Elemental composition of birdsfoot trefoil

Abstract

Developmental and environmental effects on mineral nutrient concentration in birdsfoot trefoil (Lotus corniculatus L.) are not well documented. In this study, elemental composition of two birdsfoot trefoil stands were determined from a late vegetative stage through reproductive growth. ‘Norcen’ birdsfoot trefoil was established on a Glyndon silt loam (coarsesilty, frigid Aeric Calciaquolls) in Roseau County, Minnesota (49°N), in 1980, and Norcen and ‘Leo’ birdsfoot trefoil were seeded on a Waukegan silt loam (fine‐silty over sandy or sandy‐skeletal, mixed, mesic Typic Hapludolls) near Rosemount, Minnesota (45°N), in 1981. Shoot and root samples were taken at approximately biweekly intervals in the year following establishment. Shoots were separated into stems, leaves, umbels, and seed.

Environment influenced the concentration of most elements. This environmental effect was generally consistent among plant parts for Ca, Mg, S, Na, and Mn; i.e., all parts had a lower elemental concentrations at Rosemount than at Roseau. The relationship between environments for P, K, Zn, and Cu concentrations varied with different plant parts; i.e., some”; plant components had element concentrations higher at the southern than northern location, whereas other components had element concentrations that showed the converse. Although most elements were less concentrated with advancing developmental stage, environment modified the rate and extent of change in concentration of every element in at least one plant part. Interactions of environment with developmental stage were not as evident for shoots as for the separate shoot components. Whereas other reports have often emphasized the large differences in nutrient concentrations among legume species, our data suggest that nutrient concentration may be as strongly influenced by environment as by species.     

铵硝配比对巴西香蕉生长和氮素营养的影响

采用水培法,在等氮条件下设置5种不同铵硝配比处理,探讨不同铵硝配比对巴西香蕉幼苗生长及其氮素营养特性的影响。结果表明,等氮条件下,适当地提高铵态氮比例可以提高香蕉的生物量;铵硝比为10∶90最适合香蕉的生长;增铵促进根系的生长,根系中铵、硝含量分别与培养液中铵态氮和硝态氮的含量有关。香蕉幼苗中氮的含量、累积量与铵硝配比有关,增加铵的比例地上部分氮含量和累积量高于全硝处理,促进氮的吸收和利用;铵硝配比影响香蕉叶绿素含量、光合速率以及硝酸还原酶活性,光合速率与叶绿素含量、硝酸盐含量与硝酸还原酶活性没有明显的正相关关系。在香蕉生长早期适当增加铵态氮供应可以促进香蕉根系的生长,有利于香蕉的早发、稳长。     

Compositional Nutrient Diagnosis of a Sample of Plantain from Sur del Lago de Maracaibo (Venezuela)

The aim of the present study was the estimation of reference concentration values for plantain (Musa AAB subgroup plantain cv. Hartón) using the Compositional Nutrient Diagnosis system. Eighty-eight plants were sampled in 2000–2001 in commercial orchards in Sur del Lago de Maracaibo (Venezuela), their yields recorded, and nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), zinc (Zn), copper (Cu), iron (Fe), manganese (Mn), and sodium (Na) concentrations determined in the foliar material. A yield cutoff of 16.98 kg·bunch^?1, obtained after modeling the cumulative variance ratio function versus yield relationships with sigmoidal (Boltzmann) equations, was selected as the value above which plants were regarded as high yielders. Estimations from the high-yield group (N = 31) resulted in the following reference concentrations for macronutrients (in g·kg^?1): 27.4 (N), 2.0 (P), 41.2 (K), 6.5 (Ca), 2.8 (Mg), 1.9 (S), and 0.5 (Na). For micronutrients the reference concentrations were (in mg·kg^?1): 15.6 (Zn), 8.3 (Cu), 64.0 (Fe), and 76.3 (Mn).     

Annual crop rotation of tropical pastures with no-till soil as affected by lime surface application

Soil acidity and low natural fertility are the main limiting factors for grain production in tropical regions such as the Brazilian Cerrado. The application of lime to the surface of no-till soil can improve plant nutrition, dry matter production, crop yields and revenue. The present study, conducted at the Lageado Experimental Farm in Botucatu, State of São Paulo, Brazil, is part of an ongoing research project initiated in 2002 to evaluate the long-term effects of the surface application of lime on the soil’s chemical attributes, nutrition and kernel/grain yield of peanut (Arachis hypogaea), white oat (Avena sativa L.) and maize (Zea mays L.) intercropped with palisade grass (Urochloa brizantha cv. Marandu), as well as the forage dry matter yield of palisade grass in winter/spring, its crude protein concentration, estimated meat production, and revenue in a tropical region with a dry winter during four growing seasons. The experiment was designed in randomized blocks with four replications. The treatments consisted of four rates of lime application (0, 1000, 2000 and 4000 kg ha⁻¹), performed in November 2004. The surface application of limestone to the studied tropical no-till soil was efficient in reducing soil acidity from the surface down to a depth of 0.60 m and resulted in greater availability of P and K at the soil surface. Ca and Mg availability in the soil also increased with the lime application rate, up to a depth of 0.60 m. Nutrient absorption was enhanced with liming, especially regarding the nutrient uptake of K, Ca and Mg by plants. Significant increases in the yield components and kernel/grain yields of peanut, white oat and maize were obtained through the surface application of limestone. The lime rates estimated to achieve the maximum grain yield, especially in white oat and maize, were very close to the rates necessary to increase the base saturation of a soil sample collected at a depth of 0–0.20 m to 70%, indicating that the surface liming of 2000 kg ha⁻¹ is effective for the studied tropical no-till soil. This lime rate also increases the forage dry matter yield, crude protein concentration and estimated meat production during winter/spring in the maize-palisade grass intercropping, provides the highest total and mean net profit during the four growing seasons, and can improve the long-term sustainability of tropical agriculture in the Brazilian Cerrado.     

Aluminum Tolerance in Sunflower Plants Is Associated with Phosphorus Content in the Roots

Sunflower is considered one of the most promising crops for agro-industry development. This plant is adaptable to different soil and climate conditions but is very sensitive to aluminum (Al). Considering that the different plant species have developed different mechanisms to cope with Al, this work evaluated the effect of Al stress on plant growth and nitrogen (N), phosphorus (P), and potassium (K) contents in 25 sunflower genotypes. The results showed that Catissol, EXP 11-26, HLA 860 HO, and H 358 were the most Al-tolerant and IAC-Uruguai, AG 960, EXP 44-49, IAC-Iarama, BRS G27, EXP 887, and H 251 were the most Al-sensitive. We also observed that maintenance of P content in roots of stressed plants seems to play an important role in Al-stressed sunflower plants, suggesting that it could be used as a physiological marker during the screening for Al tolerance in this species.     

Effect of peach root residues,lime and supplemental nitrogen on survival and yield of peach trees in a decline area

Abstract

Supplemental N fertilization significantly increased survival and yield of Elberta peach trees growing in a severe decline area. There was a trend for supplemental N plus dolomitic lime to give further increases in tree survival and individual tree yields but did not significantly influence nutrient content of leaves. Trees did not respond to peach root residue applications.     

Soil tests for predicting plant available phosphorus in newly reclaimed alkaline minespoil

Abstract

Four selected soil tests (Olson's bicarbonate, Bray P‐l, Bray P‐2, and a modified Bray P‐l test) were compared over a four year period as methods for predicting plant available‐P in a slightly alkaline (pH 7.25) minespoil from a west‐central coal field in Illinois. Phosphorus recovery by hybrid corn, measured under both greenhouse and field conditions, showed that the minespoil was extremely P deficient. Extractable Olson's bicarbonate P and standard Bray P‐l phosphorus were highly correlated with total‐P recovery by corn, with respective coefficients of r =0.973 and r =0.957 in the greenhouse; and r =0.998 and r =0.983 respectively, under field conditions. Consistent Mitscherlich‐Bray proportionality constants were calculated from corn grain yields under field conditions in three of four years, after adjustments for annual differences in plant population density. Minespoil was found to require about twice as much extractable‐P (about 40 mg/kg Olson‐bicarbonate or Bray P‐l) as topsoil to support maxiumum corn productivity. It was estimated that more than 500 kg/ha fertilizer‐P will be required to achieve maximum corn grain production in spoil.     

Swedish long‐term experiments

In 1996 there were 124 individual long‐term experiments in Sweden financed by the Swedish University of Agricultural Sciences to a cost of 648.000 Euro. Of these 39 were plant nutrition and soil fertility experiments distributed between the 54th to the 63rd latitude.

At three sites, south, central and north, N mineralization in cropping systems with ley and manure was investigated. Approximately 90 kg N per ha and year was removed by the crops at all three sites. Temperature, cropping history and ley proportions are factors that influenced the N mineralization. In rotations without ley and manure at the central and south sites the N uptake was around 30 kg per ha and year.

Soil C content decreased during 35 years in the south but changed insignificantly at the central and north sites, 31 and 28 years respectively. Only minor effects on soil C content were observed by increased biomass production due to N fertilization. The efficient C metabolism of the heterotrophic microflora emphasises the significance and importance of the simultaneous ongoing N mineralization for the N supply of crops and for the environment.     

Adoption of Crossbred Cow Technologies and Increased Food Security Among Smallholder Dairy Farmers in the East African Highlands

SUMMARY

This study investigates the household-level impacts of market-oriented dairy technologies (crossbred cows and complementary feed and management technologies) on incomes, food and non-food expenditures, nutrient intakes, and health of pre-school children. A recursive econometric model was employed using detailed household level survey data of production, income and consumption, nutrition, and health. Results show that market-oriented technologies are significant determinants of income. The size of the cultivated area, herd size, and purchased inputs are positively and strongly associated with the level of per capita income. Predicted income has a positive and significant influence on expenditures of food and non-food items. Price of food, however, has a negative and significant impact on expenditures. Results also indicate that womens' knowledge, expenditure on food, and price of nutrients are important determinants of nutrient intakes. The analysis of the factors affecting the health status revealed that womens' practice and knowledge, and age of the mother and female headship are important determinants of the weight-for-age and weight for height scores. Also, participation in village level health programs has a significant effect (at 10% level) on the weight for height. The policy implications resulting from this study clearly indicate that strategies that promote market-oriented smallholder dairy can improve food security as it contributes to an increased per capita income, thereby increasing per capita expenditure on food and non-food items. This increase in turn, positively affects the intake of nutrients. Therefore, to improve health, it is useful to focus on the role of woman in the household.