Dissertation abstracts study on improving the cropping systems on some main soil types in dong hy district thai nguyen province

With the land, crop structure as well as the natural - economic and social conditions of Dong Hy District as mentioned above; to gradually change the cropping system forward to market or

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PART 1 INTRODUCTION

1 Background

Dong Hy is a mountainous district of Thai Nguyen Province with total natural area of 46,177 ha in which there are 26% of agricultural land, 45% of forest land, 0.37% of aquaculture, 5% of land for specific purposes; 2% of living land; 22% of unused land The structure of agricultural land includes 53% for annual crops, 39% for perennial crops, and 8% for others The annual crops include cereal crop group, short-term industrial plant group, group of vegetables and beans The perennial crops include tea, litchi, longan, mango, jackfruit plants etc With the land, crop structure as well as the natural - economic and social conditions of Dong Hy District as mentioned above; to gradually change the cropping system forward to market oriented production and to develop the sustainable agriculture system definitely needs research on improving cropping systems in Dong Hy District Based on these issues, we conducted a study titled “Study on improving the cropping systems on some main soil types in Dong Hy District - Thai Nguyen Province.”

2 Research objectives

- Researching for improved cropping systems with proposed cropping structure on rice-based land in Dong Hy District, Thai Nguyen Province in the period of 2010 -2020

- Researching and applying some cultivation techniques for the tea production on hilly land in Dong Hy District, Thai Nguyen Province

- Building demonstration plots on rice-based and hilly land based

on research results obtained

- Proposing development plans for new cropping systems in Dong Hy District in the future

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4 Research limit

The study focuses on analyzing and evaluating the status of crop production on some main kinds of agriculture land in Dong Hy District, including cropping systems on one-rice crop land, two-cropland and three-crop land of rice-based land system; perennial cropping systems

on hilly land in Dong Hy District;

The study focuses on testing for selection of some new varieties with high yield - high economic efficiency and building demonstration plots on rice-based lowland in Dong Hy District, testing for selection of chemical fertilizer rates combined with microbial fertilizer for tea on hilly land, testing some techniques for moisture maintenance in tea field

in winter season and building demonstration plots for sustainable tea production – high economic efficiency from tea production in Dong Hy District

5 New findings of the study

- For annual crops on rice-based lowland in Dong Hy District: Improved crop varieties in this area have increased the productivity and economic efficiency of the rotation treatment

- Additional winter potato crop on two-rice lowland has increased the economic efficiency of crop rotation treatment and improved soil nutrient content

- Additional peanut crop or soybean crop on one-rice lowland has increased the productivity and economic efficiency of cropping systems and soil nutrient properties

- Studying and building the demonstration model of sustainable tea production with some technical methods such as balanced-fertilizer combined, moisture maintenance in winter-spring crops increased not only productivity - economic efficiency but also soil nutrient properties

PART 2 LITERATURE REVIEW AND SCIENCETIFIC BASIS 2.1 Scientific basis of cropping systems

2.1.1 Concepts

* Cropping systems

A cropping system is a composition of breeds and varieties that are arranged in areas and time in all kinds of agricultural ecosystems to make the best of natural - economic and social conditions (Dao The Tuan, 1984) A cropping system is an arrangement of all plants in an

3 interaction-relationship that is suitably arranged in areas and time (Nguyen Duy Tinh, 1995)

*Improved cropping systems

According to Pham Chi Thanh et al (1996), an improved cropping system includes local cropping system and advanced techniques This is the way of inheriting the good that was accumulated

by local people; therefore researching and developing the cropping system must evaluate the current cropping system The word “current” means the techniques that have been accepted by local people Advanced techniques are the new ones that have never appeared in locate and increased production efficiency

* Logical cropping systems

A logical cropping system is stabilization in aspect of organizing

crops on farmland in quantities, ratio, species, locations and time to create a synergy of organic interaction relationships among all kinds of crops to exploit and use economically and reasonably natural resources for economic-social development purposes (Khai Tran, 1994)

The logical cropping system is the system suitable with natural and economic - social conditions of province (Dao The Tuan, 1989), (Phung Dang Chinh et al, 1987) The logical cropping system also show the effectiveness of the relationship between plants located on the field

- make the cultivation production develop comprehensively, strongly and firmly towards intensive cultivation associated with multi-cultivation, production of goods and high economic efficiency The logical cropping system is a reality objective that is formed from specific natural and socio-economic conditions and motivates over time

2.2 Overview of cropping system research

2.2.1 Cropping system research in the world

According to Flach et al (1989), the crop rotation is sequences of plant arrangements on the same part of land in each seasonal crop of each type of crop The crop rotation is used importantly in maintaining the fertility of soil; preventing the increase of diseases, pests, weeds; and controlling and limiting erosion

Since 1980 in the Southern region in China, there has studied for the ecological agriculture Xiaoliang is a hilly area of Guangdong that had vigorous desertification, erosion and high ground temperature It is used to be planted eucalyptus, but were unsuccessful Finally, local

4 people selected cropping systems with crop diversification and multi-layer plants There were protected forest trees at the top of the hill, orchard plants in the middle and crops grown in the valley

Rubber trees at hills were planted in rows of 10-15 meters long and 2.5 meters wide combined with one row of tea plants intercropped According to Trieu Quoc Ky (1994) on two-rice cropland in Southern mountainous region used to be planted two to three seasonal crops with cropping systems of rice-wheat-potato or peanut-soybean-wheat On one-rice crop-land of plateau (Van Nam, Quy Chau, Tu Xuyen and Tay Tang provinces), cropping systems were rice in rotation with upland crops

2.2.2 The cropping system research in Vietnam

Bui Huy Dap (1977, 1987, 1994), on his overview of research in Northern mountainous region, indicated that the proper cultivations in some type of agricultural land in mountainous areas are cropping systems of spring rice-summer rice on lowland in the valley and terrace fields in low mountainous areas; cropping systems of summer rice-potato (or green bean- green manure plants) in areas where there is no water in the winter-spring crops

On the land with history of planting one-crop of spring maize or spring-summer maize, we can added peas, white beans as winter crops The research on applying technical methods to improve the efficiency of one-crop-lowland in Northern mountainous region (Le Quoc Doanh et al, 2007) showed that by variety selection and land mulching we can increase the seasonal crops with 2 treatment: spring soybean-short term summer rice resulting in the profits from 16.8 million VND/ha/year compared to one-rice crop with 8.0 million/ha/year Treatment of spring peanut- short-term summer rice gave the profit of 21.2 million VND/ha/year higher than the control of one-rice crop by 9.6 millions VND/ha/year

PART 3 REASERCH CONTENTS AND METHODOLOGY 3.1 Research Contents

3.1 Assessing the impact of natural, economic - social conditions in Dong Hy District on cropping systems

3.2 Assessing the current cropping systems in Dong Hy District 3.3 Study on improving cropping systems in a main kind of land in Dong Hy District

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3.3 Research Methodology

3.3.1 Collecting secondary data

Sources of data extracted from related organizations in research areas

The experiments were designed according to the method of

field experiments and were conducted on farmer fields in study sites

3.3.4 Building demonstration plots

The plots on two-rice cropland, one-rice cropland and for sustainable tea production on hilly land

3.3.5 Analyzing nutrient elements of soil in the model areas

Taking soil samples before and after implementing models (taken from the cultivation soil layer from 0 to 30 cm of hilly land; layer from

0 to 20 cm for rice-based lowland),

3.3.6 Analyzing experimental data: Field experiments’ data were

analyzed by analysis of variance, regression analysis using SAS and IRRSAT software

PART 4 RESULTS AND DISCUSSION 4.1 Results from assessing impacts of natural, economic - social conditions on cropping systems in Dong Hy District, Thai Nguyen Province

4.1.1 Topography and land

According to statistic data, a total area of land used for cultivation was 46.117,2 ha and is divided into five main groups The survey results

on current use of these types of land were shown in Table 4.1

Table 4.1: The main soil types in Dong Hy District

Soil Groups Area

1 Alluvial soil with less

2 Alluvial soil with no

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3 Eluvial soil at valley 8,188.3 Rice

4 Acrisols 22,357.4 Forest, tea plants, fruit trees

5 Alisols 13,846.4 Forest, tea plants, fruit trees

Total 46,117.2

Source: Statistic Department, Dong Hy District, 2005

4.1.2 Economic - social characteristics

- Population: Dong Hy District has an average population level compared to other districts of Thai Nguyen Province According to statistic data in 2005, Dong Hy district's population was 124,196 people; the population density was 270 people/km2 The people mainly lived in rural areas (more than 86%); the others lived in urban areas (14%)

- The infrastructure was in average level Traffic was quite convenient; the national electricity has nearly reached to all the communes of the District

Irrigation: there are Cau River, Linh Nham stream and Dac waterfall in the District, with a total length is 94 km This is the main water source for production

4.2 Results from monitoring some characteristics of the cropping system in Dong Hy District

4.2.1 Assessing characteristics of cropping systems on rice-based lowland

4.2.1.1 Annual crops’ structure and area

Annual crops’ structure and area of Dong Hy in years 2000 - 2005 showed that there was four major crop groups, including Food grain crops; starch root plants; annual industrial crops and all kinds of vegetables, beans

Table 4.2: Annual crops’ structure and area

(Statistics Department, Thai Nguyen 2005)

4.2.1.2 Economic efficiency of crop rotation systems on rice-based lowland

Crop yields in some rotational treatments were shown in Table 4.3

Table 4.3: Crop yields on the land with tree crops per year

Yield x ± Sx (tons/ha) Rotational treatment n

Crop 1 Crop 2 Crop 3

1 Spring peanut– Rice – corn 32 1.03 ± 0.26 4.53 ± 0.32 3.49 ± 0.53

2 Soybean – Rice – corn 30 1.14 ± 0.15 4.39 ± 0.35 3.24 ± 0.47

3 Sweet potato – Rice – corn 28 3.99 ± 0.48 4.02 ± 0.38 3.13 ± 0.39

(Source: 2005 survey data)

The table 4.10 showed that: the yield of winter corn in the land with three crops were from 3.13 – 3.49 tons/ha; the yields of summer rice were from 4.02 – 4.53 tons/ha

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Table 4.4: Economic efficiency comparison among the rotation

formulas on 3-crop lowland in Dong Hy District

Total Incomes

Investment cost Interest Rotational Treatment

Million VND /ha

1 Spring peanut– Rice – corn 39.38 13.12 26.26

2 Soybean – Rice – corn 41.92 13.95 27.97

3 Sweet potato – Rice – corn 36.59 11.19 25.40

(The average price in 2005) Economic efficiency of the rotational Treatments showed that

the treatments of Soybean – Rice – corn and Spring peanut– Rice – corn gave higher incomes than the treatment of Sweet potato – Rice – corn and gained the interest from 26.26 – 27.97 million VND/ha/year These treatment also were chosen for continuous study

Table 4.5: Rice yields on the 2-crop lowland in some topography

Rice yield x ± Sx (tons/ha) Topography Area (ha) n

Spring crop Summer crop

2 Average 600 38 4.82 ± 0.52 4.53 ± 0.61

(Survey data 2005)

Table 4.6: economic efficiency Comparison of 2-rice crop treatment

in some land topography in Dong Hy District

Topography Total

incomes

Investment cost Interest Million VND /ha

9 About the economic efficiency on 2-rice crop lowland, the incomes were from 21.96 to 25.82 million VND / ha / year The average land topography with 2-rice crops had the highest income

4.2.1.3 Effects of land use systems to soil fertility

Survey data collected on five indicators of soil in three different land use systems in Dong Hy District showed that pHKCL of soil ranged from 4.2

to 6.7, increasing gradually from the first crop to third crop; the content of organic matter in surface soil increased from 0.92% - 2.97%

Table 4.7: Some indicators of soil on fields with 3-crop cultivated per year

10 beans, sweet potatoes in spring crops; cassava and sesame in periods of long-term drought

Table 4.10: Survey results on some crop characteristics on one-rice

Economic efficiency (%) Crops

High Average Low High Average Low High Average Low

Rice 60.0 26.7 13.3 40.0 36.7 23.3 50.0 26.7 23.3 Corn 56.7 20.0 23.3 26.7 46.7 26.6 33.3 50.0 16.7 Beans 73.4 23.3 3.3 63.4 30.0 6.6 73.4 20.0 6.6 Sweet

potato 60.0 23.4 16.6 73.4 16.6 10.0 30.0 50.0 20.0 Cassava 66.7 23.3 10.0 70.0 26.7 3.3 23.4 63.3 13.3

(Survey data, 2005)

In two-rice crop lowland, farmers said that some plants which were cultivated were rice plants (in spring and summer crops), corn plants (mainly in winter crops – currently has considered as an important plants in supplying feed for livestocks), peanuts and soybeans (mainly

in spring crops),

Table 4.11: Assessment results of farmers on some plant

characteristics on two-rice crop lowland

Unit: percentage / questionnaires

Adaptability to land, weather (%)

Resistance ability to pest – diseases and unfavorableness

Economic efficiency (%) Crops

High Average Low High Average Low High Average Low

Rice 90.0 6.7 3.3 40.0 51.7 8.3 51.7 30.0 18.3 Corn 46.7 40.0 13.3 68.4 28.3 3.3 58.4 36.6 5.0 Peanut 36.7 51.6 11.7 80.0 13.4 6.6 78.3 18.4 3.3 Soybean 35.0 48.4 16.6 43.4 53.3 3.3 56.7 30.0 13.3 Beans 13.4 56.6 30.0 38.4 56.7 5.0 23.4 58.3 18.3 Sweet potato 33.4 58.3 8.3 31.7 70.0 5.0 18.4 70.0 11.6 Vegetables 25.0 63.4 11.6 18.4 61.6 20.0 28.4 66.6 5.0

(Survey data, 2005)

Table 4.12: Area and productivity of perennial crops in years of 2001

Yield (tons/ha)

Area (ha)

Ratio (%)

Yield (tons/ha)

(Source: Statistics Department, Thai Nguyen 2005)

From the changes in area and yield of tea trees and fruit trees on hilly land in Dong Hy, we conducted a survey on some characteristics

of these crops The obtained results were showed in Table 4.13

Table 4.13: Survey results on crop characteristics on hilly land in

Dong Hy district Unit: percentage / questionnaires

Adaptability and farmer’s

acceptable level (%)

Labour attractiveness ability (%) Economic efficiency (%) Crops

Tea 73.4 23.3 3.3 83.4 13.3 3.3 86.7 10.0 3.3 Litchi 40.0 50.0 10.0 23.4 40.0 36.6 30.0 60.0 10.0 Longan 46.7 36.6 16.7 26.7 43.3 30.0 33.4 40.0 26.6 Mango 26.7 60.0 13.3 16.7 43.3 40.0 36.7 40.0 23.3 Jackfruit 56.7 40.0 3.3 20.0 50.0 20.0 50.0 26.7 23.3

(Survey data, 2005)

4.3 Research results on improving the cropping systems

4.3.1 The trial study on plant variety selection on rice-based lowland

4.3.1.1 Results of rive variety selection on two-rice crop lowland

12 The rice varieties was being tested continuously in the fields of farmers

in three spring crops (2004, 2005, and 2006) The yield results were shown

in Table 4.14

Table 4.14: Yield of some studied rice varieties in spring crops years

2004, 2005, 2006

Yields (tons/ha) Varieties

2004 2005 2006 Average

Compared

to control (%)

* Variety selection in summer crop

The experiment was continuously conducted in summer crops in years 2004, 2005 and 2006; the results showed that four studied varieties got higher yield than the control by 29.2 to 46.5% In four varieties, there were two varieties that were selected were HYT100 and LVN20 - higher yield than the control by 37.8 to 46.5%

Table 4.15: Yield of some studied rice varieties in summer crops years

2004, 2005, 2006

Yields (tons/ha) Varieties

2004 2005 2006 Average

Compared to control (%)

Khang dan 5.53 4.62 4.81 4.98 100