Effects of mineral nitrogen andBradyrhizobium inoculation on growth and iron nutrition of groundnut

Experiments were conducted in a glasshouse to determine the effects of the mineral N supplied as ammonium nitrate andBradyrhizobium inoculation on the growth and iron nutrition of nodulating and non-nodulating groundnut (Arachis hypogaea L.) lines. In a sterilized sand-vermiculite medium supplied with N-free nutrient solution (pH 7.0), inoculation of nodulating groundnut withBradyrhizobium strain NC 43.3 enhanced dry matter production and O-phenanthroline extractable iron and N contents of the plants. The supply of mineral N at a rate of 100 mg N L^–1 (as NH₄NO₃) through deionized water (pH 8.5) induced iron chlorosis symptoms in the nodulating groundnuts grown in Vertisols, but these symptoms were not observed at higher N levels (200–400 mg N L^–1). The induced chlorosis was only partially corrected by inoculation withBradyrhizobium strains NC 92 and NC 43.3. The iron deficiency chlorosis was, however, corrected by application of higher rates of ammonium nitrate.Submitted as JA No. 942 of the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT)     

Effect of liming and carbofuran on groundnut yield in sandy soils in Niger

One of the constraints to groundnut production in sandy soils of Niger is crop growth variability. In early 1989, a trial on the effect of lime and carbofuran on soil pH, Al toxicity, nematode population and groundnut yield was initiated to study crop growth variability. Groundnut was sown in the 1989 rainy season, followed by pearl millet (Pennisatum glaucum) in the 1989–90 dry season and again groundnut in the 1990–91 rainy, and dry seasons. In 1989 the carbofuran treatment increased the pod yield. Lime application did not change the pH and exchangeable Al⁺⁺⁺ contents in the soil and did not increase groundnut yield. In the 1990–91 rainy and dry season, however, the application of 10 t ha^–1 of lime increased pH, decreased exchangeable Al⁺⁺⁺, improved crop growth and increased the yield of groundnut to the same level as was achieved by the carbofuran treatment. Application of lime did not affect the nematode population, which were reduced by the carbofuran.International Crops Research Institute for the Semi-Arid Tropics (ICRISAT); Submitted as ICRISAT Journal Article No 1228(via Paris)     

Single superphosphate depresses molybdenum uptake and limits yield response to phosphorus in groundnut (Arachis hypogaea L.) grown on an acid sandy soil in Niger,West Africa

The effect of phosphorus (P) fertilization on dry matter production and nitrogen (N) uptake of groundnut (Arachis hypogaea L.) was studied during the growing seasons of 1989, 1990 and 1991 under rainfed conditions on an acid sandy soil in Niger, West Africa. Annual application of 16 kg P ha^–1 as single superphosphate (SSP) failed to increase the total dry matter production significantly in all three years.Fertilization with SSP increased the concentrations of P and sulfur (S) in shoots from deficiency to sufficiency levels. It decreased the already very low concentrations of molybdenum (Mo), especially in the nodules, and also the N concentration in the shoot dry matter.With SSP application, total N uptake declined over three years. Foliar application of P and soil application of triple superphosphate (TSP) enhanced dry matter production, N and Mo uptake.Although these acid sandy soils are known to be deficient in P and S, care must be taken in using SSP in groundnuts as it may induce Mo deficiency, unless supplementary Mo is applied.ICRISAT Journal Article No. 1230     

Effect of different sources of iron and sulphur on nutrient concentration and uptake by groundnut

The C and N mineralization characteristics of two organic N fertilizers were determined in a soil-less incubation system at three temperature regimes. Protox (derived from activated sewage sludge) initially degraded more rapidly by microbial action compared with dried blood. However, dried blood released more CO₂-C and inorganic N towards the end of the incubation periods. The rate of microbial degradation increased with temperature. Mineralization characteristics of protein-based N sources are discussed in relation to organic N nutrition of vegetable crops.     

Direct and residual effect of liming on yield and nutrient uptake of maize (Zea mays L.) in moderately acid soils in the savanna zone of Nigeria

Field experiments were conducted during wet season of 1980, 1981 and 1982 to determine the direct and residual effect of liming on yield and nutrient uptake of maize in moderately acid soils (pH -H₂O; 5.0–5.4) at three locations viz Kontagora, Tumu and Yandev in the savanna zone of Nigeria. Maize crop was grown at five lime rates 0, 0.5, 1.0, 2.0 and 4.0 t ha^–1 and two N sources (calcium ammonium nitrate and urea). Liming at a rate of 2 t ha^–1 maintained high maize yield for three years after application at Kontagora and Yandev. At Tumu 1 t ha^–1 was sufficient to get high yield of maize for three years. Higher rates of lime significantly depressed yield. Uptake of N, P and K was increased significantly with lime application upto 2 t ha^–1 lime at Kontagora and Yandev but at Tumu it increased only upto 1 t ha^–1. The response of P uptake to liming was higher in comparison to N and K uptake. Calcium and magnesium uptake responded upto 4 t ha^–1 lime at Kontagora & Yandev and upto 2 t ha^–1 at Tumu. The residual effect of liming lasted longer than 2 years. High lime rates reduced maize yields and crop nutrient uptake.     

Yield,water use,and nutrient uptake of corn hybrids under varied irrigation and nitrogen regimes

Defined relationships among grain yields, water-use efficiencies (WUE) and nutrient uptake of different genotypes under varied irrigation and nitrogen (N) regimes would be invaluable for optimizing production of corn (Zea mays L.). Our objective was to evaluate these factors for six popular corn hybrids grown in Nebraska. The procedure involved measuring the effects of three supplemental irrigation rates and two N rates on yields, consumptive water use (ET), water-use efficiency, and nutrient uptake of these hybrids in one field experiment. A second field experiment evaluated effects of irrigation timing on the same characteristics of the six hybrids. Soils employed for the field experiments were Sharpsburg sicl, a typic Argiudoll, and Zook sicl, a cumulic Haplaquoll. In addition, two greenhouse experiments measured above-ground and root yields, water use, and nutrient uptake of the six hybrids under limited and high soil moisture levels.From 30–40 percent reductions in grain and stover yields occurred by limiting moisture supply in the greenhouse but with no reduction in root yields. There was only a small benefit to grain and stover yields from the higher soil moisture levels provided in the field experiments because of very favorable rainfall amount and distribution in 1979. Light, frequent irrigation was advantageous to yield and WUE over the same total amount of water applied in larger, less frequent intervals explainable in part by a N use efficiency factor. Genotype B73xMo17 produced significantly higher grain, stover, root and total yields than the other hybrids under all moisture and N regimes. Amounts of water consumed by the six hybrids in the field experiments were similar, but because of higher yields B73xMo17 had the highest WUE values. This hybrid had greater root development in the field and took up disproportionately more P, Ca, S, Fe, Cu, and Zn and less Mn and Cl than the other hybrids suggesting that its superior yielding capacity may be related to efficiency in mobilizing and utilizing certain nutrients.Contribution of the Nebraska Agric Exp Stn, Lincoln, NE as paper No. 7041 Journal Series.     

Growth rate,yield and nitrogen uptake response of grain sorghum (Sorghum bicolor (L) Moench) to nitrogen rates in humid subtropics

Field experiments were conducted during wet seasons (June to October) of 1974, 1976 and 1977 to determine the response of newly developed hybrids and varieties of grain sorghum to N fertilization under humid subtropical conditions of Pantnagar in India. In addition to the enhancement in flowering and maturity stages brought about by N application, it also resulted in increased plant dry weight, translocation coefficients, grain yield plant^–1 and grain yield ha^–1. Varietal differences existed with respect to their responses for yield and N uptake to N rates. Most of the entries responded up to 120 kg N ha^–1. Hybrid CSH 5 utilized applied N more efficiently than other varieties.Publication No 1612 of GBPUA and T, Experiment Station, Pantnagar.     

Effects of nitrogen on growth,and nitrogen and phosphorus uptake in tops and roots of sorghum grown in an Alfisol and a Vertisol

A greenhouse pot experiment was conducted to study the effects of added nitrogen (0, 10, 25, 50 and 100 mg N kg^–1 soil) on dry matter production, and N and P uptake in tops and roots of sorghum (cv CSH6) grown in a Vertisol and an Alfisol for 42 days at field capacity soil moisture content. More dry matter accumulated in the tops and roots of sorghum growing in the Alfisol than in the Vertisol. This resulted in higher N and P uptake. Top dry weight responded to N application up to 50 mg N kg^–1 soil, whereas the root weight increased at N application up to 25 mg N kg^–1. Ratios of root dry weight to total plant dry weight and N uptake in roots/total N uptake were similar in the two soils. Ratio of P uptake in roots to total P uptake was higher in Alfisol than in Vertisol. This result was attributed mainly to higher ratio of P content in roots compared to tops in the Alfisol.Approved for publication as ICRISAT Journal Article No. 709.     

Effect of organic inputs from agroforestry species and urea on crop yield and soil properties at Wondo Genet, Ethiopia

The effect of combined inputs of green manure (GM) and urea on maize (Zea mays L.) productivity and soil characteristics was studied in an on-farm trial at Wondo Genet, southern Ethiopia. The GM species used were the legumes Albizia gummifera G.F. Gmel and Milletia ferruginea (Hochst.) Baker and the non-legumes Cordia africana Lam and Croton macrostachyus Del. The GM and urea were applied separately or combined in different proportions to give equal rates of 100 kg N ha⁻¹, while varying amounts of P and K were supplied by the GM. The experiment was carried out for two consecutive cropping seasons, but treatments were applied only during the first season. Yield increased by 10–84% in the combined treatments compared to the control, with the increase being significant in those treatments containing GM from Cordia and Croton, which had higher P and K but lower N and total polyphenol contents than those from Albizia and Milletia. Increasing the proportion of GM from the non-legumes tended to increase yield, but the opposite was true when the proportion of GM from the legumes was increased. This suggests that N interacted negatively with polyphenols, and/or the P and K supply from GM was more important than that of N. However, treatment effects on soil properties were not pronounced. It was concluded that a ȁ8modestȁ9 input of ≤3.0 Mg ha⁻¹ GM from Cordia/Croton might effect a reasonable yield but that the additional use of inorganic fertilisers is necessary for the GM to have a substantially increased effect. In addition, when organic materials having both high N and high total polyphenol contents (e.g. Albizia and Milletia) are used, they should constitute the smaller proportion of the GM/fertiliser mixture.     

Effect of urea management on yield and N use efficiency of lowland rice on an acid sulfate soil

Field experiments were conducted during 1988–1989 at two adjacent sites on an acid sulfate soil (Sulfic Tropaquept) in Thailand to determine the influence of urea fertilization practices on lowland rice yield and N use efficiency. Almost all the unhydrolyzed urea completely disappeared from the floodwater within 8 to 10 d following urea application. A maximum partial pressure of ammonia (pNH₃) value of 0.14 Pa and an elevation in floodwater pH to about 7.5 following urea application suggest that appreciable loss of NH₃ could occur from this soil if wind speeds were favorable. Grain yields and N uptake were significantly increased with applied N over the control and affected by urea fertilization practices (4.7–5.7 Mg ha^–1 in dry season and 3.0–4.1 Mg ha^–1 in wet season). In terms of both grain yield and N uptake, incorporation treatments of urea as well as urea broadcasting onto drained soil followed by flooding 2 d later were more effective than the treatments in which the same fertilizer was broadcast directly into the floodwater either shortly or 10 d after transplanting (DT). The¹⁵N balance studies conducted in the wet season showed that N losses could be reduced to 31% of applied N by broadcasting of urea onto drained soil and flooding 2 d later compared with 52% loss by broadcasting of urea into floodwater at 10 DT. Gaseous N loss via NH₃ volatilization was probably responsible for the poor efficiency of broadcast urea in this study.     

How do soil P tests,plant yield and P acquisition by <Emphasis Type="Italic">Lotus tenuis</Emphasis> plants reflect the availability of added P from different phosphate sources

The relative effectiveness (RE) of each one of three different sources of P—P in solution (Psol), triple superphosphate (TSP) and phosphate rock (PR)—for reflecting the availability of P in a P-deficient soil were assessed by measuring in Lotus tenuis variables associated with growth, organ morphology, and plant tissue P-content together with the amounts of P extracts from soil by two of the currently used soil-P tests—Bray I and Olsen. A hyperbolic equation was used to fit the response curves of each one of those plant variables to added-P. The ratio between the shapes of paired response curves of any P-sources was used to compute the RE and substitution rate (K) of one source relative to the other. More P was needed from TSP and PR compared to Psol-100% soluble P-source. On the average P applications as TSP relative to Psol and PR relative to TSP were only 68 and 63% effective respectively for plant growth. Plant roots were more sensitive than soil-P tests to detect shifts in P-availability from different P-sources. Because soil tests are commonly used to estimate the current P status in soil in order to calculate the optimum application levels of fertilizer P for a crop or pasture, these results would have practical agronomical consequences if reproduced in other cultivated species because they show that the response curve of a plant species as a function of added P and soil test might differ among fertilizer types, measured plant variables, and the test used to measure P availability in the soil.     

A comparison of seven soil P tests for plant species with different external P requirements grown on soils containing rock phosphate and superphosphate residues

Seven soil tests for phosphate (P) (Bray 1, Bray 2, Truog, ammonium oxalate, Colwell, iron oxide-strip (Pi) and resin-strip soil tests) were evaluated for predicting the yield of plant species which have very different external P requirements. Two acid, sandy soils that had been fertilized six years previously with superphosphate and three rock phosphates were used. A glasshouse pot experiment with lettuce, wheat and maize was used to calibrate the soil tests.For some soil P tests, different calibrations relating yield to soil P test values were required for each plant species, P fertilizer and soil combination. The Bray 2 and Truog soil P tests were the worst predictors of yield for both soils and all plant species. The Pi and ammonium oxalate tests were the most predictive tests for one soil when data for all fertilizers were considered. The Bray 1 and Colwell soil P tests were the most predictive for the other soil. The resin-strip P test was poorly predictive of yield of lettuce and wheat for both the soils. The accuracy in prediction of yield on the basis of P test value decreased in the sequence maize > wheat > lettuce. This rank is opposite to the increasing external P requirements of these species.