• Authors:
    • Zhang, S. B.
    • Gong, X. F.
    • Zhang, R. F.
    • Wang, X. X.
    • Xie, K. Y.
    • Mares,V.
    • Gavilan,C.
    • Posadas,A.
    • Quiroz,R.
  • Source: Scientia Horticulturae
  • Volume: 134
  • Year: 2012
  • Summary: Two field experiments were conducted in two semi-arid areas in northern China to test the response of three potato varieties to supplemental irrigation. Conventional furrow irrigation was compared to the partial root-zone drying (PRD) irrigation system at different watering levels, with and without plastic mulching. Reducing the supplementary water to one half, under both soil-climate conditions tested, did not affect fresh tuber yield; whereas water use efficiency (WUE) was equally incremented by all the reduced water treatments. When this reduction in the amount of supplementary water was managed through the PRD system, the distribution of moisture in the soil seemed to be improved and the potential evaporation was decreased due to the reduced evaporative surface exposed by PRD. The results showed that application of irrigation water per unit area can be reduced relative to common practice in Inner Mongolia and Gansu, maintaining the tuber yields currently obtained by local farmers. A further reduction in the amount of supplemental water, without a substantial decrease in yield, might be feasible with the PRD technique but this may require a more sophisticated irrigation management; and further research to estimate the cost-benefit ratio of such sophistication is needed. Results also showed that under low precipitation and low water retention capacity, the use of plastic mulching and a potato variety selected for drought-prone environments can make the difference for maintaining a high yield while reducing the wasteful use of the water resources.
  • Authors:
    • Ma, C. L.
    • Wang, P.
    • Guo, P.
    • Peng, H. Y.
    • Chen, L .S.
    • Yang, L. T.
  • Source: Scientia Horticulturae
  • Volume: 133
  • Year: 2012
  • Summary: 'Sour pummelo' ( Citrus grandis) seedlings were irrigated for 18 weeks with nutrient solution containing 0 (-Al) and 1.2 mM (+Al) AlCl 3.6H 2O * 0, 10 and 500 M sodium nitroprusside (SNP), a nitric oxide (NO) donor. Leaf malate content did not significantly change in response to SNP with or without aluminum (Al) except for an increase under 1.2 mM Al+10 M SNP, while leaf citrate content decreased with increasing SNP supply. Root malate content kept unchanging with or without Al except for an increase under 500 M SNP in the absence of Al, while SNP-treated roots had a higher or similar citrate content. Al decreased or did not affect malate content in roots and leaves, and citrate content in roots, but increased leaf citrate content. Al-treated roots and leaves displayed lower or similar activities of acid-metabolizing enzymes [phospho enolpyruvate carboxylase (PEPC), NAD-malate dehydrogenase (NAD-MDH), NADP-malic enzyme (NADP-ME), citrate synthase (CS), aconitase (ACO), NADP-isocitrate dehydrogenase (NADP-IDH), phospho enolpyruvate phosphatase (PEPP) and pyruvate kinase (PK)] except that they had higher or similar activities of NADP-ME and PK and Al-treated leaves had a higher or similar activity of PEPP. In conclusion, the OA metabolism in leaves and roots is differently affected by NO and Al interactions.
  • Authors:
    • Chachalis, D.
    • Mavromatis, A.
    • Khah, E. M.
    • Kostoula, S.
    • Zaxos, D.
    • Sakellariou, M.
  • Source: International Journal of Plant Production
  • Volume: 6
  • Issue: 1
  • Year: 2012
  • Summary: The effect of row spacings and irrigation levels on the earliness of seed production of cotton was investigated under the Mediterranean environment of central Greece. This particular cotton growing area is exposed to risk of autumn rainfall that might cause low seed quality in fields allocated primarily for seed production. Two varieties of cotton, Celia and Hersi, were planted in two row spacings (93 and 75 cm) and two irrigation levels (normal and low levels 6160 and 3080 mm ha(-1)). No significant difference in the yield was found among the two varieties, nor between the two row spacings. The low irrigation level had significantly negative effects on the number of squares, bolls, total dry weight and seed cotton production when compared with irrigation level. However, the low irrigation level resulted in a harvest earlier by ten days, which contributed to avoiding autumn rainfall. Seed quality (measured by germination and Warm-Cold Vigour Index Test) was better in seeds from the low irrigation level than in those from the normal irrigation level. Although yield of both varieties was higher under normal irrigation, seed quality was lower compared to low irrigation level. This was evidenced by the higher Free Fatty Acid (FFA) in "normally" irrigated plants. The results of this study showed that low irrigation level offers substantial benefits for early harvesting and production of high seed quality. Moreover, the FFA could be successfully employed as a quick criterion for seed quality ranking.
  • Authors:
    • Zhang, W. F.
    • Zhang, Y. L.
    • Luo, H. H.
    • Wang, J.
    • Yang, L.
    • Zhang, Q. B.
  • Source: China Agriculture Science
  • Volume: 45
  • Issue: 12
  • Year: 2012
  • Summary: Objective: It is of great significance to explore the effects of different irrigation methods and fertilization measures on soil carbon balance in cotton field during cotton growth season in arid region, and to compare the effects of different management practices on soil carbon sequestration intensity in cotton field. Method: Two-factor experiments with two irrigation methods and four fertilizer treatments were conducted during cotton growth period. Drip irrigation and flood irrigation were arranged as two different irrigation methods and organic manure (OM), N P K fertilizer (NPK), combined application of NPK fertilizer and organic manure (NPK+OM) and no fertilization (CK) were arranged as four fertilizer treatments. Soil respiration rate in cotton field was measured by LI-8100 automated soil CO 2 efflux system and root contribution of soil respiration was detected by root exclusion method. Soil carbon sequestration intensity in cotton field under different irrigation methods and fertilization measures was analyzed by calculating net ecosystem productivity (NEP). Result: Under the conditions of different irrigation methods and fertilization measures, seasonal variation of cropland soil respiration rate showed an increase at first, then followed a declining trend with air temperature change. Soil respiration rate reached a peak in mid-July and then reduced to the minimum in mid-October after cotton harvest. Soil carbon emission under drip irrigation was larger than that under flood irrigation, and under the same irrigation condition, the soil carbon emission with NPK+OM treatment was the highest, then with OM, CK, NPK in turn. The ratio of root respiration contribution to soil respiration was fluctuated between 36.38% and 58.74% under drip irrigation method, whereas between 33.73% and 52.03% under flood irrigation method. Root respiration contribution was the highest at the boiling stage. During the whole growth period, the root respiration contribution under drip irrigation and flood irrigation was averagely 48.05% and 44.31%, respectively. The order of net primary productivity (NPP) of cropland was NPK+OM > NPK > OM > CK under different irrigation methods in the whole season. Cotton field was carbon sink under different management practices in the whole season, and the intensity of carbon sink under drip irrigation was stronger than that under flood irrigation. Under the same irrigation condition, the order of the intensity of carbon sink was NPK+OM > NPK > OM > CK. Under the condition of interaction between irrigation method and fertilization measure, the carbon sink intensity was the strongest under drip irrigation method and NPK+OM. Conclusion: In arid region, cotton production using cropland management measures, such as water saving technology of drip irrigation under mulch, combined application of NPK fertilizer and organic manure and straw returning, could not only increase soil organic carbon content, fertilize the soil fertility and improve cotton yield, but also promote to fix carbon and reduce discharge.
  • Authors:
    • Zhang, Z
    • Sui, X.
    • Wang, S.
    • Zhang, L.
    • Gao, L.
    • Zhang, L.
  • Source: Scientia Horticulturae
  • Volume: 138
  • Year: 2012
  • Summary: Water and nitrogen in soil have a great effect on growth and productivity of cucumber (Cucumis sativus L.), which is widely cultivated with high economic benefit in solar greenhouse in North China. To understand the effects of alternate furrow irrigation (AFI) and nitrogen levels on migration of water and nitrogen in soil, accumulation of nitrate-nitrogen (NO3--N) and root growth of cucumber in the solar greenhouse, cucumber variety Jinyu No. 5 was fertilized with different amounts of nitrogen [no nitrogen (CK2), optimal nitrogen (AINo), conventional nitrogen (AINc)] under AFI. Conventional furrow irrigation and conventional nitrogen were used as the control (CK1). The results indicated that soil NO3--N content, electrical conductivity values in the 0-20 cm, 20-40 cm and 40-60 cm layers, and soil residual NO3--N content at the end of the two growing seasons were all increased as the nitrogen fertilizer increased under AFI, especially in the top layer of soil (0-20 cm). However, compared with conventional furrow irrigation, AFI with optimized fertilizer led to increases of root length, root biomass yield, root-shoot ratio of the cucumber crop and economic coefficient (K). AFI also greatly improved both biomass and economic yield water use efficiency. Altogether, AFI with optimized fertilizer (AINo) was a good irrigation practice in the solar greenhouse for increasing the use efficiency of both water and fertilizer, reducing salinity accumulation in the top soil, and maintaining economic yield of cucumber crop. (C) 2012 Elsevier B.V. All rights reserved.
  • Authors:
    • Luo,Y.
    • Zhou,C.
  • Source: Journal of Food, Agriculture and Environment
  • Volume: 10
  • Issue: 2
  • Year: 2012
  • Summary: Panzhuang Irrigation District is one of the Yellow River irrigation areas. The spatial and temporal distribution of water resources is severely uneven in the upper, middle and lower reaches of the irrigation district. In order to solve this problem, it is necessary to study the differences of crop water consumption (evapotranspiration-ET), irrigation amount, soil water and water use efficiency (WUE) of winter wheat, summer maize and cotton which are the main crops in the irrigation district. This paper improved calculating methods of the capillary rise and percolation of the established model. The model was then applied to the upper, middle and lower reaches of the irrigation district. Conclusions by the model simulation were as follows: (I) The model could simulate the dynamics of water balance components of wheat-maize and cotton relatively accurately in the irrigation district. (II) Winter wheat and summer maize (wheat-maize) had the highest ET in the upper reaches, followed by the middle reaches and then the lower reaches. There was almost no difference for cotton ET in the upper, middle and lower reaches. (III) Irrigation amount of wheat-maize was 225-300 mm in the upstream, 300 mm in the middle reaches, and 500 mm in the downstream. Cotton irrigation quantity was 60-150 mm in the upper and middle reaches, and 60-390 mm in the lower reaches. (IV) Soil water basically showed a decreasing trend in growth periods of wheat-maize and cotton in the middle and lower reaches, its recharge was primarily from irrigation of wheat. Combined with other references, there was a trend of soil drying in the North China Plain. (V) Mean values of water use efficiency (WUE) of winter wheat, summer maize and cotton were highest in the middle reaches and lowest in the upstream and downstream.
  • Authors:
    • Li, J.
    • Xu, Y.
    • Yang, J.
    • Liu, J.
    • Wang, J.
    • Zhou, S.
  • Source: Hydrological Processes
  • Volume: 26
  • Issue: 8
  • Year: 2012
  • Summary: Eddy covariance flux measurements were performed at a cotton crop site of an oasis in northern Xinjiang, northwest China from 2008 to 2010 in order to study ecosystem evapotranspiration (ET). The soil surface area was approximately 80% covered by plastic film mulch and a cotton crop was grown with a mean population density of around 24 plants m-2 under drip irrigation. The total annual ET was measured to be 560 mm, which was 350 mm more than the average annual mean precipitation for the time period 19632006. Due to the low vapor pressure deficit associated with low temperatures, the ET was low from November to March. The ET totaled 538 mm during the cotton crop growing season, generally from early-April through mid-October. Mean daily ecosystem ET was 1.41.6 mm day-1 in April and May, 3.44.7 mm day-1 from June through August, 1.82.3 mm day-1 in September and 0.70.8 mm day-1 in October. The diurnal variations of ET in all months were consistent with those of net radiation, although the leaf area index (LAI) and climate conditions changed substantially. Soil water content was not a limiting factor for ET during the period from April through September, as the crop was regularly irrigated. Therefore, ET was mainly controlled by the available energy in April and May, and by leaf area from June through September. Due to a complete lack of irrigation, ET was constrained by soil water in October. These results of ET variability are helpful for improved allocation of water resources and agricultural water use practices in the region. Copyright (c) 2011 John Wiley & Sons, Ltd.
  • Authors:
    • Folegatti, M. V.
    • Paulino, J.
    • Coelho, R. D.
    • Zolin, C. A.
  • Source: Engenharia Agrícola
  • Volume: 32
  • Issue: 3
  • Year: 2012
  • Summary: Although several studies have been conducted to evaluate the uniformity of water application under center pivot irrigation systems, there are few studies concerning the economic perspective of such coefficient. The aim of this study is to present a methodology to accomplish an economic analysis as support for the decision-making to retrofit emitters in center pivot irrigation systems, and to attribute an economic meaning to the uniformity coefficient of water application taking into account the response function productivity to the amount of water applied and the sale price of the crops. In the hypothetic calculation example considering the variation of revenue of potato crop under center pivot irrigation system, it was verified that the area with uniformity coefficient of water application of 90% brought an income increase of BR$ 1,992.00, considering an area about 1,0 ha. Thus, it can be concluded that the methodology presented has met the objectives proposed in the study and made it possible to attribute an economical meaning to the coefficient of water uniformity application.
  • Authors:
    • Coquet, Y.
    • Justes, E.
    • Benoit, P.
    • Alletto, L.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 153
  • Year: 2012
  • Summary: Water drainage and herbicide degradation and leaching were studied during four years in a continuous maize field managed with two tillage systems and two types of fallow periods. The tillage systems consisted of either a conventional practice with mouldboard ploughing (28 cm-depth) or a conservation practice with superficial tillage (
  • Authors:
    • Mengistu, A.
    • Bellaloui, N.
    • Fisher, D. K.
    • Abel, C. A.
  • Source: Journal of Crop Improvement
  • Volume: 26
  • Issue: 3
  • Year: 2012
  • Summary: The objective of this research was to evaluate the effect of drought and Phomopsis on seed composition constituents in Phomopsis susceptible (S), moderately resistant (MR), and resistant (R) soybean genotypes grown under irrigated and non-irrigated environments. Genotypes of maturity group (MG) III and V were grown under field conditions in 2003 and 2005. Seed protein, oil, fatty acids, sugars, and minerals were evaluated in seeds harvested at harvest maturity (R8) and 15 days after harvest maturity (delayed harvesting). The results showed that seed protein and oleic acid were higher in S than in MR or R genotypes at 15 days after harvest maturity in MG III in non-irrigated soybean. For MG V genotypes, seed protein, oil, and oleic acid were higher and linoleic and linolenic acids were lower in MR and R than in S in irrigated and non-irrigated soybean at harvest maturity and 15 days after harvest maturity. In MG III genotypes, seed sucrose, raffinose, and stachyose were higher in MR and R than in S genotypes in irrigated soybean at maturity only. In irrigated or non-irrigated soybean, seed sucrose, raffinose, and stachyose were higher in R than in MR or in S in MG V in 2003 and 2005 at harvest maturity or 15 days after harvest maturity. Seed minerals were also altered in MG III and V. This research demonstrated that seed composition components were altered by drought and Phomopsis and the degree of alteration depended on the level of resistance of the genotype and MG.