• Authors:
    • Yang, W.
    • Liu, W.
    • Wan, Y.
    • Zhang, J.
    • Xiang, D.
    • Yong, T.
  • Source: Acta Prataculturae Sinica
  • Volume: 20
  • Issue: 6
  • Year: 2011
  • Summary: The aim of this paper was to study the mechanisms of interspecific nitrogen facilitation and transfer in the relay strip intercropping systems of "wheat/maize/soybean" and "wheat/maize/sweet potato". The methods of root barrier and 15N-isotope dilution were used to investigate the nitrogen transfer, nitrogen uptake and residual effect in the two relay strip intercropping systems. Comparing the no barrier with solid barrier, the results showed that in-season 15N uptake and 15N recovery efficiency of wheat increased remarkably, and 15N% abundance left in soil and total N content reduced obviously. In the "wheat/maize/soybean" system, the in-season 15N uptake and 15N recovery efficiency, 15N% abundance left in soil and total N content of maize with no barrier increased by 25.16%, 25.16%, 13.89% and 10.15%. But in the "wheat/maize/sweet potato" system, the value of above indices reduced by 15.98%, 15.99%, 17.37% and 5.19%. For soybean, the in-season 15N uptake and 15N recovery efficiency, 15N% abundance left in soil reduced, the soil total N content increased by 3.03%. For sweet potato, the in-season 15N uptake and 15N recovery efficiency increased, 15N% abundance left in soil and total N content reduced by 0.91% and 4.95%. In the "wheat/maize/soybean" system, the 15N uptake and 15N recovery efficiency of wheat and maize obtained from previous wheat, maize and soybean were higher than that of the "wheat/maize/sweet potato" system. The 15N uptake and 15N recovery efficiency of soybean obtained from previous wheat or maize were lower than that of sweet potato, but that from previous soybean was higher than that from previous sweet potato. The "wheat/maize/soybean" system was more beneficial to increase annual nitrogen uptake, nitrogen residual effect and maintaining soil fertility.
  • Authors:
    • Wang, R.
    • CHEN-Zhi
    • Sun, Y.
    • Zhao, Y.
  • Source: Journal of Northwest A & F University - Natural Science Edition
  • Volume: 39
  • Issue: 4
  • Year: 2011
  • Summary: Objective: The paper uncovered the wheat and potato strip intercropping farmland's resistance effects to wind erosion in the agro-pastoral ectone in order to provide theoretical foundation and techonological direction. Method: Based on agro-pastoral mixed areas of Yinshan Mountain in Inner Mongolia, soil-erosion testing experiments were conducted on three stubble coverage farmland (wheat stubble coverage, coverage 65% and 76%, stubble height 20 cm and 30 cm; naked oats stubble coverage, coverage 90%, stubble height 30 cm) under 5 scheduled velocities (6, 9, 12, 15 and 18 m/s) by means of the movable wind tunnel and its suited velocity and sand sampling equipments. The author analyzed the change disciplinarian of the surfaces' aerodynamic roughness and wind erosion amount with the increasing distance of tested points (3, 3.75, 4.5, 5.25 and 6 m) from wind tunnel experiment section entrance (Simulating conservation tillage farmland's stubble widths). Result: The roughness of three kinds of surface showed early increasing and subsequent decreasing trend with the increasing distance of tested points from wind tunnel experiment section entrance under different velocities and the majority reached the max when the distance was 5.25 m; The wind erosion amount revealed rapid decreasing trend with the increasing distance of tested points from wind tunnel experiment section entrance under different velocities, the decreasing trend of wind erosion amount was gentle when the distance reached 5.25 m. Conclusion: Conservation tillage farmland's stubble height and vegetation coverage increase anti-wind erosion significantly. Anti-wind erosion effect of conservation tillage farmland tends to be more steady and significant when conservation tillage farmland effective width reaches 5.25 m.
  • Authors:
    • [Anonymous]
  • Source: Soils Newsletter
  • Volume: 34
  • Issue: 1
  • Year: 2011
  • Summary: Through an IAEA technical cooperation project, the Turkish Atomic Energy Agency, in cooperation with the Nigde Potato Research Institute and the Soil and Fertilizer Research Institute, an innovative drip fertigation technology was implemented to improve water and nitrogen fertilizer use efficiency in potato production in the Nigde-Nevsehir Region. This technology reduced the amount of irrigation water needed by 50% and nitrogen fertilizer use by 40%, from 1000 to 600 kg N/ha. Drip fertigation technology increased water and nitrogen use efficiency by applying water and nitrogen directly to the immediate vicinity of the plant roots through a network of pipes and water emitters. Considering the magnitude and importance of potato production in the arid and semiarid areas of Turkey, the 50% reduction in crop water requirements through drip fertigation has a major impact on agricultural production and water management strategies in these areas. It was calculated that a transition from sprinkler irrigation to drip fertigation requires an initial investment cost of up to US $200/ha, depending on the sophistication of the drip fertigation system. This investment can be balanced against projected savings in time, energy, fertilizer and labour costs amounting to an estimated US $2000/ha/year. As a consequence, interest in drip fertigation has been remarkable among potato farmers in the region, so that in only three years the area under drip fertigation has increased from humble beginnings of 500 ha in 2005 to 4000 ha in 2007 and to nearly 7000 ha in 2010.
  • Authors:
    • Ren, H.
    • Rosen, C.
    • Qing, C.
    • Fan, M.
    • Alva, A.
  • Source: Journal of Crop Improvement
  • Volume: 25
  • Issue: 1
  • Year: 2011
  • Summary: Potato ( Solanum tuberosum L.) is the fourth most important food crop in the world after corn, wheat, and rice. It is adapted to a wide range of growing conditions, producing high yields with a near-optimum balance of nutrients for human consumption. China is the world's largest potato producer and continues to account for a large part of the global increase in potato production. Although the potato can be highly productive, it has a relatively shallow root system and often requires significant nutrient inputs to maintain tuber productivity and quality. Each metric ton of tubers removes approximately 3.8 kg nitrogen (N), 0.6 kg phosphorus (P), and 4.4 kg potassium (K). Proper nutrient management, therefore, is extremely important for sustaining high tuber yield and quality. Lack of adequate balanced fertilization in China is reportedly a yield-limiting factor in some areas. For example, potassium (K) is very important for producing a potato crop with high tuber yield and quality. Limited K resources in China and continued cropping have resulted in below-adequate levels of soil K in many regions of the country, which will impact potato production. On the other hand, based on U.S. experience, the high nutrient demand by potato, application of high rates of fertilizer, and production on coarser textured soils can result in nutrient losses. Nutrient best-management practices are developed with the objective of optimizing production, net returns, and minimizing environmental degradation. In general, optimal N management has had the most important impact on tuber yield and quality compared with the other essential elements. Best management practices for N fertilization include appropriate selection of rate, source, timing, and method of application. Optimal management of irrigation is also important to improve N-uptake efficiency and minimize N losses while maintaining high yields and quality. Phosphorus is another key nutrient important from both production and environmental standpoints. Adequate P is required for optimum tuber-set, while excessive rates may result in soil-P buildup and potential runoff problems. This review will focus on various management techniques to maximize nutrient-uptake efficiency by potatoes.
  • Authors:
    • Mohamed, M.
    • Azam, A.
  • Source: Bulletin of Faculty of Agriculture, Cairo University
  • Volume: 62
  • Issue: 2
  • Year: 2011
  • Summary: The present study aimed at identifying the knowledge level of potato farmers regarding export conditions of potatoes to the European Union (EU), to determine the differences between the knowledge degrees of the farmers in two villages to identify farmer opinions regarding the environmental effects of the agricultural part of the Egyptian-European convention, and to identify the problems facing farmers since the implementation of the Egyptian-European convention. The study was conducted in the village of "Sayedna Solomon" in Nobariya area, Beharia Governorate as one of the largest areas inside the Pest Free Area (PFA), and the village of "Talia", Menofia Governorate as one of the largest areas outside the Pest Free Area (PFA). A random sample of 50 farmers was chosen from Sayedna Solomon village and 100 farmers from Talia village. Data were collected through personal interviews with respondents by using pre-tested questionnaires prepared specifically to achieve the study objectives. Frequencies, percentages, means, and standard deviations, in addition to "t" test were used to present and analysis of the obtained data. The most important results of the study were 1 - There was significant differences at 0.05 level between farmers' level of knowledge in the two studied villages regarding the export conditions of potatoes to the (EU). 2 - There was an increase in the negative environmental effects on small farmers resulting from applying the Egyptian-European convention as the investigated farmers expressed, and the differences between the two studied villages were significant at 0.01 level. 3 - There were main problems facing small farmers in the "Sayedna Solomon" village concerning the market of the crop locally, the low export prices, and the shortage of irrigation water in the summer, while the main problems in "Talia" village were concerning the lack of input supply and the high prices of the inputs, the irrigation problem, and the problem of marketing the crop locally.
  • Authors:
    • El-Tohamy, W.
    • Taalab, A.
    • Badr, M.
  • Source: Australian Journal of Basic and Applied Sciences
  • Volume: 5
  • Issue: 7
  • Year: 2011
  • Summary: Drip irrigation offers excellent method of water and nutrient supply for vegetable crops in precise amounts at a rate, which matches the plant requirements. In addition to allowing precise control of irrigation water applications, drip irrigation system offers the ability to use high frequency fertigation with water soluble N materials throughout the growing season. Little information about optimum fertigation interval for drip-irrigated crops in general and for potato in particular, is available. The present study was conducted to determine the effects of two N rates (200 and 300 kg N ha -1) and four fertigation frequencies (1, 2, 7, and 14 days) on potato yield, N uptake and soil N status in a sandy soil under drip irrigation system. Total potato yield and yield components were responsive to increase N rate and to decrease fertigation frequency. The highest tuber yields (47.16, 46.32 and 44.75 t ha -1) occurred at 300 kg N ha -1 with the frequencies of 1, 2 and 7 days, respectively while yield with the longest interval were significantly lower (37.89 t ha -1). Leaves N concentration at all sampling dates was higher in the plants received high N rate, but fertigation frequency did not significantly affect leaves N concentration except at the longest duration. Similarly, N rate and fertigation frequency resulted in significant differences in total N uptake, N recovery and apparent N use efficiency (NUE). Total N uptake was appreciable higher with increasing N rate and with more frequent than with less frequent fertigation. The averaged N recovery across fertigation frequencies was 68% and 62% and NUE was 151 and 142 kg yield -1 kg N -1 with applied 200 and 300 kg N ha -1, respectively. Analysis of soil samples at the end of last fertigation indicated considerable influence of fertigation frequency on NO 3--N distribution in the root zone of potato. The NO 3--N in lower soil profiles,(40-60 cm) depth with high N rate was marginally affected in daily, alternate and weekly fertigation while NO 3--N in the corresponding soil depth was appreciable higher in biweekly fertigation. Thus, frequent fertigation was needed to obtain maximum yield of potato in sandy soil with less nitrate leaching from root zone.
  • Authors:
    • Sanjani, S.
    • Bannayan, M.
  • Source: Agricultural and Forest Meteorology
  • Volume: 151
  • Issue: 12
  • Year: 2011
  • Summary: Climate variability and weather extremes are principal sources of fluctuations of annual productivity of many crops in arid and semi-arid environments. Temperature and precipitation are the major weather variables that determine the variability of crop yields. In this study, the relationship between weather descriptors and major irrigated crops yield were assessed for Khorasan province in northeast of Iran. Long term daily weather (1984-2007) and crop yield (wheat, barley, sugarbeet, cotton, potato, chickpea, alfalfa) data were analyzed with simple correlation analysis and also the iterative chi-square analysis identified relationships of low and high wheat yield years to maximum and minimum air temperatures within each region. Our results indicated that association between various crop yield and descriptors varied in different study location. As in Bojnourd located in the north of Khorasan yields of the crops studied did not correlate with temperature indicators, whereas in Birjand the relationship between temperature descriptors and crop yields were strong. Correlation between growing season precipitation and wheat, barley, chickpea and sugarbeet yields was positive while cotton yield decreased with increasing precipitation during the growing season. The results of chi-square analysis for wheat yield demonstrated that the critical time in which extreme temperature led to yield loss differed among regions. In Bojnourd, in late April to early May, and excess days (high or low yield years have more days meeting a cardinal value than normal years) with maximum temperature higher than 30 degrees C, wheat yield decreased while in Birjand, cooler maximum temperature (
  • Authors:
    • Nelson, D.
    • Hopkins, A.
    • Barker, A.
    • Brown, A.
  • Source: IOBC/WPRS Bulletin
  • Volume: 64
  • Year: 2011
  • Summary: The mollusc specific parasitic nematode Phasmarhabditis hermaphrodita (Nematoda: Rhabditida) has been shown to infect and kill a number of economically important pest slug and snail species. This beneficial nematode is available commercially under the trade name Nemaslug (Becker Underwood Ltd., Littlehampton, UK). Use of this biological control agent by large commercial growers is increasing. This increase in use also includes expanding from its traditional markets in higher value salads, to broad acre vegetables such as potatoes. Use of P. hermaphrodita has increased in recent years on outdoor crops due to a number of factors. Firstly additional products are often needed to compliment the available chemicals (e.g. Methiocarb, Metaldehyde and Ferric phosphate) in sub-terranian environments where they are often not as effective. Secondly there is a drive for more environmentally sensitive farming practices of which biological control, as part of an integrated pest management program, is an important component. This expansion into new markets, such as potatoes, has presented a number of challenges in applying these microscopic worms. Application of these soft bodied nematodes now needs to be carried out to large areas over long periods of time. To enable a grower to be able to do this, nematode specific application equipment has been developed. The Wroot water Nemaslug Xtra applicator is an injection unit which, whilst being able to inject nematodes into irrigation water for a boom or gun, can keep the nematode solution constantly agitated and supplied with oxygen. This system has been shown to be able to keep the nematodes alive and mixed in suspension for over 24 hours. This equipment allows a grower the increased flexibility of no longer having to wait for rain to apply and reduced application labour costs by not having to spend time spraying P. hermaphrodita onto the crop with a tractor mounted boom. The Wroot water Nemaslug Xtra applicator is the first ever piece of nematode specific application equipment developed. This equipment has been designed, built and made available for commercial growers, specifically for use of applying the biocontrol agent P. hermaphrodita (Nemaslug Xtra) to broad acre vegetable crops.
  • Authors:
    • Casanova,S.
    • Garcia,C.
    • Vilaro,F.
    • Carlesso,R.
  • Source: Acta Horticulturae
  • Issue: 889
  • Year: 2011
  • Summary: The potato crop ( Solanum tuberosum L.) is of great importance in the Uruguay economy, being the major vegetable in volume of trade. Uruguay imports some amount of potato seed annually. The National Institute of Agricultural Research (INIA) has been engaged for the last decades to obtain cultivars more adapted to country agroecological conditions, easier to multiply locally for replacing imported seed cultivars such as 'Chieftain'. In this sense, promising cultivars including 'INIA-Ipora' were developed. The objective of this work was to study the morpho-physiological and yield modifications of two potato cultivars ('Chieftain' and 'INIA-Ipora') under different irrigation managements. The experiment was carried out during 2006 and 2007 growing seasons under a rainout shelter, at the Experimental Station INIA Las Brujas, in Uruguay. These two varieties were studied under two irrigation managements: (i) irrigated treatment (2003/04 rainfall+irrigation according to daily crop ETc) and; (ii) deficit irrigated treatment (2003/04 rainfall+one irrigation of 25 mm when the accumulated maximum daily crop evapotranspiration reached 90 mm). The maximum daily crop evapotranspiration was estimated using the FAO Penman-Monteith equation. The experimental design was a completely randomized split plot. The leaf area index, the total plant photosynthesis and the crop yield better responded to the irrigation regime. The two potato cultivars showed differences in length of growing season, leaf area, number of mainstems, plant height and plant transpiration rates. The yield components were modified by the irrigation managements, and differences in commercial yield and total number of plant tubers were observed between the 'Chieftain' and 'INIA-Ipora' cultivars.
  • Authors:
    • Detpiratmongkol, S.
    • Chumthong, B.
    • Ubolkerd, T.
  • Source: Proceedings of the 49th Kasetsart University Annual Conference, Kasetsart University, Thailand, 1-4 February, 2011. Volume 1. Subject: Plants
  • Year: 2011
  • Summary: Presently, little is know of the response of sweet potato to different water irrigation amounts. Thus, the purpose of this study was to investigate the effects of different water irrigation amounts on growth and yields of sweet potato. A split plot in randomized complete block design with three replications was used. Six sweet potato cultivars such as Thorpheug, Kai, China, Japan, Pichit 101 and Pichit 1665 were as main plot and sub plot were 4 irrigation regimes based on the ratios of irrigation amount (IW) to cumulative evaporation (E) (i.e., 0.3, 0.5, 0.7 and 1.0). The results disclosed that China cultivar gave the highest growth, total dry weight and root dry weight yield followed by Japan, Kai, Pichit 101, Pichit 1665 and Thorpheug, respectively. Total dry weight and yield significantly increased with increasing the amounts of irrigation from IW/E 0.3 to IW/E 1.0. The lower water regimes increased leaf temperature whereas transpiration rate and total conductance were reduced. However, we were not found the interaction between sweet potato cultivars and water irrigations.