Nutrient supply from organic amendments applied to unvegetated soil, lettuce and orchardgrass

Organic sources of nutrients are increasingly being used in horticultural and certified organic production. The nutrient-supplying potentials of poultry manure compost (PM), feather meal (FM), alfalfa meal (AA) and vermicastings (VC) and an unamended control were measured in a growth room experiment. The amendments were applied at rates equivalent to 200, 400 and 800 kg total N ha-1 to a soil of low fertility. Nitrogen supply rates and concentrations were measured over 6 mo in unvegetated pots using PRS™ probes and KCl extraction, respectively. Biomass of lettuce (Lactuca sativa L.) and orchardgrass (Dactylis glomerata L.) and N uptake of orchardgrass were measured. Repeated measures analysis revealed significant amendment × rate × time interaction effects for N supply rate and concentration. Of total N applied, available N was 50 to 70% in the FM and PM treatments, 10 to 40% in the AA treatments, and 10% in the VC treatments. High rates of FM and PM were toxic to lettuce but produced good orchardgrass yields. VC was safe for lettuce but low N availability limited long-term orchardgrass growth. Higher application rates did not result in corresponding increases in nutrient supply. Consideration should be given to balancing the ratio of available nutrients in amendments with plant requirements

Field-scale validation of an automated soil nitrate extraction and measurement system

One of the many gaps that needs to be solved by precision agriculture technologies is the availability of an economic, automated, on-the-go mapping system that can be used to obtain intensive and accurate ‘real-time’ data on the levels of nitrate nitrogen (NO3–N) in the soil. A soil nitrate mapping system (SNMS) has been developed to provide a way to collect such data. This study was done to provide extensive field-scale validation testing of the system’s nitrate extraction and measurement sub-unit (NEMS) in two crop (wheat and carrot) production systems. Field conditions included conventional tillage (CT) versus no tillage (NT), inorganic versus organic fertilizer application, four soil groups and three points in time throughout the season. Detailed data analysis showed that: (i) the level of agreement, as measured by root mean squared error (RMSE), mean absolute error (MAE) and coefficient of efficiency (CE), between NEMS soil NO3–N and standard laboratory soil NO3–N measurements was excellent; (ii) at the field-scale, there was little practical difference when using either integer or real number data processing; (iii) regression equations can be used to enable field measurements of soil NO3–N using the NEMS to be obtained with laboratory accuracy; (iv) future designs of the SNMS’s control system can continue to use cheaper integer chip technology for processing the nitrate ion-selective electrode (NO3 -–ISE) readings; and (v) future designs of the SNMS would not need a soil moisture sensor, ultimately saving on manufacturing costs of a more simple syste

Effects of Salinity and Mycorrhizal Inoculation (Glomus fasciculatum) on Growth Responses of Grape Rootstocks (Vitis spp.)

A pilot experiment was conducted to determine the effects of soil salinity and inoculation with arbuscular mycorrhizalfungus (Glomus fasciculatum) on growth (shoot length, leaf number, internode length, and total dry weight), sporecount and root colonisation of grape rootstocks (Salt Creek, St. George, Dogridge and 1613). Analysis of varianceresults revealed that increasing salinity reduces growth, spore count and root colonisation, with St. George rootstockshowing the highest reduction. Although all rootstocks responded positively to mycorrhizal inoculation, the extentof host preference varied significantly. Dogridge was the least preferred, while the 1613 rootstock was the mostpreferred. The arbuscular fungal symbiosis increased vegetative growth, with 1613 attaining the highest growthunder saline conditions. All the inoculated rootstocks exhibited longer internodes, indicating the beneficial roleof mycorrhizal inoculation for improving plant growth and salt tolerance. Based on overall growth and total drymatter accumulation, the salt tolerance ranking of the four rootstocks, in decreasing order, was Dogridge, SaltCreek, 1613 and St. George

RESPONSE OF GROWTH, ESSENTIAL OIL CONTENT AND ITS CONSTITUENT'S OF PLECTRANTHUS AMBOINICUS TO IRON AND/OR UREA FOLIAR APPLICATION UNDER SALINE IRRIGATION

Objective: To study the response of Plectranthus amboinicus plants to iron and/or urea foliar application using tap water and Nacl saline water for irrigation, a pot experiment was conducted during two successive seasons (2014 and 2015) under the natural conditions of the greenhouse of the National Research Center, Dokki, Giza, Egypt.Methods: Plectranthus amboinicus cuttings were transplanted in the pots in February of each season. After one month, seedlings were irrigated with (2 levels: Tap water (0.40 dsm-1), and Nacl solution (4 dsm-1)) and FeUrea (4 levels: None, EDTA (200 ppm), urea (1000 ppm), and mixture of urea (1000 ppm) and Fe EDTA (200 ppm)) were applied one month from transplanting. The foliar application treatments were sprayed at 60, 90, 120 and 150 d from transplanting. Plant fresh mass (g/plant) and proline content were determined in the first and second cuts after 120 and 180 d from transplanting, respectively. The essential oil was obtained by hydrodistillation and essential oil % was expressed as ml 100 g/fresh herb. The chemical composition of the essential oil was studied using GC-MS and compounds were identified based on their mass spectra and literature.Results: Repeated measures analysis of the data showed significant effects of irrigation and iron/urea on fresh weight of herb, essential oil (%), oil yield, and proline in both first and second cuts. Plectranthus amboinicus plants sprayed with urea/or iron under tap and Nacl saline conditions were better than the control (unsprayed) plants. While saline irrigation decreased fresh weight, essential oil and oil yield, it increased proline; and 200Fe+1000Urea gave significantly higher proline for both tap and Nacl irrigations. Within each irrigation, the highest fresh mass and oil yield were obtained from 200Fe+1000Urea. Fresh mass for tap irrigation was significantly higher during the second cut than during the first cut, but it was the opposite for oil yield. This research demonstrated that application of iron and/or urea decreases salinity stress, and increases proline content. The GC/MS analysis revealed the major components of Plectranthus amboinicus to be p-cymene, carvacrol, (+)-epibicyclosesquiphellandrene, β-cadinene and α-cadinol.Conclusion: It may be concluded that Plectranthus amboinicus is tolerant to Nacl irrigations, thus we may recommend its cultivation in slain soil of Egypt. Foliar spraying with iron and/or urea under these conditions could be much more efficient than the not application of nutrients. So, we recommended that foliar application of iron and/or urea to raise the salt stress tolerance of Plectranthus amboinicus

Micronutrients in the Soil and Wheat: Impact of 84 Years of Organic or Synthetic Fertilization and Crop Residue Management

Crop residues are an important source of plant nutrients. However, information on the various methods of residue management on micronutrients in soil and wheat (Triticum aestivum L.) over time is limited. A long-term (84-year) agroecosystem experiment was assessed to determine the impact of fertilizer type and methods of crop residue management on micronutrients over time under dryland winter wheat-fallow rotation. The treatments were: no N application with residue burning in fall (FB), spring (SB), and no residue burn (NB); 45 kg N ha−1 with SB and NB; 90 kg N ha−1 with SB and NB; pea vines; and farmyard manure (FYM) and a nearby undisturbed grass pasture (GP). Wheat grain, straw, and soil samples from 1995, 2005, and 2015 were used to determine tissue total and soil Mehlich III extractable Mn, Cu, B, Fe, and Zn, and soil pH. After 84 years, extractable Mn and B in the top 10 cm of soil decreased in all plots, except for B in FYM and SB. The FYM plots had the highest extractable Mn (114 mg kg−1) in the top 10 cm soil; however, it declined by 33% compared to the GP (171 mg kg−1). Extractable Zn in the top 10 cm of soil increased with FYM while it decreased with inorganic N application in 2015; however, total Zn in grain increased by 7% with inorganic N (90 kg ha−1) application compared to FYM application. The results suggest that residue management had similar impact on soil micronutrients. Inorganic N and FYM application can be integrated to reduce micronutrient losses from cultivatio

Soil Test Phosphorus Recovery from Livestock Manures Compared with Inorganic Fertilizer in Soil Incubations

This paper compared dairy and hen manure P recovery relative to fertilizer P recovery for two Nova Scotia soils with different antecedent soil test P (STP), incubated for 5, 15, 30, 60, and 110 days. Fertilizer equivalence of manure P was expressed as P recovery ratio in percentage points (%PRR). Repeated measures analysis with soil pH covariate revealed: (1) manure %PRR averaged 72% (low-STP soil) and 80% (medium-STP soil), (2) there were no significant differences in %PRR between dairy and hen manure, and (3) manure %PRR decreased with incubation time for the low-STP soil but not for the medium-STP soil. The soil pH covariate was significant for both low- and medium-STP soils, and the relationship with %PRR was positive for low- but not for the medium-STP soil

Sucrose and light effects on in vitro cultures of potato (Solanum tuberosum L.), chokecherry (Prunus virginiana L.) and Saskatoon berry (Amelanchier alnifolia Nutt.) during low temperature storage

Cultures of potato (Solanum tuberosum) cv. Atlantic, chokecherry ( Prunus virginiana L.) cv. Garrington and saskatoon berry (Amelancher alnifolia Nutt.) cv. Northline grown in vitro for 3 weeks at 24/22 °C, 16-h photoperiod, 150 μmol m-2 s-1 photosynthetic photon flux density (PPFD) mixed fluorescent/incandescent light were stored for 6, 9 and 12 weeks at 4 °C under 0 (darkness) and 3 μmol m-2 s-1 PPFD (690 nm red light continuous illumination). Growth regulators free MSMO medium either with or without 30 g l-1 sucrose was used to store the cultures. All cultures retained capacity to re-grow after storage. Tested factors, sucrose, light and the length of the storage period had an impact on shoot quality and re-growth capacity of the cultures. For either light treatment sucrose was essential for the low temperature maintenance of vigorous stock plants of potato, if stored for over 6 weeks. Chokecherry and saskatoon cultures stored well without sucrose; although chokecherry benefited from sucrose in the storage medium when the stock cultures were kept at the low temperature for 12 weeks. Low light significantly improved quality of the stored potato cultures, but had very little effect on both chokecherry and saskatoon berry cultures. The woody plant cultures grew during storage, and the longer the stock plants were stored, the more vigorous cultures they generated. The results indicate that growers can successfully use their existing facilities, small refrigerators and coolers with low light intensity, set at 4 °C, for short term storage of potato, chokecherry and saskatoon berry cultures. The potato cultures, which are known to be sensitive to prolonged low temperature storage, should be frequently monitored and subcultured as required. On the other hand, the woody plant stock cultures do not require any special attention when kept at 4 °C and re-grow the most vigorous shoots if stored for at least 12 weeks