Humic Substances on Soybeans Grown Under Water Stress

Hypothetically, humic substances (HSs) can improve the response of plants in sandy soils. The objective was to assess the effect of applying an organomineral fertilizer enriched with HSs on soybean plants grown with and without water stress. The experimental design was entirely randomized, in a greenhouse, in a 2 × 5 factorial setup (two moisture levels and five fertilizer doses: 0, 1, 2, 4, and 8 mL dm^?3), for a total of 10 treatments, with eight repetitions, using as substrate a Psamment. The organomineral fertilizer was applied in the soil 21 days after plant emergence, and the water regimes were established 1 week thereafter. Plant height, shoot and root dry mass, mineral nutrition, and grain yield were evaluated. There was a positive response to the doses, with the most efficient one under water stress being 6.5 mL dm^?3 and HSs favored the uptake of micronutrients.     

长期化肥有机替代对黑土颜色及腐殖物质的影响

基于30年长期定位试验,通过测定黑土光谱反射率和不同腐殖质组分含量,探究了不同施肥对黑土土壤腐殖质含量、土壤颜色及二者之间的关系。试验设置5个处理:(1)休耕(Fallow);(2)不施肥处理(CK);(3)单施化肥(NPK);(4)有机肥部分替代化肥(NPKM);(5)秸秆部分替代化肥处理(NPKS)。结果表明:与NPK处理相比,Fallow、NPKS、NPKM分别显著提高49.7%,74.3%,27.0%的土壤有机碳含量(p<0.05)。NPKM处理中胡敏酸(HA)含量最高为3.9 g/kg,随后依次为CK、NPKS、NPK、Fallow。NPKM、NPKS和Fallow处理中土壤富里酸(FA)含量为2.2~2.3 g/kg,显著高于NPK和CK。NPKM处理中胡敏素(HM)含量为18.6 g/kg,显著高于其他处理(p<0.05)。不同处理间土壤光谱反射率由高到低依次为NPK>Fallow、CK>NPKS>NPKM,与CK处理相比,NPK土壤光谱反射率在平均提高6.5%,NPKS和NPKM则分别降低11.1%和15.1%。根据线性相关分析结果,黑土土壤光谱反射率与土壤HAHM均呈显著负相关关系(p<0.01),相关系数(r)分别为-0.858,-0.681。综合上述结果,长期有机物料投入可以显著提高黑土腐殖物质含量,降低黑土光谱反射率,使黑土颜色加深,而长期化肥施入则使黑土光谱反射率提高,出现褪色现象,有机粪肥在黑土中对土壤有机质和腐殖质含量的提升效果优于秸秆。     

Effect of Humic Acid on Plant Growth,Nutrient Uptake,and Postharvest Life of Gerbera

Humic acid (HA) might benefit plant growth by improving nutrient uptake and hormonal effects. The effect of HA on growth, macro—and micronutrient contents, and postharvest life of gerbera (Gerbera jamesonii L.) cv. ‘Malibu’ were examined. Different levels of humic acid (0, 100, 500, and 1000 mg/L) were applied to nutrient solution.

Root growth increased at 1000 mg/L HA incorporated into the solution. Macro- and micronutrient contents of leaves and scapes including nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), and zinc (Zn) were significantly enhanced by HA. However, high levels of HA decreased some nutrient contents.

Five-hundred mg/L HA increased the number of harvested flowers per plant (52%). Higher HA levels extended the vase life of harvested flowers by 2—3.66 days and could prevent and delay bent neck incidence. These postharvest responses were most probably due to Ca accumulation in scapes and hormone-like activity of HA.     

Humic Acids Derived from Leonardite-Affected Growth and Nutrient Uptake of Corn Seedlings

Using organic fertilizer or soil amendment such as humic substances is an important component for sustainable agriculture. The objective of this study was to determine the effects of different factions of humic acids (HAs) on corn seedling growth and nutrient uptake. The experiment was carried out with both an agar culture in root boxes and a hydroponic culture to which 400 mg/L of different factions of humus acids, mixed HAs, and raw Leonardite were added. The experiments were repeated twice with three replications for each treatment. The results showed that applications of HAs significantly improved the leaf and root growth of corn seedlings compared with the control (no HA addition). In the agar culture, seedlings treated with HAs with relatively low molecular weights had more leaves and twice long of roots compared to control and other treatments. In the hydroponic culture, the mixture of three factions was the best treatment for both shoot and root growth of seedlings.     

Application of Humic Substances Results in Consistent Increases in Crop Yield and Nutrient Uptake

The effect of humic substances on yield and nutrient uptake of grass, maize, potato and spinach was investigated in six field experiments and two pot experiments in a high input cropping system. The humic substances originating from leonardite formations in Canada were applied as liquid solution to the soil (Humifirst liquid) or as a solid incorporated in mineral fertilizers (Humifirst incorporated). Formal meta-analysis of the results of all executed experiments showed that the application of humic substances had an overall positive effect on dry matter yield of the crops and this effect was statistically significant for Humifirst incorporated. In the case of permanent grassland, humic substances promoted mainly the production of the first grass cut, which has the highest grass quality among all cuts during the growing season. Tuber production on the potato field trial showed a high response on the application of humic substances. Total potato yield increased with 13 and 17% for Humifirst liquid and Humifirst incorporated, respectively. The effect of humic substances on maize yield was limited, probably due to the rather high nutrient status of both soils. Finally, the formal meta-analysis showed a consequent increase in nitrogen and phosphorus uptake of all studied crops as well. The effect on potassium and magnesium uptake was also mainly positive, while sodium and calcium uptake were not affected in most of the experiments.     

Improvement of Iron Uptake in Table Grape by Addition of Humic Substances

Two experiments in consecutive years were conducted at a table grape plantation located in southeastern Spain. The objective was to test whether the addition of commercial organic compounds could improve the uptake of iron (Fe) by plants. A commercial humic substance and two mixtures of amino acids were used as organic compounds in the first experiment and FeEDDHA was the source of Fe. The joint addition of FeEDDHA and organic compounds improved Fe nutrition. The humic substance was more effective than the amino acids in increasing Fe uptake. In the following year, a similar experiment was conducted by progressively replacing part of the chelate with the humic substance. An increase in foliar Fe and phosphorus (P) and a decrease in sodium (Na) levels were observed. The best results with respect to nutrient foliar content and nutrient relationships were obtained for a range of substitutions for the chelate by the humic substance of from 30% to 50% with no loss in yield or fruit quality.     

马铃薯淀粉渣对土壤保肥特性及玉米幼苗生长的影响

[目的]探究马铃薯淀粉渣对土壤保肥特性及玉米幼苗生长的影响,为马铃薯淀粉渣的利用提供依据。[方法]采用室内人工气候箱模拟自然环境和用淋洗管模拟田间淋洗的方法,测定沙壤土中施入0,1.00,5.00,10.00,20.00,30.00g/kg的马铃薯淀粉渣对土壤容重、土壤总孔隙度、土壤含水量;土壤淋洗出的硝态氮、铵态氮、速效磷和速效钾含量及玉米幼苗株高、茎粗和干鲜重等指标。[结果]马铃薯淀粉渣施用量为30g/kg时,土壤容重降幅达7.24%,土壤总孔隙度、土壤含水量升幅分别为10.15%,21.25%;土壤淋洗出的硝态氮、铵态氮、速效磷和速效钾含量降幅分别为97.13%,91.03%,63.85%和66.4%;玉米幼苗株高较对照降低8.90%,茎粗较对照增加25.53%,幼苗的干、鲜重分别比对照提高13.47%,15.79%。[结论]马铃薯淀粉渣施用量为30.00g/kg时,改善了土壤理化性状,增强了保肥能力,明显促进玉米幼苗干物质的积累。     

Effect of High Humic Substance Levels on Growth and Nutrient Concentration of Corn under Calcareous Conditions

This study investigated the effect of high humic substance (HS) levels (0, 500, 1000, and 2000 mg HS kg^?1) on growth and nutrient concentrations of corn grown on calcareous soils. For these, soil samples were collected from the six different provinces of Turkey. According to the average values, HS levels had no significant effect alone on dry weight, nitrogen (N), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), zinc (Zn), copper (Cu), and manganese (Mn) concentrations. Soil differences significantly affected dry weight, N, Mg, and Cu concentrations (p ≤ 0.05). Looking at HSxsoil interactions on K, Ca, Fe, and Mn concentrations, it could be seen that there was no effect or that the effect was negative. Only plant Fe concentrations obtained from Konya and Urfa provinces were positively affected from HSxsoil interaction. It was concluded that high level of HS had no or negative effect on corn growth and some nutrient concentration under calcareous conditions.     

Tuber yield and allocation of nutrients and carbohydrates in potato plants as affected by limestone type and magnesium supply

Abstract

Magnesium (Mg) is a nutrient that affects the development of plants and is mainly supplied through liming performed to correct soil acidity. By acting on photosynthesis and influencing carbohydrate partitioning in the plant, supplementary Mg supplied through soil or foliar application can increase the yield and quality of potato (Solanum tuberosum L.) tubers. The aim of this study was to evaluate the effect of supplemental Mg fertilization by soil or foliar application on plant nutritional status, tuber yield, and carbohydrate partitioning in potato crops in soil corrected with calcitic and dolomitic limestones. The experiment was carried out in pots under greenhouse conditions with a randomized block design in a 2?×?3 factorial scheme with four replications. Dolomitic limestone application and supplemental Mg fertilization via soil increased the concentrations of this nutrient in potato leaves. Liming with dolomitic limestone reduced the uptake of Ca and K by plants, but supplemental Mg fertilization did not alter the uptake of Ca, Mg or K. Supplemental Mg fertilization did not increase plant growth and tuber yield, even when calcitic limestone was used to elevate the base saturation to 60%; the exchangeable Mg concentration in soil was 9?mmol_c dm^?3, and the Ca:Mg relationship was 3.7. Liming with dolomitic limestone or providing supplemental Mg fertilization did not increase sugar and starch partitioning to the tubers.     

Compost,Lime, and Rock Phosphate Effects on Organic White Cabbage Growth and Nutrient Uptake

Organic white cabbage response to the application of a source-separated municipal organic-waste compost, lime, and Gafsa phosphate was investigated throughout a randomized block pot experiment under greenhouse conditions. Cabbage yield and nitrogen (N) uptake increased with all fertilizes; however, lime and phosphate effects on cabbage yield were enhanced when the compost was not applied. Phosphate application partially replaced the need for lime, showing that liming has to be estimated based on soil acidity but also on soil P availability and phosphate recommendation. Partitioning of N, phosphorus (P), potassium (K), and calcium (Ca) between leaves and roots was held for the benefit of the leaves, but to a lesser extent for P and Ca, compared to for N and K. This study shows the importance of P availability to improve cabbage growth and recommends source-separated organic waste compost to increase soil N availability for organic cabbage.     

Effect of Integrated Management of Nitrogen Fertilizer and Cattle Manure on the Leaf Chlorophyll,Yield, and Tuber Glycoalkaloids of Agria Potato

Management of nutrients, especially nitrogen (N), is one of the most important factors in potato production. Cattle manure and mineral fertilizers are two sources of N that can affect the quality and quantity of potato yield. The effects of the use of cattle manure (5, 10, 15, and 20 ton ha^?1), N fertilizer (50, 100, and 150 kg ha^?1), and their interaction on tuber yield, chlorophyll content, and glycoalkaloid concentration were evaluated during field experiments in Iran in 2008 with a randomized complete block design with a factorial arrangement of three experimental replications. At the time of flowering, chlorophyll a, b, and total (chlorophyll) were recorded by spectrophotometry. Furthermore, at the end of the growth season, tuber yield was calculated and tuber glycoalkaloids were measured by the colorimetric method for the assessment of quantitative and qualitative characteristics of potato. Chlorophyll a, b, and total content increased linearly and very significantly in response to the application of manure and N fertilizer. The interaction between manure and N fertilizer was also significant; somehow the maximum content of total chlorophyll [1.448 mg g^?1 fresh weight (FW)] was obtained by using 150 kg N + 20 ton of manure per hectare. Cattle manure, N fertilizer, and their combination had a highly significant effect on tuber yield. Maximum tuber yield (36.8 ton ha^?1) was obtained by the utilization of 20 ton manure + 150 kg N per hectare. Total glycoalkaloid content was affected by the N application only. It showed a linear increase in the presence of increased concentration of N fertilizer.     

Effect of Organic Waste and Humic Acid on Some Growth Parameters and Nutrient Concentration of Pistachio Seedlings

Pistachio crops in Iran are grown in soil with low soil organic matter. Therefore, a field experiment was conducted at Izadyaran Company, Sirjan, Iran to study the effects of municipal solid waste compost (MSWC), cow manure, and methods of humic acid application (soil and foliar) on growth parameters and nutrients concentration of pistachio seedlings in a complete randomized design with six replications for two years (2011–2013). Results showed that cow manure decreased the leakage percent and maximum leaf number and leaf surface area were obtained in MSWC with foliar application of humic acid and cow manure without humic acid, respectively. The highest chlorophyll b and carotenoid were observed in the second year with cow manure treatment whereas foliar application of humic acid increased total chlorophyll. Calcium (Ca) and iron (Fe) decreased in the second year. At the first year Cow manure application increased phosphorus (P) and manganese (Mn) but in the second year increased magnesium (Mg) concentration. MSWC at the first year increased copper (Cu) and zinc (Zn) concentration. Cow manure and foliar application of humic acid increased the Nitrogen (N) concentration in the first year. These results may have implications for pistachio production in arid and semi-arid soils.     

Effects of Tembotrione on Potato Crop in a Tropical Soil

ABSTRACT

Tembotrione is an herbicide with a high persistence in soil, a characteristic that affects the growth and development of susceptible cultures in succession. In this sense, the objective of this research was to evaluate the residual effects of tembotrione on production and quality of potato tubers in a tropical soil. A field experiment (2014/2015) with randomized blocks design with four replications was conducted. The treatments consisted of five doses of tembotrione (0, 8.4, 16.8, 33.6, and 50.4 g a.i. ha^?1) incorporated into the soil before planting the potato cultivar Atlantic. At 115 days after herbicide application were evaluated: total solids (%), dry matter content (DMCT %), nitrogen and potassium of the tubers, total yield and classification. The productivity of normal tubers decreased as doses of tembotrione were increased. The percentage of class I tubers was reduced at doses of 33.6 and 50.4 g a.i. ha^?1. The increase in the doses increased the percentage of class II tubers and did not influence the percentage of class III and discard. The appearance of cracked tubers increased with increasing herbicide doses. Tembotrione affected the productivity of potato tubers and caused cracks in the tubers, which are dependent on the applied doses.     

磷硅肥配施对盐渍土壤水稻生长及养分吸收的影响

针对滨海盐渍化稻田土壤根系易受盐碱胁迫、磷素养分含量及有效性低的问题,采用田间微区试验研究磷肥与硅肥配施对滨海盐渍化稻田土壤水稻根系生长、土壤磷素含量、水稻磷营养、产量及经济效益的作用。试验采用双因素设计,磷肥设2个水平:P1,P_2O_5 64 kg/hm~2;P2,P_2O_5 128 kg/hm~2;硅肥分土施和喷施,土施设3个水平:Si1,SiO_2 0 kg/hm~2;Si2,SiO_2 60 kg/hm~2;Si3,SiO_2 120 kg/hm~2;Si4为叶面喷施SiO_215 kg/hm~2。结果表明,喷施硅肥与低量磷肥配施的P1Si4处理在各生育时期的水稻总根长、总表面积和总根体积均为最高,与P2Si4处理无显著性差异。同时,磷肥配施硅肥可有效提高滨海盐渍化水稻土壤磷素有效性,其中P2Si4处理速效磷含量显著高于P1Si3、P2Si1,分别高出35.16%,27.47%;高磷处理的土壤全磷含量高于低磷处理。且施用硅肥的P1Si3、P1Si4处理的水稻产量显著高于不施硅肥和少量施硅的P1Si1、P1Si2处理,其中P2Si3水稻产量达9 547.5 kg/hm~2;各处理的有效穗数无显著性差异,每穗实粒数P2Si3处理最高,达162.47个/穗。P2Si3处理水稻籽粒中磷积累量最高,且显著高于其他处理,比P1Si3、P2Si1处理分别高出8.46%,9.68%。在低磷或高磷施用条件下,叶面喷施硅肥(P1Si4、P2Si4)处理收入分别达到14 953.6,14 323.2元/hm~2。综上所述,与不施硅肥的处理相比,磷肥配施硅肥可显著促进滨海盐渍化土壤水稻根系生长,提高磷素有效性、水稻产量及经济效益,其中以P1Si4处理(叶面喷硅,P_2O_5 64 kg/hm~2)处理最佳。     

Use of Humic Substances and Amino Acids to Enhance Iron Availability for Tomato Plants from Applications of the Chelate FeEDDHA

Two experiments in consecutive years were conducted in a commercial greenhouse located in the Southeast of Spain. The objective was to test if the addition of commercial organic compounds could improve the uptake of iron (Fe) by tomato plants (Lycopersicon esculentum mill.) cv Daniela. A commercial humic substance (HS) and a mix of amino acids (AA) were used as organic compounds in the first year of the experiment, and FeEDDHA (Q) as a source of iron. Both organic compounds improved iron uptake in comparison to a control without the addition of organic materials, especially the humic substance. A similar experiment was conducted the following year, but part of the chelate was progressively substituted by the humic compound. Results showed that the content of iron in the leaves increased with the substitution without any significant losses of yield or fruit quality. Plant nutrition was also improved because of an increase in the level of phosphorus in the leaves and a decrease in foliar sodium levels indicating a reduction in the effects of salinity.     

Investigation of Effects on Nutrient Uptake of Humic Acid Applications of Different Forms to Strawberry Plant

Abstract

The aim of this study was to investigate the effect of humic acid in liquid and solid form on uptake of nutrients for strawberry grown under greenhouse conditions. The experiment was designed in randomized block design with four replications for two years. Solid form of humic acid (Agrolig) that contained 85% humic acid was applied in the amounts of 0, 100, 200, 300, and 400 kg/ha before planting. Liquid form of humic acid (Blackjak) that contained 15% humic acid was applied by drip irrigation system at the concentrations of 0, 2500, 5000, 7500, and 10,000 mL/ha/month. Along with humic acid, 200 kg/ha nitrogen (N), 100 kg/ha phosphorus (P₂O₅), and 400 kg/ha potassium (K₂O) was applied by drip irrigation system after transplanting. According to the results, N, phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), manganese (Mn), and copper (Cu) contents of the leaves were not affected significantly by the applications of solid and liquid humic acid forms. Applied liquid humic acid had a significant effect on the zinc (Zn) content of the leaves causing a decrease in the Zn content. Because of having excessive calcareous soil in the experimental area, uptake of nutrients in strawberry plants was not affected significantly. Applications of humic acid at high concentrations had an inhibitory effect on some of the nutrients.     

Phosphorus and silicon effects on growth,yield, and phosphorus forms in potato plants

Silicon (Si) can increase phosphorus (P) use efficiency (PUE) by increasing P availability in the soil and altering P metabolism in the plant, thus resulting in improved yield under low soil P conditions. The objective was to evaluate the effect of P (10, 50, 100, and 200?mg dm^?3) and Si (0, 50, and 200?mg dm^?3) interrelationship on P and Si uptake by plants, forms of P in leaves and tubers, plant growth, and tuber yield of potato plants. Silicon supply increased organic and inorganic P in the leaves. At low soil P rates, Si also increased organic P in the tubers. However, alterations in the P metabolism of potato plants with Si supply did not promote significant changes in dry matter (DM) production and tuber yield. Phosphate fertilization increased growth and yield of plants. Silicon uptake by the plants were also increased by phosphate fertilization with soil Si supply.     

Effect of Nitrate/Ammonium Ratios on Growth,Root Morphology and Nutrient Elements Uptake of Watermelon (Citrullus Lanatus) Seedlings

Nitrogen is taken up by most plant species in the form of nitrate and ammonium. The objective of this study was to investigate the effect of different nitrogen forms on the growth of watermelon seedlings. Plants were grown in hydroponic culture with five nitrate (NO₃^?)/ammonium (NH₄⁺) ratios (100/0, 75/25, 50/50, 25/75, 0/100). When the proportion of NH₄⁺ was increased, the leaf number, leaf area, shoot height, net photosynthesis, biomass, and root growth were significantly decreased. Higher concentrations of nitrogen (N) and phosphorus (P) were observed when plants were supplied with mixed NO₃^? and NH₄⁺ compared to NO₃^? or NH₄⁺ alone, whereas the concentrations of potassium (K), calcium (Ca), and magnesium (Mg) were decreased with increasing NH₄⁺. The microelements concentrations were generally increased with more NH₄⁺ added. In addition, plants fed with higher NO₃^?/NH₄⁺ ratios resulted in more minerals accumulation.     

Influence of Nitrogen and Potassium Supply on Contents of Acrylamide Precursors in Potato Tubers and on Acrylamide Accumulation in French Fries

Fried potato products may accumulate substantial amounts of acrylamide due to high precursor contents, namely reducing sugars and asparagine. In a two-factorial experiment increasing N supply, increased the contents of reducing sugars in most cases, and resulted in higher contents of free amino acids. α -amino-N, which was tightly correlated with the contents of free amino acids, can be regarded a suitable rapid test for free asparagine for a given variety. Increasing K addition always raised the citrate contents, but lessened the contents of reducing sugars. Selected treatments were processed into French fries. Highest acrylamide contents were observed in tubers grown with high N and inadequate K supply, which also contained the highest contents of precursors. The experiment clearly demonstrates that nutrient supply has significant impact on the contents of acrylamide precursors and thus for the acrylamide formation during frying.     

Growth and Nutritional Disorders of Eggplant Cultivated in Nutrients Solutions with Suppressed Macronutrients

The objective was to evaluate the effects of omitting macronutrients in the nutrients solution on growth characteristics and nutritional status of eggplants. The treatments were complete nutrients solution and solutions with nutrient omission: nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sulfur (S). The experiment was carried out under greenhouse conditions with three replicates in a completely random design. Plant height, number of leaves per plant, leaf area, relative chlorophyll index, photosynthesis rate, stomatal conductance, dry matter, concentration levels of macronutrients in plant aerial part and root system, and nutritional disorders were evaluated. Omitting elements interfered in the concentration of elements in the various plant tissues and this had as consequences limited vegetative growth, reduced dry matter and led to the development of the typical deficiency symptoms of each element. Although potassium was the most demanded of all elements, nitrogen and calcium were the most growth limiting ones.