• Authors:
    • Zhou, X.
    • Wu, F.
  • Source: Acta Pedologica Sinica
  • Volume: 46
  • Issue: 5
  • Year: 2009
  • Summary: Plenty of reports about effects of intercropping improving yield and reducing disease incidence are available, but little was reported about the mechanism of the effects. RAPD and T-RFLP methods were used to study effects of intercropping of cucumber with wheat, vicia villosa and clover, individually, on cucumber disease indexes, cucumber rhizosphere soil microbial community diversity and yield. Results showed that intercropping of cucumber with wheat and vicia villosa increased soil microbial community diversity in cucumber rhizosphere, and the effect of the latter was the most prominent. All intercropping modes increased cucumber yield significantly ( p
  • Authors:
    • Sun, J.
    • Chen, L.
    • Cheng, D.
    • Liu, Y.
    • Chen, J.
    • Zhou, H.
  • Source: Acta Phytophylacica Sinica
  • Volume: 36
  • Issue: 2
  • Year: 2009
  • Summary: To study the ecological effect of genetic diversity of wheat cultivars on Sitobion avenae, the population dynamics of S. avenae and its natural enemies was investigated in wheat fields. The spatial distribution of S. avenae was also analysed. Compared with monocultures, Beijing 837, the number of S. avenae apterae per 100 plants in intercropping patterns was significantly lower during the aphid peak period, and the cascade of population densities was: Beijing 837 monoculture (7422.0) > intercropped with KOK (5796.7) > intercropped with Hongmanghong (5406.7) > intercropped with Zhengzhou831 (5291.7) > intercropped with JP2 (4493.4) > intercropped with Zhongsiwumang (4155.0). The spatial distribution of S. avenae was changed from aggregated to uniform pattern. In the aphid parasitoid peak period, there were higher population densities of the aphid parasitoids in each intercropping field with a very significant level of P
  • Authors:
    • Suleau, M.
    • Heinesch, B.
    • Dufranne, D.
    • Bodson, B.
    • Moureaux, C.
    • Aubinet, M.
    • Vancutsem, F.
    • Vilret, A.
  • Source: Agricultural & Forest Meteorology
  • Volume: 149
  • Issue: 3/4
  • Year: 2009
  • Summary: A crop managed in a traditional way was monitored over a complete sugar beet/winter wheat/potato/winter wheat rotation cycle from 2004 to 2008. Eddy covariance, automatic and manual soil chamber, leaf diffusion and biomass measurements were performed continuously in order to obtain the daily and seasonal Net Ecosystem Exchange (NEE), Gross Primary Productivity (GPP), Total Ecosystem Respiration (TER), Net Primary Productivity (NPP), autotrophic respiration, heterotrophic respiration and Net Biome Production (NBP). The results showed that GPP and TER were subjected to important inter-annual variability due to differences between crops and to climate variability. A significant impact of intercrop assimilation and of some farmer interventions was also detected and quantified. Notably, the impact of ploughing was found to be limited in intensity (1-2 mol m -2 s -1) and duration (not more than 1 day). Seasonal budgets showed that, during cropping periods, the TER/GPP ratio varied between 40 and 60% and that TER was dominated mainly by the autotrophic component (65% of TER and more). Autotrophic respiration was closely related to GPP during the growth period. The whole cycle budget showed that NEE was negative and the rotation behaved as a sink of 1.59 kgC m -2 over the 4-year rotation. However, if exports are deducted from the budget, the crop became a small source of 0.22 (0.14) kgC m -2. The main causes of uncertainty with these results were due to biomass samplings and eddy covariance measurements (mainly, uncertainties about the u* threshold determination). The positive NBP also suggested that the crop soil carbon content decreased. This could be explained by the crop management, as neither farmyard manure nor slurry had been applied to the crop for more than 10 years and because cereal straw had been systematically exported for livestock. The results were also strongly influenced by the particular climatic conditions in 2007 (mild winter, and dry spring) that increased the fraction of biomass returned to the soil at the expense of harvested biomass, and therefore mitigated the source intensity. If 2007 had been a 'normal' year, this intensity would have been twice as great. This suggests that, in general, the rotation behaved as a small carbon source, which accords with similar studies based on multi-year eddy covariance measurements and export assessment and with modelling or inventory studies analysing the evolution of crop soil organic carbon (SOC) on a decennial scale.
  • Authors:
    • Darbyshire, S.
    • Clements, D.
    • DiTommaso, A.
    • Dauer, J.
  • Source: Canadian Journal of Plant Science
  • Volume: 89
  • Issue: 5
  • Year: 2009
  • Summary: Hemp dogbane, Apocynum cannabinum (Apocynaceae), is a perennial herb with white to greenish flowers in terminal clusters that produces pencil-like pods 12-20 cm long. A highly variable plant, A. cannabinum may be distinguished from spreading dogbane ( Apocynum androsaemifolium) by its shorter corolla (2-6 mm compared with 5-10 mm), erect greenish-white petals (compared with recurved or spreading pinkish petals), seeds more than 3 mm long (compared with seeds less than 3 mm), and more erect leaves (compared with spreading or drooping leaves), although frequent hybridization between the two species obscures the identity of some individuals. Hemp dogbane is native to the United States and southern Canada, but most abundant in the upper Mississippi River Valley and east to the Atlantic coast. It has been increasing in other areas, and becoming more of a problem where conservation tillage is adopted. It infests crops such as corn ( Zea mays), soybeans ( Glycine max), wheat ( Triticum aestivum), sorghum ( Sorghum bicolor) and forages, and may cause livestock poisoning due to cardiac glycosides within its milky sap (but livestock generally avoid it). Potential medicinal uses of these compounds have been investigated, and the roots are a source of fibre. Control of A. cannabinum with various herbicides is difficult due to a thick cuticle, and one solution may be to target susceptible stages, such as seedlings or early spring growth. Cultivation may also control A. cannabinum, but care must be taken not to promote the proliferation of the plant through regrowth from fragmented roots and rhizomes. Rotation with alfalfa also reduces populations of A. cannabinum.
  • Authors:
    • Paolo, E.
    • Garofalo, P.
    • Rinaldi, M.
  • Source: Crop & Pasture Science
  • Volume: 60
  • Issue: 3
  • Year: 2009
  • Summary: The aim of this work was to apply the CropSyst simulation model to evaluate the effect of faba bean cultivation as a break crop in the continuous durum wheat cropping system in southern Italy. The model was previously calibrated and validated for durum wheat and faba bean on data derived from experiments carried out in southern Italy (for different years and treatments), comparing observed and simulated crop growth, yield, soil water, and nitrogen output variables. The validation showed good agreement between simulated and observed values for cumulative above-ground biomass, green area index, and soil water content for both crops and grain yield for durum wheat; a negative correlation for grain yield in faba bean was observed due to a reduction in harvest index in the well-watered crop, which the model does not simulate well. Subsequently, a long-term analysis was carried out to study the effects on durum wheat of introducing a legume crop in rotation with the cereal in 2 and 3-year sequences. A long-term simulation, based on 53 years of daily measured weather data, showed that faba bean, due to a lower level of transpirated water (on average 247 mm for durum wheat and 197 mm for faba bean), allowed for greater soil water availability at durum wheat sowing for the cereal when in rotation with a legume crop (on average, +84 mm/m for durum wheat following the faba bean), with positive effects for nitrogen uptake, above-ground biomass, and grain yield of wheat. The yield increase of wheat when following a faba bean crop was on average +12%, but this effect was amplified in drier years (up to 135%). In conclusion, the case study offered the potential to confirm the positive results previously obtained in long/medium-term field experiments on the introduction of faba bean in rotation with durum wheat, as well as reduction in the chemical application of nitrogen.
  • Authors:
    • Singh, V.
    • Gill, M.
  • Source: Indian Journal of Fertilisers
  • Volume: 5
  • Issue: 4
  • Year: 2009
  • Summary: The cultivated area for the last two decades is almost constant 1402 million ha and efforts are to be made to grow food grains from 230 million tonnes to 300 million tonnes by 2025. The vertical enhancement In productivity is the possible option, which has been substantiated by various research investigations. Undoubtedly, with the introduction of high yielding varieties of cereals and their continuous cultivation caused the deficiency of secondary and micronutrients in time and space, which resulted in yield stagnation. The productivity computed in terms of rice equivalent yield was highest, ranged between 8.5-12.0 tonnes/ha for rice-wheat system, 8.6 to 11.4 tonnes/ha for maize-wheat system and 5.8-7.5 tonnes ha -1 for pearl millet-wheat system under Trans Gangetic Plains amply explains about the increase in food grain production. The application of sulfur at 30-45 kg/ha enabled rice crop to fetch return per rupee invested from Rs. 11.7 to 22 while it varied from Rs. 26.4 to 35.1 under rice-wheat system. Zinc application to rice resulted to give response varying from 0.2 to 1.0 tonnes/ha in 62% of field trials out of 2154 trials. The corresponding values for wheat was 51% in 2391 field experiments. Application of S, Zn, Mn, Fe, B and at some places Mo under site specific nutrient management helped to achieve the high yield targets of 15-171 tonnes/ha per annum of rice-wheat and 14-16 tonnes/ha per annum of rice-rice cropping systems. The foliar use of micronutrients particularly Zn, Fe and Mn proved highly economical tonnes than their soil application. To enhance the food grain production, it is pertinent to delineate and map the extent and magnitude of multi-nutrient deficiencies (secondary and micronutrient) in different agro-ecological regions. Such studies are of prime Importance to check the nutritional imbalance in the food chain which will not only solve the health livelihood of the living organisms but at the same time enhance the input use efficiency, curtail the cost of production and above all enable to sustain the food security of the country by breaking the yield barrier coming on account of multi-nutrient deficiencies.
  • Authors:
    • Gentry, T.
    • Aitkenhead-Peterson, J.
    • Gonzalez-Chavez, M.
    • Zuberer, D.
    • Hons, F.
    • Loeppert, R.
  • Source: Soil & Tillage Research
  • Volume: 106
  • Issue: 2
  • Year: 2009
  • Summary: Tillage and crop rotation/intensity can influence soil biological properties and relevant soil processes including C sequestration. This study determined the effects of long-term (25 years) no till (NT) and conventional tillage (CT) management and cropping sequence [continuous wheat (CW; Triticum aestivum L.) and a rotation of sorghum ( Sorghum bicolor L. Moench), wheat and soybean (RW; Glycine max L. Merr)] on soil microbial community structure and labile and recalcitrant microbial bio-products in central Texas. Fatty acid methyl ester (FAME) profiles, microbial biomass (MB-C, -N and -P), hot water extractable soil carbohydrates (HWE-SC) and easily extracted- (EE-) and total-glomalin-related soil proteins (T-GRSP) were analyzed. Principal component analysis of the FAME data indicated that crop management modified and selected microbial populations. In general, NT-RW resulted in the greatest richness and biodiversity of the total microbial community, soil organic C, MB-P, HWE-SC, EE- and T-GRSP. No tillage increased labile and more recalcitrant bio-products, soil organic C and total N compared to CT. The soil microbial biomass C:N:P ratio, an indicator of ecosystem nutrient limitation, suggested that the CT-RW treatment may have a soil P limitation, which was not observed in the other treatments. The treatments preferentially selected for different microbial communities, which generated microbial products that significantly influenced soil C and N retention. Our results suggested that NT in conjunction with crop rotation (RW) can be recommended for increased soil C sequestration.
  • Authors:
    • Sanjay, K.
    • Sharma, S.
    • Kaushik, V.
  • Source: Journal of Environmental Research and Development
  • Volume: 4
  • Issue: 4
  • Year: 2009
  • Summary: Suitable to environment or eco-friendly means not harmful to our system of environment i.e. not harmful to land, air etc. Presently, due to agriculture a lot of pollutants are added day by day in our environment. Because of these pollutants, the soil fertility is decreasing, the fear of disease in living beings are increasing, a lot of poisonous chemicals and gases prevails in the environment. There is a great need to the use of such a cropping system which is suitable to environment i.e Eco-friendly system of cropping. The Eco-friendliness of cropping system may be viewed from two different angles i.e systems which help in soil and water conservation and system which reduce the use of pesticides, insecticides, herbicides, organic fertilizers. As far as the pesticides use is concerned at national level, it is a still for below the alarming proportions. Inclusion of such crops in the cropping systems in problem areas can play a significant role in minimizing the use of agro-chemicals in the crop production. Insecticides or fungicides use can also be minimized to a considerable extent through cropping system approach. It has been reported that sorghum ear-head fly damage is extremely rare where pigeon pea is planted in alternate rows. Intercropping of coriander in autumn planted sugarcane prevent top borer in sugarcane Sorghum helepense ( L) pers (Tohangen grass) becomes predominant weed in continuous maize cultivation but can be controlled by rotating with cotton. Adoption of sugarcane wheat system in place of rice-wheat decreases philaries minor infestation to almost negligible level which is otherwise not achieved through herbicides. In maize-potato cropping system raising of pearl millet for green fodder or sesamum for green manure during summer was also found advantageous in reducing Cyprus rotundas in succeeding crop of maize and potato. Position of ground water owing to leaching of nitrates is a selectively new concern in India. Because usage of N-fertilizer is low in India, nitrate is not likely to pose serious problems in most farming situations. Choice of appropriate system and management practices helped minimizing nitrate leaching besides improving N-use efficiency.
  • Authors:
    • Zhu, Y.
    • Wang, H.
    • Xie, Y.
    • Sun, Y.
    • Liu, L.
    • Yang, J.
    • Zhao, G.
    • Tang, Y.
    • Xu, J.
    • Long, Y.
    • Wang, G.
    • Yang, J.
    • Fan, J.
    • Yang, J.
    • Li, Y.
    • Wang, Y.
    • Zhou, H.
    • Zhu, S.
    • He, X.
    • Li, C.
  • Source: PLOS One
  • Issue: November
  • Year: 2009
  • Summary: Traditional farming practices suggest that cultivation of a mixture of crop species in the same field through temporal and spatial management may be advantageous in boosting yields and preventing disease, but evidence from large-scale field testing is limited. Increasing crop diversity through intercropping addresses the problem of increasing land utilization and crop productivity. In collaboration with farmers and extension personnel, we tested intercropping of tobacco, maize, sugarcane, potato, wheat and broad bean - either by relay cropping or by mixing crop species based on differences in their heights, and practiced these patterns on 15,302 hectares in ten counties in Yunnan Province, China. The results of observation plots within these areas showed that some combinations increased crop yields for the same season between 33.2 and 84.7% and reached a land equivalent ratio (LER) of between 1.31 and 1.84. This approach can be easily applied in developing countries, which is crucial in face of dwindling arable land and increasing food demand.
  • Authors:
    • Elliott, N.
    • Michels, J.
    • Ansley, J.
    • Mirik, M.
  • Source: Southwestern Entomologist
  • Volume: 34
  • Issue: 2
  • Year: 2009
  • Summary: The Russian wheat aphid, Diuraphis noxia (Mordvilko), is a severe pest of wheat, Triticum aestivum L.; barley, Hordeum vulgare L.; other small grains; and grasses. Although the Russian wheat aphid is a significant pest of small grains, its feeding effects on grain yield and vegetative biomass in large-scale wheat fields have not been well documented. Data were collected for 3 years in dryland and irrigated wheat fields in Texas and Oklahoma. The insect reduced grain yield 50.2 to 82.9% and biomass by 55.4 to 76.5%. These results suggested that winter wheat suffers significant economic loss from Russian wheat aphid.