Productivity, Water- and Nitrogen-Use Efficiency, and Profitability of Pearl Millet (Pennisetum glaucum) under Different Nitrogen Applications in Semiarid Region of Nigeria

An experiment was conducted to examine the performance of pearl millet under different nitrogen (N) fertilizer rates in two locations in the semiarid zone of Nigeria. The objective was to evaluate the effects of different N rates on pearl millet yields, water- and nitrogen-use efficiency, and profitability. Grain yield increased by 23, 26, 32, 32, and 27% and by 38, 41, 54, 58, and 56% compared to unfertilized plots when applying 20, 40, 60, 80, and 100 kg Nha−1 in Minjibir and Gambawa, respectively. Similarly, stalk yield increased by 4, 3, 9, 9, and 9% and by 16, 24, 36, 40, and 37% compared to unfertilized plot when applying 20, 40, 60, 80, and 100 kg Nha−1 in Minjibir and Gambawa, respectively. The variations in GY that could be explained by TWU and NUE were 28% and 26% in Minjibir and 46% and 41%, respectively, in Gambawa. There was a strong and positive correlation (R = 0.81 and R = 0.95) between WUE and GY across N-fertilizer rates and pearl millet varieties in both locations. An increase in N-fertilizer levels increased WUE, confirming the optimal application of 60 kg Nha−1 in Minjibir and of 80 kg Nha−1 in Gambawa. Similarly, the highest net economic return (NER) of US$610 ha−1 was obtained at 60 kg Nha−1 in Minjibir and the highest NER of US$223 ha−1 was obtained at an application rate of 80 kg Nha−1 in Gambawa. Break-even yield was above 1000 kg ha−1, signifying that average farmer with a mean yield of less than 1000 kg ha−1 produces millet at a loss.

Growth and yield of onion (Allium cepa L.) as affected by farmyard manure and nitrogen fertilizer application in Tahtay Koraro District, Northwestern Zone of Tigray, Ethiopia

A field experiment was carried out in Tahtay Koraro district of Northwestern zone of Tigray from October 2017 to April 2018, to assess the effect of organic and inorganic fertilizer on growth, yield and yield components of onion. The experiment consisted of four levels of FYM (Farmyard manure) as 0, 10, 20 and 30 t ha−1 and four levels of inorganic N as 0, 34.5, 69 and 103.5 kg ha−1 factorially arranged in RCB design with three replications. Analysis of variance revealed that the main effect of N, FYM as well as their interactions significantly (P < 0.05) influenced days to maturity, plant height, leaf number, leaf diameter, bulb diameter, neck diameter, average bulb weight, above ground dry biomass, marketable bulb yield and total bulb yield of onion. Similarly, main effects of N and FYM significantly (P < 0.05) affected leaf length, bulb length, unmarketable bulb yield and harvest index. The highest marketable bulb yield of 35.93 t ha−1 and 34.72 t ha−1 were obtained at combinations of 103.5 kg N ha−1 + 30 t FYM ha−1 and 103.5 kg N ha−1 + 20 t FYM ha−1 respectively. However, the lowest marketable bulb yield of 13.88 t ha−1 was obtained from the unfertilized plot. Moreover, the highest marginal rate of return was obtained at combined application of 103.5 kg N ha−1 and 10 t FYM ha−1 and thus can be recommended for onion production in the study area.

CO2 Emissions from Tropical Peat Soil Affected by Fertilization

The conversion of peat soils to agricultural uses has been thought to increase CO2 emission due to several factors, including fertilization. However, evidence on the effect of fertilization on CO2emissionsfrompeat soils is rareand often inconsistence. We measured the effects of different types of fertilizer, including N, P and K sources, and clay as an ameliorant on CO2 emission from a bare peat soil in Lubuk Ogong, Riau Province. Nutrients were added in the following combinations: 0 (unfertilized plot), N source (urea), slow-release N (slow release urea), N and Psource (Urea+SP-36), N, P and K sources (urea+SP-36+KCl) and combined NPK-Clay. Fertilization resulted in a decreasein CO2 emissions compared to that prior to fertilization except when slow-release urea was applied. Decreasing of CO2 emissions was probably due to pH-related effects because the pH in the N treatment was lower than in both the control and the unfertilized plot. A decreasein the level of CO2 emissions among the treatments followed the order NPK-Clay>NP>NPK>urea>slow-release urea. Covariance analyses showed that the difference in CO2 emissions prior to treatment was not significant. The application of individual and combined treatments of N, P, K and NPK mixed with 5 Mg ha-1 clay led to significantly reduced CO2 emissions from bare peat soil in Lubuk Ogong, Riau Province. In addition to fertilization, the water table depth was the only parameter that significantly affected the CO2 emissions (P<0.05). We conclude that the application of nutrient combinations, including N, P, K and clay, could reduce CO2 emissions because these treatments maintain a balanced nutritional condition in the soil with respect to the microbial activity.Keywords: Amelioration, CO2 emission, fertilization, tropical peat soils

Long-term effect of fertilization on soil fertility

The surplus of the NPK balances of Hungarian agriculture, appearing in the nutrient balance sheet is a consequence of intensive fertilization in the past. Hungary had a positive P-balance between 1960 and 1990 for 30 years, and a positive NK-balance between 1970 and 1990 for 20 years during the 20th century.Studying the long-term effects of superphosphate in a field experiment on calcareous chernozem soil, it was found that the “half life time” of residual P was 5–7 years. The trial, i.e. the P after-effect lasted for 20 years.Liming and fertilization are the main soil fertility improving considerations for acidic sandy soils. These soils are often poor in all major nutrients. Mineral fertilizers, mainly NH4NO3, acidify soil, the pH values sink in comparison to the unfertilized plot. Liming and use of dolomite powder may counterbalance the acidification.

Study regarding the influence of the nPK fertilizers use in long term trial on heavy metals concentration in wheat grains

The paper presents research results obtained in stationary experiments, carried out at Agricultural Research and Development Station Oradea, regarding the influence of nitrogen, phosphorus and potassium fertilizers, on Cd, Pb, Cu, Zn and Ni concentration on wheat grains. The minimum concentration of cadmium in wheat grains was recorded in the case of the unfertilized plot N0P0K0, 0.12 mg kg-1, and maximum value 0.22 mg kg-1, was registered at the fertilized plot with N160P80K120, relative difference relative to control was 84.2%. Lead concentration had the lowest value in the unfertilized plot, the value (0.4 mg kg-1) being under the maximum allowed (1.0 mg kg-1). In case of the fertilized plot with N160P80K120, the lead concentration had the highest value, 0.47 mg kg-1, but even in this case it was located beneath the maximum limit allowed. In all four systems of fertilization, copper has not exceeded the maximum allowed limit (5 mg kg-1), the values have been comprised between 1.68 mg kg-1 at the unfertilized plot and 2.81 mg kg-1 at the fertilized plot with N160P80K120. In other plots of fertilization copper had concentrations of 1.97 mg kg-1, at the fertilized plot with N80P40K40, and 2.78 at the fertilized plot with N80P80K80. The lowest concentration of zinc, 26.47 mg kg-1, has been registered in the control N0P0K0. In the other fertilization plots studied, the zinc concentrations had the following values: 27.66 mg kg-1 (N80P40K40), (N80P80K80) 29.87 mg kg-1 and 33.62 mg kg-1 (N160P80K120). Nickel has registered the lowest value in the unfertilized plot, 3.47 mg kg-1. The fertilized plot with N160P80K120 had the highest value 4.94 mg kg-1, with 42.39% higher compared to the control N0P0K0.

ORGANIC FERTILIZERS FOR LOWBUSH BLUEBERRY

Acommercial lowbush blueberry field with a history of N and P deficiency was used to study the response to several organic fertilizers. Diammonium phosphate (DAP) is the standard fertilizer for correcting N and P deficiencyin non-organic production. At a rate of 67 kg N/ha Rennaisance (8–2–6), Pro-Holly (4–6–4), Pro Grow (5–3–4), Nutri-Wave (4–1–2), or DAP (18–46–0) was applied preemergent to 1.8 × 15 m treatment plots. An unfertilized plot served as the control. Leaf N and P were deficient in the controls. DAP and Pro-Holly raised leaf N to satisfactory levels (1.6%). Only DAP raised leaf P concentrations (0.144%), compared to controls (0.122%). Leaf K was not deficient but was raised by Pro-Holly. Pro-Holly and DAP were equally effective in increasing stem height, branching, branch length, flower bud formation, and yield. Pro-Holly could effectively substitute for DAP in organic wild blueberry production.

EFFECT OF LONG-TERM APPLICATION OF MANURES AND FERTILIZERS ON CHANGES IN THE WEED SPECIES IN THE 138TH CROPPING UNDER RAINFED CONDITIONS

A field study was made at Tamil Nadu Agricultural University, Coimbatore, India in a permanent fertilization experiment to assess the influence of the long-term application of manure and fertilizer schedules on changes in the weed flora and their growth in the 138th (rainfed) crop of sorghum (Sorghum bicolor (L.) Moench). The weed flora of the experimental field in the unfertilized plot at 50 days after sowing (DAS) consisted of 44.1% grasses, 26.4% sedges and 29.5% broad-leaved weeds, of which Dactyloctenium aegyptium (L.) Beauv., Cynodon dactylon, Cyperus rotundus, Digera arvensis Forsk. and Phyllanthus maderaspatensis were the most dominant weed species. Maximum weed growth was recorded in the plot treated with cattle manure. A relative grain yield of 391% over the control was recorded in the balanced fertilizer plot (combined application of N, P and K).

Effets à moyen terme de la fertilisation par urée ou par potassium sur Pinusbanksiana L. et le comportement de ses insectes dévastateurs: tel que Neodiprionswainei (Hymenoptera, Tenthredinidae) et Toumeyellanumismaticum (Homoptera, Coccidae)

The effect of fertilization on the physiology of jack pine (Pinusbanksiana Lamb.) in a natural stand and on two important foliage pests, Neodiprionswainei Middleton and Toumeyellanumismaticum Pettit and McDaniel, was studied.It was established in 1973 that fertilization with 400 kg of urea per hectare (1 ha = 1 × 104 m2) in 1969 and in 1970 was still influencing the level of chloride, the osmotic pressure and the activity of two enzymes, glutamic–oxaloacetic transaminase (GOT) and glutamic dehydrogenase (GLDH) contained in the foliage. In June 1974 in current and previous years' growth, the amount of chloride had decreased, respectively, to 81 and 50 p.p.m. (mg/kg) in fertilized trees, and the osmotic pressure increased by 37 and 49 m[Formula: see text]smol/kg. The activity of GOT and GLDH in the foliage of fertilized trees was 41 and 14 mU/g, respectively, compared with 163 and 21 mU/g, respectively, in the foliage of unfertilized trees.It was found 3 years after fertilization that the mortality of N. swainei larvae was 50% higher and the damage they caused was 42% less in fertilized trees. Also, it was observed that urea fertilization, even at low dosage, favoured T. numismaticum, this infestation increasing 2,7 and 9 times in plots fertilized with 100, 200 and 400 kg of urea nitrogen per hectare.The studies revealed, however, that fertilization with potassium may reduce T. numismaticum. The infestation in the fertilized plot showed a reduction from 42 to 21%, and in the unfertilized plot there was an increase from 38 to 80%.

Potassium: calcium exchange in soils of the Broadbalk experiment at Rothamsted

SUMMARYSoils from Broadbalk field were used to find whether differences in K-manuring had altered K:Ca exchange relationships during 100 years cropping with wheat, by measuring cation exchange capacities and quantity/intensity (Q/I) relationships.Cation exchange capacities (CECs) were measured with and without the contribution of the soil organic matter and the following mainly non-significant trends arose during 100 years: (1) The CECs of plots given K fertilizer increased slightly when the organic contribution is included and decreased slightly when it is not. (2) The CEC of the plot given farmyard manure increased greatly when the organic contribution is included and decreased slightly when it is not. (3) The CEC of the unfertilized plot increased very slightly, whether or not the organic contribution is included.The K buffer capacity, the slope of the Q/Icurve when the soil neither gains nor loses K, was related to the K saturation of the CEC better when the organic contribution was omitted from the CEC than when it was included, suggesting that K: Ca exchange measured by the Q/Icurves occurs mainly on the non-organic part of the CEC. Two soils depleted of K had anomalously large buffer capacities, but two undepleted samples behaved similarly.Superimposing Q/Icurves by eye showed no appreciable differences between samples from different years or from different plots, even at large activity ratios. Plotting exchangeable K against I0, the activity ratio when the soil neither gains nor loses K, gave a single curve embracing all plots from all years, similar to the superimposed Q/I curves. Long–term manuring with ammonium sulphate has not affected K–Ca exchange.

PHYSICAL AND BIOLOGICAL PROPERTIES OF SOIL FERTILIZED WITH GREEN MANURE

Agricultural practices that improve agricultural sustainability are needed particularly for brown luvic soil. Soil enzyme activities can provide information on how soil management is affecting the processes in soil such as decomposition and nutrient cycling. Soil enzyme activities (actual and potential dehydrogenase, catalase, acid and alkaline phosphatase) were determined in the 0–10, 10–20, and 20–30 cm layers of a brown luvic soil submitted to a complex fertilization experiment with different types of green manure. It was found that each activity decreased with increasing sampling depth. It should be emphasized that green-manuring of maize led to a significant increase in each of the five enzymatic activities determined. The enzymatic indicators of soil quality calculated from the values of enzymatic activities showed the order: lupinus + rape + oat > lupinus > vetch + oat + ryegrass > lupinus + oat + vetch > unfertilized plot. This order means that by determination of enzymatic activities valuable information can be obtained regarding fertility status of soils. There were significant correlations of soil enzyme activities with physical properties.