Growth of Brazilian Cotton Cultivars in Response to Soil Applied Boron

ABSTRACT

The growth of cotton (Gossypium hirsutum L.) was evaluated in a 6 × 5 factorial experiment with 6 boron (B) levels (0.0, 0.5, 1.0, 1.5, 2.0, and 3.0 mg dm^?3), 5 cultivars (‘CNPA 8H’, ‘BRS Aroeira’, ‘BRS Antares’, ‘BRS Sucupira’, ‘BRS Ipe’), and 3 replications. As B increased in the soil, leaf B concentrations increased linearly in ‘BRS Aroeira’ and ‘CNPA 8H’, and quadratically in ‘BRS Ipe’ and ‘BRS Sucupira’. The concentrations of B in the leaves and in the soil increased with the B increasing in the soil. The agronomic characteristics evaluated showed ‘BRS Aroeira’ and ‘BRS Sucupira’ responding more and BRS responding less to the B doses applied. The variation in the effFiciency of B utilization was: ‘BRS Aroeira’ > ‘CNPA 8H’ = ‘BRS Antares’ > ‘BRS Sucupira’ > ‘BRS Ipe’. Cultivar ‘BRS Aroeira’ had the greatest potential to respond positively to the addition of B to the soil.     

Effect of B,Mn and Zn on nodulation and N2‐fixation in southernpeas

Abstract

Two greenhouse studies were conducted to evaluate the effect of B, Mn and Zn on nodulation and N₂‐fixation of southernpea (Vigna unguiculata (L.) Halp.) cultivars ‘Freezegreen’, ‘Mississippi Silver’ and ‘Pinkeye Purple Hull’. The cultivars were grown in plastic pots with a Norfolk sandy loam (fine, loamy siliceous thermic, Typic Paleudult) soil treated with B, Mn and Zn at rates of 0, 5, 10 and 20 kg/ha each at pH levels 5.5, 6.0 and 6.5. At pH 6.5 all micronutrient treatments significantly increased nodulation and N₂‐fixation over the control (no micronutrient applied). The effects of B, Mn and Zn on nodulation and N₂‐fixation depended on the cultivar and soil pH. For plants given the 5 kg/ha B and Mn treatments, ‘Mississippi Silver’ produced the highest number of nodules and ‘Pinkeye Purple Hull’ the least. At 20 kg/ha Zn, nodulation of ‘Freezegreen’ was highest and ‘Pinkeye Purple Hull’ the lowest. As a whole, maximum nodulation was at 5 kg/ha B and Mn and 20 kg/ha for Zn. Nitrogen fixation rates responded similarly except that the optimum rate for Zn was 10 kg/ha. Seed yield of plants peaked at 5 kg/ha for B and 10 kg/ha for Zn, indicating a possible relation of N₂‐fixation to seed yield.     

Study of Soil Fertility and Plant Nutrition of Proteas Cultivated under Subtropical Conditions

Abstract: A study of soil physicochemical characteristics and mineral nutrition of four cultivars of Leucospermum cordifolium (‘Scarlett Ribbon,’ ‘High Gold,’ ‘Veldifre,’ ‘Sunrise’) and Leucospermum patersonii species was carried out along 2 years in commercial protea plantations, distributed throughout a subtropical region (La Palma Island, Canarian Archipelago). Soils presented a slightly acid pH range, whereas organic matter showed suitable values. Generally, available soil phosphorus (P) contents were less than 25 mg kg^?1, with high available potassium (K) and calcium (Ca) levels, though the ratio of Ca of the sum of available cations was usually appropriate. Despite the high electrical conductivity (EC) levels (4.31–8.87 dS m^?1) determined in some soils, no salinity symptoms were ever detected. Distribution and behavior of foliar nutrients nitrogen (N), P, K, Ca, magnesium (Mg), and sodium (Na) along time showed that nutritional needs varied in some cases among cultivars and species. L. patersonii presented the least N concentration, whereas ‘High Gold’ and ‘Veldfire’ had the greatest levels. Data denoted that P requirements were larger in younger plants, during the recovery after pruning, and while new buds developed. ‘Sunrise’ cultivar stood out for its large foliar levels of P, whereas ‘Scarlett Ribbon’ and ‘Veldfire’ had the least K contents. As a general pattern, K decreased in winter samplings. L. patersonii species and the cultivar ‘Sunrise’ exhibited the highest Ca values, and the same was true for Mg only in the species. A special need for Na appeared in all the cultivars and species studied. L. patersonii and the cultivar ‘Sunrise’ showed the greatest Na levels. A general stabilization of nutrient concentrations was observed in the fourth, fifth, and/or sixth samplings, so that November is recommended for taking samples for current foliar analysis. In this context, foliar ranges for the studied nutrients are suggested.     

Effect of superphosphate applications on soil phosphorus and on crop phosphorus removal by the strawberry

Abstract

Rate of superphosphate application significantly increased the Bray #2 (easily acid soluble plus adsorbed P) and “AlPO₄”; fractions for 3 successive years. A single dolomitic limestone application increased “FePO₄”; by an average of 36% one year after application. Crop P removal by the strawberry cv. ‘Acadia’ was approximately 2–3 ppm each year and it was not possible to relate this small amount to any of the soil P fractions determined.     

Toxicity symptoms and tissue levels associated with excess boron in pear trees

Abstract

High levels of B were applied to the soil around ‘Bartlett’ and ‘d'Anjou’ pear trees in a non‐irrigated orchard. B levels in the soil profile and in the flowers, leaves and fruit were monitored for 6 years. Levels of B in the soil dropped to below 2 ppm within 5 years following the application. By then all visible symptoms of toxicity had disappeared. The B content of ‘Bartlett’ tissues was always higher than that of ‘d'Anjou’ and the symptoms of toxicity were more severe. Under conditions of this research, full bloom blossom cluster levels and levels in the fruit at harvest time were better indicators of toxicity than were the levels in leaves. Boron levels in blossom clusters above 90 and 115 ppm and in fruit above 55 and 45 ppm for ‘d'Anjou’ and ‘Bartlett’ pears respectively were considered to be toxic.     

A survey of Michigan soils as related to possible boron toxicities

Abstract

The saturation extraction method for measuring available B in soil provided variable results and a narrower range thus making this test more difficult to interpret than tests with the boiling water method.

No close relationship between available soil B and either soil texture or soil pH level was found. The available B in soil ranged from 0.16 to 0.95 ppm with the highest level reflecting the recent use of B. The B level in the profiles of three typical sugarbeet‐bean soils ranged from none detectable in the subsoil to 0.54 ppm in the surface soil.

A survey of cropped versus uncropped soils showed that, on the average, cropped soil contained two‐thirds as much B as uncropped soil, suggesting that more extensive B deficiencies may occur in the future. Soil test levels for B in a calcareous soil decreased rapidly after B application. In this experiment soil B levels in excess of 1.5 ppm represented a potentially toxic condition for beans while any level above 2.0 ppm represented a definite toxicity. The bean plant B threshold level was in excess of 100 ppm. In the range of potential toxicity, bean yields and B soil tests were more closely related than were bean yields and B plant tests.     

Impacts of acid precipitation on coniferous forest ecosystems

This paper summarizes the results from current studies in Norway. One main approach is the application of artificial acid ‘rain’ and of lime to field plots and lysimeters. Application during two growth seasons of 50 mm mo^?1 of ‘rain water’ of pH 3 to a podzol soil increased the acidity of the humus and decreased the base saturation. The reduction in base saturation was mainly due to leaching of Ca and Mg. Laboratory experiments revealed that decomposition of pine needles was not affected by any acid ‘rain’ treatment of the field plots. Liming slightly retarded the decomposition. No nitrification occurred in unlimed soils (pH 4.4-4.1). Liming increased nitrification. The soil enchytraeid (Ohgochaeta) fauna was not much affected by the acidification. Germination of spruce seeds in acidified mineral soil was negatively affected when soil pH was 4.0 or lower. Seedling establishment was even more sensitive to increasing soil acidity. Analysis of throughfall and stemflow water in southernmost Norway reveals that the total deposition of H₂SO₄ beneath spruce and pine is approximately two times the deposition in open terrain. A large part of this increase is probably due to dry deposition. Increased acidity of the rain seems to increase the leaching of cations from the tree crowns. Tree-ring analysis of spruce (Picea abies (L.) Karst.) and pine (Pinus sylvestris L.) has been based on comparisons between regions differently stressed by acid precipitation and also between sites presumed to differ in sensitivity to acidification. No effect that can be related to acid precipitation has yet been detected on diameter growth.     

A rapid procedure to calculate lime requirements based on single titration with base

The lime requirement (LR) in 39 surface acid soil samples (0–30 cm) from western Greece was calculated using a single-addition titration of successive 3-mL 0.022 M calcium hydroxide [Ca(OH)₂]. Soil pH measurements and titrations were performed in soil/water (1:2) and in a soil/0.01 M CaCl₂ (1:2) suspension while being stirred. The results were referred to as ‘pH data group I’ and ‘pH data group II’, respectively. In each ‘pH data group’, the samples were separated into ‘pH data subgroups’, according to the total volume (mL) of 0.022 M Ca(OH)₂ added to increase the initial pH (pH_a) to a target value of 6.5 (pH_t). The fitted linear regression equation pH_t = b × volume + pH_a was used for each ‘pH data group’ to determine the slope b. The b-weighted mean for each ‘pH data group’ was calculated. The LR was then calculated as follows: Mg CaCO₃ ha^?1 = 0.495 (pH_t – pH_a)/b, where b is the average weighted mean from the two ‘pH data groups’ and is equal to 0.227. The validity of the above equation was confirmed after incubation with Ca(OH)₂ for 72 h. This procedure is simple and gives a rapid and accurate estimation of LR with respect to the environment.     

Compost Practices for Improving Soil Properties and Turfgrass Establishment and Quality on a Disturbed Urban Soil

Urban land disturbance degrades physical, chemical, and biological soil properties by removing topsoil and compacting the remaining subsoil. Such practices create a soil environment that is unfavorable for vegetation establishment. A 3-year field study was conducted to compare the effects of various one-time compost application treatments on soil properties and re-vegetation of a disturbed soil. A disturbed urban soil received the following treatments: (1) inorganic fertilizer; (2) 2.5-cm-depth surface-applied compost; (3) 2.5-cm-depth incorporated compost; (4) 5.0-cm-depth incorporated compost; (5) inorganic fertilizer plus 0.6-cm compost blanket; and (6) inorganic fertilizer plus straw mat cover. The plots were seeded with a mixture of tall fescue Festuca arundinacea Shreb.: ‘Magellan,’ ‘Coronado Gold,’ ‘Regiment,’ and ‘Tomcat,’ perennial ryegrass Lolium perenne L. ‘Linn’, and Kentucky bluegrass Poa pratenis L. ‘Baron.’ Soil chemical and physical attributes and plant growth and quality parameters were measured during 840 days following study establishment. Soil C, N, P, K, Ca, and Mg, and turfgrass growth and quality were increased and soil bulk density was reduced by amending with composts. Incorporation of compost into soil improved soil and plant attributes more than unincorporated surface application, but the differences diminished with time. Compost benefits increased with time. One-time applications of compost can provide immediate and long-term benefits to soil and plant attributes, but there may be no need to incorporate the compost into soil, particularly if the soil has recently been loosened by tillage.     

Differential responses of alfalfa cultivars to aluminum stress

Abstract

Toxic levels of aluminum can cause severe yield reduction in alfalfa (Medicago sativa L.), especially in the presence of drought stress. Reactions to Al stress of alfalfa cultivars and germplasms, representing a broad genetic base and the entire range of dormancy types, were evaluated in a Monmouth soil study [26.2% Al saturation (pH 4.8) vs 2.8% Al saturation (pH 5.7)] and in two nutrient solution experiments (0 vs 111 μmol Al; pH 4.5). The soil study, Experiment 1, and Experiment 2 were harvested 28, 40, and 25 d after seeding, respectively.

In all studies, entries differed significantly in vigor and yields were reduced significantly by Al stress. In the soil study, only ‘Lahontan’ was not affected significantly by Al stress, although Lahontan, ‘Atlantic’, ‘B13‐A14’ (tolerant check), ‘Ladak 65’, and ‘Mesa‐Slrsa’ had comparable relative weights (dry weight stressed/dry weight unstressed). There were no statistically significant differential responses to Al stress in Experiment 1, however the relative weight of B13‐A13 (tolerant check) was considerably larger that those of the other entries. Many entries were not affected significantly by Al stress in Experiment 2; B13‐A14, ‘Moapa 69’, ‘Saranac’, and ‘Teton’ had the largest relative weights. Relative weights for Experiment 1 and Experiment 2 were significantly correlated (r=0.46?) as was mean dry matter production in the soil study and Experiment 2 (r=0.73??).