- Authors:
- Li, Z.
- Liu, W. Z.
- Zhang, X. C.
- Chen, J.
- Source: Agricultural and Forest Meteorology
- Volume: 151
- Issue: 10
- Year: 2011
- Summary: Trends and uncertainty of the climate change impacts on hydrology, soil erosion, and wheat production during 2010-2039 at El Reno in central Oklahoma, USA, were evaluated for 12 climate change scenarios projected by four GCMs (CCSR/NIES, CGCM2, CSIRO-Mk2, and HadCM3) under three emissions scenarios (A2, B2, and GGa). Compared with the present climate, overall t-tests ( n=12) show that it is almost certain that mean precipitation will decline by some 6% (>98.5% probability), daily precipitation variance increase by 12% (>99%), and maximum and minimum temperature increase by 1.46 and 1.26 degrees C (>99%), respectively. Compared with the present climate under the same tillage systems, it is very likely (>90%) that evapotranpiration and long-term soil water storage will decease, but runoff and soil loss will increase despite the projected declines in precipitation. There will be no significant changes in wheat grain yield. Paired t-tests show that daily precipitation variance projected under GGa is greater than those under A2 and B2 ( P=0.1), resulting in greater runoff and soil loss under GGa ( P=0.1). HadCM3 projected greater mean annual precipitation than CGCM2 and CSIRO ( P=0.1). Consequently, greater runoff, grain yield, transpiration, soil evaporation, and soil water storage were simulated for HadCM3 ( P=0.1). The inconsistency among GCMs and differential impact responses between emission scenarios underscore the necessity of using multi-GCMs and multi-emission scenarios for impact assessments. Overall results show that no-till and conservation tillage systems will need to be adopted for better soil and water conservation and environmental protection in the region during the next several decades.
- Authors:
- Wen, Y.
- Gong, Z.
- Gu, S.
- Lu, J.
- Zhao, J.
- Source: Transactions of the Chinese Society of Agricultural Engineering
- Volume: 27
- Issue: 12
- Year: 2011
- Summary: The objective of this study was to distinguish effects of main growing factors on the corn yield under dry-farming conditions. A corn field experiment with three factors and four levels for each factor was conducted using the same corn cultivar and the same design in three consecutive years on a black soil classified as typic udolls of which the available nitrogen is middle but both available phosphorus and potassium are high. The results showed that, the most limiting factors to corn yield were respectively precipitation in growing season (PGS), rate of nitrogen fertilizer and available nitrogen contents of soil. Only when the PGS was greater than 280 mm, was nitrogen fertilizer effect statistically noticeable. The appropriate combination of nitrogen, phosphorus and potassium fertilizers increased the water use efficiency by 24.3% compared to no fertilizer treatment. Corn yield was positively correlated with the available nitrogen contents of soil too, meaning that higher soil available nitrogen contents are favorable to the increase in corn yield.
- Authors:
- Shahid, A.
- Saghir, A.
- Jamil, M.
- Zubair, M.
- Farooq, M.
- Awais, R.
- Source: Pakistan Sugar Journal
- Volume: 26
- Issue: 2
- Year: 2011
- Summary: Sugarcane is a long duration crop and is suitable for intercropping with other short duration crops to maximize the farmer income from the unit area. Thus, this study was designed to find out the possibility of wheat, lentil and gram intercropping with autumn planted sugarcane crop. The study was carried out at National Agricultural Research Centre, Islamabad during 2004-05 cropping season. Sugarcane variety RB-72-454 was used as test crop and planted at 1.2 meter row distance in the first week of September, 2004. Two rows of each wheat, lentil and gram crop were seeded in the month of November in between cane rows. Sugarcane crop was harvested in the month of December, 2005. Lentil and gram were harvested in the month of April while, wheat in May. The results of the study indicted that sugarcane planted alone produced highest cane yield of 130.5 t ha -1, while sugarcane intercropped with wheat produced lowest cane yield of 105.5 t ha -1. The yields of wheat, lentil and gram were 1.18, 0.57 and 0.43 t ha -1, respectively. However, it was observed that intercropping of wheat, lentil and gram with sugarcane decreased cane yield by 19.2, 18.6 and 14.3%, respectively. The maximum economic return of Rs. 156641 ha -1 was noticed when sugarcane was planted without intercropping, whereas, intercropping of sugarcane with wheat resulted in minimum return of Rs. 138889 ha -1. Findings of the study revealed that autumn planting of sugarcane without any intercropping is more profitable than intercropping with cereal and leguminous crops.
- Authors:
- Kumari, S. G.
- Ekzayez, A. M.
- Ismail, I.
- Source: Plant Disease
- Volume: 95
- Issue: 1
- Year: 2011
- Summary: A field survey covering the major cereal-production areas of Syria was conducted during May 2009. A total of 938 wheat and 971 barley samples with typical symptoms of viral infection were collected from 45 wheat and 58 barley fields. Serological tests showed that Wheat dwarf virus (WDV) was detected in 16 wheat (cv. Cham 8) and 5 barley (cv. Arabic abiad) samples collected from Al-Hasskah governorate (eastern region of Syria) and showing dwarfing, yellowing, and reduced heading. The identity of WDV was confirmed by PCR assay. Leafhopper transmission tests indicated that only Psammotettix provincialis was able to transmit Syrian barley WDW isolates from infected barley plants to healthy barley (48 plants became infected of 50 plants inoculated) and oats (45 of 50) under greenhouse conditions. WDV has been reported to infect cereals in other countries in West Asia and North Africa (Turkey, Tunisia and Morocco) and causes economic losses on wheat in many countries in Europe (e.g. Sweden). WDV has been reported to be transmitted in a persistent manner only by leafhoppers ( Psammotettix alienus) to a wide range of cereal and wild grasses. Two strains of WDV are known, one that primarily infects wheat and another that infects barley. This is thought to be the first report of WDV (both strains) infecting wheat and barley crops in Syria and the first report of P. provincialis as a WDV vector worldwide.
- Authors:
- Emeran, A. A.
- Shtaya, M. J. Y.
- Fernandez-Aparicio, M.
- Allagui, M. B.
- Kharrat, M.
- Rubiales, D.
- Source: Crop Protection
- Volume: 30
- Issue: 8
- Year: 2011
- Summary: Chocolate spot incited by Botrytis fabae is a serious faba bean disease of worldwide distribution. The increasing interest in sustainable tools for disease control, together with the lack of sufficient levels of genetic resistance triggered our interest in the use of intercropping as a tool for the management of this disease. The effect of intercropping on chocolate spot severity was studied in field experiments performed in Egypt, the Palestinian Territories, Spain and Tunisia, in which a susceptible faba bean cultivar was grown as a monocrop or with two mixed species intercrops of either barley, oat, triticale, wheat, pea or common vetch, or with three mixed species intercrops of wheat and berseem clover. Chocolate spot was significantly reduced when faba bean was intercropped with cereals, but not when intercropped with legumes. Suppressive effects can be ascribed to a combination of host biomass reduction, altered microclimate and physical barriers to spore dispersal.
- Authors:
- Source: Wine and Viticulture Journal
- Volume: 26
- Issue: 3
- Year: 2011
- Summary: This paper describes the suitability of rolled cover crops (including oats, triticale and faba beans), white alyssum ( Lobularia maritima), saltbush ( Atriplex semibaccata and Enchylaena tomentosa) and chicory for cultivation with grape under the mid-row crop management system (MCS). The characteristics of vineyards suitable for MCS, and the beneficial effects of the aforementioned crops on vineyard profitability and productivity are covered.
- Authors:
- Jimenez-Munoz, J.
- Sobrino, J.
- Julien, Y.
- Source: International Journal of Applied Earth Observation and Geoinformation
- Volume: 13
- Issue: 5
- Year: 2011
- Summary: Several previous studies have shown that the inclusion of the LST (Land Surface Temperature) parameter to a NDVI (Normalized Difference Vegetation Index) based classification procedure is beneficial to classification accuracy. In this work, the Yearly Land Cover Dynamics (YLCD) approach, which is based on annual behavior of LST and NDVI, has been used to classify an agricultural area into crop types. To this end, a time series of Landsat-5 images for year 2009 of the Barrax (Spain) area has been processed: georeferenciation, destriping and atmospheric correction have been carried out to estimate NDVI and LST time series for year 2009, from which YLCD parameters were estimated. Then, a maximum likelihood classification was carried out on these parameters based on a training dataset obtained from a crop census. This classification has an accuracy of 87% (kappa=0.85) when crops are subdivided in irrigated and non-irrigated fields, and when cereal crops are aggregated in a single crop, and performs better than a similar classification from Landsat bands only. These results show that a good crop differentiation can be obtained although detailed crop separation may be difficult between similar crops (barley, wheat and oat) due to similar annual NDVI and LST behavior. Therefore, the YLCD approach is suited for vegetation classification at local scale. As regards the assessment of the YLCD approach for classification at regional and global scale, it will be carried out in a further study.
- 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.
- Authors:
- Muchaonyerwa, P.
- Chiduza, C.
- Murungu, F. S.
- Mnkeni, P. N. S.
- Source: Nutrient Cycling in Agroecosystems
- Volume: 89
- Issue: 1
- Year: 2011
- Summary: Increasing land degradation has prompted interest in conservation agriculture which includes growing cover crops. Besides providing soil cover, decaying cover crops may release substantial amounts of nutrients. Decomposition, N and P release from winter cover crops [grazing vetch ( Vicia darsycarpa), forage peas ( Pisum sativum) and oats ( Avena sativa)] were assessed for suitability in a cropping system found in the smallholder irrigation sector of South Africa. Nitrogen and P contribution to maize growth by cover crop residues was also estimated. Decrease in mass of cover crop residues was highest in grazing vetch (7% remaining mass after 124 days) followed by forage peas (16%) and lastly oats (40%). Maximum net mineralized N and P were higher for grazing vetch (84.8 mg N/kg; 3.6 mg P/kg) than for forage peas (66.3 mg N/kg; 2.7 mg P/ha) and oats (13.7 mg N/kg; 2.8 mg P/kg). Grazing vetch and forage pea residues resulted in higher N contribution to maize stover than oat residues. Farmers may use grazing vetch for improvement of soil mineral N while oats may result in enhancement of soil organic matter and reduction land degradation because of their slow decomposition. Terminating legume cover crops a month before planting summer crops synchronizes nutrient release from winter-grown legume cover crops and uptake by summer crops.
- 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