571. Research situation and prospect of maize rough dwarf disease.

• Authors:
  • He, K.
  • Wang, Z.
  • Li, W.
  • Huang, Q.
• Source: Journal of Maize Sciences
• Volume: 19
• Issue: 2
• Year: 2011
• Summary: Research history and the current status of maize ( Zea mays) rough dwarf disease (MRDD) were reviewed with respect to distribution, symptoms, pathogen, host range, transmission path, and varietal resistance to MRDD. Rice black streaked dwarf virus (RBSDV), maize rough dwarf virus (MRDV) and Mal de Rio Cuarto virus (MRCV) are all causative agents of MRDD around the world. RBSDV is the causative agent of MRDD in China. Small brown planthopper ( Laodelphax striatellus) was the vector of RBSDV. Crop interplanting, especially wheat intercropping with a maize cropping pattern, was closely related to the MRDD, which provided suitable habitat and a recurrent host for L. striatellus and RBSDV. Resistant germplasms have been lacking, and the application and prevention of technology did not meet the demands for managing MRDD until now. Coordinating the relationship between the high-effect planting model (interplanting) and disease prevention, developing simple, practical and high-effect control measures including the innovation of maize germplams resistant to the disease, are the problems needing to be solved in production.

572. Integrating a simple shading algorithm into CERES-wheat and CERES-maize with particular regard to a changing microclimate within a relay-intercropping system.

• Authors:
  • Piepho, H.
  • Hartung, K.
  • Graeff-Honninger, S.
  • Grozinger, H.
  • Knorzer, H.
  • Claupein, W.
• Source: Field Crops Research
• Volume: 121
• Issue: 2
• Year: 2011
• Summary: Wheat/maize related multi-cropping systems are the dominant cropping systems in North China. To improve and adjust those systems, and to study competition effects within intercropping, extended field experiments are necessary. As field experiments are time consuming, laborious and expensive, a viable alternative is the use of crop growth models that can quantify the effects of management practices on crop growth and productivity. Field experiments showed that intercropped maize yielded as high as monocropped maize, and grain yield of intercropped wheat increased by up to 32%. Based on a process-oriented modeling approach, this study focuses on analyzing and modeling competitive relationships in a wheat/maize relay intercropping system with regard to yield, solar radiation and microclimate effects. A simple shading algorithm was applied and integrated into the CERES models, which are part of the DSSAT software shell vs. 4.5. The algorithm developed estimates the proportion of shading as affected by neighbouring plant height. The model was tested to investigate the applicability of this shading algorithm within the CERES models in the simulation of grain yield and dry matter yield of wheat and maize. Model error of grain and dry matter yield for both species was below 10%. There was a tendency for grain yield to be simulated adequately but for dry matter yield to be slightly underestimated. Increased top soil temperature in intercropped wheat increased the mineralization of nitrogen and improved N supply. The wheat/maize system was N efficient. Thus, N dynamics were taken into account for simulation as well as CO 2 dynamics based upon modified wind speed. Wheat border rows were exposed to a higher wind speed until mid-June and to reduced wind speed thereafter. As a result, solar radiation, soil temperature and wind speed differed between monocropping and intercropping and could provide a starting point for simulating intercropping. Microclimate effects are often small, subtle or non-existent, while spatial and climate variability and the heterogeneity of plant populations can be considerable. Quantifying microclimatic effects may prove difficult but should not be neglected when simulating intercropping systems.

573. Swine manure injection with low-disturbance applicator and cover crops reduce phosphorus losses.

• Authors:
  • Tomer, M.
  • Cambardella, C.
  • Singer, J.
  • Moorman, T.
  • Kovar, J.
• Source: Journal of Environmental Quality
• Volume: 40
• Issue: 2
• Year: 2011
• Summary: Injection of liquid swine manure disturbs surface soil so that runoff from treated lands can transport sediment and nutrients to surface waters. We determined the effect of two manure application methods on P fate in a corn ( Zea mays L.)-soybean [ Glycine max (L.) Merr.] production system, with and without a winter rye ( Secale cereale L.)-oat ( Avena sativa L.) cover crop. Treatments included: (i) no manure; (ii) knife injection; and (iii) low-disturbance injection, each with and without the cover crop. Simulated rainfall runoff was analyzed for dissolved reactive P (DRP) and total P (TP). Rainfall was applied 8 d after manure application (early November) and again in May after emergence of the corn crop. Manure application increased soil bioavailable P in the 20- to 30-cm layer following knife injection and in the 5- to 20-cm layer following low-disturbance injection. The low-disturbance system caused less damage to the cover crop, so that P uptake was more than threefold greater. Losses of DRP were greater in both fall and spring following low-disturbance injection; however, application method had no effect on TP loads in runoff in either season. The cover crop reduced fall TP losses from plots with manure applied by either method. In spring, DRP losses were significantly higher from plots with the recently killed cover crop, but TP losses were not affected. Low-disturbance injection of swine manure into a standing cover crop can minimize plant damage and P losses in surface runoff while providing optimum P availability to a subsequent agronomic crop.

574. Crop-livestock integration: use efficiency of nitrogen in corn culture.; Integracao lavoura-pecuaria: eficiencia de uso do nitrogenio na cultura do milho.

• Authors:
  • Carvalho, P. C. de F.
  • Sulc, R. M.
  • Moraes, A. de
  • Pelissari, A.
  • Lang, C. R.
  • Lopes, E. C. P.
• Source: Scientia Agraria
• Volume: 12
• Issue: 1
• Year: 2011
• Summary: Producers seeking higher corn ( Zea mays) production efficiency have pursued more sustainable, integrated systems. The objective of this investigation was to determine the effect of nitrogen fertilization on corn yield and yield components in an integrated crop-livestock production system. The experiment was conducted on the experimental farm Fazenda Capao da Onca of the Universidade Estadual de Ponta Grossa, Brazil during the 2002/2003 harvest. Treatments were replicated four times in a split-plot randomization of a randomized complete block design. Whole plot treatments were two N rates (0, 150 kg ha -1) with and without grazing applied to a winter cover crop of black oat and Italian ryegrass established in April 2002 and desiccated prior to planting the corn in October 2002. Sequentially, treatments were four N rates (0, 75, 150, 225 kg ha -1) applied to the corn. The corn presented an increasing yield in relation to increasing N rates in plots without neither grazing nor N fertilization during winter; however, grazing allows for higher corn yields with lower N rates.

575. Crop nitrogen use and soil mineral nitrogen accumulation under different crop combinations and patterns of strip intercropping in northwest China.

• Authors:
  • Zhang, F.
  • An, M.
  • Christie, P.
  • Sun, J.
  • Yu, C.
  • Li, Y.
  • Li, C.
  • Li, L.
• Source: Plant and Soil
• Volume: 342
• Issue: 1/2
• Year: 2011
• Summary: Increasing crop nitrogen use efficiency while also simultaneously decreasing nitrogen accumulation in the soil would be key steps in controlling nitrogen pollution from agricultural systems. Long-term field experiments were started in 2003 to study the effects of intercropping on crop N use and soil mineral N accumulation in wheat ( Triticum aestivum L. cv 2014)/maize ( Zea mays L. cv Shendan16), wheat/faba bean ( Vicia faba L. cv Lincan No. 5) and maize/faba bean intercropping and monocropping systems. Monocropping was compared with two types of strip intercropping: continuous intercropping (two crops intercropped continuously on the same strips of land every year) and rotational intercropping (two crops grown adjacently and rotated to the other crop's strip every year). Maize/faba bean intercropping had greater crop N uptake than did wheat/faba bean or wheat/maize. Wheat/maize accumulated more mineral N in the top 140 cm of the soil profile during the co-growth stage from maize emergence to maturity of wheat or faba bean. Continuously intercropped maize substantially decreased soil mineral N accumulation under wheat and faba bean rows (60-100 cm soil depth) at maize harvest. Soil mineral N accumulation under wheat rows increased with rotational intercropping with faba bean. Rotational intercropping may potentially alleviate the adverse effects of wheat on N use by other crops and increase the nitrogen harvest index of wheat, maize and faba bean. Intercropping using species with different maturity dates may be more effective in increasing crop N use efficiency and decreasing soil mineral N accumulation.

576. Overyielding and interspecific interactions mediated by nitrogen fertilization in strip intercropping of maize with faba bean, wheat and barley.

• Authors:
  • Li, L.
  • Zhang, F.
  • Christie, P.
  • Wei, X.
  • Sun, J.
  • Li, Q.
• Source: Plant and Soil
• Volume: 339
• Issue: 1/2
• Year: 2011
• Summary: Interspecific interactions and soil nitrogen supply levels affect intercropping productivity. We hypothesized that interspecific competition can be alleviated by increasing N application rate and yield advantage can be obtained in competitive systems. A field experiment was conducted in Wuwei, Gansu province in 2007 and 2008 to study intercropping of faba bean/maize, wheat/maize, barley/maize and the corresponding monocultures of faba bean ( Vicia faba L.), wheat ( Triticum aestivum L.), barley ( Hordeum vulgare L.) and maize ( Zea mays L.) with N application rates of 0, 75, 150, 225 and 300 kg N ha -1. Total land equivalent ratios (TLER) were 1.22 for faba bean/maize, 1.16 for wheat/maize, and 1.13 for barley/maize intercropping over the 2-year study period. Maize was overyielding when intercropped with faba bean, but underyielding when intercropped with wheat or barley according to partial land equivalent ratios (PLER) based on grain yields of individual crops in intercropping and sole cropping. There was an interspecific facilitation between intercropped faba bean and maize, and interspecific competition between maize and either wheat or barley. The underyielding of maize was higher when intercropped with barley than with wheat. Fertilizer N alleviated competitive interactions in intercrops with adequate fertilizer N at 225 kg ha -1. Yield advantage of intercropping can be acquired with adequate nitrogen supply, even in an intensive competitive system such as barley/maize intercropping. This is important when using intercropping to develop intensive farming systems with high inputs and high outputs.

577. Decomposition of the cultural residue and release nitrogen to culture of maize.; Decomposicao de residuos culturais e liberacao de nitrogenio para a cultura do milho.

• Authors:
  • Lang, C.
  • Rios, E.
  • Moraes, A.
  • Carvalho, P.
  • Medrado, R.
  • Lopes, E.
• Source: Scientia Agraria
• Volume: 12
• Issue: 2
• Year: 2011
• Summary: This study aimed to evaluate the decomposition of the residual dry mass and the initial release of nitrogen from different coverages winter for the subsequent cultivation of maize. The work was conducted in Major Vieira, SC, on a family property. The experimental design was a randomized block, with five treatments (alternative soil cover) and three replications. The treatments: (a) consortium of oat ( Avena strigosa)+ryegrass ( Lolium multiflorum)+vetch ( Vicia spp.)+vesiculoso clover ( Trifolium vesiculosum), with grazing and nitrogen fertilization (100 kg of N); (b) Grassland of black oat+ryegrass+vetch+clover vesiculoso, with grazing and without nitrogen fertilization; (c) coverage (oat+ryegrass+vetch+vesiculoso clover), without grazing and without nitrogen fertilization; (d) forage turnip ( Raphanus sativus), without grazing and without nitrogen fertilization, and (e) fallow (control). The rate of decay was measured through pockets of decomposition (litter bags), collected in seven seasons during the corn crop. The turnip forage was the treatment that was more difficult to decompose according to their chemical characteristics. This limited the supply of nitrogen for the corn crop. Treatment coverage consortium made rapid initial release of N and thus was considered the most appropriate for use in succession with the corn crop. The grazing influenced the release of nitrogen, mainly by the lower amount of total dry mass produced. The grain yield of maize was not influenced by soil cover.

578. Mulch effects on soil moisture and nitrogen, weed growth and irrigated maize productivity in a warm-temperate climate of South Africa.

• Authors:
  • Muchaonyerwa, P.
  • Chiduza, C.
  • Murungu, F. S.
  • Mnkeni, P. N. S.
• Source: Soil & Tillage Research
• Volume: 112
• Issue: 1
• Year: 2011
• Summary: Low soil fertility and weeds reduce maize yields on most smallholder (SH) irrigation schemes in South Africa (SA). While cover cropping can increase maize productivity, benefits from different types of mulch are not well understood, leading to challenges in selecting the most appropriate cover crop species to grow. Field experiments investigating the effects of oat ( Avena sativa), grazing vetch ( Vicia dasycarpa), faba bean ( Vicia faba), Lupin ( Lupinus angustifolius) and forage pea ( Pisum sativum) mulch on maize grown at two fertilizer levels (0 and 60 kg N/ha) were undertaken in the 2007/08 and 2008/09 seasons. Plots where maize was grown without mulch were included as controls. Treatments were arranged in a randomised complete block design with three replications. Grazing vetch and forage pea mulch significantly ( P

579. Tillage and mulching effects on performance of maize ( Zea mays)-wheat ( Triticum aestivum) cropping system under varying land slopes.

• Authors:
  • Dube, R. K.
  • Dhyani, S. K.
  • Sharma, A. R.
  • Ratan, S.
• Source: Indian Journal of Agricultural Sciences
• Volume: 81
• Issue: 4
• Year: 2011
• Summary: A field experiment was conducted at Selakui, Dehradun during 2001-04 to study the effect of tillage (conventional and minimum) and mulching practices (no mulching and live mulching) under artificially created varying land slopes (0.5, 2.5, 4.5 and 9.5%) on soil-moisture conservation, productivity and nutrient uptake in maize ( Zea mays L.)-wheat ( Triticum aestivum L. emend Fiori & Paol.) cropping system. Sunnhemp ( Crotalaria juncea L.) intercropped with maize gave 0.87-1.09 tonnes biomass (dry weight) and accumulated 24.8-31.4 kg N/ha at 30 days of growth when it was mulched. Biomass and N accumulation generally decreased with increasing land slope and under minimum tillage. Maize performed better on moderate slopes (2.5-4.5%) than on the relatively flat (0.5%) and highly sloping land (9.5%). However, the yield of wheat decreased linearly and significantly with increasing slope due to less conservation of soil moisture on sloping lands during the previous rainy season. Conventional tillage gave significantly higher productivity of both maize and wheat than the minimum tillage. Intercropping of maize with sunnhemp and spreading the cut biomass as mulch at 30 days (live mulching) improved soil moisture conservation at maize harvest (+1.63 to 1.94%), and yield of maize (12.0%) as well as of following wheat (13.8%) compared with the no mulching.

580. Energy conversion and balance of integrated crop-livestock production systems under no-tillage.; Conversao e balanco de energia de sistemas de producao com integracao lavoura-pecuaria sob plantio direto.

• Authors:
  • Spera, S.
  • Fontaneli, R.
  • Santos, H.
  • Maldaner, G.
• Source: PESQUISA AGROPECUARIA BRASILEIRA
• Volume: 46
• Issue: 10
• Year: 2011
• Summary: The objective of this work was to assess energy conversion and balance of integrated crop-livestock production systems, under no-tillage. The experiment was carried out from 2001 to 2008. From 2001 to 2002, the following systems were evaluated: 1, wheat/soybean, and black oat pasture+common vetch/corn; 2, wheat/soybean, and black oat pasture+common vetch+ryegrass/corn; 3, wheat/soybean and black oat pasture+common vetch/millet pasture; 4, wheat/soybean and black oat pasture+common vetch+rygrass/millet pasture; 5, wheat/soybean, white oat/soybean, and black oat pasture+common vetch/millet pasture; 6, wheat/soybean, white oat/soybean, and black oat pasture+common vetch+rygrass/millet pasture. From 2003 to 2008, the following systems were evaluated: 1, wheat/soybean, and common vetch/corn; 2, wheat/soybean, and black oat pasture/corn; 3, wheat/soybean, and black oat pasture/soybean; 4, wheat/soybean, and field pea/corn; 5, wheat/soybean, common vetch/soybean, and double purpose triticale/soybean; and 6, wheat/soybean, double purpose white oat/soybean, and double purpose wheat/soybean. Corn showed highest returned energy in comparison to the other grain crops, and to winter and summer annual pastures. Of the winter cover crops and green manure species evaluated, field pea was the most efficient in energy conversion. Systems 1, 2, and 4, from 2003 to 2008, had the most efficient energy balance.