Phosphorus Fertilizer Rates Research Articles

Effects of phosphorus fertilizer rate and Pseudomonas fluorescens strain on field pea (Pisum sativum subsp. arvense (L.) Asch.) growth and yield

A field experiment was conducted at Rezvanshahr, Guilan province, Iran, to evaluate the effects of phosphorus fertilizer rate and Pseudomonas fluorescens strains on growth and yield of field pea (Pisum sativum L.). The experimental design was a randomized complete block in a factorial arrangement with three replicates. Factors were phosphorus fertilizer rates (0, 25, 50, 75, and 100 kg P2O5 ha-1 as triple superphosphate), and seed inoculation with P. florescens strains [control (non-inoculated), inoculated with strain R41, and strain R187). Analysis of variance showed that plant height, seed yield, pod number per m2, 100-seed weight, biological yield, harvest index, and leaf P concentration were significantly influenced by phosphorus fertilizer rate and P. florescens strain. At the same time, phosphorus fertilizer rate × P. fluorescens strain interaction was significant only for 100-seed weight. On the other hand, seed number per pod was significantly affected neither by phosphorus fertilizer rate nor by pseudomonas strains. Result showed that seed yield was significantly increased from 1099 ± 67 to 1898 ± 118 kg ha-1 as P2O5 application rate increased from 0 to 75 kg ha-1, and thereafter relatively remained constant. There was no significant difference in seed yield between plants raised from inoculated seeds with P. fluorescens, strain R187 (1664 ± 97 kg ha-1) and those raised from inoculated seeds with P. fluorescens, strain R41 (1669 ± 104 kg ha-1). At the same time, plants raised from inoculated seeds with P. fluorescens (both strains) produced greater grain yield compared to those raised from uninoculated seeds (1370 ± 80 kg ha-1). Based on the results of this study, P2O5 application at the rate of 75 kg ha-1 and inoculation with pseudomonas bacteria are recommended for obtaining the greatest seed yield in field pea.

Cassava (Manihot esculenta Crantz) Tuber Quality as Measured by Starch and Cyanide (HCN) Affected by Nitrogen, Phosphorus, and Potassium Fertilizer Rates

Cassava (Manihot esculenta Crantz) is an important subsistence crop for many poor rural families in Africa. Cassava contains cyanogenic glucosides (linamarin and lotaustralin) which liberate hydrogen cyanide (HCN) during tuber processing. Once liberated, HCN attaches to the processed tuber. Continuous consumption of processed tuber containing high HCN concentration coupled with low protein intake causes Konzo – a paralyzing disorder that impacts children and women of childbearing age. There are ways to reduce HCN concentration during tuber processing; however, this can also reduce the overall starch content in the cassava tuber. A study comprising twenty treatments consisting of different combinations of nitrogen (N), phosphorus (P), and potassium (K) fertilizer rates was initiated in 2013 in the coastal Dondo District of Mozambique to assess cassava tuber quality as measured by starch and HCN. Significant differences were observed in starch content (CSC) of unprocessed tubers due to combined addition of N, P and K fertilizer rates, sample size, and estimation procedure. However, no significant differences were observed in HCN concentration in tubers due to the addition of N, P and K fertilizer. The HCN concentration in cassava tuber appears to be a function of the physiology of the crop or possibly cassava variety rather than the environment or conditions under which the crop is grown.

Phosphorus Fertilization Under Different Land Preparation Methods and Performance of Groundnut (Arachis hypogea L.) in Rainforest Zone of Southern Nigeria

A field experiment was conducted on an Arenic paleudult in the rainforest zone of Southern Nigeria to determine the response of an improved variety of peanut (Arachis hypogea L. var. Samnut 23) to phosphorus, under different land preparation methods. Selected land preparation methods were “slash and burn” (SB) and “slash and mulch” (SM), and the phosphate fertilizer rates were 0, 30, 60, 90 and 120 kg P ha-1. The experiment was laid out as a randomized complete by block design. Each land preparation was divided into plots. Macro- and micro nutrient contents of peanut plants were determined, and the growth and yield components were also assessed. Results showed that the pre planting soil analysis for the SB management had a pH of 5.77, N (1.8 gkg-1), P (2.05 mgkg-1) and K (0.11cmol (+) kg-1), while that of the SM had a pH of 5.95, N (0.9 g kg-1), P (0.86 mg kg-1) and K (0.07cmol(+)kg-1). Plant height was not significantly different (pd” 0.05) in the land preparation methods, but leaf area was significantly different. However, plant height and leaf area responded better under the SB treatment with 90 kg P ha-1 rate of phosphorus fertilizer than the SM treatment under the same rate. Fresh pod weight of 908.6kg ha-1 and dry pod weight of 558.0kg ha-1 was obtained at 60 kg P ha-1 under the SB treatment and was significantly different from all other treatments including the SM. Significant differences were also observed in the nutrient concentrations of leaves and roots. Highest leaf phosphorus content (3.502 mg kg-1) was recorded at 90kg P ha-1 in the SM treatment while the highest nutrient content of P in the roots (0.272 mg kg-1) was recorded at 30 kg P ha-1 also in the SM treatment. However, the SB treatment recorded the highest peanut seed pods / shell at 60 kg P ha-1. Generally, phosphorus fertilization under the SB management practice gave better results than the SM management practice.Keywords: groundnut, land preparation, phosphorus fertilization, Slash and burn, slash and mulch [How to Cite: Joseph SO and RO Oyibo. 2014. Phosphorus Fertilization Under Different Land Preparation Methods and Performance of Groundnut (Arachis hypogea L.) in Rainforest Zone of Southern Nigeria. J Trop Soils 19(1): 1-7. Doi: 10.5400/jts.2014.19.1.1]

Performance of <i>Thevetia peruviana</i> (PERS.) Schum. Under two agronomic management practices (irrigation and application of in-organic fertilizers) in Edidi southern Nigeria.

Most studies on T. peruviana have revolved around its clinical, toxicological and pharmacological aspects, while study on its agronomy is scanty. Field experiments were conducted during the 2011 and 2012 growing seasons, at the Research Farms of the Bio-fuel Alternative and Renewable Energy Ltd, Edidi, Kwara State, Nigeria. The study evaluated the effects of supplementary irrigation during the dry season and different rates of nitrogen and phosphorus fertilizers on the growth and yield of the oil crop. The experiment was a 2 x 3 x 3 factorial arranged in split-split plot design. Two levels of irrigation (irrigated and non irrigated) constituted the main plots, three levels of nitrogen fertilizer (0, 30 and 60 kg N ha-1) the sub-plots, and three levels of phosphorous fertilizer (0, 30 and 60 kg P2O5 ha-1), the sub-sub-plots. The results showed that irrigating T. peruviana plants significantly improved the vegetative growth parameters, kernel size, number and weight of harvested kernels, but delayed number of days to the first and 50% flower appearance. Nitrogen fertilizer rate of 60 kg N ha-1 produced highest values of growth and yield parameters which were significantly better than those of the control, but similar to those of 30 kg N ha-1; and application of 60 kg P2O5 ha-1 resulted in early flower appearance and increased the yield parameters, even though the values were statistically similar to those with the application of 30 kg P2O5 ha-1. Thus, it can be recommended that T. Peruviana should be irrigated and given fertilizer at a factorial combination of 30 kg N ha-1 and 30 kg P2O5 ha-1 for optimum yield.

Effect of Nitrogen and Phosphorus Fertilizer Rates on Yield and Yield Components of Barley (<i>Hordeum Vugarae L.</i>) Varieties at Damot Gale District, Wolaita Zone, Ethiopia

A field experiment was conducted at Damot Gale District, Wolaita Zone, SNNPRS to evaluate the response of barely varieties to nitrogen and phosphorus fertilizer application since the response varies from location to location due to several factors. Thus, there is a need to determine specific nitrogen and phosphorus fertilizer requirement of specific variety. The barley varieties (HB1370 and Shage) were used as test crop and the experiment contained factorial combination of four levels of N/P (0/0, 23/10, 46/20, 69/30 kg ha^-1) and was laid out in randomized complete block design with three replications. The results from this study indicated that nitrogen and phosphorus fertilizer showed no significant effect on number of days to heading while number of fertile tillers, total biomass and yield were significantly increased by application of nitrogen and phosphorus. However, the effects of nitrogen and phosphorus were significant (P < 0.05) on plant height, spike length, number of seeds per spike and grain yield. In general, grain yield tended to be higher under NP 69/30 kg ha^-1 treatment (2.02t/ha). In contrast, the lowest grain yield (0.86t/ha) was obtained from 0/0 NP treatment, although the interaction effects of nitrogen and phosphorus were significant on treatments with varieties and balanced amount of nitrogen and phosphorus. The future studies should articulate towards the studies involving more varieties, multi-location and additional rates of nitrogen and phosphorus applications, under diverse management practices such as research and farmer’s field’s conditions, which may facilitate fine-tuning of fertilizer recommendations.

Effect of Azotobacter and Chemical Phosphorus Fertilizer on Maize = تأثير الآزوتوباکتر و الفوسفور الكيميائي على الذرة

To study the effects of phosphorus and Azotobacter on yield of maize, a factorial experiment was carried out based on randomized complete block design with three replications in Astara, north of Iran, in 2012. The treatments were phosphorus fertilizer rates (0, 62.5, 125, 187.5 and 250 kg P2O5 ha-1) and seed treatment (inoculated with Azotobacter Vinelandii and uninoculated). The analysis of variance indicated that phosphorus fertilizer improved significantly grain yield. Because of non significant effect of two factors, the average of data across two conditions of inoculated and uninoculated with Azotobacter Vinelandii was used for drawing the graph. For nitrogen content in grain the interaction effects of two factor was significant and the graph drawn separately. The effects of Azotobacter were significant on nitrogen concentrations in grain and ear length. Phosphorus at the rate of 187.5 kg ha-1 was the optimum rate to cause a desirable increase in grain yield, thousand grain weights, biological yield, leaf area index, nitrogen content in grain, grain P uptake and ear length. Overall, utilization of biological nitrogen with chemical phosphorus fertilizer could be a strategy to achieve sustainable agriculture.

Responsiveness of Soil Series in Southwestern Nigeria to Single Super Phosphate Fertilization

Application of Single Super Phosphate (SSP) fertilizer in soils with inadequate phosphorus (P) should elicit crop response. However, there is an indication of inconsistent response behaviour to SSP fertilizer in some Nigeria soils despite their low available P. This study identified major soil types in Southwestern Nigeria that are unresponsive to P fertilizer application under screenhouse condition and soil properties that are related to this unresponsive behaviour were determined. Soils from twenty locations in Southwestern Nigeria were selected to evaluate their response to four phosphorus fertilizer rates with a control replicated three times in a factorial arrangement laid out in randomized complete block design. Results indicated that most of the locations responded to initial P application except for Fashola 2 which produced significantly higher maize shoot yield in control soils. There were five other locations where no-response was observed. Multiple regression analysis showed that phosphorus sorption index was related to sand, organic matter and clay. Phosphorus accumulation in soil P reserves may explain the behaviour of the P-unresponsive soils irrespective of their available P levels.

Effects of Phosphorus Fertilizer Type and Rate on Plant Growth and Heavy Metal Content in Lettuce ( Lactuca Sativa L. ) Grown on Calcareous Soil = تأثير استعمال الأسمدة الفوسفاتية على نمو و محتوى العناصر الثقيلة في نبات الخس المزروع بالتربة القلوية

A field experiment was carried out to investigate effects of phosphorus (P) fertilizer type and rate on plant growth and toxic heavy metals contents (Cd, Pb and As) in head lettuce plant on calcareous soil. Four P fertilizer types {single super phosphate (SSP), di ammonium phosphate (DAP), mono ammonium phosphate (MAP) and a local phosphate rock (PR)} were applied as main plot treatments and five rates of each fertilizer (0, 125, 250, 375, and 500 kg P2O5/ha) as subplot treatments. P fertilizer type, rate and their interaction showed a significant effect on the fresh plant yield and dry matter production. Both P fertilizer type and rate didn’t induce significant differences in heavy metals contents of the plant and soil, as they were within tolerable limits. The examined P fertilizers constitute no potential risks for heavy metals accumulation in the soil-plant system over short-term.

Mechanical Damage to Chickpea Seeds as Affected by Npk Fertilization

Abstract The aim of research was to determine the effect of nitrogen (N), phosphorus (P) and potassium (K) fertilizers onthe some physical properties and mechanical damage to chickpea seeds under impact. The martial for tests was from a field experiment with varied levels fertilization with nitrogen (0 and 50 kg/ha, N), phosphorus (0 and 100 kg/ha, P2O5) and potassium (0 and 100 kg/ha, K2O). The variation of the mechanical damage was analyzed depending on the mode of varied fertilization, seed moisture content and impact energy. It was found that the chickpea seeds were bigger with NPK supply. The effects of phosphorus and potassium fertilizers rates on the mechanical damage to chickpea seeds was significant at 1% probability level (P&lt;0.01) and increased its hardness and resilience therefore caused the better resistance to impact damage. Potassium fertilization ratehad the most influence and phosphorus fertilization rate had the least. The effect of the nitrogen fertilizer rate was not significant (P&gt;0.05). Harvesting chickpea seeds at higher moisture content and lower impact energy should give lower breakage when NPK is supplied, as well as when no NPK is supplied.

The Response of Haricot Bean (Phaseolus vulgaris L.) Varieties to Phosphorus Levels on Nitosols at Wolaita Zone, Ethiopia

A field experiment was conducted at two locations (Bolosso Sore and Damot Sore) in Wolaita Zone of Southern Nations Nationalities and People’s Regional State to evaluate the response of two varieties of haricot bean ( phaseolus vulgaris L .) to phosphorus fertilizer rates on acidic soils. Combinations of four levels of P (0, 10, 20 and 30 kg ha -1 ) were used on two varieties. The treatments were arranged in factorial RCBD with three replications. Analysis resulted of soil samples showed that Available P, Organic carbon, Total Nitrogen & Soil pH values were very low. Application of lime with P resulted significant changes on these chemical properties of the soils in the two locations. The maximum values of these parameters recorded at 30 kg Pha -1 . Growth parameters yield and yield components were significantly increased with increasing rates of P at the two locations. Maximum grain yields (1488.40 and 1523.7 kgha -1 for Hawse Dume at Gunno and Dollar, respectively and 1242.12 and 1352.01 kgha -1 for Omo-95 at Gunn and Dollar, respectively) recorded at rates of 30 kgPha -1 in the both locations. From the result of this study it could be conclude that improve soil pH, Available P and performance of haricot bean varieties but till now there is some gap on correcting P application of grain yield of the varieties. So application of P could be increased the production of the crops. Keywords: Hawse Dume, Omo-95 , soil acidity and yield

Optimization of Phosphorus Fertilizer in Supplemental Feed-Fed Based Nile Tilapia (Oreochromis niloticus) Ponds

An experiment was conducted in earthen ponds at the Asian Institute of Technology, Thailand to determine different phosphorus fertilizer dose effects on Nile tilapia production, water quality variables, nutrient utilization and cost-benefit under supplemental feeding. Five phosphorus fertilization rates were used as treatments e.g. 100%, 75%, 50%, 25% and 0% of 7 kg P ha week−1. Nitrogen fertilization rate was fixed at 28 kg N ha week−1 for all the treatments. Sex-reversed Nile tilapia were stocked at 3 fish m−2, and 30% CP floating feed fed at 50% satiation feeding rate. Nutrient budget showed higher phosphorus fertilizer input resulted in higher phosphorus sink in the sediment. Mean weight, mean weight gain, daily weight gain and net yield were not significantly different among treatments (P > 0.05). Total Kjeldahl nitrogen, total phosphorus and soluble reactive phosphorus were significantly different among treatments. Economic analysis showed phosphorus fertilization resulted in positive net returns. Though the gross income was not affected by different fertilization rates, significantly lowest cost was found in the treatment using 25% phosphorus fertilizer. It can be concluded from the research that 25% phosphorus fertilization might be used as an alternative strategy of Nile tilapia pond culture in terms of economic return and nutrient loss in sediment.

Growth and yield of barley (&lt;i&gt;Hordeum vulgare L&lt;/i&gt;.) as affected by nitrogen and phosphorus fertilization and water regimes in Tigray, Ethiopia

The understanding of the interactive effects of abiotic stresses is a crucial issue for improving cereal production in arid environment. For this reason, study was conducted in northern Ethiopia, Tigray region in three sites characterized by different climatic conditions during the cropping season of 2009/10 to understand the agronomic responses of the barley crop to nitrogen and phosphorus fertilization rates combined with supplementary irrigation. Nitrogen (N) and phosphorus (P) fertilizers were applied under three water regimes to 'Sasa' barley variety using split - split plot design with three replications where the sites were treated as a main plot, water regimes assigned to the sub-plot and N and P fertilizers to the sub-subplot. fertilizers and sites had significant (p<0.001) effect on grain yield, thousand grain weight (TGW) and phenological traits. Supplementary irrigation had no effect traits investigated. Most interaction effects, N×P, N×site and P×site had very significant to significant effects on studied barley traits. Supplementary irrigation × site interaction had significant effect only on thousand grain weight (TGW). Optimum yield, for each site, was obtained from different combination of N and P, implying the need of different recommendation package instead of the general 100 - 100 kg ha -1 UREA and DAP or combination of 28 and 20kg ha -1 of nitrogen and phosphorus fertilizers across all barley growing areas. Therefore, universal recommendation of 100 UREA and 100kg ha-1 DAP should not be treated as best production package for all barley growing areas and this study suggests further thorough investigation for specific NP fertilizers rate recommendation for different barley growing areas. Keywords : Nitrogen, Phosphorus, Sasa, Phenological traits, Interactions, Grain yield, TGW, Arid environment.

Evaluation of White yam (Dioscorea rotundata) genotypes for arbuscular mycorrhizal colonization, leaf nutrient concentrations and tuber yield under NPK fertilizer application

Yield decline in yam may not only be due to soil nutrient depletion but also to the activity of soil microflora. Arbuscular mycorrhizal (AM) symbiosis helps in plant nutrition but may be affected by the application of fertilizer. The effects of nitrogen (N), phosphorus (P), and potassium (K) fertilizer rates on the AM colonization, leaf nutrient concentrations, and tuber yields of eleven genotypes of Dioscorea rotundata were investigated at Ibadan, Nigeria. The soil was ferric luvisol. Eleven genotypes were selected from the previously conducted screening of 75 genotypes of D. rotundata for fertilizer response. Four application rates: 0, 200, 400, and 600 kg ha−1 of NPK 15-15-15 were applied in a split plot design with four replications. Fertilizer rate was the main plot and variety was the sub plot. Percentage AM colonization was significantly reduced at 600 kg ha−1 but not at lower rates when compared to zero rate and it was negatively correlated with leaf N, P, and zinc (Zn) concentrations. Leaf N concentrations were significantly increased at 200 kg ha−1 in five genotypes and at 600 kg ha−1 in two genotypes compared to zero application. Leaf P and K concentrations were decreased with the application of fertilizer in most of the genotypes. The NPK fertilizer of 15-15-15 at the rate of 200–400 kg ha−1 gave yield response in eight genotypes of D. rotundata, with minimal or no effect on their AM colonization when compared to zero application. Long term study on the effect of fertilizer application on AM symbiosis in yam is recommended.

An analysis of factors influencing the output value of unit sown area based on grey incidence analysis

Purpose – The paper aims to clarify the relationship between the output value of unit sown area (OVUSA) and its major influential factors by taking Jiangsu Province, People's Republic of China as an instance, followed by some suggestions for adjusting the agricultural inputs. Design/methodology/approach – The paper is characterized by an exploratory research by constructing a grey incidence model (GIM) based on the grey system theory (GST) initiated by Chinese professor Julong Deng. The original data processed in the model are quoted from Jiangsu Statistics web site and the Statistical Yearbook of Jiangsu Province. Findings – The analysis indicates several noteworthy points in the following areas. To start with, the proportion of irrigated area to sown area has turned out to be a stabilizing factor influencing OVUSA; next, the contributions of nitrogen and phosphorus fertilizers' output to the growth of the OVUSA were reduced, while the marginal outputs of nitrogen and phosphorus fertilizers seemed to be lower; then the outputs of potash and compound fertilizers have made significant contributions to the growth of the OVUSA, although their application rates were drastically increased; besides, the total power of agricultural machinery was a major factor boosting the growth of the OVUSA; furthermore, the decrease of labor force was obviously remarkably related to the reduction of OVUSA; finally, the areas affected by natural disasters have had a foremost impact on OVUSA reduction. Originality/value – Suggestions are also proposed to the related policy-makers as follows: to reasonably control the application rates of nitrogen and phosphorus fertilizers, to encourage fertilizer manufacturing enterprises to develop potassium mineral resources with the purpose of guaranteeing the potash fertilizer's supply, to scientifically design the composition of compound fertilizers in order to satisfy the needs of cultivated lands in different areas, to improve the quality and structure of agricultural labor forces with the aim of meeting emerging trends in the agricultural industry, to make every effort to further modernize the current agricultural industry, and to enhance the disaster-prevention capability of the agricultural industry by gradually converting it into a controllable one.

Residual Effect of Phosphorus Fertilizer on Yield of Pigeon Pea (Cajanas cajan) in Ultisol

Phosphorus (P) is one of the essential plant nutrients and plays an important role in nitrogen fixation of leguminous crops. A two-year experiment was conducted at the Teaching and Research Farm of Ambrose Alli University, Ekpoma, Nigeria to investigate the effect of different rates of phosphorus fertilizer on the growth, yield, nodulation and nutrient uptake of pigeon pea ( Cajanas cajan ). Seven P rates (0kg (control), 25, 50, 75, 100, 125 and 150kg ha -1 ) were laid out in a Randomized Complete Block Design with three replicates and managed for two consecutive years. Data on plant growth, yield, nutrient uptake and soil properties were collected for the two seasons. The application of phosphorus significantly increased the soil nutrient content after the first season. There was no significant difference in height and stem girth of pigeon pea. The application of 75 kg ha -1 significantly (p=.05) increased the number of leaves, biomass and nodules of pigeon pea. The application of 25 - 75kg ha -1 of phosphorus fertilizer increased the grain yield of pigeon pea than other rates of application in the first cropping season. In the residual experiment, the control and 25kg ha -1 application of P had the grain yield of 1,493.3kg ha -1 and 1,498.0kg ha -1 respectively, and were significantly (p=.05) higher compared to other treatments. The application of phosphorus fertilizer at the rate of 25 ‐ 75kg ha -1 significantly improved the yield, nodulation and nutrient uptake of pigeon pea in

Effect of Tillage, Fertilizer and Sorghum/Desmodium Intercrop Cultivation on Soils’ Quality and Yield of Sorghum in an Alfisol of a Northern Guinea Savanna of Nigeria

Soil quality protection under intensive land use and fast economic development has become a major challenge for sustainable resource use in the developing countries such as Nigeria. Conventional tillage practice is commonly practiced at land preparation and effect of this on soil quality for sustainable productivity was investigated in this study, in comparison with No Till, Conservation tillage, and split old ridge practices in combination with four nitrogen and three phosphorus fertilizer rates. Sorghum was the test crop. Results show that the soils were initially acid (pH 5.0 to 6.0), had low organic carbon (2.3 to 2.5gkg -1 ), total nitrogen (0.05gkg -1 ) and low to moderate available phosphorus (6.7 to 8.5mgkg -1 ) and needed restoration to support sustainable agricultural production. Tillage, sorghum/ Desmodium and N and P fertilizer managements imposed showed that No Till practice (SDNT) sequestered significantly (P<0.05) higher organic carbon value (6.9 gkg -1 ), followed by Conservation tillage with incorporated and relayed D. Uncinatum

Assessment of the Profitability and the Effects of Three Maize-Based Cropping Systems on Soil Health in Western Africa

Enhanced livelihoods for populations, especially smallholder farmers in sub-Saharan Africa may be achieved through improved cropping systems. We assessed the economic returns from maize grain yield and the effects of three cropping systems on soil properties in an eight-year study segmented in cycles of two years each: continuous maize (Zea mays L.), maize-mucuna (Mucuna pruriens var. utilis), and maize-pigeon pea (Cajanus cajan). The rainfall pattern in the study region allows for two growing seasons per year, leading to four growing seasons per cycle. Nitrogen (N) and phosphorus (P) fertilizer rates were imposed on maize in each system and maize grain yields and associated cash values as well as soil properties were measured. Seeding mucuna and pigeon pea crops into maize crop in the first year did not result in maize grain yield increases from N and P fertilizers in the subsequent year. Continuous maize system increased mean maize grain yields by 6.2 to 60.3% in the fallow year of the 2002-2003 and 2006-2007 cycles and by 5.1 to 8.2% on a cycle basis in the 2002-2003 cycles. For the remaining periods of the study, mucuna and pigeon pea based maize cropping increased grain yields by 28.6 to 47.6%, 22 to 260% and 28.3 to 136.1% in fallow year, non-fallow years and on a cycle basis, respectively, compared to yields under continuous maize. On a cycle basis, economic returns for maize-mucuna and maize-pigeon pea based systems were 105.1 and 66.5%, respectively, higher than that for continuous maize. The mucuna and pigeon pea based systems increased the initial soil total carbon (C) content by 55 and 69%, respectively, resulted in increases of 110 to117%, 33 to 63%, 29%, and 16-17% for exchangeable Ca2+, Mg2+, K+ and total cation exchange capacity (CEC), respectively, and enhanced water stable macroaggregates stability, compared to continuous maize. Maize mucuna and pigeon pea-based maize cropping systems with mucuna and pigeon crops in alternate years should be advised towards sustaining enhanced profitability and improved soil physical and chemical properties.

ENRICHMENT OF PHOSPHORUS FOR COWPEA (Vigna unguiculata L. Walp.) UNDER CALCAREOUS SOIL CONDITIONS AT EL-ARISH REGION

This study was carried out during 2012 and 2013 summer seasons at The Experimental Farm of Fac. Environ. Agric. Sci., El-Arish, North Sinai, Egypt, to study the effect of lowering the recommended phosphorus dose with foliar phosphorus addition on growth and productivity of cowpea (Vigna unguiculata L. Walp.) plants. This experiment included 7 treatments which were: The control which was the recommended rate of phosphorus fertilizer as soil addition (40kg P2O5/fed.) (T1), 100% of the recommended dose + spraying with phosphorus once weekly at rate of 2% of super phosphate (T2), 100% of the recommended dose + foliar spray twice weekly (T3), 75% of the recommended dose + foliar spray once weekly (T4), 75% of the recommended dose + foliar spray twice weekly (T5), 50% of the recommended dose + foliar spray once weekly (T6) and 50% of the recommended dose + foliar spray twice weekly (T7). Results show that application of T6 caused maximum plant height, stem length and total dry weight and differed significantly with other treatments, while T5 gave rise to maximum number of branches and leaves area per plant. Most of growth parameters were enhanced with the decrease of phosphorus soil addition and spraying with foliar phosphorus. Treatments have a significant effect on green pods yield, seeds yield, number of seeds per pod, protein %, protein yield and pod weight. Phosphorus treatments have a significant effect on weight loss % at room and cold storage conditions. Color changes as b* and c* at the case of storage at room temperature (28.5 ±5°C) were more acute after 5 days of storage than cold storage (14±1°C) conditions.

Cowpea (Vigna unguiculata L. Walp) response to phosphorus fertilizer under two tillage and mulch treatments

The response of cowpea to four rates of phosphorus (P) fertilizer (0, 15, 30 and 45kgPha−1) on an Ultisol in south-eastern Nigeria was evaluated under two tillage and two mulch treatments. Tilled plots produced plants with significantly larger leaf area indices (2.82–4.05) than the untilled plots (2.11–3.22), while significant differences in dry matter accumulation occurred when plots were mulched, tilled plot values ranged from 3.83 to 5.53t/ha while the untilled plots were between 2.77 and 3.97t/ha. Plants in mulched plots were 39–80% and 20–62% higher in grain yield and dry matter accumulation, respectively, compared to the un-mulched plots. Yield response to phosphorus levels on each tillage–mulch combination was significant for linear and parabolic responses. Maximum yields occurred at 34, 37, 35, and 33kgPha−1 on the tilled–mulched (TM), tilled–un-mulched (TU), untilled–mulched (UM) and untilled–un-mulched (UU) plots, respectively. Dry matter response to P level was of a quadratic polynomial form and indicated apparent maximum accumulation (at flowering) at 30kgha−1 rate under the tillage mulch treatments. Apparent maximum accumulation of dry matter was however at 45kgha−1P rate for the TM treatment. Phosphorus use efficiency (grain yield per P applied) decreased in the order TM (72.4)>UM (66.6)>TU (48.9)>UU (36.4), where the figures in parenthesis represent phosphorus use efficiency (kgkg−1). The rate of change in available P in mulched plots increased faster compared to the un-mulched plots, with the rate in UM plots being significantly faster than in the other plots at the ninth week. Tissue P did not vary in plants following the tillage–mulch treatment. The results also indicated that the tilled treatments (TM and TU) gave 12.3–34.9% comparatively higher gross margin (profit) when compared to their untilled equivalents (UM and UU), however when the profits were considered against the investment costs, the untilled treatments (UM and UU) gave higher returns per unit investment (189.0–588,800).

RESPONSE OF ALFALFA SEED YIELD AND YIELD COMPONENTS TO PHOSPHORUS FERTILIZING SYSTEMS AND SEEDING RATE AT SEMI-SALINE SOIL CONDITIONS

To study the effects of phosphorus (P) fertilizer (cow manure, phosphorus solublizing bacteria) and sowing density on seed production of alfalfa, an experiment was laid out in a three-replicated split-split plot design with four phosphorus fertilizer rates (0, 30, 60 and 90 kg ha−1) in main plots, three phosphorus-solublizing bacteria (9, 41strains, and no bacteria) in sub-plots and three sowing densities (2, 6 and 10 kg ha−1) in sub-sub plots. The highest seed yield resulted from 60 and 90 kg P ha−1. Application of bacteria strain 41 was more efficient than bacteria strain 9 in seed yield and 1000-seed weight. Seed yield at 6 seed kg ha−1 treatment was higher than 10 kg ha−1, although there was no significant difference between them. Based on the results of this experiment the triple application of P60, B41 and SD6 could be recommended as the best treatment for seed production of alfalfa (Cultivar ‘Nikshahri’) under the semi-saline condition.