African Journal of Agronomy

African Journal of Agronomy Vol. 1 (6), pp. 106-110, December, 2013. © International Scholars Journals

Full Length Research Paper

Inconsistent rate of fertilizer application in Turkish wheat agriculture: Economic evaluation

Tamer K. Akande

Department of Plant and Crop Science, Faculty of Agriculture, Ege University, Bornova, izmir, Turkey. Email: [email protected]

Accepted 25 September, 2013

Abstract 

Fertilizer application is one of the most important operations in agricultural production. Traditionally, fertilizer is applied onto the whole farmland regardless of the variations across the land. Soil cores are taken randomly through the field and mixed into a single sample, which is then analyzed, and consequently a unique fertility recommendation is made in accordance with the results. However, with this new technology of precision farming, grid or zone sampling is employed to determine the variability of the farmland soil fertility and fertilizers at variable-rates are applied onto each of these grids or zones. In this study, economics of variable-rate fertilizer application in Turkish wheat production is examined, an investment appraisal and partial budgeting analysis is made to determine the applicable conditions for farmers. Applying fertilizer considering the variations in soil nutrients could be economically justified. The key factor for the implementation of precision agriculture is the degree of variability; highest variability easiest the implementation. The annual cost per hectare of the above equipment over a 5 year depreciation period, at an interest rate of 21% together with maintenance vary between $13 and $131 ha^-1 for an area managed by the precision farming system of 500 - 50 ha. The benefits is of greater importance the additional costs of the investment in precision farming systems for only considering the yield varies between 10 to 1% due to the farmed area. Whereas, percentage was 37 to 4% for fertilizer saving. The costs of detailed soil sampling and analyzing is a barrier for collection from a dense grid of data points.

Key words: Precision agriculture, economic assessment, wheat production, variable rate fertilizer application.

African Journal of Agronomy Vol. 1 (6), pp. 099-105, December, 2013. © International Scholars Journals

Full Length Research Paper

Causes of green manure legume - maize rotation on maize grain yield and wild plant infestation levels

Oliver R. Khama, Kaiser Cedric and Lule E. Nelson

Department of plant and crop science, Faculty of Science and Agriculture, University of Fort Hare, East London, Eastern Cape, South Africa. Email:[email protected]

Accepted 02 September, 2013

Abstract 

The use of green manure legumes (GLM) as cover crops in rotation with maize has the potential to enhance maize yields. The objectives of this study were to determine the effect of GML - maize rotation system on (i) maize growth and yield and, (ii) weed infestation levels. The two year (2007/8 and 2008/9 seasons) rotation system consisted of five GML cover crops, viz. mucuna, lablab, sunhemp, cowpea and butterfly pea followed by maize. GML biomass ranged between 0.8 and 13.6 Mg ha^-1, while nitrogen (N) content ranged between 10 and 279 kg N ha^-1. Maize grain yield following GML ranged between 2.6 and 10.59 Mg ha^-1. In 2007/8 season cowpea, mucuna, lablab and sunhemp plots had a lower weed dry matter (5.30, 11.97, 5.83 and 21.03 g m^-2, respectively) than the control (+N) (49.47 g m^-2). In 2008/9 season, at 6 - 8 WAP, control (+N) had a higher weed dry matter than the other treatments, except of butterfly pea. The dominant weed species were Mexican ricardia (Ricardia brasiliensis), Yellow nutsedge (Cyperus esculentus), Guinea-fowl grass (Rottbollia cochinchinesis), Witch weed (Striga asiatica), Bermuda grass and Cynodon species. Green manure legume fallows can increase maize grain yield significantly and suppress the weed population as compared to natural fallow. However, maximizing biomass production and N accumulation is critical in order to reap the benefits of green manure. Hence, integrating GML into the existing cropping system will require that appropriate timing for planting GML be well established.

Key words: Green manure legume, maize, rotation, weed infestation.

African Journal of Agronomy Vol. 1 (5), pp. 085-091, November, 2013. © International Scholars Journals

Full Length Research Paper

The Application rates and Fertilizer effects on tea cultivation on nitrogen and potassium efficiencies

Simon Calvin, Nduta Hanjari and Bedan H. Jacques

Department of Crop Science, Faculty of Agriculture, Egerton University, kenya.

Accepted 05 October, 2013

Abstract 

As the most important cultural practices for tea production, single effects of nitrogen (N) and potassium (K) fertilization on yield are well documented but their interactions and impact on their use efficiencies are poorly understood. It was necessary therefore to assess interactions and impact on their use efficiencies in tea cultivation as influenced by fertilizer application rates. This objective led to a comprehensive field investigation in strongly acidic soil tea plots at Tea Research Foundation of Kenya, Kangaita substation in Kerugoya using clone TRFK 11-4 in a 3x3, NxK RCB design. Treatments were nitrogen (0, 100 and 200 Kg N ha^-1) as urea and potassium (0, 40 and 80 Kg K ₂O ha^-1) as muriate of potash (MoP) replicated thrice. A uniform single dose of phosphorus (40 Kg P₂O₅ ha^-1) was applied. Tea yield, plant biomass and plant nutrient concentrations were measured for calculation of plant nutrient uptake and efficiencies. Increased nitrogen rates from 100 to 200 Kg N ha^-1 increased agronomic efficiency of nitrogen from 0.33, 0.93 and 0.33 to 1.32, 1.08 and 0.37 at respective rates of potassium. Increased nitrogen rates from 0 to 200 Kg N ha^-1 increased agronomic efficiency of potassium from - 0.59 and 0.04 to 6.67 and 1.26 at respective rates of potassium.

Key words: Camellia sinensis (L.), interactions, clones, concentration, nutrient removals.

African Journal of Agronomy Vol. 1 (5), pp. 092-098, November, 2013. © International Scholars Journals

Full Length Research Paper

The result of phosphorus fertilizer application on growth and yield of three soybean (Glycine max) cultivars in Limpopo Province

Jovic T. Hadi, Tahid Munir and Soraya Damasey

Department of plant and crop science, Faculty of Agriculture, University of Melbourne, Parkville, Victoria, Australia.  E-mail: [email protected]

Accepted 29 July, 2013

Abstract 

This study aimed at assessing the effects of phosphorus (P) rates on the growth and yield of three soybean cultivars in Vhembe district, Limpopo Province, South Africa. Field experiments were carried out at the University of Venda’s experimental farm, Thohoyandou over two seasons (season I: February– May 2006; season II: November 2006 – March 2007). The experiments consisted of a factorial combination of P fertilizer rates (0, 30 and 60 kg P ha^-1) and soybean cultivars (Pan 520RR, Highveld Top, and LS 555) arranged in a randomized complete block design and replicated three times. Crop biomass (three stages: vegetative phase, 50% flowering and harvest maturity) and grain yield were determined. The (Agricultural Production Systems Simulator) APSIM model (version 5.3) was used to simulate crop biomass and grain yield and to assess the long-term risks associated with yield production of soybean crop. P did not affect crop biomass at harvest maturity but the effect of cultivar was significant (P = 0.01); LS 555 had lower grain yield (701 kg ha^-1) compared with Pan 520RR (1457 kg ha^-1) and Highveld Top (1241 kg ha^-1). There was a strong positive relationship (R ² = 0.97) between observed and predicted grain yield data but the predicted yields were generally lower than the observed values. These preliminary findings show firstly, that the addition of P may not affect grain yield of soybean in this area, secondly, that Pan 520RR and Highveld Top may be suitable for cultivation in this area, and lastly, that APSIM model may be a useful tool in predicting soybean productivity in this area.

Key words: P application, cultivar, crop biomass, grain yield, APSIM simulation.