African Journal of Soil Science

African Journal of Soil Science ISSN: 2375-088X Vol. 3 (1), pp. 079-085, February, 2015.© International Scholars Journals

Short Communication

Predicting soil water retention curves based on particle-size distribution using a Minitab macro

Xuejun Dong^1,2,* and Bob Patton¹

¹North Dakota State University, Central Grasslands Research Extension Center Streeter, ND 58483 USA.

²Texas A&M AgriLife Research and Extension Center, Uvalde, TX 78801 USA.

Accepted 19 November, 2014

Abstract

Soil water retention curves are essential for solving water flow problems, but direct measurement usually is laborious, time-consuming and expensive. Thus indirect methods using more easily measured soil properties are frequently used. The model of Arya and Paris (1981) [Soil Sci. Soc. Am. J., 45: 1023-1030] has been used widely to predict water retention curves based on particle-size distribution and bulk density. A major difficulty in the application of this model is determining the empirical parameter describing soil particle shape. Despite numerous efforts for alternative calibration of this parameter, the original Arya-Paris model remains pervasive and relevant for varying textured soils. We developed an easy-to-use spreadsheet-like Minitab macro to automate the parameter estimation for use with the Arya-Paris model. This method was tested on prairie soils from North Dakota, USA. Results showed that parameter estimation for soil water retention curves was improved by allowing both soil particle shape and particle density parameters to vary. The best estimates of shape factors varied from 1.08 to 1.44 and those for particle density ranged from 1500 to 2650 kg/m³.  The macro facilitates the rapid characterization of soil water retention relations and is applicable to other soil types.

Key words: Soil bulk density, soil particle shape, soil particle density, soil particle-size distribution, soil water retention curve, total porosity, Arya-Paris model. 

African Journal of Soil Sciences ISSN: 2375-088X Vol. 2 (4), pp. 077-078, October, 2014. © International Scholars Journal

Full Length Research Paper

Floristic composition, life form and leaf spectra of plant communities recorded at Sarsawa hills district Kotli, Azad Kashmir

¹Ashfaq Nazir, ¹Riffat NaseemMalik¹ and HamayunShaheen²

¹Department of Environmental Sciences, Quaid-i-Azam University, Islamabad, Pakistan.

²Department of Botany, University of Azad Jammu & Kashmir, Muzaffrabad, Pakistan.

E-mail: [email protected]

Accepted 14, March 2014

Abstract 

The flora of Sarsawa Hills, District Kotli, Azad Kashmir consisted of 40 plant species belonging to 24 families. Of them, 18 families were Dicots; 4 Monocots and 1 Pteridophytes. Gymnosperms were represented by Pinaceae only. Poaceae had 12 species which was followed by Euphorbiaceae (3 spp.). Acanthaceae, Leguminoseae and Urticaceae had 2 species each while remaining families had single species. The biological spectrum showed that hemicryptophytes (27.5%) and megaphanerophytes (25%) were the most abundant, followed by nanophanerophytes (22.5%) and therophytes (17.5%). Geophytes (5%) chemophytes (2.5%)had low occurrence in the investigated area. Leaf spectra investigation revealed thatleptophylls were dominant (40%), followed by nanophylls (22.5%), microphylls (22.5%), and mesophylls (15%). No megaphylls were reported in the investigated area due to severe drought condition.

Key words: Floristic list, Leaf size, Leaf form, Sarsawa hills, Kotli.

African Journal of Soil Science Vol. 2 (3), pp. 072-076, September, 2014. © International Scholars Journals

Full Length Research Paper

A digital soil textural class determination from the percentages of silt and clay

F. O. Adekayode ¹ and D.T. Akomolafe ²

¹Department of Crop, Soil and Pest Management, Federal University of Technology, Akure, Nigeria.

²Department of Mathematical Sciences, Faculty of Science, Ondo State University of Science and Technology, Okitipupa, Ondo State, Nigeria. Email: [email protected]

Accepted 27, May 2 014

Abstract 

The input of the percentages of silt and clay on the interface generated with the C Sharp (C#) computer programme gave an automated soil textural class determination. The programme incorporated in the coding, the percentage silt and clay values in order to classify the soil into one of the categories of the sand, loamy sand, sandy loam, sandy clay loam, sandy clay and clay textural classes. The Design Interface was created in Microsoft Visual Studio and the Toolbox activated for the application of the Label, Text and Button Tools. The parameters ‘Enter percent silt’ and ‘Enter percent clay’ were typed in the two Label boxes respectively while empty box spaces were created against each for the information of percent silt and percent clay to be filled by the user. The debugging of code page brought up the User Interface. When the percent silt and clay were entered in the spaces on the User Interface and the ‘Determine the Soil Texture’ button clicked, the soil textural class category was generated and displayed. The automated method gave an instant soil textural class without the use of the soil textural triangle.

Key words: Soil texture, automated determination, percent silt, percent clay.

African Journal of Soil Science Vol. 2 (3), pp. 063-067, September, 2014. © International Scholars Journals

Full Length Research Paper

Use of green manure legume cover crops in smallholder maize production systems in Limpopo province, South Africa

Kaiser Cedric

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 07 August, 2014

Abstract 

Much of the smallholder farming sector in Limpopo province of South Africa is located on infertile degraded soils, with nitrogen being one of the predominantly deficient nutrient. The use of green manure legume cover crops in combination with Nitrogen (N) fertilizers is one option for improving N inputs into such farming systems. The objectives of this study were to (1) screen a number of green manure legume cover crop species, mucuna (Mucuna pruriens); sunhemp (Crotalaria juncea), lab- lab (Lablab purpureus); cowpea (Vigna unguiculata) and butterfly pea (Clitoria ternatea) in order to determine their suitability for the region and (2) to determine the effect of the green manure and nitrogen fertilizer on maize yield. The legumes were screened during the winter seasons of 2005 and 2006 and the summer seasons of 2005 - 2006 and 2006 - 2007. The best-bet legumes (mucuna, sunhemp and lab-lab) were then evaluated to determine their effect on maize grain yield with or without nitrogen fertilizer. The treatments imposed were mucuna, sunhemp, lab-lab, and a control with (75 kg N ha^-1) or without (0 kg N ha^-1) N fertilizer. Maize was harvested at maturity to determine the grain yield. In the screening trials, legume biomass yield ranged between 41 to 1,672 kg ha^-1, while the N content ranged between 2 to 58 kg N ha^-1 in the winter trials. In the summer trials, biomass yield ranged from 899 to 13,586 kg ha^-1, while the N content ranged between 27 to 302 kg N ha^-1. Maize yield ranged between 4.0 to 6.4 tons ha^-1 in the 2006 - 2007 seasons and between 5.8 to 8.4 tons ha^-1 in the 2007- 2008 season. Control (-N) treatment had the lowest yield in both seasons. Overall, legume treatments, with or without N fertilizers produced between 19 to 58% more grain yield than control (-N). Of the green manure legumes screened, mucuna, lablab and sunhemp seem to be the most suitable green manure legume cover crops for this area and should be planted in the early summer season to maximize biomass production and N accumulation. Use of green manure legumes has the potential to increase maize yield in smallholder farms in Limpopo province.

Key words: Green manure legumes, maize, N fertilizer, smallholder farms.

African Journal of Soil Science Vol. 2 (3), pp. 068-071, September, 2014. © International Scholars Journals

Full Length Research Paper

Assessment of the use of herbicide (Imazapyr) and fertilizer relevance in integrated management of Striga asiatica in maize in Malawi

Derren Matarauka and Masawi Samaz

Department of Soil Science, Faculty of Agriculture, University of Zimbabwe, Mount Pleasant, Harare, Zimbabwe. Email:[email protected]

Accepted 25 August, 2014

Abstract 

The parasitic weed species Striga asiatica (L.) Kuntze is one of major constraints in maize production in Malawi. Studies were conducted from 1999/2000 to 2001/2002 seasons to evaluate the effects of seed dressing with imazapyr (an acetolactate synthase [ALS] - inhibiting herbicide) at 0 and 45 g ha^-1 and two fertilizer rates (0 and 69N:21P₂O₅:0+4S kg ha^-1) on maize with ALS target site resistance on Striga suppression and grain yield at Chitedze Research Station and farmers’ fields. In the first season, imazapyr suppressed Striga emergence across all sites but did not increase yield. In contrast, fertilizer application had no effect on Striga emergence (P>0.05), but significantly increased yield (P<0.05). In the second season results were similar, but in addition the use of herbicide increased yield. In the third season a local hybrid (SC627) was included to compare yield potential of the untreated Imazapyr Resistant (IR) variety. The local check yielded higher than the IR hybrid with or without herbicide treatment, but sustained the highest emergence of witchweeds. The untreated IR hybrid had less Striga than SC627 and more than the treated. Overall, fertilizer use is found to be the single most important factor in increasing maize yield under S. asiatica infection, while herbicide use is important for reducing emergence.

Key words: Striga asiatica, imazapyr, Zea maize (L), Malawi, acetolactate synthase.

African Journal of Soil Science Vol. 2 (2), pp. 052-057, August, 2014. © International Scholars Journals

Full Length Research Paper

Genotype difference in grain yield response to basal N fertilizer supply among various rice cultivars

Zelene Wang, Kihinet K. Huang and Xue Xiaoyue

Department of Crop science, Faculty of Agriculture, Wuhan, Hubei Province, China. Email: [email protected]

Accepted 01 June, 2014

Abstract 

Considering the great amount of basal N fertilizer but lower uptake ability at rice seedling, it was essential to increase the N use efficiency of basal fertilizer and reduce N pollution. So, a field experiment was conducted at Wuxi, China, under non-basal N and basal N fertilizer conditions, to identify the variation of grain yield response to basal fertilizer among 199 rice varieties with different genetic background, and finally choose the suitable rice varieties for us to increase basal N fertilizer efficiency and reduce N fertilizer pollution. The results show that highly significant genotype differences for grain yield and almost yield parameters existed in 199 rice varieties, and there were also great differences for agronomic N use efficiency (ANUE) and apparent recovery of applied basal N fertilizer (AR) among 199 rice varieties. Little response rice varieties HJY, 80-4, L454, SXJ, Daesong, WNZ and DXW2, and great response rice varieties NJ1X, HC106, QYDD, YTDBM, YJ2H, 4020 and 4024 were also screened in this study. Our results also show that the effects of basal fertilizer were mainly reflected on the early period of rice growth but not on the grain yield. This study identified genotype variation in grain yield response to basal N fertilizer supply and great ANUE and AY differences among the 199 rice cultivars, and also explored the reasons for these phenomena, which would provide us good information in increasing basal fertilizer efficiency and reducing N pollution.

Key words: Basal fertilizer, rice varieties, response, nitrogen, grain yield.