• Authors:
    • Christie, P.
    • Streck, T.
    • Li, L.
    • Qin, Z. C.
    • Ingwersen, J.
    • Ju, X. T.
    • Qiu, S. J.
    • Zhang, F. S.
  • Source: Soil & Tillage Research
  • Volume: 107
  • Issue: 2
  • Year: 2010
  • Summary: In recent years large areas of conventional cereal production in China have been transferred to greenhouse production with huge excessive nitrogen (N) fertilizer application and massive irrigation. However, the effects of this change in land use on soil carbon and nitrogen pools remain to be explored. Here we report a comparative study in which paired soil samples were taken from four greenhouses and from adjacent conventional cereal fields. Soil organic carbon (SOC), carbonate carbon (IC), total nitrogen (TN) and mineral nitrogen (N min) to 100 cm depth and the soil active organic pools, including particulate organic matter (POM), soil microbial biomass (SMB) and dissolved organic matter (DOM), to 0-40 cm depth were determined. The natural isotopic signatures of SOC, TN and POM were also analyzed. In both production systems all of the carbon and nitrogen pools in the surface soil (0-10 cm) were greater than deeper in the soil profile except for dissolved organic nitrogen (DON) and NH 4-N. SOC and TN and dissolved organic carbon (DOC) concentrations were higher in the greenhouse system than in conventional cereal soils ( P>0.05). A similar trend was found for POM ( P0.05) and IC in the greenhouse system showed a dramatic decline. The SOC/TN ratios of different pools in the greenhouse soils were lower than in the conventional cereal system ( P>0.05). The SOC/TN ratio ranged from 8.4 to 10.0 in greenhouse soils and 8.5 to 11.7 in the cereal soils. At each depth POM content in the greenhouses (1.5-7.1 g kg -1) was significantly greater than that in the field soils (0.8-2.9 g kg -1) ( P
  • Authors:
    • Reid, R.
  • Source: Plant Science
  • Volume: 178
  • Issue: 1
  • Year: 2010
  • Summary: High boron concentrations in soil and in irrigation water reduce crop productivity in many areas of the world. Plant tolerance to boron toxicity has been identified in a range of genotypes and recent research has revealed a physiological mechanism behind this tolerance in cereals. Cultivars with high levels of expression of a gene encoding a boron-efflux transporter in roots and shoots have been reported to show tolerance to high boron in soils and in solution culture experiments conducted under controlled conditions in glasshouses and growth rooms. However, field trials of tolerant cultivars in rain-fed semi-arid environments have been disappointing with few showing even modest improvements in yield, and others showing either no effect or a decrease in yields.
  • Authors:
    • Sommer, R.
    • Ryan, J.
  • Source: Proceedings of the 19th World Congress of Soil Science: Soil solutions for a changing world, Brisbane, Australia, 1-6 August 2010. Division Symposium 3.2 Nutrient best management practices
  • Year: 2010
  • Summary: While globally fertilizers have had a major impact on food production for the past half-century, the general use of chemical fertilizers in the semi-arid areas of the world is a more recent development. This is particularly true of the Mediterranean region, especially in North Africa and West Asia. Traditionally, the cropping system involved growing cereals (barley and wheat) in rotation with fallow to conserve moisture; sheep and goats were an integral part of the low-input system. Drought was a constant constraint on crop yields. In the past few decades, significant developments have occurred to increase agricultural output; new high-yielding disease resistant varieties; mechanization; irrigation; pest control; and particularly the use of chemical fertilizers as a supplement to the limited animal manures available. Research at the International Center for Agricultural Research in the Dry Areas (ICARDA) in collaboration with the national agricultural systems in the mandate countries of the region has made significant strides in fertilizer research. While much has been achieved in terms of best fertilizer management practices, much remains to be done. This presentation examines the use of fertilizers under the headings of the best management practice concept; right source, right application rate, right time of application, and right place. As fertilizer use will expand in the Mediterranean region, efficiency of use will be an underlying consideration. As agricultural land is on a global level is finite, with limited possibilities to expand cultivation, the increasing population of the world has correspondingly increased the needs for food and fibre. An inevitable development has been intensification of land use, particularly in developing countries of the world, leading to poverty and increased concerns about food security (Borlaug 2007). Pressure on land has been particularly acute in the arid and semi-arid regions, which are characterized by drought and land degradation. The lands surrounding the Mediterranean have been cultivated for millennia and are the site of settled agriculture and the center of origin of some of the world's major crops, especially cereals and pulses. Much development efforts have centered on the West Asia- North Africa (WANA) area, which is characterized by a Mediterranean climate and where drought is the main production constraint (Smith and Harris 1981).
  • Authors:
    • Deka, S.
    • Kattarkandi, B.
    • Singh, S.
    • Choudhary, R.
  • Source: Current Advances in Agricultural Sciences
  • Volume: 2
  • Issue: 1
  • Year: 2010
  • Summary: Global warming poses a potential threat to agricultural production and productivity. Maize ( Zea mays L.) is one of the most important cereals of the world and provides more human food than any other cereal. The study reported in this paper, uses field experiments and simulation models to understand the impact of changing climate on growth and yield of maize plant. In field environment, growth and yield of maize was greatly affected by temperature changes associated with sowing dates. Yield was reduced in late sown crops due to the harmful effect of chilling temperature. Application of irrigation had positive effect on crop growth. Biomass and grain yield as well as other yield attributes were higher in irrigated treatments than the rainfed one. InfoCrop model satisfactorily simulated crop phenology, leaf area index, dry matter production and yield of maize in Delhi. Impact assessment of maize yield to temperature rise showed reduction in yield in both Delhi and Patna with atmospheric temperature rise during the kharif season with percentage reduction was similar in both locations. In rabi crop, future temperature increase initially showed a positive response up to 2degreesC. Climate change is projected to reduce kharif maize yield in India, however, projected increase in rainfall may be beneficial in some locations during rabi season.
  • Authors:
    • Huang, G.
    • Chai, Q.
    • Yang, C.
  • Source: Zhongguo Shengtai Nongye Xuebao / Chinese Journal of Eco-Agriculture
  • Volume: 18
  • Issue: 4
  • Year: 2010
  • Summary: A field experiment was carried out to investigate the effect of alternative irrigation on water consumption, yield and water use efficiency ( WUE) under wheat-maize intercropping in the oasis region of Shiyang River Basin, Gansu Province. The results indicate that evaporation for alternative irrigated intercropping system (AI) decreases by 44.0 mm compared to conventional irrigated intercropping system (CI). Water consumption under AI also increases by 15.4 mm while yield and WUE are respectively enhanced by 13.92% and 9.21% compared to CI. All these results show that alternative irrigation is an effective and practicable way to improve yield and WUE of wheat-maize intercropping. Although evaporation and water consumption in alternative irrigated intercropping system increase with increasing irrigation quota, overall WUE actually decreases.
  • Authors:
    • Yang,C. H.
    • Chai,Q.
    • Huang,G. B.
  • Source: Plant Soil and Environment
  • Volume: 56
  • Issue: 6
  • Year: 2010
  • Summary: A field experiment was conducted to investigate the effects of alternate irrigation (AI) on root distribution and yield of wheat ( Triticum aestivum L.)/maize ( Zea mays L.) intercropping system during the period of 2007-2009 in an oasis of arid north-west China. Five treatments, i.e. sole wheat with conventional irrigation (W), sole maize with alternate irrigation (AM), sole maize with conventional irrigation (CM), wheat/maize intercropping with alternate irrigation (AW/M), and wheat/maize intercropping with conventional irrigation (CW/M). The results showed that root growth was significantly enhanced by alternate irrigation (AI), root weight density (RWD), root length density (RLD) and root-shoot ratios (R/S) in AI treatments were all higher than those in conventional irrigation (CI) treatments. Moreover, intercropped wheat and maize also had a greater root development at a majority of soil depths than wheat and maize in monoculture. In three years, AW/M always achieved the highest total seed yield under different treatments. Higher yield and reduced irrigation resulted in higher water use efficiency (WUE) for the AW/M treatment. Our results suggest that AI should be a useful water-saving irrigation method on wheat/maize intercropping in arid oasis field where intercropping planting is decreased because of limited water resource.
  • Authors:
    • Iqbal, M.
  • Source: Electronic Journal of Environmental, Agricultural and Food Chemistry
  • Volume: 9
  • Issue: 3
  • Year: 2010
  • Summary: An investigation was conducted at Bangladesh Sugarcane Research Institute Farm to assess effects of irrigation on yield of potato and sunhamp as 1st and 2nd intercrops with Isd 31 variety of sugarcane by STP polybag settlings. There was remarkable increase in yield of potato, sunhamp and sugarcane by water application. The highest yield of potato, sunhamp and sugarcane obtained were 10.06 t/ha, 16.96 t/ha and 85.50 t/ha in T 3, T 2 and T 3 treatments and of that control treatments yield were 6.94, 12.69 and 71.48 t/ha respectively. Yield of potato, sunhamp and sugarcane reduced due to excess application of water in each T 4 treatment. Therefore, the profitability of intercropping potato and sunhamp with sugarcane significantly did not reduce the yield of the sugarcane compared to the alone cane.
  • Authors:
    • Stone, L.
    • Schlegel, A.
    • Klocke, N.
    • Blanco-Canqui, H.
    • Rice, C.
  • Source: Soil Science Society of America Journal
  • Volume: 74
  • Issue: 4
  • Year: 2010
  • Summary: Deficit irrigation is an important strategy to manage water, but its impacts on soil C sequestration and physical properties have not been well documented. We assessed changes in soil organic C (SOC) and soil inorganic C (SIC) concentrations and selected soil physical properties at two no-till experiments on Ulysses silt loam (a fine-silty, mixed, superactive, mesic Aridic Haplustoll) with <1% slope under six irrigation treatments (66, 86, 117, 152, 182, and 217 mm of water applied) at Garden City and three (127, 254, and 381 mm of water applied) at Tribune in western Kansas after 5 and 8 yr of management, respectively. For the 0- to 10-cm depth, SOC concentration and wet aggregate stability increased with an increase in irrigation amount, but bulk density, particle-size distribution, and SIC concentration were unaffected. At Garden City, the SOC pool in the 0- to 10-cm depth increased by 46% (11.2 vs. 16.4 Mg ha -1) from the lowest (66 mm) to the highest (217 mm) irrigation amount. At Tribune, the SOC concentration in the 5- to 10-cm soil depth increased by 30% when the irrigation amount increased from 127 (7.8 g kg -1) to 254 (10.2 g kg -1) mm. The amount of macroaggregates increased with an increase in the irrigation amount, particularly in the 5- to 10-cm depth. At Garden City, irrigation-induced increase in SOC concentration increased the mean weight diameter of aggregates ( r=0.66; P<0.001). Overall, deficit irrigation affected SOC concentration and soil structural development near the soil surface, but the magnitude of impacts was site specific.
  • Authors:
    • Li, H. F.
    • Peng, L. C.
    • Yan, B. L.
    • Wang, W. P.
    • Li, Y.
    • Huang, Z. B.
    • Jiao, Z. H.
  • Source: Journal of Agro-Environment Science
  • Volume: 29
  • Issue: 2
  • Year: 2010
  • Summary: In a pot experiment, soybean plants were irrigated with the second grade and third grade reclaimed water to study the changes of physicochemical properties and the microorganism groups in root zone of soybean. The results indicated that irrigation with reclaimed water improved soil fertility, and contents of organic mater and available phosphorus increased markedly. Compared with the control without irrigation with reclaimed water or irrigated with fresh water, the contents of heavy metals lead (Pb) and cadmium (Cd) in soil had no significant accumulation, but the electric conductivity (EC) of the soil increased significantly which resulted in the increased of salinity to a certain extent. Irrigation with reclaimed water enhanced the bacteria and Actinomyces amounts while the fungi amount was not enhanced. The difference in number of Actinomyces between irrigation with second grade reclaimed water and the third reclaimed water was obviously and higher than that of control of fresh water irrigation. Irrigation with reclaimed water increased the urease activity in root zone of soybean, and the alkaline phosphatase activity was the highest. The soil microbe number and enzyme activities were significantly correlated with soil nutrients, so they could be used as the indexes to evaluate the fertility and environment quality of soil.
  • Authors:
    • Towett, B. K.
    • Ogola, J. B. O.
    • Kinyua, M. G.
    • Gottschalk, K.
    • Kimurto, P. K.
  • Source: Agricultural Engineering International: CIGR Journal
  • Volume: 12
  • Issue: 3/4
  • Year: 2010
  • Summary: Carrying out field trial-research in dryland areas is usually expensive and costly for most national breeding programmes; hence development of simple crop simulation models for predicting crop performance in actual semi-arid and arid lands (ASALS) would reduce the number of field evaluation trials. This is especially critical in developing countries like Kenya where dry areas is approximately 83% of total land area and annual rainfall in these area is low, unreliable and highly erratic, causing frequent crop failures, food insecurity and famine. This paper used data generated from the rain shelter by measurement of evapotranspiration together with weather variables in Katumani to predict wheat yields in that site. Maximum yield of the wheat genotype considered for genotype Chozi under ideal conditions was 5 t/ha. Total above-ground biomass was obtained and grain yield was to be predicted by the model. Transpiration was estimated from the relationship between total dry matter production and normalised TE (7.8 Pa). The results presented are based on the assumption that all agronomic conditions were optimal and drought stress was the major limiting factor. Predicted grain yield obtained from the conceptual model compares very well with realised yields from actual field experiments with variances of 14%-43% depending on watering regime. This study showed that it is possible to develop simple conceptual model to predict productivity in wheat in semi-arid areas of Kenya to supplement complicated and more sophisticated models like CERES-maize and ECHAM models earlier used in Kenya. The presence of uncontrolled factors in the simulation not accounted for in the estimation and could have contributed to decrease in observed yield need to be included in the model, hence modulation of the equations by introducing these factors may be necessary to reduce variances; thus need to be quantified. To improve the accuracy of prediction and increase wheat production in these areas measures that conserve water and/or make more water available to the crop such as prevention or minimisation of run-off, and rain water harvesting for supplemental irrigation are necessary.