Study on Site Specific Nutrient Management (SSNM) for sugarcane (Saccharum officinarum L.) in the Mekong Delta (tóm tắt + toàn văn)

Nevertheless, it seems to be as a “qualitative method” by showing “lack or excess ofnutrients” situation but not providing fertilizer application rates tocrop; iii the Site-Specific Nutr

CHAPTER 1 INTRODUCTION1.1 Rationale

Sugarcane (Saccharum officinarum L.) is an annual crop

producing the most biomass then it requires a large amount ofnutrient inputs for its life cycle There are some methods to assessnutrient status of sugarcane in order to determine correct rate offertilizer, such as: (i) the Critical Nutrient Concentration (CNC)method has developed table of critical nutrient value and optimumrange of sugarcane leaf that is considered as standard for diagnosis;however, this way will be not precise when other nutrientconcentrations vary in tissue (Walworth and Sumner, 1986; Bailey,

1989, 1991 and 1993); (ii) the Diagnosis and RecommendationIntegrated System (DRIS) is suggested by using at least 3 ratios(normally 6 to 7) of nutrient concentration for diagnosis (Walworthand Sumner, 1987) The DRIS has been applied successfully toexplain result of leaf analysis in many kinds of crops, includingsugarcane (Beaufils and Sumner, 1976; Elwali and Gascho, 1984;

Beverly, 1991; Reis, 1999 and Hundal et al., 2005) Nevertheless, it

seems to be as a “qualitative method” by showing “lack or excess ofnutrients” situation but not providing fertilizer application rates tocrop; (iii) the Site-Specific Nutrient Management (SSNM) is based

on crop yield at a particular plot gained from two main sources: soilnutrient-supplying capacity and fertilizer application Determiningamount of fertilizer input will reduce nutrient loss on one hand andimprove fertilizer use efficiency on the other hand The SSNM

approach has been applied successfully for rice crop (Dobermann et

al., 2002) and hybrid corn over the world (Pasuquin et al., 2014), but

the application for sugarcane is limited

Besides the need to determine fertilizer rate, timing offertilization for increasing nutrient use efficiency by crops need to beconsidered as well Using leaf colour chart (LCC) to diagnosenitrogen content in crop was considered a simple, easy method andhave been popularly applied to rice However, the study of LCC insugarcane is still limited

1.2 Research objectives

(i) To assess current sugarcane farming and use of NPKfertilizer in alluvial (Soc Trang province) and acid sulfate soils (HauGiang province)

(ii) To determine effect of NPK fertilizer inputs to thenutrient uptake, growth and yield of sugarcanes under the two soiltypes

(iii) To determine recovery efficiency (RE) and agronomicefficiency (AE) in order to suggest NPK application for sugarcanecultivation

(iv) To evaluate LCC application for nitrogen timing onsugarcanes in two soils

1.3 Object and scope of research

 Object of research: NPK application for sugarcane

(Saccharum officinarum L.)

 Scopes of research:

 Field experiments were carried out on sugarcane farmers

in Cu Lao Dung district of Soc Trang province and Long

My district of Hau Giang province

 Research period: January 2011 to January 2013

 Omission plot experiments were implemented to evaluatethe omission of N, P, K nutrients

 Study on growth and N, P, K uptake of sugarcaneaims at improving scientific knowledge having adatabase for calculating “soil nutrient-supplyingcapacity” and fertilizers rate to achieve “target yield”based on SSNM principle

1.4 Limitations of research

 About fertilizer: only study N, P, K nutrients by inorganic

fertilizer for sugarcane; the sugarcane pressmud wasintroduced as “improved treatment” according to the SSNMrecommendation

 About location and experimental design: to minimize

variation in statistical analysis, the experiments were

designed as randomized completely block with 4 replications

at two soil conditions The research did not apply “on-farmresearch” in several locations as recommended by SSNM

 About soils: limited in two soil types in the Mekong delta

such as: (i) alluvial soil (Dystric Fluvisols) in Cu Lao Soc Trang and acid sulfate soil (Thionic Gleysols) in Long

Principally, calculation of fertilizer rates based on the SSNMmethod comes from nutrient balance which is manifested by cropyield According to this approach, there are two sources of nutrient,such as soils and fertilizers to create optimum yield of crop In thisresearch, NPK fertilizer rates have been extrapolated based on thedifference between sugarcane nutrient requirements and the soils nutrient supplying capacity In addition, the database on growth andnutrient uptake of sugarcane in Mekong delta soils has beenconstructed in this study, which would be useful to assess cropgrowth and nutrient balance on the sugarcane soils

+ Practical significance

The results can be applied for sugarcane farming in theMekong delta By simple and easy practice, the study results help toreduce production costs then increase price competition in theregion

In the coming crops, determination of NPK fertilizers rates can

be updated by extension workers or farmers through “omission plottechnique” at some representative sugarcane fields in the Mekongdelta

The result from LCC application for sugarcane is importantreference to help farmers estimate when to test leaf color and applynitrogen exactly as crop need in the two soil types

1.6 Innovativeness

- SSNM and LCC have been applied first time in the Mekongdelta, the results showed that the method is helpful for determiningNPK fertilizers rates and nitrogen application timing for sugarcane

in the Mekong delta

- Soil-supplying capacity of N, P, K for sugarcane have beendetermined Percent ratio of N, P, K from soils to total croprequirement in order to achieve target yield were recorded as32.6%N, 46.2%P2O5, 56.1%K2O in Cu Lao Dung and 32.9%N,59.6% P2O5 và 63.4% K2O in Long My

- At the same NPK fertilizer application rates, response tosugarcane yield in Long My was about 89% compared to Cu LaoDung Using “improved treatment” by using sugarcane pressmud at

10 tons/ha made sugarcane yield increased at both study sites

- Farmers in the research areas almost have not applied K forsugarcane The application of potassium made Brix degree ofsugarcane increased in both Cu Lao Dung and Long My

CHAPTER 2 LITERATURE REVIEW2.1 Sugarcane farming in Soc Trang and Hau Giang

Soc Trang and Hau Giang are located in the lower Mekongdelta According to Hua Thanh Xuan (2008), Soc Trang is one of thelargest sugarcane producers in the Mekong delta in term of plantedareas Most sugarcanes are planted in the island of Cu Lao Dung andLong Phu formed by alluvial deposition Currently sugarcane yield

in Cu Lao Dung is higher than average of the world Hau Giang hasthe highest ranks of sugarcane planted area as well as production inthe Mekong delta, annual planted area of sugarcane in Hau Giang issituated after rice with 13,063 ha and yield of 82,60 tons per ha(Statistical Year Book, 2010)

2.2 Botanical characteristics, growth and nutrient requirement

2.2.1 Botanical characteristics of sugarcane

2.2.2 Periods of growth

2.2.3 Nutrient requirement

Sugarcane is a long crop that belongs to C4 pathway creatingbig amount of production and needs high humidity, nutrients,sunshine to optimize its productivity It is estimated that one ton ofsugarcane production requires 0.56-1.20 kgN, 0.38-0.82 kgP2O5,1.00-2.50 kgK2O, 0.25-0.60 kgCa, 0.20-0.35 kgMg, 0.02-0.20 kgNaand 2.0-2.7 kgS together with micronutrients (Zender, 1990) Onaverage, one sugarcane crop takes away 208, 53, 280, 30, 3.4, 1.2and 0.2 kg N, P, K, S, Fe, Mn and Cu respectively from soils toachieve yield of 100 tons per ha (Singh and Yadav, 1996) Nutrientrequirements are different by soil conditions from place to place

(Natesan et al., 2007)

2.2.4 Quality parameters of sugarcane

2.3 Characteristics of K88-92 sugarcane variety

2.4 Fertilizer

2.4.1 Fertilizer recommendation for sugarcane

Fertilizer is the most important factor of nutrient supply forsugarcane, accounting for about 50% of yield increase Fertilizerrecommendation is higher in the tropical than sub-tropical regions

Saini et al (2006) recommended fertilizer for sugarcane production

as 400 kgN, 170 kgP and 180-190 kgK depending on time and soilconditions

2.4.2 Role of N, P and K

2.4.2.1 Nitrogen (N)

Nitrogen is a key nutrient affecting yield and quality ofsugarcane Nitrogen increases sugarcane yield through increases ofshoots, stalk height, diameter of internode (Abayomi, 1987).Seasonal nitrogen use efficiency is estimated at 0.841 tons sugarcane

kg-1N (Chattopadhyay et al., 2004) Quantity of nitrogen fertilizer in

the world ranges from 50 to 300 kgN ha-1 and 1 kg of nitrogen cancreate 0,5-1,2 tons ha-1 (Hunsigi, 1993)

2.4.2.2 Phosphorous (P 2 O 5 )

Phosphorus is an essential element to promote creation of rootsand increase of branches but its availability depends on local soilsand fertilizer application Increase of sugarcane yield afterphosphorus use is results of sucker development, biomass, anddensity At optimum phosphorous level, sugar concentration and

juice purity are also better (Elamin et al., 2007)

2.4.2.3 Potassium (K 2 O)

Potassium nutrient plays important roles in plant growth andmetabolism Potassium fertilizer application often increases sugarconcentration and juice return, especially the case of late harvest(Hunsigi, 2011)

2.5 Site-specific Nutrient Management approach

2.5.1 Definition

Site-specific nutrient management (SSNM) is an approach tofeeding crop with nutrients as and when needed The application andmanagement of nutrients are dynamically adjusted to crop needs of thelocation and season This method helps farmers adjust fertilizers toaddress lack of nutrients between required nutrients to maximize cropyield and nutrient reserve of the soils, organic materials, and irrigationwater The SSNM approach aims to increase farmers profit throughhigher yield, application of nutrients (mainly N, P and K) locally andseasonally, and optimal use of existing indigenous nutrient source such

as crop residues and organic fertilizers

2.5.2 Principles of SSNM

2.5.2.1 Principles of SSNM

According to Witt et al (2006) the SSNM provides maize

farmers knowledge to maximize fertilizer use and profit by balance

of required nutrients for high yield and indigenous nutrient supplyfrom soils, organic matters, crop residues, fertilizers and water Thisnew method is based on model of QUEFTS (Quantitative Evaluation

of the Fertility of Tropical Soils) developed in Africa for maize crop

(Janssen et al., 1990; Smaling và Janssen, 1993) and later for rice crop (Witt et al., 1999; Wang et al., 2001; Dobermann et al., 2002)

Technology of omission plots is useful to determine fertilizersrequired to meet target yield (Witt and Doberman, 2002) In thismethod N, P and K fertilizers are applied in sufficient amounts to

overcome deficiencies and ensure high yield The target yield can bedetermined from plots without limitation of NPK In other words, theSSNM is an approach based on the plant that utilizes the omissionplot technique to determine the yield obtained with only the soilreserves (omission plots) compared to the attainable yield obtainedwhen nutrients are not limiting

2.5.2.2 Steps of SSNM

Step 1: Determine target yield

Step 2: Estimate soil nutrient-supplying capacity

Step 3: Calculate N, P and K nutrient inputs to meet deficiencies between crop need and soil supply

2.5.2.3 Parameters in the SSNM

2.5.3 Agronomic efficiency of N, P and K

Agronomic efficiency of N, P or K (AEN, AEP or AEK) is theincrease in yield per unit of fertilizer N, P2O5 or K2O applied.Fertilizer recommendation based on yield response and agronomicefficiency is an alternative approach where soil testing is not usedregularly This sounds good approach compared to other supportivedecision making tools

2.5.4 Use of “improved treatment” in SSNM for sugarcane 2.5.5 Managemnet of nitrogen in sugarcane farming

2.5.5.1 Determine timing to apply nitrogen fertilizer

2.5.5.2 Manage nitrogen nutrient to balance supply and demand

2.5.5.3 Diagnose nitrogen by LCC technique

Leaf color is considered as an indicator to diagnoserequirement of nitrogen fertilizer for crop Previous studies showthat rice genotype and nitrogen management based on LCC affected

yield and yield components (Nagappa et al., 2002) Farmers believe

that when the leaves shift from dark to light green or yellow, cropneeds more nitrogen Similarly, LCC is applied for sugarcane too

(Gaddanakeri et al., 2007) Chandrashekara (2009) reported that

application of nitrogen at 50 and 60 kgN/ha with LCC=6, sugarcaneyields were high (150.5 and 151.7 tons/ha in the first crop and 123.8and 125.0 tons/ha in the second crop respectively), CCS, juice, Brix,Pol and fructose, total uptake of N, P, K less than traditionalpractice

2.6 Method of soil nutrient assessment in sugarcane

2.7 Nutrient interaction in sugarcane farming

CHAPTER 3 RESEARCH METHODOLOGY

This study consists of four main activities:

3.1 Activity 1: Survey on current sugarcane farming and fertilizer application in the research areas

Household survey was conducted in sugarcane areas of Cu LaoDung (Soc Trang) and Long My (Hau Giang) districts to understandfarming techniques such as veriety, quantity of fertilizer use, yield

3.2 Activity 2 Study effects of fertilizers on sugarcane growth, NPK uptake, and yield

This is a factorial experiment in a randomized complete blockdesign with 2 factors, 4 replications, and 8 treatments as NPK, NP,

NK, PK and NPK, NP, NK, PK in combination with sugarcanepressmud in Cu Lao Dung (Soc Trang) and Long My (Hau Giang) toassess effects of nutrient omission application (N, P, K) andsugarcane pressmud to growth, nutrient uptake, and yield ofsugarcane The experiment was carried out from January 2011 toJanuary 2012

3.3 Activity 3 Determine return efficiency (REX) and agronomic efficiency (AEX) to recommend fertilizer (N, P, K) application for sugarcane

There were two field experiments including sugarcanecultivated by planting (January 2011 to January 2012) and byratooning (January 2012 to December 2012) which is a practice ofgrowing a crop from the stubbles of previous crop at the same field

in Activity 2 to determine AE and RE for NPK fertilizerrecommendation of sugarcane at two research sites

3.4 Activity 4 Diagnose for nitrogen application timing by LCC technique

The experiment was randomized complete block design with 4replications and four treatments as PPB-1, PPB-2, PPB-3 and PPB-4

in Cu Lao Dung-Soc Trang and Long My-Hau Giang (Table 3.5).The experiment was carried out from January 2012 to January 2013

to diagnose timing for nitrogen application by LCC technique

Table 3.5: Treatment of nitrogen application timing

Treatment Nitrogen application timing (Day after cultivation)

10-20 60 90 120 150 PPB-1 1/5 1/5 1/5 1/5 1/5

4.1 Activity 1: Survey on current sugarcane farming and fertilizer application in the research areas

In Cu Lao Dung, most farmers applied nitrogen fertilizer atlevel of 250-300 kgN/ha (36.1%) and 300-350 kgN/ha (31.1%).Similarly, farmers in Long My used nitrogen fertilizer at level of300-350 kgN/ha (34.5%) For phosphorus fertilizer, common dosagewere 100-150 kgP2O5 (37.7%) in Cu Lao Dung whereas in Long Mymost cases were below 100 kgP2O5 Farmers payed less attention onpotassium application in both of study sites According to NguyenHuy Uoc (2001) it is necessary to apply potassium fertilizer at 140-

200 kgK2O/ha to reach 70-80 tons/ha sugarcane and sugarconcentration above 10 CCS

On average, at household level sugarcane yield were 158 tons/

ha in Cu Lao Dung and 135 tons/ha in Long My if farmers appliedNPK sufficiently

4.2 Activity 2 Study effects of fertilizers on sugarcane growth, NPK uptake, and yield

4.2.1 Effects of nutrient omission application in combination with sugarcane pressmud use on growth and development of sugarcane

Nitrogen omission application (Treatment PK) resulted inplant height, diameter, and density lower than nitrogen applicationtreatments (NPK, NK, NP) at 40, 120, 150, 210 and 330 days aftercultivation However, phosphorus omission application (TreatmentNK) and potassium omission (Treatment NP) such above yieldparameters were neglibigle decrease The efficiency of sugarcanepressmud application increased the stalk height in Cu Lao Dung butnot in Long My The stalk height is an important parameter ofgrowth and yield

4.2.2 Effects of nutrient omission application in combination with sugarcane pressmud use on N, P, K uptake

* Nitrogen uptake (N)

On Cu Lao Dung and Long My, treatments of without Napplication showed that total nitrogen uptake was lower than that ofnitrogen application

Table 4.20: Effects of N, P, K omission application in combination withsugarcane pressmud on total nitrogen uptake (kgN/ha) in sugarcane CuLao Dung – Soc Trang, December 2011

Factor 40 Days after planting (DAP)120 150 210 330Inorganic

in Cu Lao Dung showed that nitrogen was high when NPK applied

in combination with sugarcane pressmud at 150 and 210 days aftercultivation, the NPK+BBM treatment had the highest nitrogenuptake (as 262.8 and 362.7 kgN/ha respectively).

Table 4.21: Effects of N, P, K omission application in combination withpressmud on total nitrogen uptake (kgN/ha) of sugarcane in acid sulfatesoils in Long My – Hau Giang, December 2011

Factor 40 Days after planting (DAP)120 150 210 330Inorganic

in Cu Lao Dung at 120 and 150 days after cultivation (Table 4.22)

Table 4.22: Effects of N, P, K omission application in combination with pressmud on total phosphorus uptake (kgP 2 O 5 /ha) of sugarcane in alluvial soils in Cu Lao Dung – Soc Trang, December 2011.

Factor 40 Days after planting (DAP)120 150 210 330Inorganic

Factor 40 Days after planting (DAP)120 150 210 330Inorganic