ABSTRACT:
In this study, the multinomial logit model was applied to measure adaptability of farmers agricultural production with drought. The data was collected by interviewing 246 farmers (5/2016). Key results showed that adaptability of farmers agricultural production is low, as well as a level impact of drought increased the probability of stop production in Bac Ai district or change production in Ninh Hai and Ninh Phuoc district. The adaptability of farmer with drought affected by level impact of drought, area cultivated, drought tolerant plant or not.
Keywords: Drought, adaptation, multinomial logit model.
1. IntroductionClimate-related natural disasters (drought, flood, and typhoon) are principal sources of risk and uncertainties in agriculture. Drought has emerged as a major worldwide threat to crop production, especially in areas where irrigation is an inevitable aid to agriculture. The Crop face drought either due to impaired water supply to roots or higher transpiration rate (Manivannan et al. 2007). Drought influences the growth events, nutrient uptake and metabolism, and the crop productivity (Engelbrecht et al. 2007, Farooq et al. 2009).
In the last 50 years, Viet Nam suffered around 36 drought events. In the context of climate change, the temperature rises, evaporation greater, more extreme rainfall distribution and drought risk of more intense, major impact on agricultural production (Truong, 2015).
Ninh Thuan is known as severe climate areas. In dry season, prolonged drought, water shortage are frequent. Almost people are farmer about agriculture, forestry and aquiculture. So, drought have impacted to social economic in area. In Viet Nam, drought is third calamity of three calamity (drought, flood and storm). However, drought is the most calamity in Ninh Thuan province. At the present time, the provinces crop area directly and indirectly affected to over 700 billion dong, the total area cant be production 5,775 ha and 2,515 cattle were died, the situation of drought is growing sandy desert and difficult cultivation (Department of agriculture and rural development, 2015). The purpose of this research assess the effects of drought in adaptability of farmers’ agricultural production. A farmer may have the choice to adopt a water-saving technology that reduces his water application rates. More efficient technologies may allow the farmer to survive through drought periods by reducing water applications to minimum possible levels (Schuck et al, 2005).
2. Literature review
Conceptually, drought is considered to describe a situation of limited rainfall that is substantially below what has been established to be a normal value for the area concerned, leading to adverse consequences on human welfare. Althought drought is a climatically induced phenomenon, its impact depend on social and economic context. Three generally used definition of drought are based on meteorological, hydrological, and agricultural prespectives (Wilhite and Glantz, 1985).
Agricultural drought is said to occur when the soil moisture is insufficient to meet crop water requirements resulting in yield losses. As the effect of rainfall deficiency on crops also depends on soil and crop characteristics, the definition of agricultural drought requires consideration of actual and potential evapotranspiration, soil water deficit, and production losses simultaneously.
Schuck, 2005, using survey data for adoption of efficient irrigation technology in drought-affected regions of Colorado, find that drought indeed significantly increases the percentage of farms adopting modern irrigation technologies, with the farmers having the most reliable sources of water being the major adopters.
3. Study area
Ninh Thuan Province is located in central Viet Nam, bordered on the east by the South China Sea, on the west by Lam Dong Province, on the north by Khanh Hoa Province and on the south by Binh Thuan Province. The province has an area of 3,358 km2 and is divided into seven administrative districts. The estimated population is 590,377 in 2014 with about 213,716 (36.20%) urban residents and 376,660 (63,80%) rural residents.
Ninh Thuan Province has scarest quantity of overground water in the country, with the annual rainfall of about 1.100 mm. In fact, the rainfall is distributed irregularly spatially and timely. Precipitation decreases from plain to mountainous place. The upstream areas of Cai river have rainfall of over 2.000 mm while the coastal plain have only rainfall of 700 mm. The Cai river is crucial with total area of 3.043 km2, 105 km length, supply mainly water during drought season. The flow of Cai river distributes during two different seasons. The flow of river is dense but focus on short time with the flood peak of 5.000 m3/s. The flow of river in dry season is only 3,35m3/s. Ninh Thuan Province annual suffered the impact of natural disasters due to drought, water shortage (Dang, 2015).
4. The method and data source
4.1. Data source
This research is based on information collected from household survey of 246 farmers, collected randomly from Bac Ai District (high drought), Ninh Hai District (medium drought) and Ninh Phuoc district(non dought). Data were collected in through household survey with a questionnaire, which contained questions to provide answers. In this study, Limdep 9.0 was used to estimate the multinomial logit model.
4.2. The method
The Multinomial Logit (MNL) model is one of the most important models for multicategorical responses. This model is used to make predictions about and explain relationships among variables in awide variety of areas, including business, economics, education, health care, and geography. As it is an enhanced version of logistic regression, multinomial logistic regression shares the problem associated with logistic regression but with more complications involved (Pannapa, 2013).
The MNL model is expressed as follows:
Where, Pij is Prob(Y=j/x), which is obtained as follows:
We can beegressio by the method of maximum likelihood. In
this model, the probability is obtained as follows:
The benefit of using multinomial logit model is that it models the odds of each category relative to a baseline category as a function of covariates, and it can test the equality of coefficients even if confounders are different (M. R. Kohansal,2013).
In this study, the Multinomial Logit (MNL) model is used to
analyse the factors influencing drought in adaptability of Farmers agricultural
production in Ninh Thuan Province. Variables was defined in the table 1.
Marginal probabilities of choice (marginal effects) can be calculated from equation below:
We can find changes in probabilities for primary choice in adaptability farmers, while holding all other explanatory variables fixed. The empirical specification for examining the influence of explanatory variable which are described in table 1 on the choice of Y is giveas follows:
5. Result and discussion
5.1. Farmers socioeconomic charateristics
The summary of the socioeconomic characteristics is presented in Table 2. A comparative analysis of the socioeconomic variables between groups showed that majority of the all farmer are male,where 80,49% and 85,37% of Ninh Phuoc Distric, Ninh Hai Distric. These male farmers are engaged in agricultural farming rather female headed farmers and they are more active in taking adaptation actions to cope with drought instead of female farmers in these areas.
Age is an important factor which helps to understand the real scenarios happening in drought issues. Table 2 shows that three groups farmers age lies between 26 and 50 years. This indicates that the middle aged farmers are likely to be more active in applying farming experiences better, so older farmers are able to assess the characteristics of modern technology than younger farmers. Moreover, education not only increases the level awareness, but also higher income positively affects public perception of drought. It can be seen that education level of the household head has completed secondary school, but 39,02% of Bac Ai Distric farmers are illiterate. Finally, income is the most imperative issue that protects and ensures farmers livelihoods from any consequence that arises from drought. Data shows the annual income of different farmer groups. It is evident that 90,24% and 79,26% of farmers annual income is less than 40 million vnd in Bac Ai distric and Ninh Hai Distric, while 43,9% of farmers annual income is more than 80 million vnd in Ninh Phuoc distric. In rural areas where agricultural production is a major source of income. A decrease in agricultural income will reduce adaptable to drought.
Regarding land holding size could be either risk-increasing or risk-reducing. Because their small pieces of land did not allow them to invest in these activities. Therefore, it is evident that represents different farmers group, 70,07% and 53,66% of farmers land is between 1 ha and 3 ha in Ninh Hai District and Ninh Phuoc District, but in Bac Ai District 58,54% of farmer’s land more than 3 ha.
5.2. Farmers perception on drought
An effective drought risk reduction approach is essential not only in order to reduce drought impact but also to put communities back on the track of development. In this study, the farmers are asked about their perception on drought. Table 4 shows that drought is well perceived by farmers in Bac Ai, District Ninh Hai and Ninh Phuoc. Farmers interviewed in this research gave feedback on temperature, munber of rainfall days, rainfall intensity, water used and specially groundwater. Groundwater is estensively use for agricultural pusposes. This groundwater is mainly recharged through rainfall during the monsoon season. However, lack of rainfall during the monsoon season cannot revitalize the groundwater for irrigation purposes, is not completely replenished during the drought year causing groundwater depletion of this region.
5.3. Explaining farmers adoption decisions of drought
The estimated results from the multinomial logit model are represented in table 5. Base on R2 pseudo stastics, it can be clearly seen that estimated multinomial logit model is a suitable egression and independent variables of the model explain variation of dependent variable in three groups. Morover, the chi-square value of 131,10 showed that likelihood ration staristics are highly significant (0,00001) suggesting the model has a strong explanatory power.
It is clear from Table 5 that X3 (land quality), X4 (level impact of drought), X5 (education of the household head), X6 (area cultivated), D1 (dummy for plant) variables affected farmers primary choice of stopping production over the farm to continue in the first equation. In other words, X2 (agricultural imcome), X4 (level impact of drought), X6 (area cultivated), D1 (dummy for plant), D2 (ethnic) variables affected farmers second choice of change production over the farm to continue. Income variable significantly influenced the change production at 10% level but not significant in stop production, farmers who have high agricultural income is conscious about change production than farmers with low agricultural income.
From Table 5, it is obvious that the sign of level impact of drought variable is positive and statistically significant in both equations. These show that an increase in level impact of drought increased the probability of stop production in Bac Ai distric or change production in Ninh Hai and Ninh Phuoc Distric.
In this model, marginal effect measure the change in the
probability of the farmers primary preference outcome with respect to a change
in each explanatory variable. Results of calculating variables marginal effects
are presented in table 6. Marginal effect of farm scale variable indicates that
an increase in farm scale by 1000 m2 decreased the probability of choosing stop
production and change production by 0,05 and 1,76%, respectively.
Also, marginal effect of education of the household head variable indicated that higher education gives farmers the ability to interpret and respond to new information much faster than their counterparts with lower education. An increase in education level by one year increased the probability of choosing non production by 0,25%, respectively. However, the probability of choosing farm to continue increases by 0,04%. At last, the variable of plant shows that the plant drought will decrease the probability of non and change production by 3,66 and 38,34%, respectively. On the other hand, the probability of choosing farm to continue increases by 42,01%. Also, instead of calculation of marginal effect for each variable, we can calculate and interpret odds rations. The interpretation of the results of marginal effects and odds ration leads the same direction.
According to Table 7, it is clear that the overall predictive power of the estimated multinomial logit model is 69,1%. It mean that this model and its coefficients could appropriately predict the farmers adaptive drought. Results of predictive power are represented in table 7 individually for each group. Base on this table, statistics of prediction power for farmer who chose farm to continue or change production was more than those who chose non production.
6. Conclusions
Research shows the impact of drought to each region of Ninh Thuan Province and the factors that affect the ability of farmers to respond to drought. In the survey region includes Bac Ai, Ninh Hai, and Ninh Phuoc District. Bac Ai is where most powerful impact-resistant by rought, and little influenced as Ninh Phuoc District. So, Ninh Phuoc has no farmers choose out of production and this area is also the chosen rate production continued to occupy the highest.
The research results showed that the production area shall not affect the option to continue or stop production or switch crops of farmers, which is important to the extent of the impact of the drought to individual farmers, what farmers are producing crops, plants that are drought resistant or non - drought. Possibilities for production of farmers were mainly concentrated in Bac Ai, where a severe drought, the majority of crop planting non-drought (rice), bad soil quality are difficult to convert to other crops. So that, to diminish of drought influence and raise to cope with drought better, local authorities must upgrade current irrigational work to help reserve water better, provide adequate water for all farmer and especial distant farmers
Strong impact factor to the conversion plant is the nation. If the minorities, the rate of conversion options is very low because of the ethnic minorities are usually less liable to change its manufacturing practices. Therefore, local authorities need to improve education and encourage the minority to change crops to suit the current drought situation.
All in all, adaptability of farmers agricultural production is low. They don't have much choice because the level education is low, soil quality is poor. Most of them accept continued to produce because agricultural production is the main source of income of the people of this place, if not produced, they are difficult to do other work to have more revenue.
REFERENCES:
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2. Engelbrecht, B. M. J., L. S. Comita, R. Condit, T. A. Kursar, M. T. Tyree, B. L. Turner, and S. P. Hubbell, 2007. Drought sensitivity shapes species distribution patterns in tropical forests. Nature, 447, 80 - 82.
3. Farooq, M., A. Wahid, N. Kobayashi, D. Fujita, and S. M. A. Basra, 2009. Plant drought stress: effects, mechanisms and management. Agron. Sustain. 29, 185 - 212.
4. Jaleel, C.A., P. Manivannan, B. Sankar, A. Kishorekumar, R. Gopi, R. Somasundaram and R. Panneerselvam, 2007. Water deficit stress mitigation by calcium chloride in Catharanthus roseus; effects on oxidative stress, proline metabolism and indole alkaloid accumulation. Colloids Surf Biointerfaces, 60, 110 - 116.
5. M. R. Kohansal, and A. Firoozzare, 2013. Applying multinomial logit model for determining socio- economic factors affecting major choice of consumers in food purchasing: the case of Mashhad. J. Agr. Sci. Tech, 15, 1307-1317.
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10. Đặng Thanh Bình, 2015. Đánh giá tác động của hạn hán thiếu nước đến sản xuất nông nghiệp tại Ninh Thuận. Tạp chí Khí tượng Thủy văn, 4.
11. Trương Đức Trí, 2015. Tác động của biến đổi khí hậu đến hạn hán khu vực Nam trung bộ Việt Nam, khả năng dự tính và giải pháp ứng phó. Luận án tiến sĩ khoa học môi trường, Trường Đại học Khoa học tự nhiên Hà Nội.
12. http://baotainguyenmoitruong.vn/moi-truong-va-phat-trien/201606/ninh-thuan-han-han-gay-thiet-hai-hang-tram-ty-dong-2702830/.
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TRƯỜNG HỢP NGHIÊN CỨU TẠI TỈNH NINH THUẬN
ThS. TRẦN HOÀI NAM
ThS. NGUYỄN VĂN CƯỜNG
ThS. ĐỖ MINH HOÀNG
Bộ môn Kinh tế nông lâm, Khoa Kinh tế
Trường Đại học Nông lâm TP. Hồ Chí Minh
TÓM TẮT:
Nghiên cứu này đã sử dụng mô hình hồi quy đa thức nhằm đo lường khả năng thích ứng với hạn hán của nông hộ trong sản xuất nông nghiệp. Số liệu được thu thập bằng cách phỏng vấn trực tiếp 246 nông hộ (5/2016). Kết quả nghiên cứu cho thấy, khả năng thích ứng của nông hộ đối với hạn hán là thấp, cũng như khi có sự gia tăng tác động của hạn hán sẽ làm tăng xác suất ngưng sản xuất của các nông hộ tại huyện Bác Ái, hoặc làm tăng khả năng chuyển đổi cây trồng của các nông hộ tại huyện Ninh Hải và Ninh Phước. Các nhân tố ảnh hưởng đến khả năng thích ứng của nông hộ đối với hạn hán là biến mức độ hạn hán, khu vực sản xuất, đặc tính của cây trồng chịu hạn hay không chịu hạn.
Từ khóa: Hạn hán, khả năng thích ứng, mô hình logit đa thức.
Xem tất cả ấn phẩm Các kết quả nghiên cứu khoa học và ứng dụng công nghệ số 08 tháng 07/2017 tại đây
