Cropping Pattern And Cropping Schedule Environmental Sciences Essay

Chapter 1

Introduction

Background

Agriculture is a crucial role in the careers of nations all over the world. As the focal point of the agricultural sector is to raise the crop yield and to fulfill the food security for continuing population increase, irrigation becomes vital support to provide additional water. Nowadays, precipitation cannot be reliable in many parts of the world and temperature increases continuously due to the climate change. Moreover, there are changes in air temperature and increase in atmospheric CO2 concentrations. Furthermore, geographical changes might also have severe effect on the local water resources. As a result, water resources become scare and it threats a serious challenge to irrigation water supply, agriculture water demand, food security, and environmental protection. Irrigation water resources and agricultural water demand are strongly vulnerable. As climate change affects hydrological cycles locally and globally, its potential changes will have a significant impact on agriculture and water resources. There is an increasing stress of the impact of climate change on water resources and probable implications for water resource management. The consequences of climate change may alter the reliability, the amount and timing of river flow, challenge the coping capacities of existing water-related infrastructures and bring higher risks of water shortages and floods.

Myanmar (formerly called as Burma)which locates in South East Asia lying between 10° and 29° N latitude and between 92° and101° longitudes, also suffers from climate change impacts on water cycle due to the sudden change of weather pattern. Flood and long drought occurs consequently and thus sustainability of water environment in some areas is facing difficulties. Moreover, rainfall pattern and intensity have been evidently changing in some regions of the country according to topographical condition. There are three climate conditions in Myanmar specified as summer, rainy and winter seasons. Two third area of the country enjoys in the tropics and the remaining one third falls within temperate climate conditions. Average annual rainfall in coastal regions is over 5000 mm and in the Dry Zone which locates in Central Myanmar is less than 750mm. The average temperature is 21°C in northern regions which are the coolest areas and 32°C in coastal area. Temperature sometimes reaches to 40°C during the hot seasons and over in central dry zone areas which are the hottest regions in Myanmar.

Water resources in Myanmar are absolutely abundant and can be used to fulfill the agricultural water demand and other sectors. Agriculture is a main economic sector in Myanmar and rice-based irrigation systems, have been implemented to improve agricultural production. Paddy fields are mostly found in the delta region which includes Ayeyarwady, Bago and Yangon region of Lower Myanmar and central dry zone areas which includes Mandalay, Sagaing and Magway regions (Figure 1). Irrigation Projects have been implementing a lot in Myanmar to stabilize traditional rainfed rice and to introduce double-rice to promote the rice production. According to the hydrological conditions it is divided into two seasons, wet and dry. Paddies are traditionally cultivated by monsoon rain during the wet season. Summer paddies have grown as a second rice crop throughout the dry season according to the water availability in the regions where irrigation projects have been initiated.

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The delta region in lower Myanmar is the major rice production area. As water resources are affected adversely by global climate change, it makes seriously vulnerable to crop water requirement. Ngamoeyeik Irrigation Project Area which is just outside of Yangon City in Lower Myanmar, paddy cultivation during rainy season has traditionally been conducted under rainfed conditions and summer paddies with irrigation were added since 1995 after the project has been completed. Both paddies are cultivated completely in the rainy and summer periods, respectively. Summer paddies are cultivated only by irrigation. As there is no rain within the dry season, and the reservoir inflow is very limited. Therefore, the summer paddies are constrained by the limited water-storage in the reservoir during the dry season. Considering the wide range of the adverse effect in this area, there is needed to evaluate and access future irrigation water requirement in a changing climate for promoting crop production.

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Figure Regions in Myanmar

Rice, wheat, and maize are predominate three grain-crops for food, and these are the products of agriculture sector, coming from rain fed and irrigated fields.

Statement of the problem

According to the Asian Development Bank (2009), Myanmar is one of the most vulnerable countries to climate change associated with global warming. Summer paddies are cultivated only by irrigation in lower Myanmar. In dry season, the reservoir inflow is very limited and consequently the water availability of summer paddies is very limited. Severe climate change effects could affect the irrigation water requirement as well as the production of rice and other crops on which the population depends. Decreasing rainfall and increasing temperature pose an insufficient demand for crop and cause delay in agricultural cycles. As a result, it will disturb crop growth in the subsequent months. During the growing season, abnormal weather will damage the crops and in the harvesting period, adverse climate can damage the ripening crop. This study will compare and evaluate the impact climate change and estimate and manage the crop water requirement to cope with the future scare water resources.

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Objectives

The specific objectives of this study are as follows:

to analyze the future climate change impact for projection period of 2015 to 2030 using statistical downscaling analysis method (SDSM 4.2),

to find out the future irrigation water requirements for rice production with climate change impact using AquaCrop,

to make adaptations in order to enhance and manage the irrigation water demand to cope with the future scare water resources.

Chapter 2

Literature Review

Chapter 3

Methodology

Conceptual framework for evaluating future crop water requirement

Purpose and Strategy of evaluation of future irrigation water requirement

Objectives of future irrigation water requirement evaluation

Rice is the main food in Myanmar and it is also a major crop of the agriculture sector. The Ministry of Agriculture and Irrigation (MOAI) has imposed summer paddy cultivation with irrigation in 1992-1993 to promote the rice production. Irrigation water requirement will change under changing climate with the effects of decreasing rainfall patterns and increasing temperature. Moreover as climate change directly impacts on rice production, there has to be evaluated and adopted the future agricultural water requirements under the combined effects of growing population demands and competition from other economic sectors under future socioeconomic development.

Smajstrla and Zazueta (1995) state that the irrigation water requirement (IWR) for crop production is the amount of water that must be applied to fulfill a crop’s evapotranspiration needs in addition to rainfall without significant yield reduction . It has to be needed that irrigation water applied to paddies cultivation must be fixed the different water requirement with the different growing stages. Therefore, future irrigation water requirement with climate change impact must be assessed to conduct proper management for rice cultivation.

The main objective of evaluation of future irrigation water requirement is to promote the rice production with proper management to meet the crop water requirement under changing climate. To achieve this aim the evaluation embraces all required data concerning the impacts of climate change combining the growing population and environmental impacts.

Description of the study area

Location

Ngamoeyeik Irrigatin Project is one of the large irrigation projects in Lower Myanmar. It has been developed by the Department of Irrigation under the counsel of the Ministry of Agriculture and Irrigation. The project was completed in March, 1995. The project is situated in Hlegu Township, which is about 20-50 km northeast of Yangon City (Fig.3.1). The target area of the irrigated cultivation is 28,330 ha. There is also a plan to supply water to Yangon City for domestic use with the amount of 0.41 MCM per day.. The area is bounded by creeks and rivers providing natural drainage, such as the Balar Creek, Khayein Creek and Bago River (Fig.3.2). The project’ area is mostly within Hlegu Township.

Location – about 20-50 km northeast of Yangon City

(in Hlegu Township)

Name of river – Ngamoeyeik Creek

Catchment area – 28330 ha

Average annual rainfall – 2540 millimeters

Average annual inflow –

Dam type – earthen dam

Dam length – 1.86 kilometers

Dam height – 22.9 meters

Full storage volume – 222 million cubic meter

Dead storage volume – 15 million cubic meter

Type of spillway –

Width of spillway –

Designed spillway discharge –

Full supply level –

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Climate

Climate of the study area is warm and tropical and enjoys the southwest monsoon. The rainfall is rich enough for rice cultivation. Even in drought years, the region receives a stable with average annual rainfall of 2,540 mm. This region has a rainy season and dry season in a year. Rivers, rivulets and natural drainages are flooding every year during the rainy season due to the monsoon heavy rain. However, their flow discharges are very limited and there is almost no rain within the dry season. Daily average temperature is above 25 ¾Ÿ C throughout a year. Thus, the region has a favorable weather environment for rice cultivation for a round-year, even in the dry season if water is available.

Soil Type

The rice soils of Lower Burma are gley soils or degraded soils or are intermediate between these two types (Karmanov, I. I). These soils are widely distributed in Lower Burma. (http://www.cabdirect.org/abstracts/19601902538.html) The rice yields will be highest on heavy loamy soil and light clayey gley soils and lowest on degraded soils.

Cropping Pattern and Cropping Schedule

Rice, wheat, and maize are three major crops for food, and these are the main products of agriculture sector, under rainfed and irrigated fields.

Table Cropping pattern in Hlegu Township, 1999-2000

Cultivation Area

Rice is grown in this region twice a year, rainny paddies are totally cultivated under rainfed condition from June to November and the summer paddies with irrgation are from December to May. The summer paddies were started in 1995 after completion of the project. Rainfed rice are cultivated annually in the basin about 35,000 ha . During the last 6 years, from 1996-97 to 2001-02, an average area of 14,000 ha has been irrigated for summer paddies within the project area. The total area of irrigated summer paddies was up to about 18,500 ha, 65% of the project service area, in the year 2000.