• Authors:
    • Varrelmann, M.
    • Buhre, C.
    • Kluth, C.
  • Source: Plant Pathology
  • Volume: 59
  • Issue: 4
  • Year: 2010
  • Summary: The susceptibility of intercrop species (Raphanus sativus, Brassica juncea, B. rapa, Sinapis alba and Phacelia tanacetifolia) to the sugar beet pathogen Rhizoctonia solani was investigated in vitro, in the greenhouse and in the field with artificial inoculation. Disease severity in subsequently cultivated sugar beet was monitored in the field. Differences in susceptibility between species were found to be consistent in all experimental systems. All intercrop species were susceptible to R. solani. Brassica rapa and R. sativus were less susceptible than P. tanacetifolia. Compared to fallow, the cultivation of B. rapa and R. sativus reduced disease severity in subsequently grown sugar beet (median ratings of up to 3.0 and 3.5, respectively, depending on environmental conditions). This resulted in higher white sugar yield compared to fallow (up to 210% and 157% for B. rapa and R. sativus, respectively). This study demonstrates that in vitro and greenhouse resistance tests are suitable systems to predict the effects of intercrop species susceptibility in the field on disease severity and white sugar yield in subsequently grown sugar beet. Intercrop breeding programmes might profit from fast and efficient screening tests to provide Rhizoctonia-resistant intercrops as an additional control measure against R. solani in sugar beet.
  • Authors:
    • Bidders, C. L.
    • Laloy, E.
  • Source: Journal of Environmental Quality
  • Volume: 39
  • Issue: 3
  • Year: 2010
  • Summary: The management of winter cover crops is likely to influence their performance in reducing runoff and erosion during the intercropping period that precedes spring crops but also during the subsequent spring crop This study investigated the impact of two dates of destruction and burial of a rye (Secale cereale L.) and ryegrass (Lolium multifloruni Lint) cover crop on runoff and erosion, focusing on a continuous silage maize (Zea mays L) cropping system Thirty erosion plots with various intercrop management options were monitored for 3 yr at two sues. During the intercropping period. cover crops reduced runoff and erosion by more than 94% compared with muffled, post-maize harvest plots Rough tillage after maize harvest proved equally effective as a late sown cover crop There was no effect of cover crop destruction and burial dates on runoff and erosion during the intercropping period. probably because rough tillage for cover crop burial compensates for the lack of soil cover During two of the monitored maize seasons. it was observed that plots that had been covered during the previous intercropping period lost 40 to 90% less soil compared with maize plots that had been left bare during the intercropping period The burial of an aboveground cover crop biomass in excess of 1 5 t ha (1) was a necessary, yet not always sufficient. condition to induce a residual effect. Because of the possible beneficial residual effect of cover crop burial on erosion reduction, the sowing of a cover crop should be preferred over rough tillage after maize harvest
  • Authors:
    • Mechlia, N. B.
    • Nagaz, K.
    • Masmoudi, M. M.
  • Source: Options Méditerranéennes : Série A. Séminaires Méditerranéens
  • Issue: 95
  • Year: 2010
  • Summary: Climate change scenarios predict negative impacts on agriculture in the southern Mediterranean regions. Preparedness for increasingly frequent droughts requires a good knowledge on how chronic water shortages may affect production and cropping systems. This work investigates recent variations in agricultural production and in cropping practices in Tunisia as induced by a rapidly changing environment. Using production statistics and climatic records over the period 1984-2005, our analysis shows that variation of the agricultural production could be explained by the Standardized Precipitation Index (R 2=0.45), and that resilience to drought could be evaluated in the same manner. Data from surveys was used to identify adjustments adopted by farmers under the pressure of water scarcity in semi arid (Nabeul) and arid (Medenine) environments. Contrasting changes in cropping systems seem to be taking place for both regions. Contrast is also observed between irrigation strategies adopted by farmers. In Nabeul, large citrus growers having access to water from canal tend to over irrigate whenever water is available in order to minimize risks of water delivery failure from public networks. In contrast small farmers using shallow wells in Medenine seek practices such as deficit irrigation and intercropping in order to optimize water use. It is our view that options to face drought under increasing environmental stress should have a dynamic nature integrating adaptive practices used by farmers.
  • Authors:
    • Narwal, S. S.
  • Source: Allelopathy Journal
  • Volume: 25
  • Issue: 1
  • Year: 2010
  • Summary: To make our modem agriculture successful, the use of new agricultural technology in a short span of 35-40 years have caused havoc by contaminating our soil, environment and food with toxic pesticides residues. Modem agriculture is exploitive of growth resources and has caused very serious problems such as environmental pollution through (i). contamination of underground drinking water resources, food and fodder with pesticides and nitrates, which are harmful to 0 human beings and livestock, (ii). poor soil health/soil Sickness leading to low soil productivity and (iii). poor quality of life. These problems may be overcome with the adoption of Organic Agricultural practices. The definition of Organic Agriculture used in this paper is "Organic Agriculture consists of those practices, which reduces the use of outside inputs viz., fertilizers and pesticides etc on the farm". Therefore, various types of allelopathic strategies may be used for (a) maintenance of soil fertility (use of crop rotations, Biological Nitrogen Fixation, crop mixtures, crop residues and leaf litter etc.), (b) weed management (cover crops, crop residues as mulches, intercropping, crop rotations, phytotoxic or, allelopathic varieties and natural herbicides etc.), (c) insects pest management (cropping systems, resistant varieties, insecticidal allelochemicals etc.), (d) nematodes management (plant materials, oilseed cakes, nematicidal compounds etc.), (e) diseases management (cropping systems, crop residues, organic amendments etc.) and (f) use of allelochemicals as growth regulators. Therefore, research efforts are needed to utilise inhibitory allelopathic effects of plants for natural control of crop pests (weeds, insects, nematodes, pathogens), so that use of present pesticides could be minimized or eliminated for developing Sustainable Organic Agriculture, keeping the environment clean for our future generations and reducing the cost of Organic food.
  • Authors:
    • Pasricha, N. S.
  • Source: Journal of Oilseeds research
  • Volume: 27
  • Issue: 2
  • Year: 2010
  • Summary: A review of the recently published information on the nutritional aspects of oilseed crops in relation to their yield and quality reveals a substantial scope for increasing their production in the country. National self-sufficiency of edible oil would be enhanced if the productivity of the oilseed crops on marginal soils under rainfed conditions is increased through adoption of improved management technology and improved germplasm. This warrants intensive research efforts in these areas. Applying mineral fertilizers in balanced amounts and in an integrated manner by combining with bulky organic manures and crop residues can ensure sustainable production at higher productivity and higher quality level of the oilseed crops. For optimum utilization of other essential inputs, fertilizer requirements need to be fine tuned, especially in oilseed-based cropping systems and intercropping systems. Besides making best use of the applied nutrients, such management practices can substantially benefit the major cereal crops from the fixed-N, if the accompanying oilseed crop happens to be a leguminous like soybean and groundnut. Combining a cheap source of sulphur with other basic nutrients like nitrogen, phosphorus and potassium and required micronutrients like zinc is very essential in case of oilseeds for both yield and higher oil production under irrigated as well as rainfed conditions. To make best use of the soil-derived phosphorus, inoculation with naturally occurring phosphorus solubalizing micro-organism can be successfully employed.
  • Authors:
    • Portz, G.
    • Chagas, J. P.
    • Bagatini, T.
    • Cogo, Neroli P.
    • Portela, J. C.
  • Source: Revista Brasileira de Ciência do Solo
  • Volume: 34
  • Issue: 4
  • Year: 2010
  • Summary: Soil structure plays a prominent role in plant growth and erosion control, and consequently in food production and soil and water conservation. This research was developed with the objective of implementing and accompanying the restoration process of the structure of a degraded soil, by planting crop sequences under no-tillage (autumn-winter and spring-summer, grass and legume, in single and intercropped systems), and later verifying the relations with water and soil losses caused by rainfall erosion, under distinct surface physical conditions (untitled soil, with and without crust; freshly-tilled soil by chiseling and by chiseling followed by disking after one month, and crop residue covering 100, 18, and 0 %). The field study was developed under simulated rainfall, at the Agriculture Experimental Station of the Federal University of Rio Grande do Sul (EEA/UFRGS), in Rio Grande do Sul State, Brazil, from May 2004 to Decembe, 2007. The six erosion tests, in intervals of about a week, were performed from October to December, 2007. The soil used is an Ultisol, with a sandy clay loam texture in the surface layer and 0.115 in m(-1) average slope steepness, and an advanced degree of degradation. The rains were applied with a rotating-boom rainfall simulator, at a constant intensity of 64 mm h(-1), for 1-3 h. For this study, water and soil loss data were adjusted to a rainfall duration of 1.5 h. Properties of soil and plants were measured in the experimental plots and water erosion in the surface runoff The crop sequences and erosion tests influenced the results of the study significantly, with greater differences in the latter than in the former. The erosive process was more influenced by the external or soil surface than the internal or subsurface physical conditions. In general, all crop sequences were effective in restoring the soil structure in the experimental period. The sequence involving teosinte controlled the rainfall erosion process most effectively with regard to soil and water loss and the one involving corn+cowpea and pearl millet with regard to soil loss. The highest soil and water losses in the study were observed from the soil surface with no mobilization and little crop residue cover, regardless of the presence or type of crust, but especially when this latter was slightly cracked prior to rainfall application. The soil surface entirely covered by crop residue, be it untilled or freshly chiseled, controlled runoff effectively and impeded erosion completely. Soil and water losses from the freshly-disked soil surface chiseled a month earlier, although the soil was the most mobilized of all and bare, were practically zero, opposite to what was expected.
  • Authors:
    • Asgharipour, M.
    • Rafiei, M.
  • Source: Advances in Environmental Biology
  • Volume: 4
  • Issue: 3
  • Year: 2010
  • Summary: In search for sustainable agricultural methods for medicinal plants, a field experiment was conducted on isabgol-lentil mono and row intercropping, along with irrigation interval regimes (4-, 7- and 14-days irrigation interval) at the agricultural experimental farm of Zabol University during 2009. The experiment design was split-plot randomized complete block design with four replicates. Main plot treatments were giving irrigation at 4-, 7- and 14-days interval, and subplot treatments consisted of (a) sole isabgol; (b) sole lentil; (c) 1:1 isabgol-lentil intercropping system; (d) 1:3 isabgol-lentil intercropping system; and (e) 3:1 isabgol-lentil intercropping system. The results of the experiment confirmed that drought induced by increasing irrigation interval significantly decreased the growth of both crops and total N concentration of isabgol plants. Results also showed that lentil suppressed biological and grain yield of intercropped isabgol, but the reduction in isabgol yield was compensated by lentil grain yield. Isabgol biological and grain yield was significantly different across cropping systems and the yields were as follows: sole isabgol (281), 1:3 isabgol-lentil (93), 1:1 isabgol-lentil (191), and 3:1 isabgol-lentil (230). Lentil biological and grain yields was also significantly different across the treatments and was sole lentil (1096), 1:3 isabgol-lentil (846), 1:1 isabgol-lentil (644), and 3:1 isabgol-lentil (318). Intercropping isabgol and lentil increased the productivity with LER of 1.10, 1.27 and 1.11 for 1:3 isabgol-lentil, 1:1 isabgol-lentil and 3:1 isabgol-lentil, respectively. In intercrops a significant reduction in LAI, CGR, and also significant increase in leaf and tiller numbers per plant, plant height, spike length, spike numbers per plant, grain numbers per spike and 1000-grain weight of isabgol was observed over sole isabgol. These changes were proportional with row number of isabgol in intercropping. Significant interaction effect of cropping system by irrigation regimes on many cases of measured parameters showed intercropping protects plants from drought. Total concentration of N in isabgol were increased by intercropping, however cropping system by irrigation regimes interaction on N concentration was not significant. These findings suggest that intercropping isabgol-lentil at combination of 1:1 with 7-days irrigation interval may be recommended for yield advantage, more efficient utilization of resources and N concentration on hot and dry regions of South-East Iran.
  • Authors:
    • Razafimpamoa, L. H.
    • Randrianaivoarivony, J. M.
    • Rahetlah, V. B.
    • Ramalanjaona, V. L.
  • Source: African Journal of Food, Agriculture, Nutrition and Development
  • Volume: 10
  • Issue: 10
  • Year: 2010
  • Summary: Forage availability and quality during the dry and cool season is a major constraint to dairy development in the Highlands of Madagascar. The objective of the present study was to determine optimal seeding of oat and common vetch mixtures for increased production and quality of forage. The study was conducted under irrigated conditions in two agro-ecological zones of the Vakinankaratra region in the Highlands of Madagascar. Seed proportions studied were oat-vetch 100:0; 0:100; 50:50 and 50:75. Pure stands of oat and vetch were seeded at the rate of 100 and 60 kg ha -1, respectively. Standard fertilization for forage oat production was uniformly applied on each plot. Pure stands and mixtures were given two successive cuts at flag leaf stage of oat. For both sites and their average, dry matter (DM), feed unit for lactation (UFL), crude protein (CP), and protein digested in the small intestine (PDI) yields were not significantly (p>0.05) different among mixtures and pure stands. The highest yields were obtained from the 50:50 mixture at the first site and from the 50:75 mixture at the second site. According to the two sites' results' average, the highest DM (7.71 t ha -1), UFL (6.08*103 units ha -1), CP (1.64 t ha -1) and PDI (597.1 kg ha -1) yields were obtained from 50:50 mixture. There were no significant differences (p>0.05) in forage quality characteristics except for CP and protein digested in the small intestine when rumen-fermentable nitrogen is limiting (PDIN). Mean CP concentration varied from 15.20% for pure stand of oat to 27.01% for pure stand of vetch. The highest value (178.8 g/kg DM) and the lowest value (103.5 g/kg DM) in PDIN content were obtained from pure stand of oat and pure stand of vetch, respectively. Mixtures had 4.6 to 6.3% more CP content and 15.6 to 39.1% more PDIN content than pure stand of oat. Combined land equivalent ratio values exceeded unity in both mixtures which showed an advantage of intercropping over sole system in terms of the use of environmental resources. As intercropping of oat with vetch at 50:50 (50:30 kg ha -1) mixture achieved maximum yield advantage and forage quality, it could be used as alternative practice of oat sole cropping for high forage and protein production in the Vakinankaratra region.
  • Authors:
    • Shrivastava, G. K.
    • Lakpale, R.
    • Rathiya, P. S.
    • Bargali, S. S.
  • Source: Journal of Plant Development Sciences
  • Volume: 2
  • Issue: 1/2
  • Year: 2010
  • Summary: The field experiment was conducted during kharif season of 2004 and 2005 at the Instructional Farm, Indira Gandhi Agricultural University, Raipur (C.G.) to study the effect of nutrient blending with FYM and intercropping on biomass production and economics of hybrid cotton-soybean intercrops under irrigated condition. The growth characters of cotton like-plant height, number of branches, number of leaves, dry matter accumulation, LAI, CGR, and RGR were the highest with sole cotton with 100% RDF. In case of soybean, the growth parameters like-plant height, number of branches, number of leaves, dry matter accumulation, LAI, CGR, and RGR were the highest under sole soybean with 100% RDF. The bolls per plant in cotton were the highest under sole cotton with 100% RDF. Similar trend for yield components were observed in case of soybean. Sole cotton with 100% RDF resulted in maximum seed cotton and stalk yield as compared to other intercropping treatments. Similar trend was also noted with sole soybean with 100% RDF, which recorded significantly the highest seed and stover yield as compared to others. The maximum values of LER, cotton equivalent yield, monetary advantage gross realization, net realization ha -1 and B:C ratio were recorded under C+S (2:4)+100%RDF, which was closely followed by treatment C+S (2:4)+1 t FYM ha -1+75% RDF (BL).
  • Authors:
    • Nalayini, P.
    • Praharaj, C. S.
    • Sankaranarayanan, K.
    • Bandyopadhyay, K. K.
    • Gopalakrishnan, N.
  • Source: The Indian Journal of Agricultural Sciences
  • Volume: 80
  • Issue: 7
  • Year: 2010
  • Summary: Climatic change affects cotton (Gossypium sp.) yield, photosynthesis, weeds and pest occurrence. Farmers should reduce inorganic inputs utilization to reduce the environmental effects of fertilizers and pesticides. N-fixing Azotobacter and Azospirillum, legumes rotation, application of slow-release N fertilizers, adoption of drip-fertigation, incorporation of cotton stalk could reduce fertilizer usage. The application of FYM, greengram ( Vigna radiata), Gliricidia sp. and sunnhemp ( Crotolaria juncea [ Crotalaria juncea]) as green manure recorded 15-32% increase in yield. Different cotton species should be planted on different environments. G. arboreum is suitable for environments with low and erratic rainfall with drought situations. G. herbaceum is salt tolerant. The available drought tolerant G. hirsutum genotypes, namely 'LRA 5166', 'KC 2' and 'AKH 081' may show better adaptation. The risk and uncertainty imposed by climatic change could be managed by adoption of location-specific intercropping and multi-tier cropping systems. In situ soil moisture conservation techniques include contour binding, graded, narrow or broad ridges or beds separated by furrows, ridges and furrow, opening of furrow after every rows of cotton, black polythene mulch, and spreads of crop residue were useful.