• Authors:
    • Levy, Y.
    • Raveh, E.
  • Source: Israel Journal of Plant Sciences
  • Volume: 59
  • Issue: 2/4
  • Year: 2011
  • Summary: During the last 50 years world irrigation has doubled while water withdrawal has tripled, leading to a global water crisis. As a result, growers around the world are forced to utilize effluent water for irrigation. In Israel the main source for such water is "SHAFDAN", i.e., tertiary-treated waste water, which is characterized by high chloride content that might increase in the future. These days about 33% of Israeli citrus orchards are irrigated with this water, yet its potential effect on citrus orchards is not clear. Citrus is one of the major fruit crops of the world and is relatively salt-sensitive. Recently it was reported that continuous application of KNO 3 might reduce chloride (Cl) uptake, and thus overcome the toxic effects of salinity. We examined the effect of KNO 3 fertilization and rootstock on grapefruit's response to salinized SHAFDAN reclaimed water over four years. Trees were grafted on five different rootstocks and fertigated with two KNO 3 regimes (118 vs. 148 mg 1 -1 NO 3), and exposed to five levels of salinized reclaimed water (from 221 to 765 mg 1 -1 Cl). During the experiment, soil electrical conductivity (EC) ranged from 2 dS m -1 (above the threshold for yield reduction) to 5 dS m -1. Leaf Cl (with the exception of trees grafted on Troyer) usually kept below toxicity level, i.e., >0.4%. Cumulative yield reduction due to salinity was 37.6, 21.3, 18.2, 17.2, and 12.6 kg per tree per dS m -1 of soil paste extract, for trees grafted on 812, SO, Volk, Gau, and Troy rootstocks, respectively, reflecting their sensitivity to the osmotic component of salt stress. Enhanced application of KNO 3 did not overcome the osmotic effect of salinity. These results indicate that while using reclaimed water, the osmotic component of salinity can be of higher significance than its toxic component, and more attention should be given in the future to the rootstock/scion combination's sensitivity to the osmotic component of salinity.
  • Authors:
    • Puerto-Molina, H.
    • Sacristan-Beltri, E.
    • Melian-Navarro, A.
    • Ruiz-Canales, A.
    • Molina-Martinez, J. M.
  • Source: Acta Horticulturae
  • Issue: 889
  • Year: 2011
  • Summary: Along the Mediterranean countries, water scarcity is a structural problem. In the Southest of Spain water shortage is becoming more acute, specially in the agricultural sector. In these areas the cultivation of citrus fruits is very important but those are irrigation, intensive crops with important water requirements. In order to optimize available water offer and rationalize the demand management an increase of the efficiency of existing irrigation systems could be achieved by the improvement of irrigation scheduling techniques. During the last years, irrigation systems have undergone a modernisation process, the majority of which implied the change of surface irrigation to drip irrigation systems. These changes have been promoted both by national and regional administrations and farmers. However, the adoption of drip irrigation has not involved an adequate irrigation management and thus, these irrigation facilities have not reached high values of efficiency, as compared to the potential efficiency of drip irrigation systems. An adequate irrigation scheduling is necessary in order to increase the efficiency values mainly avoiding infiltration water losses and applying only the water required to meet crop water needs. Traditional irrigation scheduling is based on a soil water balance model as the proposed by FAO. This methodology has proven to be partially accurate for fruit trees. For this reason is important to assess some possible alternatives or complements to the FAO model. Finally, the application of several systems of irrigation scheduling for citrus trees based on water content gauges has been studied. Some results, advantages and disadvantages of these systems are analyzed.
  • Authors:
    • Liu, Y.
    • Ma, L.
    • Li, X.
  • Source: Acta Phytophylacica Sinica
  • Volume: 38
  • Issue: 3
  • Year: 2011
  • Summary: In order to fully understand the regular pattern of the population dynamics of Lithocolletis ringoniella Matsumura in the apple production region of the Loess Plateau, the distribution pattern and the ecological niche index were determined and the clustering analysis was conducted to describe the dynamic change of L. ringoniella population. The results showed that the leaf insect spot caused by L. ringoniella was visible in June; the number of the insect increased in July, with the damage symptom severe in August; and the quantity of the population number was in surge in September and October. The relative abundance of the temporal sequence was in a strong rising trend since August. Population distribution in the crown was uniform in early July and aggregative after that. The spatial distribution among the vertical positions of the tree crown showed significant difference, population number following the order of lower > middle > upper parts, whereas distribution among horizontal directions had no significant difference. The general distribution within the crown appeared in cluster, with individuals attractive to each other. The ecological niche occupation of this pest in vertical and horizontal directions as well as in temporal sequences are 0.179, 0.371 and 0.594, respectively. The resource utilization rate in the lower part of the crown reached 53.73% and almost nothing utilized in the upper part, indicating a more horizontal expansion potential. Viewing from the four directions, the maximum utilization of resources was in the north and east, up to 27.90% and 21.66% respectively. The ecological niche overlap index of L. ringoniella with hawthorn spider mite in vertical and horizontal directions reached 92.65 and 64.95, respectively, in addition to temporal sequence to be 66.36, indicating that hawthorn spider mite is the most intense space-temporal competitor for the limited resources of apple's crown leaves. The dominance degree index of L. ringoniella in the young apple orchard in different intercropping patterns increased over time since August and largest increase happened in the middle of August. The highest dominance degree index was found in soybean-apple intercropping pattern and the lowest index with sweet potato-apple intercropping pattern. The index fluctuated in the orchard with weeds unwell-managed.
  • Authors:
    • Chernchom, P.
    • Wetayaprasit, P.
    • Somboonsuke, B.
    • Pacheerat, K.
  • Source: Kasetsart Journal, Social Sciences
  • Volume: 32
  • Issue: 2
  • Year: 2011
  • Summary: The rubber agroforestry system is an alternative agriculture practice for rubber smallholders to enhance the ecological integrity and crop diversity. The data collection for the study of diversification of smallholding rubber agroforestry system (SRAS) included 300 rubber farms of 21 systems in the south, east, and northeast of Thailand. The project results revealed that there are a multitude of 21 rubber farming systems in Thailand. These systems can be classified into three main types: (1) the intercropping rubber-food crop system, growing short-lived plants, for example, pineapple, chili, banana, rice, sweet potato, long bean and corn, for a rubber period, no longer than 36 months; (2) the rubber-fruit crop system, growing multicrop within the rubber area during the rubber productive period. The most common fruit crops that have been grown in Thailand are guava, gnetum, long kong, salacca, mangosteen, durian, and levistona, etc., and (3) the rubber-timber species system, normally yielding higher income to rubber smallholders since the sales of both rubber and wood products are at the same time and this is coupled with the presently high value of wood. The important timber varieties in the rubber area are neem and teak. As for profitability of Smallholding Rubber Agro forestry System (SRAS), it was noted that pineapple, chili, salacca, and gnetum are highly profitable. However, in the rubber-pineapple system which yields the highest income, the cost of investment is the highest too, when compared to the rubber-gnetum system which requires minimal input and low cost of production and management. The main conditions for decision-making in the rubber intercropping system are as follows: (1) farm household labor requirement, (2) knowledge and experience, (3) extension and policy implication, (4) marketing opportunity, (5) consistent capability of local communities, and (6) land topography and sustainability. For SRAS development strategy in the southern Thailand, improvement should be made on pricing and marketing of agroforestry products, appropriate technology for higher productivity, greater farm efficiency and risk reduction at farm level, and more synchronized co-ordination among stakeholder agencies at the regional level.
  • Authors:
    • Hore, J. K.
  • Source: The Jackfruit
  • Year: 2011
  • Summary: Jackfruit is popularly known as poor man's fruit in eastern and southern parts in India. The tree can be cultivated on marginal land and does not require intensive management to provide a good crop. The jack fruit is adopted only to humid tropical and near-tropical climates. It thrives from sea level to an altitude of 1600 m. It is grown on a variety of soils, deep alluvial, sandy loam, or clay loam of medium fertility, calcareous or lateritic soil, shallow limestone or stony soil with a pH of 5.0-7.5. The tree exhibits moderate tolerance to saline soils and poor drought and flood tolerance. The jack flourishes in rich, deep soil of medium or open texture, sometimes on deep gravelly or laterite soil. The best time for planting grafts or seedlings is June to August but with irrigation facilities it may be extended upto November. Pits of 1.0 m cube are dug at least 10 days before planting at a spacing of 8*8 m to 10*10 m. About 30 kg well-rotted farm yard manure, 500 g superphosphate and 250 g. muriate of potash are mixed with the top soil of the pit and refilled. Spraying of gibberellic acid (25-200 ppm) enhances both shoot and root growth. The young trees must be kept weed few during first three to four years. A 5-10 cm mulch will be good for suppression of weeds as well as to maintain soil moisture, particularly during the dry period. Regular punning of weak, dead and diseased branches at the end of rainy season is recommended. Fruit thinning is also recommended to prevent damage to branches due to heavy fruit load. Based on the firmness of flesh cultivated types are of two general groups (i) soft flesh - the pulp of ripe fruit is very juicy and soft, (ii) firm flesh - the flesh pulp is firm and crispy at ripe and can be preserved for several months. Some types are available with their common names viz., Gulabi, Hazari, Champaka, Rudrakshi, Singapore etc. The trees need good nutrition to promote regular and good bearing. The quantity of fertilizer required depends on vigour and age of trees and fertility of soil. The quantity of FYM varied from 20-50 kg/plant. The NPK dose (g/plant/year) for mature plant is 750:400:500 in Tamil Nadu, 800:480:1050 in Madhya Pradesh, 600:300:240 in Karnataka and 210:160:1000 in Assam. The yearly amount should be applied in two splits i.e., at the beginning of rainy season and after the rainy season is over. Manures and fertilizers should be applied in the drip zone i.e. 10 m wide circular basin, leaving 50 cm, around tree trunk. The Jackfruit is not normally irrigated. The trees are sensitive to drought and respond well to irrigation between flowering and fruiting. Since jackfruit takes about 8-10 years to attain full bearing, intercropping with vegetables like tomato, brinjal, chilli, cabbage, bhindi etc. and leguminous crops like cowpea, gram, kalai etc. will benefit the farmer. Seedling trees start bearing from 7th to 8th year onwards while the grafted ones from third year. The tree attains its peak bearing stage in about 15-16 years of planting. Period of fruit development is February to June. The optimum stage of harvesting has been reported to be 90-110 days after appearance of the spike. The fruit matures towards the end of summer in June. A tree bears upto 250 fruits annually, weighing about 3 kg to 25 kg with yield variation of 50-80 tonnes of fruit/ha.
  • Authors:
    • Fahed, S.
    • Rana, G.
    • Katerji, N.
  • Source: Hydrological Processes
  • Volume: 25
  • Issue: 1
  • Year: 2011
  • Summary: In this paper two models are presented for calculating the hourly evapotranspiration lambda E (W m -2) using the Penman-Monteith equation. These models were tested on four irrigated crops (grass, soya bean, sweet sorghum and vineyard), with heights between 0.1 and 2.2 m at the adult growth stage. In the first model (Katerji N, Perrier A. 1983. Modelisation de l'evapotranspiration reelle ETR d'une parcelle de luzerne: role d'un coefficient cultural. Agronomie 3(6): 513-521, KP model), the canopy resistance rc is parameterized by a semi-empirical approach. In the second model (Todorovic M. 1999. Single-layer evapotranspiration model with variable canopy resistance. Journal of Irrigation and Drainage Engineering-ASCE 125: 235-245, TD model), the resistance rc is parameterized by a mechanistic model. These two approaches are critically analysed with respect to the underlying hypotheses and the limitations of their practical application. In the case of the KP model, the mean slope between measured and calculated values of lambda E was 1.010.6 and the relative correlation coefficients r2 ranged between 0.8 and 0.93. The observed differences in slopes, between 0.96 and 1.07, were not associated with the crop height. This model seemed to be applicable to all the crops examined. In the case of the TD model, the observed slope between measured and calculated values of lambda E for the grass canopy was 0.79. For the other crops, it varied between 1.24 and 1.34. In all the situations examined, the values of r2 ranged between 0.73 and 0.92. The TD model underestimated lambda E in the case of grass and overestimated it in the cases of the other three crops. The under- or overestimation of lambda E in the TD model were due: (i) to some inaccuracies in the theory of this model, (ii) to not taking into account the effect of aerodynamic resistance ra in the canopy resistance modelling. Therefore, the values of rc were under- or overestimated in consequence of mismatching the crop height. The high value of air vapour pressure deficit also contributed to the overestimation of lambda E, mainly for the tallest crop. The results clarify aspects of the scientific controversy in the literature about the mechanistic and semi-empirical approaches for estimating lambda E. From the practical point of view the results also present ways for identifying the most appropriate approach for the experimental situations encountered.
  • Authors:
    • Dhankhar, O. P.
    • Sharma, K. D.
    • Sushil Kumar
    • Kaushik, R. A.
    • Kaushik, N.
  • Source: Indian Journal of Horticulture
  • Volume: 68
  • Issue: 1
  • Year: 2011
  • Summary: The combinations of different tree species namely guava ( Psidium guajava)+ shisham ( Dalberiga sissoo), guava ( Psidium guajava)+ khejri ( Prosopis cineraria), aonla ( Embilica officinalis)+ shisham and aonla+ khejri were planted during Oct. 2000 at a spacing of 6 m * 6 m. After establishment of trees from July 2001 the crop sequences, viz., ridgegourd ( Luffa acutangula)-tomato ( Lycopersicon esculentum), moongbean ( Vigna radiata) - fallow and clusterbean ( Cyamopsis tetragonoloba) - fallow were raised in the interspaces of the trees. Ridgegourd and tomato were raised with drip irrigation (100, 70 and 40% ETc), while moongbean and clusterbean were raised as rainfed crops. In general, maximum plant growth (height and diameter) was recorded under 100% level of irrigation for all the tree species. The tree species showed significant variation in growth. Irrigation treatments varied significantly only for diameter. The yield of intercrops was significantly affected by different irrigation levels and was highest at 100% irrigation level but it was not affected by different tree species. The highest yield of 385, 925, 5300 kg/ha of moongbean, clusterbean and ridgegourd were recorded under guava+ khejri at 100% ETc irrigation level. During rabi season (winter; November-March) maximum yield of tomato (46,220 kg/ha) was observed under 100% ETc. Water use efficiency for trees ranged from 1.19 to 11.0 g/l. Maximum WUE was observed in ridgegourd at all the irrigation levels under different systems.
  • Authors:
    • Uygur, F. N.
    • Koloren, O.
    • Kitis, Y. E.
  • Source: African Journal of Agricultural Research
  • Volume: 6
  • Issue: 5
  • Year: 2011
  • Summary: Weeds are one of the most important problems in newly established orchards. Especially in organic orcharding, the importance of weed management is much more than conventional orcharding. Therefore, importance of alternative methods to chemical control of weeds is increasing. This study was conducted to quantify the effects of common vetch (Vicia sativa L.) as living mulch on weeds and evaluate the availability of common vetch in organic citrus production. The study was carried out in Mandarin orchard which was established specially for this research in research and implementation area of the Plant Protection Department of Cukurova University in Turkey, in a three-year-period. Living mulch and control plots were placed between rows in newly established mandarin orchard and plots were maintained at the same locations until the end of the experiment. In this study, effects of the living mulch application on density, cover proportion, biomass, dry weight and similarity index of weed species were investigated. Overall three-years results of the study were evaluated, living mulch application reduced weed density and cover proportion average of 42.8% and 45.9% respectively compare to control. Biomass and dry weight of weeds were also reduced by living mulch in all years of the experiment. The results indicate that living mulch application by common vetch is an important alternative weed suppression method for ecological weed management.
  • Authors:
    • Mahajanashetti, S. B.
    • Kunnal, L. B.
    • Basavaraja, H.
    • Acharya, S. P.
    • Bhat, A. R. S.
  • Source: Agricultural Economics Research Review
  • Volume: 24
  • Issue: 2
  • Year: 2011
  • Summary: The nature and extent of crop diversification in the Karnataka state has been analyzed by collecting secondary data for a period of 26 years from 1982-83 to 2007-08. Composite Entropy Index (CEI) and multiple linear regression analysis have been used to analyze the nature and extent of crop diversification in the state. The CEI for different crop groups has shown that almost all the crop groups have higher crop diversification index during post-WTO (1995-96 to 2007-08) than during pre-WTO (1982-83 to 1994-95) period, except for oilseeds and vegetable crops. There has been a vast increase in diversification of commercial crops after WTO. Crop diversification is influenced by a number of infrastructural and technological factors. The results have revealed that crop diversification influences production. The study has suggested that the creation of basic infrastructural facilities like sustained supply of irrigation water, markets, fertilizer availability, proper roads and transportation is an essential pre-requisite for creating enabling conditions for fostering the process of agricultural development and crop diversification, as most of these parameters are found to influence the nature and extent of crop diversification.
  • Authors:
    • Pecchioni, N.
    • Perata, P.
    • Milc, J.
    • Meriggi, P.
    • Arru, L.
    • Caffagni, A.
  • Source: Communications in Soil Science and Plant Analysis
  • Volume: 42
  • Issue: 6
  • Year: 2011
  • Summary: Iodine is an essential microelement for human health, and the recommended daily allowance (RDA) of such element should range from 40 to 200 g day -1. Because of the low iodine contents in vegetables, cereals, and many other foods, iodine deficiency disorder (IDD) is one of the most widespread nutrient-deficiency diseases in the world. Therefore, investigations of I uptake in plants with the aim of fortifying them can help reach the important health and social objective of IDD elimination. This study was conducted to determine the effects of the absorption of iodine from two different chemical forms - potassium iodide (I -) and potassium iodate (IO -3) - in a wide range of wild and cultivated plant species. Pot plants were irrigated with different concentrations of I - or IO -3, namely 0.05% and 0.1% (w/v) I - and 0.05%, 0.1%, 0.2%, and 0.5% (w/v) IO -3. Inhibiting effects on plant growth were observed after adding these amounts of iodine to the irrigation water. Plants were able to tolerate high levels of iodine as IO -3 better than I - in the root environment. Among cultivated species, barley ( Hordeum vulgare L.) showed the lowest biomass reductions due to iodine toxicity and maize ( Zea mays L.) together with tobacco ( Nicotiana tabacum L.) showed the greatest. After the screening, cultivated tomato and potato were shown to be good targets for a fortification-rate study among the species screened. When fed with 0.05% iodine salts, potato ( Solanum tuberosum L.) tubers and tomato ( Solanum lycopersicum L.) fruits absorbed iodine up to 272 and 527 g/100 g fresh weight (FW) from IO -3 and 1,875 and 3,900 g/100 g FW from I -. These uptake levels were well more than the RDA of 150 g day -1 for adults. Moreover, the agronomic efficiency of iodine accumulation of potato tubers and tomato fruits was calculated. Both plant organs showed greater accumulation efficiency for given units of iodine from iodide than from iodate. This accumulation efficiency decreased in both potato tubers and tomato fruits at iodine concentrations greater than 0.05% for iodide and at respectively 0.2% and 0.1% for iodate. On the basis of the uptake curve, it was finally possible to calculate the doses of supply in the irrigation water of iodine as iodate (0.028% for potato and 0.014% for tomato) as well as of iodide (0.004% for potato and 0.002% for tomato) to reach the 150 g day -1 RDA for adults in 100 g of such vegetables, to efficiently control IDD, although these results still need to be validated.