Open Access Original Research Article

Dry Matter Accumulation, Nutrient Uptake and Nutrient Use Efficiency of Two Improved Cultivars of Taro (Colocasia esculenta) under Screen House Conditions in Samoa

Sanjay Anand, Danilo Flores Guinto

Journal of Agriculture and Ecology Research International, Page 1-11
DOI: 10.9734/JAERI/2017/31649

Taro (Colocasia esculenta (L.) Schott) is a staple crop of many of the South Pacific nations with an ever increasing export demand. In recent years, yields of taro have increased dramatically through breeding and selection. However, selections of improved lines are often entirely based on final yield. There are many physiological pathways by which increased potential yield may be achieved. Factors such as the accumulation of dry matter and nutrient use efficiency, merit investigation. Two improved (blight resistant) taro cultivars were planted and harvested for biomass measurements on a monthly basis for a total of eight months (30-240 days after planting) through destructive sampling. At each harvest, plants were separated into various plant parts and their dry matter accumulation and nutrient content were determined. Comparatively, cultivar Samoa 2 showed significantly higher uptake of N (25%), P (37.5%), K (33%), Mg (36.4%), Mn (22.7%) and Zn (48.3%) than cultivar Samoa 1. Even though maximum levels of total plant uptake of nutrients by the two cultivars did not differ between the cultivars, cultivar Samoa 1 plants absorbed 17% less N, 26% less P and 20% less K than those of cultivar Samoa 2 with the uptake uniformly distributed over the entire life cycle of the crop. Although cultivar Samoa 2 resulted in higher total plant (19.6%) and corm dry matter (10.4%) productions, cultivar Samoa 1 had a higher nutrient use efficiency, (kg of edible dry matter produced per kg of nutrient taken up), for N, P, K, Mg, Mn and Cu over cultivar Samoa 2. However, for Ca, Fe and Zn. Cultivar Samoa 2 had a higher nutrient use efficiency over cultivar Samoa 1. Based on nutrient use efficiency of the cultivars, Samoa 1 is recommended for marginal to rich soils while Samoa 2 for good to rich soils.

Open Access Original Research Article

Effect of Simulated Nitric and Sulphuric Acid Rains on the Nutrient Content of Amaranthus hybridus L.

A. A. J. Mofunanya, K. Egah

Journal of Agriculture and Ecology Research International, Page 1-11
DOI: 10.9734/JAERI/2017/31862

Aims: To evaluate the potential effects of simulated nitric and sulphuric acid rain on the proximate, minerals, vitamins and antinutrients contents of Amaranthus hybridus Linnaeus (A. hybridus).

Study Design: The study was carried out in a complete randomized block design.

Place and Duration: Department of Botany, University of Calabar, Calabar, Nigeria between March and June, 2016.

Methodology: Plants were harvested at two months post simulated nitric and sulphuric acid rain treatments. The leaf, stem and root were separated, dried, milled into powder and used for proximate, minerals, vitamins and antinutrients analysis according to standard methods. Simulated acid rain pH 2.0, pH 3.0, pH 4.0 and control pH 6.0 were used.

Results: Results revealed significant (P = .05) decrease in proximate, minerals or elements, vitamins and antinutrients of A. hybridus treated with simulated nitric acid rain (SNAR) and simulated sulphuric acid rain (SSAR) when compared with the control. Reductions induced by acids rain were significant according to pH of acid concentrations. Nutrients composition in the plant parts varied with more protein, carbohydrate, moisture, K, Ca, Fe, and Cu in leaf. Stem part had more of ash, fat, fibre, Zn, vitamin C, hydrocyanic acid. Others had similar amounts in leaf, stem and root. Highest nutrient reductions induced by SNAR and SSAR occurred at pH 2.0 and lowest reductions at pH 4.0, pH 6.0 had the highest amount of nutrients. Reduction in minerals imposed by acid rain on iron in leaf at pH 2.0 were 6.30±0.01 (SNAR), 6.30±0.01 (SSAR) compared with control pH 6.0 value of 14.03±0.01 mg/100 g,  the stem had values of 5.01±0.01 (SNAR), 5.65±0.01 (SSAR) compared to 14.09±0.01 mg/100 g value for the control pH 6.0, reduction values for the root were 4.28±0.01 (SNAR), 4.28±0.01 (SSAR) when compared with control pH 6.0 value of 14.88±0.01 mg/100 g. Decrease in protein values caused by acid rain at pH 2.0, 3.0 and 4.0 had values of 12.69±0.01,12.97± 0.03, 13.76±0.03 for SNAR and 9.39± 0.01, 10.82±0.02, 11.82±0.06 g/100 g  for SSAR respectively in leaf.

Open Access Original Research Article

Degree Days to 50% Flowering for 12 Cultivars of Spring Canola-Like Mustard

K. M. Hunter, D. W. Archer, R. W. Gesch, M. F. Vigil, J. L. Hatfield, B. L. Allen, J. D. Jabro, S. Kim, M. N. Meki, J. R. Kiniry

Journal of Agriculture and Ecology Research International, Page 1-8
DOI: 10.9734/JAERI/2017/33158

Modeling efforts for simulating canola have been based on growth parameters previously established in the Northern Great Plains. However, with advances in canola (Brassica sp.) genetics, establishing parameters for newly developed cultivars are essential for the best modeling projections. Accurate simulation of crop phenology, especially flowering dates, is critical for determining the duration of vegetative growth and when seed yield is most sensitive to stress. If measured flowering dates are not available, process-based models can be used to predict the flowering time based on available temperature data. In the present study, the predicted flowering date was compared to actual measured flowering data. The summed degree days (SDDs) to 50% flowering (hereafter referred to simply as “flowering”) were collected from twelve different types of cultivars planted across multiple locations. For each location predicted SDDs were computed based on temperature data from planting to the date of flowering. The measured and predicted data showed a similar pattern for SDDs to flowering for all cultivars, except for three.  Thus SDDs to flowering were relatively stable across a wide range of latitudes. Furthermore, the SDDs for most cultivars were similar to the potential heat unit sum (450) previously established for Brassica rapa (Polish canola).

Open Access Original Research Article

Creosote Bush, an Arid Zone Survivor in Southwestern U.S.: 1. Identification of Morphological and Environmental Factors that Affect Its Growth and Development

Sumin Kim, James R. Kiniry, Lynn Loomis

Journal of Agriculture and Ecology Research International, Page 1-14
DOI: 10.9734/JAERI/2017/33204

Creosote bush (Larrea tridentata [DC.] Cov.) is a perennial shrub which is a major dominant species in arid rangelands in southwestern Texas, U.S. Controlling creosote bush in desert rangelands is important because as it increases in density, perennial grass production is reduced. The purpose of this study was to investigate the association between morphological characteristics and understand how these characteristics interact with the environment to affect production of creosote bush. In this study, a range of morphological traits was investigated at several southwestern Texas sites, and growth ring and growth rate were o measured. Creosote bush plants with a wide range of ages occurred mostly in pure stands and sometimes in small groups in all study sites. Two groups were categorized based on the crown size: CB1 (mostly conical-shaped shrubs) and CB2 (mostly large hemispherical-shaped shrubs). The proportion of CB1 and CB2 at a site affected creosote bush production. Creosote bush productivity was highly associated with soil water availability. In wetter sites, more CB2 shrubs occurred than CB1, resulting in higher production. The results of this study can improve understanding of the most important factors that affect creosote bush production, which is critical for developing management strategies for desert rangelands.

Open Access Review Article

Chinese Agricultural Sector: A Review of Prospects and Challenges

Owusu Samuel Mensah, Zhuang Jincai, Chen Hua, Chun Yan Wang, Thomas Bilaliib Udimal, Jincheng Yin, Chen Cong

Journal of Agriculture and Ecology Research International, Page 1-12
DOI: 10.9734/JAERI/2017/32422

With about 22% of the global population and less than 10% of cultivated land worldwide, China faces many challenges in the agricultural sector. This paper reviewed and synthesized the major challenges facing the Chinese agricultural sector and its future prospects. The study identified urbanization, industrialization, changing dietary preference, limited land, environmental pollution and trade liberalization as major problems facing the Chinese agricultural sector. Despite these challenges, the sum of productivities of cultivated land and other agricultural inputs will increase China’s food production from 94.4% in 2000 to 101.3% in 2030, which implies that China will meet its demand for food with an increasing population. According to the predictions of food demand and comprehensive food productivity from cultivated land and other agricultural resources, China’s total agricultural productivity cannot be 100% self-efficient before 2020. However, by 2050, China will record a surplus of agricultural productivity of approximately 850 Mt, which means that China is likely to meet its future demand for food when total productivity of agricultural resources are given special attention.