The Impact of Rainfall on the Yields of Staple Crops - Sorghum and Sesame in Sudan

Research Article

The Impact of Rainfall on the Yields of Staple Crops - Sorghum and Sesame in Sudan

Abdelsami Musa Ibrahim^*

Developments Studies & Organizational Affairs administration, Ministry of Agriculture, Irrigation and Forestry, White Nile State, Sudan, Egypt

Corresponding author: Abdelsami Musa Ibrahim, Developments Studies & Organizational Affairs administration,Ministry of Agriculture, Irrigation and Forestry, White Nile State, Sudan, Egypt; E-mail: abedokosti2222@hotmail.com

Citation: Raut RV, Dhande GA, Rajput JC, Ingale AG. Rapid and Highly Competent Shoot Regeneration of Pigeon Pea (Cajanus Cajan) using Variable Explants Via In vitro Culture System . J Plant Sci Res. 2015;2(2): 132.

Copyright © 2015 Ibrahim AM, et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Journal of Plant Science & Research | ISSN: 2349-2805 | Volume: 2, Issue: 2

26/08/2015; Accepted: 26/10/2015; Published: 31/10/2015

Abstract

This study addressed the impact of the weather change mainly rainfall on the yields for the staple crops (sorghum and sesame) in a traditional rainfedsector in the White Nile State of Sudan. Time series rainfall and grain yield data for 10 years (2001-2010) are analyzed using Fisher Integral Model,Chebyshev Orthogonal Polynomial, and stepwise regression to estimate the meteorological yield. Our results indicate that an increased availability of waterenhanced productivity in terms of grain yield. An annual increase in average rainfall to 2.62 mm during crop maturing stage (harvesting stage) resulted insorghum and sesame yields higher to 32.31 kg/ha, and 7.64 kg/ha respectively. The main recommendation we strongly saying the possibility for early seedingfor sorghum and sesame in the traditional farms of rural farmers can get high yield.

Keywords: Rain-fed; Metrological Yield; Integral Model; Chebyshev Orthogonal Polynomial

Background

Agriculture is extremely vulnerable to weather changes thoughcrop yield are affected by natural and non-natural factors. Theenvironment is one such natural factor which plays an importantrole in determining the yield. Changes in yield component may bea result of plant’s response to stress at various stages of plant growthand development [1]. In other hand, Mohamed studied the impactof weather change on Sudanese cereal grains and cash crops such assesame, and groundnut and reported a higher impact of rain on yieldscompared to increased temperatures [2]. Despite recent technologicaladvancements in crop improvement methods, weather remains acritical factor that determines the agricultural productivity. Jonesand Thornton reported the severe impacts of change on rainfall andtemperature on yields of staple crops such as maize, millet, sorghum,sesame and peanut. In other hand, higher temperatures eventuallyreduce yields of desirable crops while encouraging weed and pestproliferation [3]. Agricultural economics is influenced by the weather. Sudan economy primarily depended on agricultural activitieswhich in turn is dependent on climate factors such as rainfall andvariability of temperature beside varietal genetics, soil fertility, andcrop management factors. In the mid-1970s and late 2000s, summerrainfall decreased by 15-20% across parts of western and southernSudan and declines can be visualized as a contraction of the regionreceiving adequate rainfall for viable agricultural livelihoods whichrural farmers depend on.

Mohamed and Rajaa and Abdulhamed indicated that cereal grainsand oilseed crops such as. “Sesame and peanut” were domesticated inAfrica for the existence of the right climate, as some cereal grains likesorghum was known in Ethiopia a long time ago since 5000 years andhas moved from there to the regions of Sudan to West Africa at anearly date [4,5].

Sorghum “Sorghum bicolor L. Moench” and sesame “Sesamumindium (L).” are main staple crops for local households in the sameareas of the research (White Nile State of Sudan) because of traditional style in food and cultivation. Sorghum is the most important annualcereal grain crops for rural area in the Sudan and mainly grown inrain-fed sector in both (traditional; where small farmers owns smallcultivated area in addition those farmers used production for selfsufficientalso they using traditional agricultural methods e.g. seeds,land preparation. etc. And mechanized rain-fed area which considers a big scheme farms cultivated for trade and using full technologies”[6]. This study focuses on these two widely grown major staple cropssince 86.9% of sorghum and entire sesame are grown in White Nilestate as shown in Table 1.

Selected Area and Data Description

Geological Information in selected area: White Nile Stateextends between longitudes (12-13.3) north and latitudes (31-33.3)east. The total area of the state is approximately equal to 44.615thousand square kilometers (approx. about 4 million hectares), about66% of which is under vegetation cover (FAO 2009). White NileState is considered as one of the Sudanese States with geo-ecologicaldiversity. The report of Ministry of Agriculture (2012) mentionedthat as plains region of the natural and flat has an estimated areaof 3,643,119 acres which is equivalent to about 33% of the area ofthe state, land area of sedimentary clay and sand area are estimatedto 2,268,629 acres of which correspond to about 24% of the area ofthe state, area of the Nile Valley area is estimated to 945,262 acreswhich corresponds to about 10% of the area of the state, sub-Saharansand area is estimated to 661,638 acres which is equivalent to about7% of the total area of the state, quartz sandy area, estimated areato 2,363,155 acres which is equivalent to about 25% of the area ofthe state and rocky hills area is estimated to 94,526 acres which isequivalent to about 1% of the area of the state.

Methodology

The Meteorological yield is a function used to estimate some ofmetrological factors as in rainfall, sunshine, and temperature. Fisherthought that the impact of meteorological factors on yield couldbe denoted in the form of the integral regression [7]. The extendedFisher integral regression model is:

In the function (1), Y denotes the yield, T denotes the yield trend,. Denotes the meteorological factors rainfall, and Ï„â€¦denotes thecrop growth period; while and are to be estimated parameters.

Usually, we used the orthogonal polynomial to approximatelyexpress in the following function (2),

unction (2) is substituted into (1), thus the function (3) is in thefollowing:

Here, we had:

Ï†j could be derived from the Chebyshev-orthogonal polynomialin the following(Ï†0=1).

Following the above (3) is a typical multiple linear regressionequation of the stepwise regression approach to solving the equations.After several rounds of comparison, the two equations can be close toour expectations.

Result and its Analysis

In this study, all data on meteorology and crops yield is fromMinistry of Agricultural, Forest, Animal Wealth and Irrigation ofWhite Nile State of Sudan. The CV (coefficient of variation) is whichexpresses the variation as a percentage of the mean is calculated asfollows: CV% = (SD/Mean)*100, here SD is the Standard Deviation.The CV of yield, rainfall and temperature were studied to choose theimportant variable which may influence the grain yield more.

Yield variation: The yield of sorghum and sesame were very low104 and 51 kg/ha in 2009 but 655 and 306 kg/ha in 2009 respectively.This variation in yield level is reflected by high CV of the yield of both the crops which were 0.57 for sorghum and 0.39 for sesame.

Temperature variation: The range of CV varied 0.01 to 0.06which is very small in scale. This means that the minimum andmaximum temperatures are almost stable in each month.

Rainfall variation: The range of CV was waving largely from 0.33to 1.43 during the raining season. High average rainfall was observedduring July and August which corresponds to vegetative growthperiod of the crop cycle. The fluctuations in rainfall are much greaterthan temperature. For the reason, we focus on rainfall as one of theimportant factors that determine the yield in this study. Oughan andStoddart reported that failure of some grain sorghum seeds lines infield to germinate and emerge at very high soil temperatures reaching(45 to 50 Â°C), is closely has been associated with inhibition of embryoprotein synthesis during the first few hours of seeds water absorption[8]. Our study shows in Table 1 the high temperature is 41.72 Â°C and39.99 Â°C in May and June respectively, which is lower than 45 Â°C andconducive to germination.

Table 1: The statistic mean and coefficients of yield, rainfall and temperature for sorghum and sesame during crop cycles during 2001-2010.

Now let us run the model on the relationship between yield andrainfall with the Stata software using Orthogonal Polynomial StepwiseRegression to get the significance of rainfall that can influence thesorghum and sesame metrological yield. The result shows that Rainfallco-efficiency is highly significant to the sorghum plant during the 2stages â€˜vegetative growth and flowering stages’ (Table 2).

Table 2: Coef. (αij) and Texplain the rainfall that influence crop yield.

According to the crops production characteristics, the lifecycle ofa plant is divided into four stages: seeding, vegetative, flowering/ grain filling, harvesting. The stage wise results for rainfall- yield coefficients are in Table 3 as follows.

Table 3: Sorghum yield outlook during the rainy season.

Seeding stage: The average early seeding rainfall is 7.82 mm. If there is more rainfall, it will benefit the germination of sorghum andsesame and consequently their yields tend to increase by 9.61 kg/haand 7.64 kg/ha. Coefficient Meteorological Yield in May month ishigher for both the crops. The early seeding appears to be better thanthe later seeding due to increased germination and yield increase tobe higher by 0.53 kg/ha and 2.42 kg/ha (Table 3).

Vegetative growth stage: In this stage crop grows fast and needsa lot of water. In fact, July and August are rainy seasons in Sudan;the rainfall average is 85.73 mm and 87.52 mm respectively. But therainfall-yield coefficients are negative in July for both the crops and for sesame August. The coefficient for sorghum is positive in August (2.8kg/ha mm). This indicates that plant response to rainfall in Augustis different in sorghum than sesame. It is expected since sorghumis a high biomass crop with much higher growth rate compared tosesame.

Flowering and filling stage: This stage starts in Septemberwhen average rainfall is 34.18 mm. Coefficient Meteorological Yieldindicates a rate of increase in yield trend to be14.15 kg/ha for sorghum and 2.42 kg/ha for sesame. It shows that plant needs more water inthis season than the average rainfall level.

Harvesting stage: This phase starts sometime in October whenaverage rainfall is estimated to be 2.mm which is inadequate to achievedesired seed size to ensure expected yield, though grain quality will begood if harvest is in rain-free period. Our study shows that additionalwater supply will increase yield by 32.31 kg/ha for sorghum and 7.64kg/ha for sesame.

Discussion

Weather factors include temperature, sunshine duration andrainfall etc. In this study, the key weather factor is found to be rainfallas compared to the minimum and maximum temperature regimes inrelation to staple crop yield. The Coefficient Meteorological Yield hasrevealed the influence of rainfall in predicting the response to yieldincrease.

The finding is that the same weather condition has differentoutput on the yield of sorghum and sesame, for example, in July to September, the Coefficient Meteorological Yield of these two staplecrops is similar except in August. Thus, rain is beneficial to both thecrops for germination and crop growth up to July but sorghum showsdifferential response during August due to higher inherent capacity toproduce higher biomass than sesame. At further stages, excessive raincausing water logging in sesame is injurious to it while sorghum cantolerate it upto some extent. Dabir JD has also reported that sesame isintolerant of water-logging and the rainfall late in the season prolongsgrowth and increases shattering losses in the harvesting period [9].

The Model only considers total rainfall as weather factor relativeto the crop yields. In fact, distribution of rainfall, intensity of rainfalland number of rainy days, RH and some other weather factors suchas the concentration of carbon dioxide in the air, sunshine duration,radiation intensity and wind speed also influence the yield. The effectand relationship of these factors need attention in future research.

According to the Meteorological/weather yield coefficient, thecrop yield could be forecasted and the requirement of supplementaryirrigation in low rainfall years may be assessed. Equitable distributionin rainfall in rain-fed areas is essential for desirable crop growth.Weather change will have varying effects in the rain-fed traditionalsector which may experience large declines in yield during unfavorableyears. Weather change will result in low grain production andconsequently price increase of the all the agricultural crops includingthe major staples sorghum and sesame affecting the security in bothfood and cash crops. To mitigate such abnormal situation, we needto achieve different technologies to enhance the traditional farmer’sgrain yield ensuring irrigation potential, supply of drought tolerant/short duration improved varieties and hybrids with higher WUE, lowcost input supply, improved management practices including earlyseeding and seedling establishment under higher temperature andskills associated with technical package to cope with weather change.In addition to this different scenarios are expected due to the climatechange which will result in food deficit primarily in arid and semiaridtropics particularly in developing countries. Mohamed B et al.[10,5,11] further elaborated agricultural production and food securityunder climate change in Sudan.

Annex: Orthogonal Function

In this part of the paper we are looking to the relationship betweenmeteorological factors “natural factors” and yield using ChebyshevOrthogonal Function as below: