Salinity effects on annual bedding plants in a peat‐perlite medium and solution culture

Annual vinca (Catharanthus roseus (L.) G. Don ‘Pink Carpet'), geranium (Pelargonium x hortorum L. H. Bailey ‘Jackpot'), and marigold (Tagetes erecta L. ‘First Lady') were grown in a sphagnum peat moss and perlite medium. Plants were irrigated with solutions of different salinity by the addition of 0.0, 1.0, 2.0, 4.0, and 8.0 g/1 of a NaCl and CaCl₂ mixture resulting in solution electrical conductivity (EC) values of about 1.3, 3.0, 4.5, 7.9, and 13.9 ds/m, respectively. In another experiment marigold and geranium were grown in solution culture containing the same salt mixture at 0.0, 1.0, 4.0, and 8.0 g/1 with EC values of 1.4, 3.0, 7.4, and 12.5 ds/m, respectively. All species showed some salinity tolerance up to 2.0 g/1 in peat‐perlite and 1.0 g/1 in solution culture as growth reductions were below 10% and no foliar injury occurred. Foliar injury occurred on marigold and geranium, but not annual vinca, at 4.0 and 8.0 g/1 in both growing media. On a concentration basis, recently mature leaves sampled from marigold grown in peat‐perlite contained more chloride (Cl) but less sodium (Na) than geranium and annual vinca. However results of the solution culture experiment showed that, with the exception of 1.0 g/1 treatment, geranium and marigold plants absorbed the same amount of Cl and Na when content was expressed on a mg/g dry weight basis. The low Na concentration in marigold leaves was a reflection of restricted translocation of Na from the roots to the shoots.     

Downward movement of surface‐applied P on established forage stands

Abstract

Field experiments were conducted on Black Chernozem and Gray Luvisol soils in Alberta to determine the downward movement of long‐term applications of surface‐broadcast P fertilizer on established forage grass or alfalfa stands. The majority of fertilizer P recovered in soil as extractable P remained in the top 5 cm layer. The amount and depth of movement of applied P increased with P rate, but little or none was recovered below 15 cm.     

Soil‐grinder type effects on grams of soil scooped

Abstract

Soil preparation can affect soil test results. This study was conducted to compare soil‐grinder effects on grams of soil scooped. Soil samples (n=15,000) were ground by two types of soil grinders, a roller and hammer mill, and then the soil was sieved (10‐mesh), and scooped with a one‐gram scoop (0.85 cm³). The contents of the soil scoop were weighed. Grams of soil scooped ranged from 0.4 to 1.8 g for both soil grinders. The bell‐shaped distribution was centered around 0.8 and 1.0 g for the roller‐ and hammer mill‐type grinder, respectively. When the soil was ground by the roller‐type grinder, 85% of the ground soil was retained on a 50‐mesh sieve. In contrast, with the hammer mill grinder, 45% of the soil was retained on a 50‐mesh, 13% retained on a 100‐mesh, and 42% passed a 100‐mesh sieves. The “heavier” soil scoops with the hammer mill grinder could be explained by the fact that the finer soil particles could pack into the voids that the coarse soil particles created. Bray extractable P and ammonium actetate extractable K, Mg, and Ca were increased 11 to 15% by the “heavier” scooping weight. Grams of soil scooped and soil test levels were affected by the type of soil grinder and soil type.     

Residual effects of sewage‐sludge application on plant and soil‐profile chemical composition

Abstract

Long‐term effects on plant and soil‐profile chemical composition imposed by a residential sewage sludge were studied on an Oxisol from Hawaii. Sludge was applied at 0, 45, 90, and 180 Mg/ha in 1983. An NPK‐fertilized treatment was included for comparison. Sudangrass (Sorghum bicolorL. Moench) was grown as a test crop in the 1983–84 and 1986–87 seasons. Soil samples for chemical analysis were taken in 1987 at three depths: 0–23 cm, 23–46 cm, and 46–69 cm.

Beneficial effects of sludge, measured 3 years after application (beginning of the 1986's planting), were evident by large yield increases on sludge‐amended soils relative to the unamended and the NPK‐fertilized soils. The first cutting produced approximately 5 Mg/ha of dry matter from the sludge treatments, regardless of rate, as compared with 3 and 1.5 Mg/ha from the NPK and the 0 treatments. Regrowths showed similar effect, though less dramatic; average yields were 2.6 Mg/ha with sludge and 1.6 Mg/ha without.

Heavy‐metal concentrations in plants were generally unaffected by sludge applications; probably because (i) heavy‐metal contents of the sludge were low, and (ii) soil pH was increased by sludge.

Remarkable increases in pH, exchangeable Ca and extractable P, and resultant decreases in exchangeable Al, in all three soil layers of sludge‐amended soils suggest that surface application of a low heavy‐metal sludge could serve to correct subsoil acidity and enhance subsoil P availability.     

Biochar use in a legume–rice rotation system: effects on soil fertility and crop performance

The aim of this study was to determine whether by applying biochar, it is possible to augment the beneficial effects of legume–crop rotation systems on soil fertility and crop performance. Repeated experiments were established in 2012 and 2013 in South-western Benin using a split-split plot design. Two legumes, Mucuna pruriens (mucuna) and Vigna unguiculata (cowpea), were planted for 42 days on biochar-amended and unamended plots and subsequently cut and applied as mulch 5 days before planting rice. Rice plants were either fertilized or not using a fertilizer rate of 60, 30, and 30 kg ha^?1 of N, P₂O₅, and K₂O, respectively. The results showed that the application of legume green manures and fertilizer, either singly or in combination, improved soil nutrient availability, CEC, shoot yield, and grain yield of rice on both biochar-amended and unamended plots. However, the effect was significantly (p < 0.05) greater on biochar-amended plots. The mean grain yield for all cropping seasons was 1.8 t ha^?1 for biochar-amended plots and 1.3 t ha^?1 for unamended plots. The greater grain yield of rice on biochar-amended plots was associated with improved soil fertility and increased N uptake.     

Applied phosphorus and potassium effects on yield of dallisgrass‐bermudagrass pastures 1

There are substantial areas of dallisgrass (Paspalum dilatatum Poir.)‐common bermudagrass (Cynodon dactylon (L). Pers.) summer‐type pastures in the Southeastern Central Plain, but little information is available on their response to P and K fertilization. The purpose of this study was to measure the response of dallisgrass‐common bermudagrass pastures to P and K fertilization with and with‐ out N. Phosphorus and K were applied to two soils in May each year for three years. Yield data were collected by clipping a swath through the length of the plots when the minimum forage height was approximately 30 cm. Responses to P and K applications were obtained when the soil test levels were low to very low, but not when they were medium as determined by the Mississippi Soil Test (MST). Forage P concentration of the control in the medium P and K soil was within the adequate range of 2.8 to 3.4 g/kg, but forage K concentration was below the critical range of 16 to 18 g/kg. Forage P and K concentrations of the controls in the low P and K soil were below critical levels. At both locations forage P and K concentrations were increased by P and K fertilization. Available soil P increased with rate of P application but soil extractable K was unaffected by K application. No yield response to P and K are likely at medium soil test levels (MST) even at high rates of N. There was no response to P and K application without N.     

Preliminary investigations on the effects of no‐till corn production methods on specific soil mesofauna populations

Abstract

Moldboard plowing, chisel plowing and no‐till methods were used to produce field corn (Zea mays) in an old grass sod. Grain yields were similar ranging between 13,100 and 14,186 kg/ha. The greatest spread in soil temperatures was only 2.1 C with the plowed soil always being warmest. Mean soil organic matter levels of the surface soil ranged between 1.9 percent on the moldboard plowed plots and 3.3 on the no‐till plots. Ten species of soil Collembola were identified. Collembola and Acarina populations were concentrated in the surface 5 cm of soil and were present in greatest numbers in the No‐Till soil.     

Phosphorus Fertilizer Requirements and Nutrient Uptake of Irrigated Dry‐Season Cotton Grown on Virgin Soil in Tropical Australia

Considerable amounts of phosphorus (P) fertilizer will be required on soils in the proposed Ord Stage II area of northwestern Australia if a sustainable dry‐season cotton production system is to be established, because in their virgin state the soils are known to be inherently low in P. This study aimed to determine P fertilizer requirements on these soils to optimize cotton yield as well as nutrient uptake. Five rates of P fertilizer were applied to soil recently cleared of trees and prepared for irrigation. In the second year, these same rates were imposed over the trial. We conclude that the application of 60 kg ha^?1 of P was sufficient to allow maximum yield and quality for dry‐season cotton grown in the first season on virgin soils in the Ord River Irrigation Area, whereas a total of 80 kg ha^?1 of P was required when cotton was grown over two seasons.     

The effects of straw return on potassium fertilization rate and time in the rice–wheat rotation

In order to investigate the effects of straw return on potassium (K) fertilizer application rate and time in the rice–wheat rotation, field experiments were conducted at three sites. The results showed that when the K rate was decreased to 70% of the recommended K dosage, crop yields showed no significant decrease. With K fertilization only at rice phase, crop yields showed no marked difference compared with that provided K fertilizer both at wheat and rice seasons. Though the NH₄OAc-extracted K and HNO₃-extracted K differed slightly among the treatments, the soil apparent K balance was negative without K fertilization. With crop straw fully incorporated, the recommended K dosage could be at least reduced by 30% at the experimental sites and the K fertilizer could be applied only at rice phase. A further hypothesis can be made that the best K rate was the amount of K took away by crop grain. In the long run, straw return combined with K fertilization would be an effective method to maintain soil K fertility and productivity.     

Nitrogen rate and within‐row plant spacing effects on sweetpotato yield and grade

A 2‐yr study was conducted to evaluate the effect of within‐row spacing and nitrogen (N) fertility on sweetpotato [Ipomoea batatas (L.) Lam.] yield and quality. Conducted in North Alabama on a Hartsells fine sandy loam (fineloamy, siliceous, thermic Typic Hapludult), the study consisted of four replications of a factorial arrangement of four within‐row spacings (15, 20, 25, and 30 cm) and 4 N fertility rates (0, 36, 72, and 108 kg N/ha). Nitrogen fertilization did not affect yield or quality of harvested storage roots and there was no significant interaction between row spacing and N rate in either year. In 1994, greatest total yield ofsweetpotatoes occurred with the narrowest within‐row spacing (15 cm), but in 1995 within‐row spacing did not affect total yield. In 1994, as within‐row spacing increased, yield of Jumbo sweetpotatoes increased.     

Phosphorus Fertilizer Requirements and Nutrient Uptake of Irrigated Dry‐Season Cotton Grown on Virgin Soil in Tropical Australia

Abstract

Considerable amounts of phosphorus (P) fertilizer will be required on soils in the proposed Ord Stage II area of northwestern Australia if a sustainable dry‐season, cotton‐production system is to be established, because in their virgin state, the soils are known to be inherently low in P. This study aimed to determine P‐fertilizer requirements on these soils to optimize cotton yield as well as nutrient uptake. Five rates of P fertilizer were applied to soil recently cleared of trees and prepared for irrigation. In the second year, these same rates were imposed over the trial. It was concluded that the application of 60 kg ha^?1 of P was sufficient to allow maximum yield and quality for dry‐season cotton grown in the first season on virgin soils in the Ord River Irrigation Area (ORIA), and a total of 80 kg ha^?1 of P was required when cotton was grown over two seasons.     

Effect of ammonium chloride,ammonium sulphate,and sodium nitrate on take‐all and grain yield of wheat grown on soils in South‐western Australia

Five field experiments are described which measured the effect of three sources of nitrogen (N) fertilizer, applied at 45 kg N/ha, on the incidence of take‐all and grain yield of wheat. The N fertilizers were ammonium sulphate, ammonium chloride, and sodium nitrate. Compared with the Nil N treatment, ammonium‐nitrogen fertilizer, either as ammonium sulphate (ASdr) or ammonium chloride (ACdr) drilled with the seed, lowered the severity of take‐all. Sodium nitrate topdressed (SNtd) to the soil surface reduced the severity of take‐all in three of five experiments, while ammonium sulphate topdressed (Astd) reduced the severity in four of the five experiments. Ammonium sulphate and ammonium chloride drilled with the seed were equally effective in reducing the severity of take‐all in three of the five experiments. However, ACdr was more effective than ASdr in reducing the severity of take‐all in one experiment whereas ASdr was more effective than ACdr in another experiment. In these two experiments (1 and 5), the effects of the reduction in take‐all severity between the ASdr and ACdr treatments did not affect grain yield. The results suggest that grain yield losses from take‐all are most severe where wheat plants are deficient in N. Chloride containing fertilizers are unlikely to control take‐all disease of wheat on soils of southwestern Australia.     

The glycine‐glomus‐rhizobium symbiosis III. Endophyte effects on leaf carbon,nitrogen, and phosphorus nutrition

Soybean plants [Glycine max (L.) Merr.] were grown in pots and inoculated with Rhizobium japonicum and/or Glomus mosseae (Nicol. & Gerd.) Gerd. & Trappe, either at planting or 20 days later. Nitrogen was supplied in the nutrient solution to plants without nitrogen‐fixing bacteria, and P was added to those without the mycorrhizal fungus. At harvest, 50 days after planting, all plants had leaves of similar dry mass. Each root symbiont grew best in the absence of the other. Growth of Glomus reflected the duration of its growing time and the presence and duration of competition from Rhizobium. Nodule weight in the tripartite associations, on the other hand, was inhibited only by the earlier introduction of Glomus.

Dipartite associations and the plants inoculated with both root symbionts at planting had the highest concentration of leaf N, and the lowest was in those inoculated with both organisms at d 20. Leaf P was highest in plants inoculated only with Rhizobium, and lowest in those tripartite associations involving any inoculation at day 20. The low values were presumably a result of the short duration of endophyte‐mediated P uptake before the plants were harvested.

Although there was almost no difference in leaf sugar concentrations, starch concentrations reflected the duration of Glomus growth, and were greatest in those plants that had supported it for the least time. Uninoculated plants contained the least starch, but produced a greater fresh mass of leaf tissue than any of the tripartite symbionts.     

Chelation effects on the iron reduction and uptake by low‐iron stress tolerant and non‐tolerant citrus rootstocks

The relative rates of ferric‐iron (Fe³⁺) reduction and uptake by two citrus rootstocks were measured for a series of synthetic Fe³⁺ chelates and microbial siderophores. The rates of Fe³⁺ reduction by the citrus seedlings followed the order: FeHEDTA >> FeDPTA > FeCDTA. No reduction occurred for FeDFOB (ferrioxamine B) and FeTAF (ferric triacetylfusagen). Low rates of Fe³⁺ reduction occurred for Fe2RA3 (ferric rhodotorulic acid). The levels of ⁵⁵Fe taken up the citrus seedlings showed good correlations with the reduction rates. These results indicate the importance of Fe³⁺ reduction in the Fe uptake by citrus rootstocks. The immobility of a large percent of the ⁵⁵Fe taken up by the roots is attributed to the accumulation of Fe in the root apoplasts.     

Short‐term effects of manganese toxicity on ribulose 1,5 bisphosphate carboxylase in tobacco chloroplasts

The short‐term effects of manganese (Mn) toxicity on ribulose 1,5 bisphosphate carboxylase EC 4.1.1.39 (Rubisco) activity and concentration in tobacco (Nicotiana tabacum L. ‘KY 17') chloroplasts were examined. The activity of the enzyme from both Mn‐treated and control plants was determined 6,12,18, 24, and 48 h after introduction of Mn (80 mg/L). Enzyme activity was determined by monitoring rates of carbon dioxide (¹⁴CO₂) fixation into acid stable products. A decrease in the enzyme's activity in experimental plants was noted after 48 h of exposure. Visible symptoms, such as chlorosis and decreased leaf size, were also observed after 48 h of Mn exposure in experimental plants. Using Rocket Immunoelectrophoresis, no appreciable differences between Rubisco concentration levels of the experimental plants and the control plants were noted indicating that the effect on Rubisco activity is a post‐translational phenomenon and that Rubisco is not being degraded at an accelerated rate. Manganese accumulated in the experimental plants to concentrations as high as 3282 μg/g dry wt as determined by atomic absorption spectrophotometry. A shuttling mechanism for Mn between young and old leaves was indicated by an observed decrease in the concentration of Mn in the young leaf tissue between 12 and 18 h after treatment.     

Salinity effects on growth analysis and nutrient composition in four grain legumes‐rhizobium symbiosis

The effect of salinity on growth response, nitrogen (N) fixation and tissue mineral content was investigated for four legumes: faba bean (Vicia faba L), pea (Pisum sativum L), soybean (Glycine max L), and common bean (Phaseolus vulgaris L). Plants were grown in a vermiculite culture system supplied with a N‐free nutrient solution with the addition of 0, 50, and 100 mM NaCl. Plants were harvested at the beginning of the flowering period and the dry weights of shoots and roots and acetylene reduction activity (ARA) were evaluated at the same time plant tissues were analysed for N, potassium (K), calcium (Ca), magnesium (Mg), and sodium (Na) contents.

The depressive effect of saline stress on ARA of nodules was directely related to the salt induced decline in dry weight and N content in shoots. Growth inhibition by NaCl treatments was greater for the pea than for other legumes, whereas the soybean was the most salt‐tolerant Saline stress also affected the N content in shoots and roots. In general the N content accumulated in the shoot and Na in the roots of the four legumes tested, while K accumulated both organs. The acquisition of other macronutrients differed according to the legume species. The legumes most sensitive were P. sativum and V. faba which accumulated Ca in shoot and Mg both in the shoot and the roots. On the contrary, in G. max and P. vulgaris, the two most salt tolerant legumes, accumulated Mg in the roots and Ca in both vegetative organs. Our results suggest a relationship between the salt‐tolerant range in legumes and the macronutrient accumulation in vegetative organs.     

The effects of volcanic ash influenced soils and nitrogen fertilization on douglas‐fir seedlings

Abstract

An experiment was conducted to help understand the contributions of different soil layers to soil fertility, plant growth, and response to fertilization. Douglas‐fir (Pseudotsuga menziesii) seedlings were used in a pot bioassay to delimit the effects of volcanic ash soils, urea fertilization at 100 and 200 ppm, and the technique of using undisturbed soil as a growth medium. Volcanic ash horizons contained more available phosphorus and mineralized more nitrogen than underlying horizons. Best seedling growth occurred in ash horizons fertilized with 200 ppm of urea‐N. Fertilization decreased soil pH, mycorrhizae formation and foliar‐P levels but increased foliar‐N. The technique of using undisturbed soil had little effect on seedling growth in the weak structured ash horizons but did decrease root weights in the moderate structured sub‐ash layers.     

Sulfur nutrition of winter wheat varieties with till and no‐till planting on highly weathered alfisol soils

Abstract

Winter wheat (Triticum aestivum L.) occupies large hectarage and is important in crop rotations on the highly weathered, low organic matter silt loam soils common in southern Illinois and the southern midwest United States region. Sulfur (S) is an essential element with some potential for deficiency, but it is not commonly applied to winter wheat grown on these soils. This study was conducted to determine if S nutrition is limiting winter wheat growth and grain yield. Interactive effects of topdressed fertilizer S (0 and 28 kg S/ha), tillage (disk‐till, DT and no‐till, NT), and wheat variety on plant growth, nutrient concentration, and grain yield were investigated for three crop years on two soils in southern Illinois; Cisne silt loam (fine, montmorillonitic, mesic Mollic Albaqualf), Brownstown site, and Grantsburg silt loam (fine‐silty, mixed, mesic Typic Fragiudalf), Dixon Springs site. Grain yield was unaffected by S application although flag leaf and whole plant S concentrations increased. Lack of yield response to S application was consistent each year on both soils and across all varieties and tillage systems. Equivalent yields were produced with both tillage systems at Brownstown, but slightly lower yield occurred with no‐till at Dixon Springs. Plant S concentrations and soil sulfate levels indicated sufficient S was available from sources other than fertilizer S, including extractable soil S and atmospheric deposition. Wheat variety consistently influenced plant nutrient composition and grain yield more than tillage or application of S fertilizer. If, in the future, wheat grain production, atmospheric S deposition, and extractable soil S remain at levels measured in this study, then S fertilizer applications would not be expected to increase winter wheat grain yield.     

Effect of different zinc application methods on grain yield and zinc concentration in wheat cultivars grown on zinc‐deficient calcareous soils

The effect of six different zinc (Zn) application methods on grain yield and concentrations of Zn in whole shoots and grain was studied in wheat cultivars (Triticum aestivum, L. cvs. Gerek‐79, Dagdas‐94 and Bezostaja‐1 and Triticum durum, Desf. cv. Kunduru‐1149) grown on severely Zn‐deficient calcareous soils (DTPA‐extractable Zn: 0.12 mg‐kg^‐1 soil) of Central Anatolia which is the major wheat growing area of Turkey. Zinc application methods tested were: a) control (no Zn application), b) soil, c) seed, d) leaf, e) soil+leaf, and f) seed+leaf applications. Irrespective of the method, application of Zn significantly increased grain yield in all cultivars. Compared to the control, increases in grain yield were about 260% with soil, soil+leaf, and seed+leaf, 204% with seed and 124% with leaf application of Zn. In a similar manner, biomass production (dry weight of above‐ground parts) was increased by Zn treatments. The highest increase (109%) was obtained with the soil application and the lowest increase (40%) with the leaf application. Significant effects of Zn application methods were also found on the yield components, i.e., spike number.m^‐2, grain number‐spike^‐1, and thousand kernel weight. Spike number.m^‐2 was affected most by Zn applications, particularly by soil and soil+leaf applications. Concentrations of Zn in whole shoots and grain were greatly affected by different Zn treatments. In plants without added Zn, concentrations of Zn were about 10 mg‐kg^‐1 both in shoots and grain and increased to 18 mg‐kg^‐1 dry weight (DW) by soil application of Zn, but not affected by seed application of Zn. Soil+leaf application of Zn had the highest increase in concentration of Zn in shoot (82 mg‐kg^‐1 DW) and grain (38 mg‐kg^‐1 DW). Soil application of Zn was economical and had long‐term effects for enhancing grain yield of wheat grown on Zn deficient soils. When high grain yield and high Zn concentration in grains are desired, soil+leaf application of Zn was most effective method of Zn application.     

Long-term fertilization effects on carbon pools and carbon management index of loamy soil under grass–forage legumes mixture in semi-arid environment

ABSTRACT

Soil organic carbon (SOC) is a key component for sustaining crop production. A field experiment was conducted during 2004–2018 to assess the changes in soil carbon fractions under different fertilization practices in grass-legumes mixture. The result indicates that application of farmyard manure (FYM) at 80 Mg ha^–1 has increased SOC concentration leading to carbon sequestration rate of 4.2 Mg ha^–1 year^–1. Further, it has increased the proportion of labile carbon in the total SOC and have accumulated 126, 60, 83 and 95% higher very labile, labile, less labile and non-labile C stock than that of control plot, respectively, in top 30 cm soil layer. Inorganic fertilization and FYM 20 Mg ha^–1 influenced SOC concentration, SOC stock and C sequestration rate similarly. The highest carbon management index (264) was found in the treatment receiving FYM 80 Mg ha^–1 and it was positively correlated with SOC (r = 0.84**). The sensitivity index of the SOC varied from 26 to 152% and the differences were greatest in FYM treatments. The result indicates that grass-legumes mixture build-up the SOC in long term and the addition of FYM further increases it.