallest effect at late stage of grain filling stage. The contents of protein, wet gluten, glutenin, gliadin and the ratio of glutenin to gliadin in grains increased significantly with the increase of shading. The shading influence on glutenin was greater than that on gliadin. Although the shading treatments decreased grain yield obviously, it raised some quality parameters, such as extensibility, development time, stability time, and water absorption of dough. The responses of yield and quality of wheat grain to shading were different because of the discrepant synthesis mechanisms of starch and protein under weak light condition. In wheat protective areas, yield is a priority factor and the tree-wheat intercropping mode should be avoided.