2.3. Nitrogen Profile (4th report) - Kementerian Pertanianbalittanah.litbang.pertanian.go.id/ind/dokumentasi/n-balance/N-profil… · 2.3. Nitrogen Profile (4th report) (Ladiyani

2.3. Nitrogen Profile (4th report)

(Ladiyani R. Widowati. Stefaan de Neve, D. Setyorini, Sukristiyonubowo, and Ibrahim A. Sipahutar) Abstract Nitrogen (N) is the nutrient that is most susceptible to transformations affecting plant availability. The nitrogen, which is not recovered by the crops may loss from the soil-plant system through run off, leaching, denitrification or ammonia volatilisation, causing environmental pollution. Compare to other sector, agriculture is the major contributor to nitrate contamination of groundwater. The main N source on vegetable agriculture is manure, compost, Urea, KNO3, and ZA. The aim of the research is to measure N-profile trough soil analysis of 4 soil depths (0-25; 25-50; 50-75; 75-100) every 3 weeks up to harvest time year 2006-2008 of vegetable farming system of Andisol Wonosobo, Sumowono, Kopeng, and Karang Anyar. The observation result shows that nitrogen-profile of mineral N (total N-NH4 and N-NO3) year 2006 of Andisol Wonosobo, Sumowono, Kopeng and Karang Anyar which have low bulk density very affected by amount of fertilizer applied, time of application, plant uptake, and rain intensity. At year 2007 and 2008, N-profile of the treatment of IP (Improve Practice) showed lowest N-movement compare to N-profile of FP (Farmer Practice), where in IP recommendation is consider to initial N, N-uptake, type, time and amount of fertilizer applied. Introduction

In most area of the world, nitrogen found in soil minerals is negligible (Barbarick, 2004). Nitrogen may be added to or lost from soil by a number of processes such as rainfall, legume fixation, commercial fertilizer, manure, mineralization, plant uptake, immobilization, and leaching. Nitrogen (N) is the nutrient that is most susceptible to transformations affecting plant availability. These transformations include mineralization, immobilization, nitrification and denitrification, as well as leaching and ammonia (NH4) volatilization (Petersen et al., 1998). Among the chemical fertilizers, nitrogen (N) is the most abundantly used crop nutrient. N is a major plant nutrient required for high yields of agricultural crops. Therefore, efficient use of N within agricultural production systems has been a major focus in the last decades (Oenema et al., 2005). High application rates of water and fertilizer lead to excessive leaching of NO3–N, making most of it unavailable to the plants and results in contamination of groundwater. Leaching is often the most important process of nitrogen loss from the field soils (Chowdary et al., 2004; Aulakh et al., 2000). Leaching can contribute to ground and surface water pollution problem. Loss of nitrates by leaching is undesirable from all standpoint (Barbarick, 2004). Movement of solute is strongly inter-linked with the movement of water. Agriculture is the major contributor to nitrate contamination of groundwater (Strebel et al., 1989; Fraters et al., 1998). The main N source on vegetable agriculture is manure, compost, Urea, KNO3, and ZA. The nitrogen, which is not recovered by the crops may loss from the soil-plant system through run off, leaching, denitrification or ammonia volatilisation, causing environmental pollution. Based on Stangel et al. (1985) dan Sri Rochayati et al. (1990) the lost of nitrogen through volatilization reach 70% depend on moisture content and CEC. Efficiency of nitrogen fertiliser is often low. The result study of De Datta et al. (1981) showed that nitrogen added as fertilizers only recover 10%. Craswell and Godwin (1984) reported that apparent recoveries of nitrogen fertiliser by the various crops varied from 0 to almost 100 % and most

crops recovered less than 40 % of applied N. Improper nitrogen applications in terms of quantity; time and type reduce the efficiency. N fertilizer is changed very fast from one form to others. One form of N is nitrate has character easily to leach. Nitrogen fertilizer applied in excess of crop requirements can result in accumulation of nitrate-N (NO3-N) in the soil profile (Malhi et al., 2002; Guillard et al., 1995). Nitrate leaching and contamination of ground water and surface water has became a major environmental problem in Europe, USA, China and Elsewhere because of over-application of N fertilizers and farmyard manure in rainfed areas (Di and Cameron, 2002; Zhu and Chen, 2002). Integrated use of chemical fertilizers and farmyard manure is very important to reduce the down ward movement of NO3-N into the soil profile and, subsequently, to groundwater, to maximize N uptake efficiency and crop productivity, and to minimize gaseous and leaching N losses below the root zoon. The aim of the research is to measure N-profile trough soil analysis of 4 soil depths (0-25; 25-50; 50-75; 75-100) in the period of per 3 weeks up to harvest time year 2006-2008 of vegetable farming system of Andisol Wonosobo, Sumowono, Kopeng, and Karang Anyar. In the year of 2006 and first season of 2007, location of Kopeng was less soil sampling, it was at planting and harvest time. Then starting from 2nd season of 2007 up to present was changing to Karang Anyar location which less observation. The adjustment was considered to Kopeng site has more intensive N fertilizer application compare to Karang Anyar site.

Materials and Methods

The dynamics of nitrogen was characterized by distribution of NH4–N and NO3–N in different soil layers and their changes with time and leaching loss of nitrogen. Soil samples had been collected from 4 locations times 3 farmers. Soil sampling collected every 3 weeks starting from planting time. Each location collected for four soil depth 0-25, 25-50, 50-75, and 75-100 cm. soil samples were also collected at regular intervals during the experimental periods. Maximum care was taken to minimize the contamination of samples by the soil material of overlying layers. Ten soil samples composite from each farmer had been collected from 10 beds (year 2006). Soil sample collected using auger which has depth mark. The sampling point is between two crops or in the middle of diagonal with purpose to avoid sampling the fertilizer site. At year 2007 the previous plot was divide become two plots namely IP (Improve Practice) and FP (Farmer Practice). Each treatment contains 10 beds. From 10 soil composite then make it become 3 replication where soil sample from bed 1,2,3 were mixed represent rep I, bed 4, 5, 6 as rep II, and 7, 8, 9, 10 as rep III.

Picture 1. Leek at age 2 weeks and sampling time, leek at age 2 weeks at Wobosobo site

The soil sample was placed in the plastic bag and store in the ice box, then immediately sent to Salatiga Mini laboratory and store in the freezer until reach the time to analyze mineral NH4-N and NO3-N. To avoid sample demages, it should be analyzed as soon as possible. The soil samples then had been measured for initial NH4-N+NO3-N. Nitrogen ammonium and nitrogen nitrate were extracted with 1 N KCl followed by colorimetric analysis with spectrophotometer at wavelength 636 nm for sampling year 2006, then for year 2007 and present nitrogen nitrate have been extracted with 0.01 M CaCl2 followed by colorimetric analysis with spectrophotometer UV at wavelength 210 and 270 nm.

Result and Discussion

The initial organic matter is presented in Table 1. The C-organic content of 12 farmer soil is in the range 1.5 up to 3.8 %. Four soils have C-organic content ≤ 2.0, it means have very low C-organic content. Meanwhile the value of N-organic content is in the range of 0.14 up to 0.39%. Nitrogen organic content in soil has relationship with C organic content. This data has correlation of 0,9218 from 12 locations. The organic content of 12 area is depend on the N-initial, and the history of organic fertilizer management. For example soil from Karang Anyar is has low C-organic since it lower applied organic manure compare to soil from Wonosobo which is applied high and intensive with chicken manure therefore have relative high N organic content. Observation of N-profil year 2006 and 2007

Soil nitrogen characteristic is easily change and remove from soil. This character can be observed from measuring N-profile with time. Even though some part of N (N-NH4) from fertilizer and organic matter if adsorb by surface adsorption, if it is not uptake by plan in the appropriate amount, the nitrogen will be move down by mass flow. N-profile 2006

Vegetable planting area of four locations have been managed intensively. The farmers grow vegetable continuously per year with low to high N-fertilizer application. In this report the nitrogen profile will be described generally, for example will select one case with three planting season (Wonosobo) for year 2006 and 2007. The selection of Wonosobo because this location has higher C and N organic content (Table 1), highest fertilizer application and the lowest soil bulk density.

For axample the case of Wonosobo farmers, their name’s who join to this project research are Cipto, Nurhakim and Sudarto. At the first season of year 2006 they grew leek, leek, and cabbage, respectively. All of farmer’s soils have total N-NH4 and N-NO3 < 20 ppm at 25 cm soil depth at initial. Chicken manure had been applied 15 t ha-1 at the end of soil preparation before the first soil sampling. Fertilizer which had been applied for basal application was urea 125 – 625 kg ha-1, TSP 75 – 625 kg ha-1. Then at 30-40 DAP (day after planting) farmer applied the halve rest of Urea and TSP, and added 50-75 kg NPK ha-1 which is diluted and applied as kocor to each crop. Based on the fertilizer amount and time application it can be estimated the availability at first layer (25 cm) and the movement (25-100 cm). The rain intensity of February (270 mm), March (130 mm), April (260 mm) up to May (100 mm) 2006 force the movement downward of nitrogen. For example soil of Cipto, at the planting time the total N-NH4 and N-NO3 round 8-10 ppm at soil depth 0-75 cm and near to zero at soil depth 75-100 ppm. Total mineral N at 3rd week sampling did not change much the total, this condition can be related with fast movement of N from urea and chicken manure during the first three weeks, meanwhile leek age still young (<3 weeks) which was not uptake N much. At 6th week observation, N mineral content did not much change from 3rd week. Second fertilizer application was added at 30 DAP meaning between 3rd and 6th week, it related with N content where N content increased. From the Figure 3 showed at week 9th that nitrogen already moving from layer 0-50 cm to 50-75 cm, where the N content from <25 ppm to 38 ppm. Before week 9th, the farmer still add NPK as kocor (50 DAP). At harvest time N content is categorized high, the N content at upper layer 40 ppm equal to 80 kg N ha-1, even more at lower soil depth. Nitrogen content of Cipto’s soil at harvest time still high, but when we measure at planting time for 2nd season the N content is low around 10 ppm for whole soil depth. This condition occurs because of leaching and also during soil preparation where the bench is destroyed and made the new bench by mixing the soil with soil in between the bench. At the followed N monitoring is showed the same trend, when the soil is fertilized, the N content is increase and it is moving if the plant did not uptake and rain occurred. The 2nd season is between 15 June and 28 September 2006. September is the hardest dry season where there was no rain for whole month. This condition is the answer why the N content at planting time of 3rd planting season is almost the same compare with N content at harvest time of 2nd planting season. The trend of nitrogen availability and movement is the opposite with the previous two planting season. This 3rd season is in between October 2006 up to January 2007. Highly rain intensity during December 2006 (550 mm) and January 2007 (460 mm) very affected the N availability and movement. The farmer applied 10 t manure and 1000-1250 kg Urea/ha. Almost big part of N added measured at the lower part of soil profile. For example at 9th week the N content of 50-100 cm was > 50 ppm to 75 ppm. According to Watts and Martin, 1981, in spite of the above observations it is acknowledged that zero leaching loss of NO3–N is not likely to be possible while sustaining optimal crop production.

Table 1. The initial C and N content of the soils used (2006)

Organic Matter

Farmer/Site C (%) N-total (%)

Sumarno-Sumowono 2.0 0.17

Sugengdono-Sumowono 1.9 0.19

Nasrodin-Sumowono 2.7 0.23

Sudarto-Wonosobo 5.0 0.39

Nurhakim-Wonosobo 3.8 0.34

Herman-Wonosobo 3.8 0.34

Hartatik-Karang anyar 2.6 0.23

Sumarjo-Karang anyar 1.9 0.24

Hartono-Karang anyar 1.5 0.14

Lukas-Kopeng 3.3 0.28

Ngatemin-Kopeng 2.9 0.33

Nano-Kopeng 3.5 0.34

Average 2.91 + 1.03 0.27 + 0.08

Karang Anyar

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Fig. 1. Rainfall intensity of four locations year 2006

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Fig. 2. Rainfall intensity of four locations year 2007

N-Profil of Andisol Wonosobo (2006)

Cipto/Won/I/Leek

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Fig. 3. The movement of nitrogen (NO3+NH4) through soil depth of tree planting season on Cipto’s soil, Wonosobo

Nurhakim/won/I/Leek

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Fig. 4. The movement of nitrogen (NO3+NH4) through soil depth of tree planting season

on Nurhakim’s soil, Wonosobo

Sudarto/Won/I/Cabagge

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Fig. 5. The movement of nitrogen (NO3+NH4) through soil depth of tree planting season on Sudarto’s soil, Wonosobo

N-Profil of Andisol Sumowono (2006)

Nasrodin/SMW/MT-I/Rice

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Fig. 8. The movement of nitrogen (NO3+NH4) through soil depth of tree planting season on S. Dono’s soil, Sumowono

N-Profil of Andisol Karang Anyar (2006)

Hartatik/KRA/MT-I/Leek

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Hartatik/KRA/MT-II/Potato

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Fig. 9. The movement of nitrogen (NO3+NH4) through soil depth of tree planting season on Hartatik’s soil, Karang Anyar

Hartono/KRA/MT-I/Carot

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N-Profil of Andisol Kopeng (2006)

Lukas/KPG/MT-I/Broccoli

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Ngatemin/KPG/MT-I/Broccoli

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Ngatemin/KPG/MT-II/Cabagge

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Fig. 14. The movement of nitrogen (NO3+NH4) through soil depth of tree planting season on Ngatemin’s soil, Kopeng

Observation of N-profil year 2007 Observation of N-profil year 2007 had been done of all locations. At year 2007 the previous plot of 2006 was divide become two treatments namely IP (improve fertilization) and FP (farmer practice). Out of 22 pairs (FP and IP) N-profile observations, 11 profiles showed that treatment IP show lowest N movement, 6 profiles is nearly equal, and 5 profiles was highest N movement. The lowest N profile of treatment IP due to IP is consider to N-initial, N-uptake, amount and time fertilizer application. The calculation of fertilizer applied is presented in previous Chapter (Improve Fertilization).

The clearest description of N profile is Sudarto’s soil. Farmer Sudarto at first planting season of 2007 applied manure and Urea in high amount. The amount of fertilizer of FP was : 30 tons manure, 400 kg Urea, and 500 NPK (20-20-20) for cabbage, meanwhile the fertilizer of IP was : 15 tons manure, 125 kg Urea . Rain intensity of year 2007 was higher compare to year 2006 especially at Wonosobo and Karang Anyar. The total rain 2007 was 2990.5 mm for Wonosobo and 3407.5 mm for Karang Anyar. Cabagge was planted on 27 March 2007 and harvest on 30 Jun 2007. Nitrogen profile of Sudarto’s soil was observed starting from planting time. Generally, at the initial N (N-NH4 + N-NO3) content was higher at FP, especially for layer 0-25 and 75-100 cm compare to IP. It trend followed by 3rd sampling, where the line of FP N-profile was move to the right (10-35 ppm) for 25-100 cm layer, compare to IP N-profile which move all layer to the right (10-20 ppm). At the harvest time the nitrogen profile of FP was in the range of 10-20 ppm for all layer, meanwhile the N-profile of IP is high (18 ppm) in the upper layer (0-25 cm) and low at the last three layers (< 5 ppm). The difference of N-content and movement of the layer is related with fertilizer amount, time application and rain intensity and quantity. Application of fertilizer in improper time with plant uptake will reduce fertilizer efficiency, it become worst if heavy and long rain period occurred. The N available at upper layer especially N-NO3 will leach and move to the lower layer or even move to deeper layer.

N-Profil of Andisol Wonosobo (2007)

Cipto/Won/I/Leek/FP

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Cipto/Won/II/Potato/FP

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10

20

30

40

50

60

70

80

90

100

0 50 100 150 200


Soil

Dep

th (c

m)

Planting

3rd Week

6th Week

9th Week

Harverst

Cipto/Won/III/Leek/FP

0

10

20

30

40

50

60

70

80

90

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0 50 100 150 200


Soil

Dep

th (c

m)

Planting

3rd Week

6th Week

9th Week

Harverst

Cipto/Won/I/Leek/IP

0

10

20

30

40

50

60

70

80

90

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0 50 100 150 200

N-NO3 + N-NH4 (mg/kg)So

il De

pth

(cm

)

Planting

3rd Week

6th Week

9th Week

Harverst

Cipto/Won/II/Potato/IP

0

10

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50

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0 50 100 150 200


Soi

l Dep

th (c

m) Planting

3rd Week

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9th Week

Harverst

Cipto/Won/III/Leek/IP

0

10

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60

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80

90

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0 50 100 150 200


Soi

l Dep

th (c

m)

Planting

3rd Week

6th Week

9th Week

Harverst

Fig. 15. Nitrogen profile of treatment farmer practice and Improve fertilization, at 1st , 2nd and 3rd planting season year 2007 on Cipto’s soil, Kejajar- Wonosobo

Sudarto/Won/I/Cabagge/FP

0

10

20

30

40

50

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70

80

90

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0 50 100 150


Soil

Dep

th (c

m)

Planting

3rd Week

6th Week

Harverst

Sudarto/Won/II/Potato/FP

0

10

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30

40

50

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80

90

100

0 50 100 150


Soil

Dep

th (c

m)

Planting

3rd Week

6th Week

9th Week

Harverst

Sudarto/Won/II/Potato/FP

0

10

20

30

40

50

60

70

80

90

100

0 50 100 150


Soil

Dep

th (c

m)

Planting

3rd Week

6th Week

9th Week

Harverst

Sudarto/Won/I/Cabagge/IP

0

10

20

30

40

50

60

70

80

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0 50 100 150


il D

epth

(cm

)

Planting

3rd Week

6th Week

Harverst

Sudarto/Won/II/Potato/IP

0

10

20

30

40

50

60

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80

90

100

0 50 100 150


Soil

Dep

th (c

m)

Planting

3rd Week

6th Week

9th Week

Harverst

Sudarto/Won/II/Potato/IP

0

10

20

30

40

50

60

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80

90

100

0 50 100 150


Soil

Dep

th (c

m)

Planting

3rd Week

6th Week

9th Week

Harverst

Fig 16. Nitrogen profile of treatment farmer practice and Improve practice at 1st , 2nd and

3rd planting season year 2007 on Sudarto’s soil, Wonosobo

Nurhakim/Won/MT-I/Leek/FP

0

10

20

30

40

50

60

70

80

90

100

0 50 100 150


Soil

Dep

th (c

m)

Planting

3rd Week

6th Week

Harverst

Nurhakim/Won/MT-II/Potato/FP

0

10

20

30

40

50

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70

80

90

100

0 50 100 150


Soil

Dep

th (c

m)

Planting

3rd Week

6th Week

9th Week

12th Week

Harvest

Nurhakim/Won/MT-III/FP Potato

0

10

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30

40

50

60

70

80

90

100

0 50 100 150


Soil

Dep

th (c

m)

Planting

3rd Week

6th Week

9th Week

Harvest

Nurhakim/Won/MT-I/Leek/IP

0

10

20

30

40

50

60

70

80

90

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0 50 100 150


il D

epth

(cm

)

Planting

3rd Week

6th Week

Harverst

Nurhakim/Won/MT-II/Potato/IP

0

10

20

30

40

50

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70

80

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0 50 100 150


Soi

l Dep

th (c

m)

Planting

3rd Week

6th Week

9th Week

12th Week

Harvest

Nurhakim/Won/MT-III/Potato/IP

0

10

20

30

40

50

60

70

80

90

100

0 50 100 150


Soi

l Dep

th (c

m)

Planting

3rd Week

6th Week

9th Week

Harvest

Fig. 17. Nitrogen profile of treatment farmer practice (FP) and Improve fertilization (IP) at 1st , 2nd and 3rd planting season year 2007 on Nurhakim’s soil, Wonosobo

N-Profil of Andisol Sumowono (2007)

Nasrodin/SMW/MT-I/Rice/FP

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20


Soil

Dep

th (c

m) Planting

3rd Week6th Week

9th Week

12 WeekHarverst

Nasrodin/SMW/MT-I/Rice/IP

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20


Soil

Dep

th (c

m) Planting

3rd Week6th Week

9th Week

12 WeekHarverst

Fig. 18. Nitrogen profile of treatment farmer practice and Improve practice, at 1st planting season on Nasrodin’s soil, Sumowono

S. Dono/SMW/MT-I/Rice/FP

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30N-NH4 + N-NO3 (mg/kg)

Soil

Dep

th (c

m) Planting

3rd Week

6th Week

9th Week

12 Week

Harverst

S.Dono/SMW/MT-I/Rice/IP

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30


Soil

Dep

th (c

m) Planting


Fig. 19. Nitrogen profile of treatment farmer practice and Improve practice at 1st planting season on S. Dono’s soil, Sumowono

S. Dono/SMW/MT-II/Corn/ FP

0

10

20

30

40

50

60

70

80

90

100

0 20 40 60 80 100


Soil

Dep

th (c

m) Planting


S.Dono/SMW/MT-II/Corn/IP

0

10

20

30

40

50

60

70

80

90

100

0 20 40 60 80 100


Soil

Dep

th (c

m) Planting

3rd Week6th Week12 WeekHarverst

Fig. 20. Nitrogen profile of treatment farmer practice and Improve practice at 2nd planting season on S. Dono’s soil, Sumowono

Sumarno/SMW/MT-I/Rice/FP

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20


il D

epth

(cm

) Planting3rd Week

6th Week9th Week

12 WeekHarverst

Sumarno/SMW/MT-I/Rice/IP

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20


Soil

Dep

th (c

m) Planting


Fig. 21. Nitrogen profile of treatment farmer practice and improve practice at 1st planting season on Sumarno’s soil, Sumowono

N-Profil of Andisol Karang Anyar (2007)

Hartatik/KRA/MT-I/Leek FP

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50


Soil

Dep

th (c

m)

Planting

3rd Week

6th Week

Harverst

Hartatik/KRA/MT-I/ Leek IP

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50


Soil

Dep

th (c

m)

Planting

3rd Week

6th Week

Harverst

Fig. 22. Nitrogen profile of treatment farmer practice and Improve practice, at 1st planting season on Hartatik’s soil, Karang Anyar

Hartono/KRA/MT-I/Carot/FP

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20 25


Soil

Dep

th (c

m)

Planting

6th Week

9th WeekHarverst

Hartono/KRA/MT-I/Carot/IP

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20 25N-NH4 + N-NO3 (mg/kg)

Soil

Dep

th (c

m)

Planting6th Week9th Week

Harverst

Fig. 23. Nitrogen profile of treatment farmer practice and Improve practice at 1st planting season on Hartono’s soil, Karang Anyar

Sumarjo/KRA/MT-I/Carrot/FP

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50N-NH4 + N-NO3 (mg/kg)

Soil

Dep

th (c

m)

Planting

6th Week9th Week12 Week

Harverst

Sumarjo/KRA/MT-I/Carrot/IP

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50


Soil

Dep

th (c

m)

Planting

6th Week9th Week

12 Week

Harverst

Fig. 24. Nitrogen profile of treatment farmer practice and improve practice at 1st planting season on Sumarjo’s soil, Karang Anyar

N-Profil of Andisol Kopeng (2007)

Lukas/KPG/MT-I/Broccoli FP

0

10

20

30

40

50

60

70

80

90

100

-10 10 30 50 70


Soil

Dept

h (c

m)

Planting

Harverst

Lukas/KPG/MT-I/Broccoli IP

0

10

20

30

40

50

60

70

80

90

100

-10 10 30 50 70


Soi

l Dep

th (c

m)

Planting

Harverst

Fig. 25. Nitrogen profile of treatment farmer practice and improve practice, at 1st planting season on Lukas’s soil, Kopeng

Lukas/KPG/MT-II/Leek FP

0

10

20

30

40

50

60

70

80

90

100

-10 10 30 50 70N-NH4 + N-NO3 (mg/kg)

Soil

Dep

th (c

m) Planting

3rd Week6th Week

9th Week

12th Week15th Week

Harvest

Lukas/KPG/MT-II/Leek IP

0

10

20

30

40

50

60

70

80

90

100

-10 10 30 50 70N-NH4 + N-NO3 (mg/kg)

Soil

Dep

th (c

m)

Planting3rd Week

6th Week

9th Week12th Week

15th Week

Harvest

Fig. 26. Nitrogen profile of treatment farmer practice and Improve practice at 2nd planting season on Lukas’s soil, Kopeng

Nano/KPG/MT-I/Broccoli/FP

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50 60


il D

epth

(cm

)

Planting

Harverst

Nano/KPG/MT-I/Broccoli/IP

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50 60


Soil

Dep

th (c

m)

Planting

Harverst

Fig. 27. Nitrogen profile of treatment farmer practice and Improve practice at 1st planting season on Nano’s soil, Kopeng

Nano/KPG/MT-II/Potato/FP

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50 60


Soil

Dep

th (c

m)

Planting

3rd Week

6th Week

Harverst

Nano/KPG/MT-II/Potato/IP

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50 60


Soil

Dep

th (c

m)

Planting

3rd Week

6th Week

Harvest

Fig. 28. Nitrogen profile of treatment farmer practice and improve practice at 2nd planting season on Nano’s soil, Kopeng

Ngatemin/KPG/MT-I/Broccoli/FP

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50 60


il D

epth

(cm

)

Planting

3rd Week

6th Week

9th Week

Harverst

Ngatemin/KPG/MT-I/Broccoli/IP

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50 60


Soil

Dep

th (c

m)

Planting

3rd Week

6th Week

9th Week

Harverst

Fig. 29. Nitrogen profile of treatment farmer practice and Improve practice at 1st planting season on Ngatemin’s soil, Kopeng

Ngatemin/KPG/MT-II/Potato/FP

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50 60


Soil

Dep

th (c

m)

Planting

3rd Week

6th Week

9th Week

Harverst

Ngatemin/KPG/MT-II/Potato/IP

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50 60


Soil

Dep

th (c

m)

Planting

3rd Week

6th Week

9th Week

Harverst

Fig. 30. Nitrogen profile of treatment farmer practice and Improve practice at 2nd planting season on Ngatemin’s soil, Kopeng

Observation of N-profile year 2008

Total N-profile observation at year 2008 was 12 pairs from IP and FP. Out of 12 pairs, 5 pairs of FP are higher compare to IP, then 5 pairs is nearly equal, and 2 pairs of IP are higher (Figure 30-38) . Nitrogen profile of year 2008 observation shows change of trend compare to 2007. The difference is percentage of N-profile FP was 50% at year 2007 and change to 41% at year 2008. The trend has possibility to change depend on the N-profile data of season 2 and 3 year 2008. The trend movement of N-profile is specific for each location. The factors affecting the movement namely type, rate and time of fertilizer added, rain intensity, season, plant uptake, and soil characteristic. As the case of Cipto’s soil, where the source of N of FP and IP was almost differ, but resulting almost similar movement of N-profile. The fertilizer added of FP was 35 t chicken manure, 300 kg urea/ha, and 100 kg NPK/ha (15-15-15), and IP was 15 t chicken manure and 500 kg urea/ha (applied 2 times). The reason of that is since chicken manure easily to be demineralize/decomposes resulting the release of mineral N in short time; therefore the application of 35t manure will contribute 20% from total N content (1.14%) within 3 months. The total mineral nitrogen release from chicken manure and from inorganic fertilizer of IP is almost equal to total mineral nitrogen of FP. During the first planting season of 2008, the crop of two sites were failed namely Nurhakim’s site (cabagge) and Hartatik’s site (leek). The data N-profile presented only which is measured before the occasion/incident. The plant dying was due to disease attack.

Nitrogen profile of Wonosobo soil (2008)

Cipto/Won/I/Cabbage/2008/FP

0

10

20

30

40

50

60

70

80

90

100

0 20 40 60


Soil

Dept

h (c

m)

Planting

3rd Week

6th Week

9th Week

Harverst

Cipto/Won/I/Cabbage/2008/IP

0

10

20

30

40

50

60

70

80

90

100

0 20 40 60


Soil

Dep

th (c

m)

Planting

3rd Week

6th Week

9th Week

Harverst

Fig. 30. Nitrogen profile of treatment farmer practice and improve practice at 1st planting season on Cipto’s soil, Kejajar-Wonosobo

Nurhakim/Won/I/Cabbage/2008/FP

0

10

20

30

40

50

60

70

80

90

100

0 20 40 60


il D

epth

(cm

)

3rd Week

6th Week

Nurhakim/Won/I/Cabbage/2008/IP

0

10

20

30

40

50

60

70

80

90

100

0 20 40 60


Soil

Dep

th (c

m)

3rd Week

6th Week

Fig. 31. Nitrogen profile of treatment farmer practice and improve practice at 1st planting season on Nurhakim’s soil, Kejajar-Wonosobo

Sudarto/Won/I/Cabbage/2008/FP

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50


Soil

Dep

th (c

m)

Planting

3rd Week

6th Week

9th Week

Harverst

Sudarto/Won/I/Cabbage/2008/FP

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50


Soil

Dep

th (c

m)

Planting

3rd Week

6th Week

9th Week

Harverst

Fig. 32. Nitrogen profile of treatment farmer practice and improve practice at 1st planting season on Sudarto’s soil, Kejajar-Wonosobo

Nitrogen profile of Sumowono soil

S. Dono/Sumo/I/Rice/2008/FP

0

10

20

30

40

50

60

70

80

90

100

-5 5 15 25


Soil

Dep

th (c

m)

Planting

3rd Week

6th Week

9th Week

12nd w eek

Harverst

S. Dono/Sumo/I/Rice/2008/IP

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20 25


Soil

Dep

th (c

m)

Planting

3rd Week

6th Week

9th Week

12nd w eek

Harverst

Fig. 32. Nitrogen profile of treatment farmer practice and improve practice at 1st planting season on S. Dono’s soil, Bumen-Sumowono

Nasrodin/Sumo/I/Rice/2008/FP

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20 25


Soil

Dep

th (c

m)

Planting

3rd Week

6th Week

9th Week

12nd w eek

Harverst

Nasrodin/Sumo/I/Rice/2008/IP

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20 25


Soil

Dep

th (c

m)

Planting

3rd Week

6th Week

9th Week

12nd w eek

Harverst

Fig. 33. Nitrogen profile of treatment farmer practice and improve practice at 1st planting season on Nasrodin’s soil, Bumen-Sumowono

Sumarno/Sumo/I/Rice/2008/FP

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20 25


il D

epth

(cm

)

Planting

3rd Week

6th Week

9th Week

12nd w eek

Harverst

Sumarno/Sumo/I/Rice/2008/IP

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20 25


Soil

Dep

th (c

m)

Planting

3rd Week

6th Week

9th Week

12nd w eek

Harverst

Fig. 34. Nitrogen profile of treatment farmer practice and improve practice at 1st planting season on Sumarno’s soil, Bumen-Sumowono

Nitrogen profile of Kopeng soil

Lukas/Kopeng/I/Leek/2008/FP

0

10

20

30

40

50

60

70

80

90

100

0 20 40 60 80 100 120


Soil

Dep

th (c

m)

Planting

3rd Week

6th Week

9th Week

Harverst

Lukas/Kopeng/I/Leek/2008/IP

0

10

20

30

40

50

60

70

80

90

100

0 20 40 60 80 100 120


Soil

Dep

th (c

m)

Planting

3rd Week

6th Week

9th Week

Harverst

Fig. 35. Nitrogen profile of treatment farmer practice and improve practice at 1st planting season on Lukas’s soil, Kopeng

Nano/Kopeng/I/Broccoli/2008/FP

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20


il D

epth

(cm

)

Planting

3rd Week

6th Week

Nano/Kopeng/I/Broccoli/2008/IP

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20


Soil

Dep

th (c

m)

Planting

3rd Week

6th Week

Fig. 36. Nitrogen profile of treatment farmer practice and improve practice at 1st planting season on Nano’s soil, Kopeng

Ngatemin/Kopeng/I/Leek/2008/FP

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20 25


Soil

Dep

th (c

m)

Planting

3rd Week

6th Week

Harverst

Ngatemin/Kopeng/I/Leek/2008/IP

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20 25


Soil

Dep

th (c

m)

Planting

3rd Week

6th Week

Harverst

Fig. 37. Nitrogen profile of treatment farmer practice and improve practice at 1st planting season on Ngatemin’s soil, Kopeng

Nitrogen profile of Karang Anyar soil

Hartatik/KRA/I/Leek/2008/FP

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50 60


Soil

Dep

th (c

m)

Planting

Hartatik/KRA/I/Leek/2008/IP

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50 60


Soil

Dep

th (c

m)

Planting

Fig. 38. Nitrogen profile of treatment farmer practice and improve practice at 1st planting season on Hartatik’s soil, Argoyoso-Karang Anyar

Hartono/KRA/I/Carrot/2008/FP

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50 60


Soil

Dep

th (c

m)

Planting

Harvest

Hartono/KRA/I/Carrot/2008/IP

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50 60


Soil

Dep

th (c

m)

Planting

Harvest

Fig. 38. Nitrogen profile of treatment farmer practice and improve practice at 1st planting season on Hartono’s soil, Argoyoso-Karang Anyar

Sumardjo/KRA/I/Carrot/2008/FP

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50 60


il D

epth

(cm

)

Planting

Harvest

Sumardjo/KRA/I/Carrot/2008/IP

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50 60


Soil

Dep

th (c

m)

Planting

Harvest

Fig. 38. Nitrogen profile of treatment farmer practice and improve practice at 1st planting season on Sumardjo’s soil, Argoyoso-Karang Anyar

Conclusions Nitrogen-profile of mineral N (total N-NH4 and N-NO3) year 2006 of Andisol Wonosobo, Sumowono, Kopeng and Karang Anyar which have low bulk density very affected by amount of fertilizer applied, time of application, plant uptake, and rain intensity. At year 2007 and 2008, N-profile of the treatment of IP (Improve Practice) showed lowest N-movement compare to N-profile of FP (Farmer Practice), where in IP recommendation is consider to initial N, N-uptake, type, time and amount of fertilizer applied.

References

Aulakh, M.S., Khera, T.S., Doran, J.W., Singh, K., Singh, B., 2000. Yield and nitrogen dynamics in rice-wheat system using green manure and inorganic fertilizer. Soil Sci. Soc. Am. J. 64, 1867–1876.

Barbarick, A.K. 2004. Nitrogen sources and transformation. Colorado State University, Soil and Crop Sciences.

Craswell E. T., and Godwin D. C. 1984. In Thinker P B, Lauchli A (Eds). The efficiency of nitrogen fertilizer applied to cereals grown in different climates. Advances in Plant nutrition, Preager Scientific, New York, USA.

Chowdary, V.M., Rao, N.H., Sarma, P.B.S., 2004. A coupled soil water and nitrogen balance model for flooded fields in India. Agric. Ecosyst. Environ. 103, 425–441.

Di H.J., and Cameron, K.C. 2002. Nitrate leaching in temperate agroecosystems: sources, factors and mitigation strategies. Nutr Cycl Agroecosyst 46: 237-256.

Fraters, D., Boumans, L.J.M., vanDrecht, G., de Haan, T., de Hoop,W.D., 1998. Nitrogen monitoring in groundwater in the sandy regions of the Netherlands. Environ. Pollut. 102, 479–485.

Gillard K, Griffin G.F., Allison D.W. Yamartino W.R., Rafey MM, and Pietryzk S.W. 1995. Nitrogen utilization of selected cropping systems in the U.S. Northeast. II. Soil profile nitrate distribution and accumulation. Agron J 87:199-207

Lin B., Lin J., and Li J. 1996. Changes of crop yield and soil fertility by long-term fertilization. Chinese Agriculture Science and Technology Press, Beijing, China. Pp 26-90.

Malhi SS., Solberg E.D., Izaurralde R.C., and Nyborg M. 1999. Effects of simulated erosion and amendments on grain yield and quality of wheat. Chapter 68. In: Anac D., Martin-Prevel P (eds) Improved crop quality by nutrient management. Kluwer Academic Publishers, Dordrecht, TheNetherlands, pp 297-300.

Petersen, S.O., Lind, A.-M., Sommer, S.G., 1998. Nitrogen and organic matter losses during storage of cattle and pig manure. J. Agric. Sci., Cambridge 130, 69–79

Oenema, O., Wrage, N., Velthof, G.L., Groenigen, J.W., van Dolfing, J., Kuikman, P.J., 2005. Trends in global nitrous oxide emissions from animal production systems. Nutr. Cycl. Agroecosyst. 72, 51–65.

Strebel, O., Duynisveld,W.H.M., Bottcher, J., 1989. Nitrate pollution of groundwater In Western Europe. Agric. Ecosys. Environ. 26, 189–214.

Spalding, R.F., Exner, M.E., 1993. Occurrence of nitrate in groundwater—a review. J. Environ. Qual. 22, 392–402.

Watts, D.G., Martin, D.L., 1981. Effects of water and nitrogen management on nitrogen leaching loss from sands. Trans. ASAE 24, 911–916

Wu J., Shen H., Sun J., Zhen G., Liu H., Li Y., Zhao B., and Zhang F. 2002. Effect of long-term fertilization on crop yield, fertilizer and water use efficiency. Plant Nutr Fert Sci 8:82-86.

Zhang W.L., Tian Z.X., Zhang N., and Li X.O. 1995. Investigations on effect of nitrogen fertilizer application on nitrate pollution of ground water in northern China. Plant Nutr Fert Sci 1:80-87

Zhang W.L., Tian Z.X., Zhang N., and Li X.O. 1996. Nitrate pollution of groundwater in northern China. Agric Ecosyst Environ 59:223-231

Zhu Z. L., and Chen D.L. 2002. Nitrogen fertilizer use in China-contributions to food production, impacts on the environment and best management strategis. Nutr Cycl Agroecosyst 63:117-127.

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2.3. Nitrogen Profile (4th report) - Kementerian Pertanianbalittanah.litbang.pertanian.go.id/ind/dokumentasi/n-balance/N-profil… · 2.3. Nitrogen Profile (4th report) (Ladiyani