• Authors:
    • Rocha, H. S.
    • Souza, A. P. de
    • Carvalho, D. F. de
    • Lima, M. E. de
    • Guerra, J. G. M.
  • Source: Revista Brasileira de Engenharia Agrícola e Ambiental
  • Volume: 16
  • Issue: 6
  • Year: 2012
  • Summary: This study was carried out in the municipality of Seropedica-RJ, in order to determine, under organic farming and no tillage system, the yield of eggplants under different irrigation depths and cropping systems (intercropped with legumes and alone). The experimental design was in randomized blocks in a split plot design with four replications. The plots were characterized by the treatments corresponding to different water depths (40, 70, 100, 120% ETc), and the sub plots, the intercropping systems with cowpea and eggplant alone. Cropping systems did not influence the final yield of eggplant. However, considering the different irrigation depths, the highest commercial yield (65.41 Mg ha -1) was obtained for a total depth of 690.04 mm (106.8% ETc). The lower applied depth provided lower quality of fruit compared with that observed in the higher depths. The rate of fruit discard was 3 and 14%, respectively, for the higher and lower depths of irrigation.
  • Authors:
    • Al-Amoud, A. I.
    • Alabdulkader, A. M.
    • Awad, F. S.
  • Source: Agricultural Economics – Czech
  • Volume: 58
  • Issue: 2
  • Year: 2012
  • Summary: A mathematical sector model has been formulated to optimize the cropping pattern in Saudi Arabia aiming at maximizing the net annual return of the agricultural sector in the country and ensuring the efficient allocation of the scarce water resources and arable land among the competing crops. The results showed the potential for Saudi Arabia to optimize its cropping pattern and to generate an estimated net return equivalent to about 2.42 billion US$ per year. The optimized cropping pattern in Saudi Arabia has been coupled with about 53% saving in water use and about 48% reduction in the arable land use compared to the base-year cropping pattern. Comparable weights was given to different crop groups by allocating about 48.4%, 35.4%, 13.1%, and 3.2% to grow cereals, fruits, forages, and vegetables, respectively. These findings are in line with the national strategy to rationalize the cultivation of water-intensive crops in favour of highly water-efficient crops.
  • Authors:
    • Taha, A. S.
    • Muneer, S. E.
    • Alzahrani, K. H.
    • Baig, M. B.
  • Source: JAPS, Journal of Animal and Plant Sciences
  • Volume: 22
  • Issue: 1
  • Year: 2012
  • Summary: Fresh water is one of the most important and scarcest natural resources around the globe. In Saudi Arabia fresh water shortage for different uses represents one of the main challenges hindering development efforts in the country. As such there is a need to pursue a water demand management policy which should include any measure or initiative that will result in reduction of water usage and/or water demand. This study is intended to explore the potential of proper cropping pattern as a water demand management tool to enhance water and food security in Saudi Arabia. Secondary data were obtained from the ministry of Agriculture and Ministry of Electricity and Water. The analyses revealed that existing cropping pattern did not benefit from the relative advantage of different regions in producing different crops. Thus, there is a great potential for enhancing food and water security in Saudi Arabia through altering existing cropping pattern by encouraging production of different crops in the regions that have clear relative advantage in their production i.e. give the highest productivity. For example production of cereals could be concentrated in Jouf and Tabuk areas, while vegetables production in the eastern region and Asser area.
  • Authors:
    • Brainard, D.
  • Source: Acta Horticulturae
  • Issue: 950
  • Year: 2012
  • Summary: In response to declines in yield and stand longevity, Michigan asparagus growers are experimenting with multiple cultural practices including irrigation, shallow tillage, and "living-mulches" sown immediately following harvest in late June. Drought stress may play an important role in limiting fern growth and increasing fern susceptibility to pests. Living mulches are thought to reduce soil degradation and suppress weeds, but may also suppress asparagus through competition for water. Research was initiated in Hart, Michigan, USA, in 2008 with the following long-term objectives: (1) to evaluate the effects of irrigation on asparagus yields and weed management under two cropping systems; and (2) to determine the effects of cereal rye ( Secale cereal) living-mulch on soil moisture, weed growth, and asparagus yield. In a research farm field experiment, 4 treatments were examined: (1) no-till with standard herbicides; (2) no-till with standard herbicides plus irrigation; (3) shallow-tillage with rye living-mulch; (4) shallow tillage with rye living-mulch plus irrigation. Irrigation increased weed density and weed dry weight but had no detectable effect on asparagus yields. Rye living mulch (1) reduced soil volumetric water content by approximately 2-3% at 60 cm; (2) suppressed weeds compared to weedy control treatments, but resulted in increased weed density and dry weight compared to conventional herbicide treatments; and (3) had no detectable effect on asparagus yield.
  • Authors:
    • Noyes, D. C.
    • Bakker, J.
    • Brainard, D. C.
    • Myers, N.
  • Source: HortScience
  • Volume: 47
  • Issue: 1
  • Year: 2012
  • Summary: Living mulches growing below asparagus ( Asparagus officinales) fern can improve soil health and suppress weeds but may also suppress asparagus through competition for water or nutrients. The central objective of this research was to test whether cereal rye ( Secale cereale) living mulch, in combination with overhead irrigation, could provide comparable weed suppression to standard residual herbicides without reducing asparagus yields. A field experiment was conducted from 2008 to 2010 in a mature asparagus planting on sandy soils in western Michigan to evaluate the effects of irrigation (none vs. overhead) and weed management systems (standard herbicides vs. rye living mulch) on weed suppression, soil moisture content, and asparagus yield. Rye living mulch and herbicide treatments were established immediately after asparagus harvest in late June of each year. Rye living mulch reduced soil-available water in early August by 26% to 52% compared with herbicide treatments but had no detectable effect on asparagus yields. Compared with herbicide treatments, rye living mulch reduced fall-germinating weed emergence and resulted in lower densities of horseweed ( Conyza canadensis) during asparagus harvest. However, in 2 of 3 years, the living mulch system resulted in higher densities of summer annual weeds - including Powell amaranth ( Amaranthus powellii) and longspine sandbur ( Cenchrus longispinus) - during the fern growth period compared with herbicide treatments. After 3 years, the density of summer annual weeds was more than 10-fold greater in rye living mulch treatments compared with standard residual herbicides treatments. Our results suggest that (1) soil-improving rye cover crops can partially suppress weeds but may also compete with asparagus for soil moisture in dry years unless irrigation is used; and (2) successful use of rye living mulches for weed management will depend on identification of complementary weed management practices to avoid build-up of the summer annual weed seedbank.
  • Authors:
    • Van Eerd, L. L.
    • Vyn, R. J.
    • Lauzon, J. D.
    • O'Reilly, K. A.
  • Source: Canadian Journal of Soil Science
  • Volume: 92
  • Issue: 2
  • Year: 2012
  • Summary: In order to improve N best management practices in southwestern Ontario vegetable farming, the effect of cover crops on N dynamics in the fall and spring prior to sweet corn planting and during sweet corn season was assessed. The experiment was a split plot design in a fresh green pea - cover crop - sweet corn rotation that took place over 2 site-years at Bothwell and Ridgetown in 2006-2007 and 2007-2008, respectively. The main plot factor was fall cover crop type with five treatments including oat (Avena saliva L.), cereal rye (Secale cereal L.), oilseed radish (OSR; Raphanus sativus L. var. oleoferus Metzg Stokes), mixture OSR plus cereal rye (OSR&rye) and a no cover crop control. Compared with no cover crop, sweet corn profit margins were higher by $450 ha(-1) for oat at Bothwell and $1300 and $760 ha(-1) for OSR and OSR&rye, respectively, at Ridgetown. By comparing plant available N over the cover crop season, the cover crops tested were more effective at preventing N loss at Bothwell than at Ridgetown likely due to higher precipitation and sandier soil at Bothwell. Despite differences in site characteristics, cover crops did not result in increased plant available N compared with no-cover during the sweet corn season at either site, indicating that these cover crops will not provide an N credit to the following crop and growers should not modify N fertilizer applications based on cover crops.
  • Authors:
    • Vencill, W.
    • Schomberg, H. H.
    • Phatak, S. C.
    • Díaz-Pérez, J. C.
    • Skinner, E. M.
  • Source: HortScience
  • Volume: 47
  • Issue: 1
  • Year: 2012
  • Summary: Sunnhemp (Crotalaria juncea L.) is a tropical legume that could be an important summer cover crop in the southeastern United States, but it has the potential for suppressing both crops and weeds. Allelopathic effects of sunnhemp on weeds, vegetable crops, and cover crops were evaluated in greenhouse and growth chamber experiments. In the greenhouse, ground dried sunnhemp residues (applied mixed with the soil at 1.6% w/w) reduced percent germination of lettuce (Lactuca sativa L.) and smooth pigweed (Amaranthus hybridus L.) to a similar degree as that caused by cereal rye (Secale cereale L. subsp. cereale) residues (applied at 1.5% w/w). The allelopathic activity of sunnhemp was greater in the leaves than in the roots or stems. In growth chamber studies, the mean reduction in germination (relative to the control) caused by sunnhemp leaf aqueous extracts was: bell pepper (100%), tomato (100%), onion (95%), turnip (69%), okra (49%), cowpea (39%), collard (34%), cereal rye (22%), sweet corn (14%), Austrian winter pea (10%), crimson clover (8%), cucumber (2%), and winter wheat (2%). In lettuce, carrot, smooth pigweed, and annual ryegrass, sunnhemp aqueous leaf extract reduced seedling length to a degree similar as that produced by rye aqueous leaf extract. Sicklepod [Senna obtusifolia (L.) H.S. Irwin & Barneby CA] germination was not inhibited by any of the sunnhemp or rye aqueous extracts. In conclusion, sunnhemp reduced the germination percentage and seedling growth of various crop species. The allelochemical activity in sunnhemp was primarily in the leaves and remained active at least 16 d after harvest under dry conditions. Sunnhemp's allelochemical effect may be a useful attribute for weed management in sustainable production systems. However, plant growth in the field in crops such as bell pepper, tomato, onion, and turnip may be impacted as a result of allelopathic activity of sunnhemp residues. Thus, weed management may be more effective when sunnhemp is grown in rotation with crops that tolerate the allelochemicals from sunnhemp, resulting in optimization of the rotation effects.
  • Authors:
    • Cornet, D.
    • Gaiser,T.
    • Srivastava, A. K.
    • Ewert, F.
  • Source: Field Crops Research
  • Volume: 131
  • Year: 2012
  • Summary: Soil fertility restoration and crop performance in many developing countries with low input agriculture strongly relies on fallow duration and management. More precise information about the availability of fallow land may provide a way to improve the simulation of yarn (Dioscorea spp.) yields at the regional scale which has hardly been considered in prevailing approaches to model regional crop production. The probable reason behind this is scarce availability of data on fallow duration and variation across the farms in a region. Therefore, this study attempts to estimate effective fallow availability for yam production at the regional scale and to simulate the effect of fallow on regional yam yield. Yam growth and yield were simulated with the EPIC model which was incorporated into a Spatial Decision Support System (SDSS) covering a typical catchment with variable land use intensity within the sub-humid savannah zone of West Africa. Yarn-fallow rotations were simulated within 1120 quasi-homogenous spatial units (LUSAC = Land Use-Soil Association-Climate units) and aggregated to the 121 sub-basins and ten districts within the catchment under three different scenarios of fallow availability: (Si) Total savannah area was available as fallow land, (S2) 50% of the bush savannah was available as fallow land and (S3) 25% of the bush savannah was available as fallow land. The aggregation procedure adopted in this study was based on changes in the frequency of fallow-cropland classes within the sub-basins to render the SDSS sensitive to changes in fallow availability. Comparison of the average simulated tuber yield with the observed mean yield over the entire catchment showed that the simulations slightly overestimated the yields by 0.4% for scenario S1, whereas, underestimated by 14.2% and 36.8% in scenario S2 and S3 respectively. When compared with the effective fallow availability to maize, it was concluded that, (1) due to farmers preferences to plant yam mainly on virgin savanna land and as the first crop in the rotation after fallow, the effectively available fallow area for yam is higher than for maize and (2) the applied approach is suitable to derive effective fallow availability for yarn production at the district scale. (C) 2012 Elsevier B.V. All rights reserved.
  • Authors:
    • Dresboll, D. B.
    • Thorup-Kristensen, K.
    • Kristensen, H. L.
  • Source: European Journal of Agronomy
  • Volume: 37
  • Issue: 1
  • Year: 2012
  • Summary: One of the core ideas behind organic production is that cropping systems should be less dependent on import of resources, and minimize negative effects on the surrounding environment compared to conventional production. However, even when clearly complying with regulations for organic production, it is not always obvious that these goals are reached. As an example, strong dependence on import of manure is often seen in current organic production, especially in systems producing high value crops such as vegetable crops. The aim of the present study was to test novel approaches to organic rotations, designed to reduce the reliance on import of external resources significantly. We compared a conventional system (C) and an organic system relying on manure import for soil fertility (O1) to two novel systems (O2 and O3) all based on the same crop rotation. The O2 and O3 systems represented new versions of the organic rotation, both relying on green manures and catch crops grown during the autumn after the main crop as their main source of soil fertility, and the O3 system further leaving rows of the green manures to grow as intercrops between vegetable rows to improve the conditions for biodiversity and natural pest regulation in the crops. Reliance on resource import to the systems differed, with average annual import of nitrogen fertilizers of 149, 85, 25 and 25 kg N ha(-1) in the C, O1, O2 and O3 systems, respectively. As expected, the crop yields were lower in the organic system. It differed strongly among crop species, but on average the organic crops yielded c. 82% of conventional yields in all three organic systems, when calculated based on the area actually grown with the main crops. In the O3 system some of the area of the vegetable fields was allocated to intercrops, so vegetable yields calculated based on total land area was only 63% of conventional yields. Differences in quality parameters of the harvested crops, i.e. nutrient content, dry matter content or damages by pests or diseases were few and not systematic, whereas clear effects on nutrient balances and nitrogen leaching indicators were found. Root growth of all crops was studied in the C and O2 system, but only few effects of cropping system on root growth was observed. However, the addition of green manures to the systems almost doubled the average soil exploration by active root systems during the rotation from only 21% in C to 38% in O2 when measured to 2.4m depth. This relates well to the observed differences in subsoil inorganic N content (N-inorg. 1-2 m depth) across the whole rotation (74 and 61 kg N ha(-1) in C and O1 vs. only 22 and 21 kg N ha(-1) in O2 and O3), indicating a strongly reduced N leaching loss in the two systems based on fertility building crops (green manures and catch crops). In short, the main distinctions were not observed between organic and conventional systems (i.e. C vs. O1, O2 and O3). but between systems based mainly on nutrient import vs. systems based mainly on fertility building crops (C and O1 vs. O2 and O3). (C) 2011 Elsevier B.V. All rights reserved.
  • Authors:
    • Nieder, R.
    • Ma, W. Q.
    • Roelcke, M.
    • Heimann, L.
    • Gao, Z. L.
    • Hou, Y.
  • Source: Nutrient Cycling in Agroecosystems
  • Volume: 92
  • Issue: 3
  • Year: 2012
  • Summary: An in-depth understanding of nutrient management variability on the regional scale is urgently required due to rapid changes in cropping patterns and farmers' resource use in peri-urban areas of China. The soil surface nitrogen (N) balances of cereal, orchard and vegetable systems were studied over a 2-year period on smallholder fields in a representative peri-urban area of Beijing. Positive soil surface N balances were obtained across all three cropping systems. The mean annual N surplus of the vegetable system was 1,575 kg N ha(-1) year(-1), or approximately 3 times the corresponding values in the cereal (531 kg N ha(-1) year(-1)) and orchard systems (519 kg N ha(-1) year(-1)). In the vegetable system, animal manure (1,443 kg N ha(-1) year(-1) on average) was the major source of N input (65 % of the total N input) and the factor with strongest impact on the N surplus. In the cereal system, however, about 74 % of the total N input originated from mineral fertilizer application which was the major contributor to the N surplus, while in the orchard system, the N surplus was strongly and positively correlated with both mineral fertilizer and animal manure applications. Furthermore, within each cropping system, N fertilization, crop yields and N balances showed large variations among different smallholder fields, especially in orchard and vegetable systems. This study highlights that differences in farming practices within or among cropping systems should be taken into account when calculating nutrient balances and designing strategies of integrated nutrient management on a regional scale.