Lime application reduces potassium and nitrate leaching on sandy soils

Kalium (K)-Auslaugung kommt in leicht strukturierten Böden häufig vor und reduziert die im Boden für die Pflanzen verfügbare Menge K. Diese Studie untersuchte die Auswirkung der Kalkanwendung und der K-Raten (null, 20, 60 kg K/ha) auf die K-Auslaugung und andere Sickerwasserparameter von vier sandigen Böden im Westen Australiens. Drei von vier Böden unterschieden sich in der K-Auslaugung nicht zwischen den Raten von Null und 20 kg K/ha, während 60 kg K/ha die K-Auslaugung in allen vier Böden erhöhten. Bei den Merredin-Böden verzögerte die Kalkanwendung die K-Auslaugung bei 60 kg K/ha deutlich und zeigte einen K-Auslaugungspeak bei 4,75 Porenvolumen (PV) im gekalkten Boden (pHCaCl2: 6,20), jedoch bei 3 PV im nicht gekalkten Boden (pHCaCl2: 4,50), und das Kalken reduzierte auch die Gesamt­menge an ausgelaugtem K und NO3. In ähnlicher Weise trat der Peak der K-Auslaugung bei 2–3 PV in den anderen beiden nicht gekalkten Böden auf. Die maximalen NO3-Konzentrationen von Sickerwasser bei 60 kg K/ha betrugen 46 mg/l bei 2 PV mit Kalk gegenüber 110 mg/l bei 1,25 PV ohne Kalk, während die Menge an ausgelaugtem NO3 aus Böden ohne K-Zugabe größer war als aus den mit K behandelten Böden. Die Ergebnisse legen nahe, dass die Kalkung eines sauren Sandes die K- und NO3-Auswaschung verlangsamen und verringern kann und erhebliche Auswirkungen auf das K-Dünger-Management auf solchen Böden hat.Potassium (K) leaching is common in light-textured soils and reduces soil available K to plants. This study examined the effect of lime application and K rates (nil, 20, 60 kg K/ha) on K leaching and other leachate parameters of four sandy soils in Western Australia. Three out of four soils did not differ in K leaching between the rates of nil and 20 kg K/ha, whereas 60 kg K/ha increased K leaching in all four soils. For the Merredin soils, lime applica­tion markedly delayed K leaching at 60 kg K/ha, showing K leaching peak at 4.75 pore volume (PV) in the limed soil (pHCaCl2: 6.20) but at 3 PV in the non-limed soil (pHCaCl2: 4.50), and liming also reduced total amount of leached K and NO3. Similarly, the peak of K leaching occurred at 2–3 PV in the other two non-limed soils. Maximum leachate NO3 concentrations at 60 kg K/ha were 46 mg/L at 2 PV with lime versus 110 mg/L at 1.25 PV without lime, while the amount of leached NO3 from nil K soils was greater than from the K treated soils. The results suggest that liming of an acid sand can slow down and reduce K and NO3 leaching and have significant implication for K-fertilizer management on such soils

The Effect of Nitrogen Application on Boron Toxicity Reduction in Pistachio (Pistacia vera cv. Badami-Zarand Saplings)

Introduction: Boron is one of the seven essential microelements for the natural growth of plants. The toxicity of this element occurs in arid and semi-arid regions, which is because of its high level in soils and the irrigation water of mentioned regions. The aim of this study was to evaluate the effect of nitrogen application on boron toxicity tolerance in pistachio, Badami-Zarand variety. The effects of three nitrogen levels (0, 250, and 350 mg/kg of soil) on the reduction of toxicity due to the three levels of boron (0, 15, and 30 mg/kg of soil) were examined in Badami-Zarandi variety of pistachio under greenhouse conditions. After 7 months from sowing the seeds, pistachio seedlings were harvested and desired traits were measured. The results showed that by increasing boron application level, boron concentration in the shoot and root of seedlings increased whereas their dry weight decreased. Using of nitrogen reduced the negative effects of boron on the dry weight and led to increase dry weight and decrease boron concentration in the shoot and root of pistachio, Badami variety. Nitrogen application at the levels of 250 and 350 mg N per kg of soil reduced boron uptake in shoots by reinforcing plant vegetative system and increasing chlorophyll content by 13.5% and 30.2%, respectively and finally led to diluted boron concentration in the plant (dilution effect) and reduced the effects of boron toxicity. Hence, optimized nitrogen application is suggested as one of the management methods in controlling Boron toxicity under these conditions. Materials and Methods: A factorial experiment based on randomized complete block design with four replications was carried out. Soil sampling was done in 0-30 cm depth in a zeekzack way from a pistachio garden that located in mahmoodiye area in Rafsanjan. The soil sample was air-dried and passed through a 2mm sieve. The soil chemical and physical properties were measured. In this study, badami-zarand cultivar seed was used because it is one of the most important pistachio cultivars. The seeds were soaked in water for 24 hours and disinfected by benomyl fungicide. When the seeds germinated, they were planted in the pots containing 4.5 kg soil and without drainage, so nutrients balance was kept during growing period. After 7 months, the seedlings were harvested and B was measured. Results and Discussion: The results showed that increasing the boron levels from 0 to 30 mg kg-1 led to decrease shoot dry weight from 3.72 to 2.45 gram and root DM from 2.28 to 1.50 gram. Increasing 30 mg kg-1 boron led to 2.8 times increase of shoot boron concentration. The averages of shoot boron concentration in the levels of 15 and 30 mg kg-1 boron were 87.6 and 122 mg kg-1DM, respectively. The boron toxicity level in Badami-Zarand cultivar is 8.9 mg kg-1 DM (Sepaskhahet al, 1994), so these levels were the cause of boron toxicity and boron toxicity symptoms were seen as leaf burn, often at the margins and the tips of older leaves. The results showed that increasing nitrogen levels led to decrease shoot boron concentration and increase their weight. The results also showed a significant negative correlation between the nitrogen levels and boron uptake. Boron uptake in the shoots of seedlings about 13.5 and 30.2 percent decreased when nitrogen levels increased. Shoot dry weight decreased when boron application increased, but it increased when nitrogen was used (Koohkan and Maftoun, 2009). Conclusion: The reduction of dry weight and increasing boron concentration occurred when increased boron application. The Maximum of boron uptake was seen by leaves, and boron toxicity symptoms were appeared as leaf burn especially at the tips and margins of older leaves. Since, boron is immobile in pistachio; it is absorbed by mass flow, so the accumulation of boron at older leaves is persuaded. Nitrogen reduced the bad effects of boron on dry weight and the bad effects of increasing boron concentration by the synthesis of chlorophyll, so it was more useful in shoot than root. Boron uptake was also reduced by nitrogen application. This effect of nitrogen is probably concerned to the increase of dry weight more than boron concentration (Dilution effect). On the other hand, nitrogen caused to increase leaf index and increase the number of seedling leaves. The injured leaves due to boron toxicity were restored, because of high leaf chlorophyll. It is suggested that this study will be done under field conditions for fertilizer application recommendations and to be used for creation of tolerant cultivars of pistachio

Role of chitosan on the growth, physiological parameters and enzymatic activity of milk thistle (Silybum marianum (L.) Gaertn.) in a pot experiment

Salt stress is the destructive factor in plant growth and physiological activities. Using biobased stimulants, such as chitosan, is important to reduce the adverse effects of salinity. This study was carried out in a greenhouse located at the University of Tehran, in 2016. The goal of this study was to evaluate the effect of chitosan application on modification of adverse effects of soil salinity on growth and physiological characteristics of milk thistle (Silybum marianum (L.) Gaertn.). A pot experiment with a factorial arrangement of treatments was conducted based on a randomized complete block design (RCB) with three replications Four irrigation water salinity levels were control (tap water 0.8), 4, 8 and 12 dS/m and four levels of chitosan were mixed with dry soil to yield 0, 0.01, 0.05 and 0.1% chitosan (DW/DW). The results showed that salinity reduced root dry weight; shoot dry weight, total plant biomass, and increased soluble sugars, proline content, CAT spell out first use and POD spell out first use enzyme activity and H2O2 concentration in leaves. The use of chitosan led to a reduction of salinity adverse effects and increased plant growth and improved physiological traits. Chitosan application at 0.01% increased chlorophyll a and total chlorophyll and at 0.05% level increased chlorophyll b compared to other chitosan treatments. The highest concentration of soluble sugars and proline was achieved by chitosan application across all salinity levels. Chitosan application under 0.01 and 0.05% enhanced the enzymatic activity and decreased H2O2 concentration in leaves. The results illustrated that chitosan could protect plants from salt stress damage by modulating intracellular ion concentration and by enhancing the capacity of antioxidant enzyme activities. It seems that the average concentration of chitosan as a bio-stimulant (0.01 and 0.05%) plays a positive role in reducing salinity and enhancing growth in milk thistle

(Chitosan nano-particles application on growth, physiology and mineral element contents of milk thistle (Silybum marianum) under salinity stress condition)

Salinity stress is one of the most limiting factors in plant growth and physiological activities. To extend crop production in saline regions, application of plant promoting growth substances like Chitosan is necessary to modify the adverse effects of salinity. Milk thistle is an agro-medical plant that is familiar as a weed. However, Silymarin (which is produced by Milk thistle as a secondary metabolite) is one the most important material for treating such disease as; liver diseases, blood fat, diabetes, hepatitis, and cancer. Application of bio stimulants is one of the solutions for decreasing adverse effects of abiotic and biotic stresses on plants and increasing quality and quantity of plant yield production, so chitosan is a compound that induces defense mechanisms against stresses

Application of nanomaterial graphene oxide on biochemical traits of Milk thistle (Silybum marianum L.) under salinity stress

In recent years, application of engineered nanomaterials, in particular carbon-based nanostructures, has been initiated in agriculture. To better understand the effects of nanomaterials on plants, four concentrations of graphene oxide (0, 0.01, 0.05, 0.1%) in soil was studied on growth and biochemical traits of Milk thistle under four saline stress (0, 4, 8,12 dS/m) conditions in greenhouse. A completely randomized block design with a factorial treatment arrangement was employed with three replications. The result showed under both saline and control (non-saline) conditions, the maximum plant height (3.7% and 20% in control and saline conditions, respectively), total biomass (17% and 8.2% in control and saline conditions, respectively), and chlorophyll content (8% and 5% in control and saline conditions, respectively), were achieved for plants with graphene oxide (GO) application. By increasing the salinity level, plants treated with 0.01% concentration of graphene oxide produced the highest total biomass (518 mg) under 12 dS/m salinity levels. Also, maximum quantum efficiency of PSII, performance index, and membrane stability index decreased due to salinity stress. Proline and soluble carbohydrates noticeably increased by saline water treatments. Graphene oxide alleviated salt stress-induced damage through increasing plant growth, plant height, chlorophyll content, photosystem efficiency, performance index, membrane stability index, proline and soluble carbohydrate content. Also graphene oxide increased cell water potential through enhancing the net concentration of solutes in plant cells. Graphene nanomaterials could ameliorate the salt stress in Milk thistle plant. Graphene oxide application could be commercially and economically beneficial for Milk thistle production under control and saline conditions