Sumary of agricultural doctoral thesis studying on potassium nutrient balance for sugarcane in lam son sugarcane belt thanh hoa province

The research "Study of potassium balance for sugarcane in sugarcane area Lam Son in Thanh Hoa province" was conducted to: - evaluate the capacity of gray ferralit soils to sypply K suppl

MINISTRY OF EDUCATION AND TRAINING – MINISTRY OF AGRICULTURE AND RURAL DEVELOPMENT

VIETNAM ACADEMY OF AGRICULTURAL SCIENCES

PHAM THI THANH HUONG

STUDYING ON POTASSIUM NUTRIENT BALANCE FOR SUGARCANE IN LAM SON

SUGARCANE BELT THANH HOA PROVINCE

Major: Soil Science Code : 62.62.01.03

SUMARY O F AGRI CULT URAL DOCT ORA L THESIS

HA NOI, 2014

STUDIES RELATED TO THE RESEARCH

1 Pham Thi Thanh Huong, Đang The Giang (2009), “The sugarcane production at Lam Son

sugarcane belt Thanh Hoa province” Journal of soil sciences No.31 in 2009

2 Pham Thi Thanh Huong, Tran Cong Hanh, Nguyen Van Bo, (2013), “Potassium supply

capacity of grey soil (Haplic Ferralic Acrisols) to sugarcane in Lam Son sugarcane area Thanh Hoa

Province", Journal of Agriculture and Rural Development, No 20 in 2013

3 Pham Thi Thanh Huong, Tran Cong Hanh, Nguyen Van Bo (2013), “Efficiencies of

potassium application to sugarcane on gray soil (Haplic Ferralic Acrisols) in Lam Son sugarcane

area Thanh Hoa Province", Journal of Agriculture and Rural Development, No 21 in 2013

Thesis completed at:

VIETNAM ACADEMY OF AGRICULTURAL SCIENCE

2 Dr Tran Cong Hanh

Examinant 1:

Examinant 2:

Examinant 3:

The thesis was defended at the council of institute level:

Vietnam Academy of Agricultural science

At h date month year

Thesis can be found at library:

National library of Vietnam Library of Vietnam Academy of Agricultural science

INTRODUCTION

1 Rationale of the research

Sugarcane (Saccharum officinarum L.) originated from tropical region, has a high yield

potential, a wide adaptation range, and has been identified as a crop that has competitive advantages

over the drought condition of upland region

Among factors that contribute to increases in yield and quality of sugarcane, macro nutrients like

nitrogen (N), phosphorus (P), potassium (K) play an important role K is an element that sugarcane

absorbs the most and has an active influence to most physiological and biochemical processes occur in

cells especially in the synthesis, transport and sugar accumulation processes However, the level of

response to K fertilizer of sugarcane has large fluctuations depending on climate, soil, sugarcane

varieties, farming techniques and the interactive relationship between K with other nutrients

Unlike N and P, sugarcane has a lavish spending phenomenon on K On the other hand, K

deficiency symptoms are often not immediately evident in case of K loss by erosion, leaching or

fixation The needs to supply K are often only apparent after a few no-fertilized crops or the K supply is

not ecnough to compensate the K loss by crop harvesting, as K reserves in the soil are reduced to the

"impoverishment" level Thus, excess or deficiency of fertilizer or fertilizer K will result in a decrease

in the production efficiency of sugarcane

Sugarcane area Lam Son (Thanh Hoa province) is planned to have a total area of sugarcane 54

314 ha by 2020, located in 10 districts in the west midland and moutainous regions of the province

Yearly sugarcane-planted area (in the period 2005-2013) on average is 15,000 ha, of which over 70%

are grown in gray ferralit soil in hilly regions In tropical climate zones, mineralization, erosion, and

leaching occur drastically, together with a low organic matter content as well as low K-rich clay

minerals ratio and composition in the soils are the reasons for not only poor K soils but also low K

holding capcity As a result, K fertilizer efficiency is also affected

The research "Study of potassium balance for sugarcane in sugarcane area Lam Son in Thanh Hoa

province" was conducted to:

- evaluate the capacity of gray ferralit soils to sypply K supply for sugarcane;

- evaluate the relationship between the amount of K fertilizers applied and yields and quality of

sugarcane;

- investigate the amount of nutrient inputs and outputs in K balance in current sugarcane

productions

- assess amounts of K reserves in the soil and the causes for the K imbalance

We thereby proposed solutions for a sustainable management of K and to enhance production

efficiency and maintain reserve levels K of land for sustainable development of sugarcane production

on hilly lands

2 Aims and requirements

2.1 Aims of the research

Setting an equation to determine the amount of K fertilizers apllied for sugarcane based on a

nutrient balance, creating background knowledges for a sustainable management of K for each specific

area, contributing to improve productivity, quality and efficiency of cane production in Lam Son hilly

regions of Thanh Hoa

2.2 Requirements

- Evaluate the basic conditions of Lam Son sugarcane region in relationship with K balance for

sugarcane

- Determine the capacity to provide K for sugarcane of gray soil ferralit and amount of K inputs and

outputs in K balance for sugarcane

- Determine the relationship between the amount of K fertilizers appiled to yield and quality of

sugar cane, sugar yield and amount of K removed at harvesting

- Determine a K balance at different levels of K fertilization and in current sugarcane production

- Set up an equation determining the amount of K fertilizer for sugarcane through nutrient balance

- Determine the efficiency of an empirical model for a sustainable management of K for

sugarcane based on the nutrient balance

3 Scope of the research

Research on K nutrient balance for the sugarcane area Lam Son, Thanh Hoa was done at the small

scale (size fields) on typical gray ferralit (Hapli Ferralic Acrisols: ACfa - h) using the sugarcane variety

MY 55 - 14 and the cultivation techniques that are commonly used in the area

4 The scientific and practical significance

The results of the research thesis contribute additional scientific data to serve nutriently balanced

assessment and determine the amount of K fertilizer for sugarcane through appropriate nutrient balance

At the same time, the results will be basic bckgrounds to recommend a sustainable management strategy

of K for each specialist region in the production of sugarcane in Lamson hill in particular, the hill cane

area in Thanh Hoa province and in Vietnam

5 New findings of the research

The research has identified the K supplying capacity of soil; amount and the relationship between

the nutrient inputs and outputs in K balance An equation to determine the proper amount of K fertilizer

needed for sugarcane through nutrient balance was set up and a model for sustainable management of K

nutrition for sugarcane on the typical grey ferralit soil in hilly regions at Lam Son, Thanh Hoa was

established to achieve high yields, high cane quality and production efficiency, at the same time to

maintain soil K reserves

Chapter 1 LITERATURE REVIEW

Nutrient balance in cropping systems is the determination of the amount of all nutrients input,

output per unit area of arable land in the specific production conditions, thereby assessing the situation

nutrient reserves in the soil and the degree of land degradation The results from studies on nutrient

balance are an important basis to build and implement strategies for sustainable management of

nutrients, to meet the demands of increasing productivity, quality and efficiency of crop production,

while improve, maintain and enhance soil fertility

In the world and in Vietnam in particular, there has been many researches on plant nutrient balance

Depending on the spatial scopes and objectives of a research, nutrient balance study is done at different

scales: large scale ( global , regional or national ) with the main objective is to quantify the input and

output sources for the three macro nutrients N, P, K; medium scale (districts, ecological zones) in order to

create a basis for policy making, production and business planing in the region; small scale (fields, farms)

primarily serve the nutrient management of site-specific crops Accordingly, the content, methodology,

accuracy, relicapacity of the quantitative measurements of nutrient inputs and outputs as well as the

feasibility of the study results on nutrient balance are different between the scales of studies (FAO, 1998;

Roy R N et al, 2003; Sheldrick et al, With C et al, 2009; Buresh et al , 2010 )

For sugarcane, K plays an important role in the physiological and biochemical activities occuring

in cells, especially sugar metabolism between hexoza and saccaroza Kali participates in catalytic

activity of the invertaza enzyme in the sugar synthesis and in protein synthesis and transport leading to

increasing soluble solids (Brix), relatively sugar levels (Pol), the level of purity of pressed sugar cane

juice (AP), reducing the amount of reducing sugars (RS), increase of commercial sugar (CCS) In soil,

K exists in the form of structural K, non-exchangable K, exchangable K and K in solution There are

equilibrium and kinetic reactions between these four forms of soil K with the two proccesses, fixation

and release The K kinetic reactions in soil and K fertilizer use efficiency of sugarcane have a large

fluctuation, are site-specific and depend on climatic conditions, soils, sugarcane varieties, farming

techniques and interactive relationship with other nutrients (Van Dillewijn , 1952 ; Gururaj Hunsigi ,

2011 ; Alex Alexander Gerchell , 1973 )

Chapter 2 MATERIALS, CONTENTS AND METHODOLOGY 2.1 The research materials

The research were conducted on typical gray ferralit soil; MY 55-14 was used as a main

sugarcane variety (accounting for over 60% of the sugarcane varieties throughout the region); NPK

fertilizer specialized for sugarcane in Lam Son (NPK - HC 6.4 - 3.2 to 6.6 - HC 9.5); commonly used

mineral fertilizers on the market (46% N urea, superphosphate - SSP 16% P2O5, 60% K2O potassium

chloride) and sugarcane residues after harvesting

2.2 The research contents

To achieve the aims and requirements of the study, we focused on the following:

1) Basic conditions in Lam Son region of Thanh Hoa in relation to balance K for sugarcane

2) The K supplying capacity of the soil; the amount of K provided by rain water; the amount of K

loss by erosion and leaching

3) The relationship between the amount of K fertilizer to yield and quality of sugar cane, sugar

yield and qualitative K loss per harvested product

4) K nutrient balance for sugarcane at different K fertilizer application levels and different

sugarcane production conditions

5) Set up equations determining the optimum amount of K fertilizer for sugarcane based on

nutrient balance

6) The efficiency of a sustainable K management model for sugarcane based on the nutrient balance

2.3 Methodology

2.3.1 The research process

The research was done in the period from 1/2010 to 2/2013 in three steps: (1) investigating and

evaluating the basic situation in Lam Son region of Thanh Hoa; (2) experiments set up according to

research content; (3) empirical model building for a sustainable nutrient management of K for

sugarcane on the basic results of the nutrient balance study

2.3.2 Method of secondary data collection

Investigate, collect resources, statistical data, maps, technical processes, research findings related

to climatic conditions, land of Lamson area

2.3.3 Method of data collection

Investigation and collection of information related to the production, sugarcane cultivation techniques

in the region through the household survey using pre-printed questionnaires Number of investigated

households were 200 households in 4 major sugarcane growing districts (Tho Xuan, Ngoc Lac, Lang

Chanh, Thuong Xuan), 50 households per district Sumarizing and analyzing the obtained data by the

descriptive statistic method by group of criteria

2.3.4 Experimental layout method in jars

The experiment was conducted in jars following a batch method (no K fertilizer) The jars were put

naturally outdoors to investigate the K supplying capacity of the typical gray ferralit (Hapli Ferralic

Acrisols) in irrigated condition and with different N, P fertilizers The experiment consisted of 4

treatments and was set up following a RCB layout style with three replicates: (1) No irrigation - no

fertilizers N, P; (2) No irrigation - fertilizer N, P; (3) With irrigation - no fertilizer N, P; (4) With

irrigation - fertilizers N, P

The soils used in this experiment was collected from a ratoon farm at depth from 0-40cm Each jar

was filled with 30 kg soil, three cuttings per jar with 1 bud per cutting Fertilizers N, P were applied at rates

of 200 N + 100 P2O5 (kg/ha) (3.32 g urea / jar; 4.46 g superphosphate / jar) for fertilized treatments

(treatments 2, 4) Regular checking and irigation were done (using distilled water to avoid K contamination)

to maintain soil moisture around 70-80 % of field capacity in the irrigated treatments ( 1, 3)

to the growth indicators, elements biomass and biomass of all parts of sugarcane (above and

below ground) when the plants stop growing

Determination of dry matter content, content of K2O, K2O accumulated in parts of sugarcane

Then the amount of K2O the soil is capable of supplying was calculated

Time and location of study: planting date 10/2/2010, harvest date 15/9/2010 The experiment was

located at Hong Duc University

2.3.5 The method of field trial layout

A field experiment was established to study the effect of the amount of K fertilizer on growth,

yield and quality of sugar cane, sugar yield, the amount of K loss by harvested products and the

relationship among them

The experiment included 6 treatments, corresponding to 6 rates of K fertilizer levels (0, 50, 100,

150, 200, 250 and 300 kg K2O/ha) on the basic fertilization 200 N + 100 P2O5 Area of the experiment

was 90 m2 (with 5 sugarcane rows, 15 m long each, 1.20 m spacing), RCB -style layout, 3 replicates

Cultivation techniques: using cuttings with 2 buds (8 -month-old cane) The amount of cuttings

planted were 32,000 cuttings / ha (4 cuttings/m long) Basal fertilizing (when planting or when treating

the canes for the next seasons) 100 % P + 30 % N+ 30 % K Apply additional fertilizer at tillering 30

%N + 30 % K Apply additional fertilizer at cane elongation 40 % N + 40 % K (the amount of fertilizer

followed to each treatment) The cultivation techniques were done similarly using the currently used

techniques in the region

Keeping records on indicators of growth, yield and quality of sugar cane, sugar yield, cane foliage

mass, dry matter content, K2O content in cane stalks and leaves at harvesting

Determining the technically maximum amount of K, optimum economics for cane yield, sugar yield;

reciprocal internal efficiency of K (RIEK), harvest index of K (HIK); K –recovery efficiency of K (REK)

The experiment was repeated in 1 sugarcane cycle (1 planting cane, 2 ratoons): 11/1/2010

planting date, harvest date 01/29/2011 (planting cane); 02/10/2012 (ratoon 1); 02/25/2013 (ratoon 2) It

was located in Tho Xuan – Sao Vang, Lam Tho commune, Tho Xuan District

2.3.6 Method of determining the amount of K due to rainwater

Keeping records on monthly precipitation over the year by Pluviometer in the Hydrometeorology

station - Bai Thuong Thuong Xuan district, Thanh Hoa province Rainwater samples were analyzed at

outdoor vessels in field trial areas Water samples (sample mixture of rain in the month) were taken on

the last day of the month The amount of K provided by rainwater (kg K2O /ha/year) was determined by

rainfall and K2O content in the rainwater in months

Study period: 3 years (2010, 2011, 2012)

2.3.7 Method of determining the amount of K loss by erosion

The plots to measure erosion were followed the same layout to field trial plots, corresponding to

the amount of K fertilizer (0-300 kg K2O /ha) Area of the erosion measure plot was 90 m2 (6 x 15 m) 5

rows of sugarcane were planted, the distance between rows was 1.2 m Containers to collect washed

soil were placed at the end of the plot (size: 1.5 m length x 1.0 m width x 1.0 m height) Nylon cloths

were put at the bottom of the containers After raining, the amount of water, soil suspension and soil

sediment were sampled and analyzed to determine K2O content

The amount of K loss by erosion (kg K2O /ha/year) is the total amount of K2O loss due to runoff

water, washed out soil suspension and sediments in all months of the year

Time and location of study: 3 years (2010, 2011, 2012) at Raw Materials Station Tho Xuan – Sao

Vang, Lam Tho commune, Tho Xuan District

2.3.8 Method of determining the amount of K loss by leaching

Several Lizimet to measure leaching was set according to the field trial plots, corresponding to the

amount of K fertilizer (0-300 kg K2O/ha) Leached water were collected using funnels with size 40 x 40

cm, placed at a depth 40cm (from the surface, within 80% of rhizospheres) After raining, leached water

was taken and measured for vollume, leached soilspension soil Leached soils were sampled and

analyzed for K content

The amount of K loss by leaching (kg K2O/ha/year) is the total amount of K2O loss due to runoff

water, leached suspension of all the months of the year

Time and location of study: 3 years (2010, 2011, 2012), at Tho Xuan raw material station – Sao

Van, Lam Tho commune, Tho Xuan District

2.3.9 Methods of empirical model building for a sustainable nutrient management of K for

sugarcane on the basic results of the nutrient balance

The results of studies on nutrient balance were used to construct an empirical model for

sustainable K management for sugarcane hilly areas of Lamson with 2 treatments:

Control treatment (5 ha): fertilizer application according to the currently common technique in the

area: 2 tons / ha NPK Lamson No cane foliage return

Investigated treament (5 ha): fertilizer application based on the research results of nutrient

balance: 2 tons / ha NPK Lamson; 100 % cane foliage incorporated in soils while adding N, P mineral

fertilizers at dose of 200 N, 100 P2O5 K fertilizer was determined depending on target yields, the inputs

and outputs of K balance and requirements of K reserve levels in soils

The model was carried out on Hapli Ferralic Acrisols, previous crop was ratoon cane, and then

was prepared for a new planting Other farming techniques are implemented the same for all treaments

following to the techniques that were commonly used in the area

Record on growth indicators, yield and quality of sugar cane, sugar yield, and sugarcane

production efficiency, soil properties before and after the construction of the model

Time and location: 3/12/2011 planing date, harvesting date 12/28/2012 At Tho Xuan raw

material station - Sao Vang, Lam Tho commune, Tho Xuan District

2.3.10 Methods of recording and identifying research targets for sugarcane

Record on growth indicators, components of yield and yield of sugarcane by means of weighing,

measuring, and counting directly on the field

Keep checking on sugarcane pests (borers, aphids and white wooly aphids) according to the

National Technical Regulation on methods of plant pest detection (QCVN 0138/BNN- PTNT - 2010)

Determine the amount of K fertilizers that is technically maximum, economically optimum based

on the intereacitve equation between cane yields, sugar yield with the amount of K fertilizer proposed

by Lecompt Michel (1965)

Reciprocal internal efficiency of K (Riek %) was determined by the ratio between the amount of

K2O in cane stalks and leaves at harvesting compared to sugarcane yield

K harvest index (HIK) was determined through the ratio between the amount of K2O in cane stalks

in relation with the total amount K2O foliage and stalks

K – recovery efficiency of mineral fertilizer K (REK %) was determined by the ratio between the amount

of K2O in cane stalks and leaves in relation to the amount of fertilizer K2O provided by mineral fertilizers

Marinal benefit cost ratio (MBCR) was determined by the ratio between the value of the products

increased as compared to the cost of production increased from applying advanced techniques

2.3.11 Methods for soil, wáter, fertilizer, and crop analysis

Analysis of soil, water, fertilizers, and plant following to Vietnam standards was done at the

laboratory at Hong Duc University: the soil texture according toVietnam standards 8567 : 2010; pH

(KCl) TCVN 5979;2007; total organic matter TCVN 7376-2004; total N TCVN 7373: 2004; total P2O5

TCVN 7374: 2004; available P2O5 TCVN 5256: 2009; total K2O TCVN 7375: 2004; exchangable K2O

TCVN 8569: 2010; CEC TCVN 6646: 2000 Sewage sludge from sugar production: total N: TCVN

8557: 2010; effective P2O5 8563: 2010; effective K2O TCVN 8560: 2010; the amount of K in water

QCVN 39: 2011; K content in cane stalks and foliage TCN - 454: 2001

Analysis of cane juice quality criterias: soluble solids (Brix); apparen sucrose content (Pol); purity

of pressed sugar cane juice (AP); reducing sugar (RS); commercial cane sugar (CCS) according to the

methods currently applied in cane quality assurance department, Joint-Stock Company Sugar Lam Son

2.3.12 Methods of data processing

Equations and correlation graphs using EXCEL - 2007

Data analysis by IRIRSTAT 5.0 program

Chapter 3 RESEARCH RESULTS 3.1 Basic conditions of LamSon region in relation to K balance for sugarcane

3.1.1 Climate

Sugarcane area Lam Son - Thanh Hoa located in the west of Thanh Hoa Province, has a tropical

climate influenced by the dry and hot southwest monsoon, and dry and cold northeast monsoon The

total area of land under cane cultivation is planned to achieve 54.314 ha by 2020, distributed over 10

geographical districts, three sub-regions of terrain: plains sub-regions (Yen Dinh and Thieu Hoa, Trieu

Son), mid-land sub-regions (Cam Thuy district, Tho Xuan, Nhu Thanh, Nhu Xuan, Ngoc Lac),

mountainous sub-regions (Thuong Xuan district, Lang Chanh) Changing in climate over the months of

the year (average data for 20 years, from 1993 to 2012) are shown in Figure 3.1

Figure 3.1 Evolution of climatic factors in Lam Son - Thanh Hoa (1993 – 2012)

Figure 3.1 shows that climate in Lamson region has many advantages, which allow effectively

exploiting the potential yield and high sugar content of sugarcane: total temperature (annual average ) is

8.9600, temperature 23.80C, rainfall 1,659 mm / year, 84.8% air humidity, evaporation 897mm, 1,542

hours of sunlight (average 4.2 hours / day) In particular, from May to October it has high temperature,

air humidity, light and high rainfall (May to October) coincides with the period of strong growth of

sugarcane plants, zoos and create economic productivity From November to April next year,

temperature, air humidity, light and rainfall are low; temperature difference between day and night is

highly, which is favorable conditions for the accumulation of sugar cane as well as the process of

harvesting, transporting and processing of sugar

The main drawbacks of this climate condition are low temperature, air humidity and rainfall

during the planting season, and ratoon cane treatment (on December, January, Febuary), which cause

bad affects on germination and regeneration of sugarcane High precitaion on August, September,

October causes erosion and nutrient leaching

3.1.2 Sugarcane planted areas

Table 3.1 Area of planted cane in Lam Son region Thanh Hoa (Planning to 2020)

(ha)

% compare with whole

reigion

% compare with soil

group

1.2 Gray ferralit with stone and farm Acfe 7.839 14,4 16,3

(Source: Lam Son sugarcane Joint-Stock Company, 2008)

The results in Table 3.1 show that the total sugarcane area of region is 54.314 ha, including

ferralit (AC) accounted for 88.5% (48.064 ha), the remaining is alluvial soil (FL) 6,250 ha In ferralit

gray soil, area of typical gray ferralit (Acfa - h) is 40.225 ha, accounting for 83.7% and 74.1% of the

total gray ferralit soil areas and of the whole region, respectively

3.1.3 Sugarcane varieties

Table 3.2 The structure of the sugarcane varieties in Lam Son region of Thanh Hoa (season 2007-2008)

(ha)

Yeild

(tấn/ha)

% compare with total

% compare with group

Main varieties: QĐ 94 -119; ROC 10; ROC 23 1.684 67,89 10,8 58,2

(Source: Lam Son sugarcane Joint-Stock Company, 2009)

Table 3.2 shows that the varieties structure of whole region includes early maturity varieties

acounting for 14%, yield of 62.46 t / ha on average, the main varieties is QD 93-159 Mid-early

maturity group accounts for 18.6%, with an average yield of 66.61 t / ha, the main variety is QD

94-119, ROC 10 and ROC 23 Group of Mid-late maturity varieties accounts for 67.4%, with an average

yield of 59.38 t / ha, the main variety is MY 55-14 Planted area of MY 55-14 is 9,589 ha, yield 58.3

tons / ha, accounts for 91.3% and 61.6% of the Mid-late varieties and of the whole region, respectively,

and is identified as a key variety in the current structure of the Lamson region

3.1.4 Sugarcane areas and yield

Results from a survey of cane areas and cane yield of 200 farmers of four major sugarcane

growing districts in Lam Son area, categorized by land groups: hilly land, farm land (land has been

shifted from rice cultivation to sugarcane) and alluvial land (alluvial soil beyond dikes)presented in

Table 3.3 shows that: In the Lam Son region, sugarcane is grown mostly on hilly land, accounting for

77.1% of the total area, the average yield of 58.8 tons / ha In particular, newly planted cane yield of

61.9 tonnes / ha, higher than the ratoon canes of 10% Ratio between the area of newly planted

sugarcane and ratoon cane is 44.8% and 55.2% Compared to sugarcane grown on farmland and alluvia

land, planted sugarcane yields on hilly land is lower than 22.2% (16.8 tonnes / ha) and 26.1 (20.8 tons /

Newly cane

Ratooncane

Total Newly

cane

Ratoon cane

3.1.5 Fertilizers for sugarcane

Results of the farmer survey about fertilizer using situation for sugarcane in the Lam Son area are

shown in Table 3.4 and Table 3.5

Table 3.4 Situation of fertilizer using for sugarcane in the Lam Son region of Thanh Hoa

Table 3.5 The utilization of NPK Lam Son for sugarcane in Lam Son region of Thanh Hoa

No Land for planting

sugarcane

Survey area (ha) Area classification according to

fertilizing level (ha)

Newly cane Ratoon

Note:level 1: 1500 - < 2000; level 2: 2000 -< 2500; level 3: 2500 - < 3000

- For organic fertilizers: there are 43.5 ha out of 571.4 ha of the survey (7.6%) are organic

fertilizers Proportion of cane planted area on hills is used only organic fertilizers 3.8%; farmland

19.2%, 24.4% alluvia land compared to the area covered by each group

- For Mineral: 571.4 ha of investigation has 542.3 (94.9%) of cane area that is entirely used NPK

Lamson (NPK - HC 6.4 - 3.2 to 6,6 HC 9.5) by the Fertilizer Corporation Lamson production and invest

for farmers through sugarcane purchase contracts sugarcane; 3.1% NPK fertilizers by the Lam Son and

additional inorganic N In addition, a small proportion of the area ( 2 % ) with inorganic fertilizer or

other NPK fertilizers on the market The amount of fertilizer NPK Lamson average 2000-2200 kg / ha

Organic materials for NPK fertilizer production Lam Son is sugar refinery sludge

3.1.6 Irrigation

Forms for sugarcane irigation is applying in Lam Son area include: (1) craft irigation (mainly for

sugarcane growing area in the garden, garden hills, use of the pressure pump capacity small irrigational

system with pipes directly into the trench cane; (2) furrow irrigation (applied to the area of land planted

in sugar cane fields, flat terrain, there are proactive system of canals for irrigation, drainage) and (3 )

drip - drip irrigation (under construction project model test irrigate sugarcane hills of Israeli technology,

size of 1,000 ha, mainly in Tho Xuan district)

Table 3.6 The situation of sugarcan irrigation in the Lam Son region of Thanh Hoa

Root cane Total Level 1 Level 2 Level 3

Note: Level 1: irrigation 1 time; Level 2: irrigation 2 - 3 times; Level 3: usually irrigation

The survey results for situation of sugarcane irrigation presented in Table 3.6 shows that except

for area in which constructs a trial model for sugarcane drip irrigation; areas were used both two forms

including scraft and furrow irrigation, which are limited In total 571.4 ha survey, only 32.2 ha (5.6%)

of sugarcane is irrigated from one or more times In group of hilly land, only 6.2% of irrigated area

under irrigation shaped craft, irigation one times when planting Thus, the production of sugarcane in

the hills Lamson primarily based on rainfed

3.1.7 Using the top and foliage of sugarcane after harvesting

The household survey on the using of sugarcane foliage showed management of sugarcane foliage

post-harvest have not been given due attention by growers In the period, they burned or buried and

cornered, returned to the land However, now part of poor management and part of high labor cost of

sugarcane, growers applied forms a part of the rent paid workers harvest sugar cane by sugar cane

leaves them taken tops carry on Thus, almost the entire sugarcane tops were removed from the field

immediately after the end of sugar cane harvesting

3.2 The capacity of K Supply of soil; amount of K by rainwater supply; amount of K loss by

erosion and leaching

3.2.1 The capacity of K supply of soil

3.2.1.1 Experimental soil properties

The results of analysis of soil agrochemical targets of typical gray ferralit in Lam Son hilly region,

used in experiment about the K supply capacity of soil for cane showed that soils with light mechanical

composition 1,05 g/cm3; acidic soil (pH 4.64); poor organic matter content (1.22% OM); N, P, K

compound are poor level (0.11% N, P2O5 0,05% K2O: 0.08%); phosphorus, exchange potassium are

poor (P2O5 4,15 mg/100 g soil, K2O 5,75 mg/100 g soil exchange); low cation exchange capacity (CEC

11,31 mg/100 g soil)

3.2.1.2 The situation of sugarcane growth

Results of monitoring the sugarcane growing criteria presented in Table 3.7 show that:

In irrigated condition, the growing indicators of sugarcane increased compared with no irrigation

in both cases, no fertilizing and N, P fertilizing As N, P fertilizing, growing indicators increased

compared with no N, P fertilizin in both no irigation and irigation cases, but the increasing level was

lower than in irrigated conditions