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Table 1. Comparative effect of simulated vs. field solarization on concentrations of soluble mineral nutrients in two soils

Soil Type
Treatment¹		 NH4-N
(?g/g)		 NO3-N
(?g/g)		 NH4-+NO3-N
(?g/g)		 P
(?g/g)		 K
(?g/g) 		Ca+Mg
(me/l)
Loamy Sand  
Heated
(moist soil)		            
0.1a² 15.0a 15.1a 7.4a 90a 6.3a
Control
(moist soil)³		  
0.1a 7.5b 7.6b 7.7a 96ab 4.0b
Control
(dry soil)		  
1.5b 0.9c 2.4c 6.3 100ab 2.5c
Solarized
(6 wk)4		            
5.9c 11.1ab 17.0a 7.4a 108b 4.3b
Silty Clay  
Heated
(moist soil) 		           
33.0b 35.7a 68.7b 20.7a 448a 7.2a
Control
(moist soil)		            
0.2c 15.1b 15.4c 16.5a 444a 3.1b
Control
(dry soil)		            
7.4c 7.9b 15.3c 13.0a 426a 2.8b
Solarized
(6 wk) 		           
73.5a 33.9a 107.4a 19.0a 428a 7.2a


1 Soil moistened to cat field capacity and incubated in polyethelene bags for four weeks. Incubator diurnal heating regime: high 45°C; low 28ºC.

2 Values within columns followed by different letters are different at (P<0.05) according to Duncan s Multiple Range Test.

3 Soil prepared as for heated samples but incubated for four weeks in darkness at ambient air temp. (ca. 20-24ºC).

4 Reference values from concurrent field experiment (see reference No. 7).

Table 2. In vitro effects of ammonium phosphate fertilization and soil heating on galling of tomato roots by Meloidogyne incognita and numbers of Pythium ultimum

Treatment M. incognita P. ultimum
and dosage Gall rating¹ cfu/g soil
100 mg/1 2.0 8.1
100 mg/1 + Heat 0.8 4.5
200 mg/1 1.0 8.3
200 mg/1 + Heat 0.3 3.6
300 mg/1 0.9 9.5
300 mg/1 + Heat 0.2 5.1
400 mg/1 0.7 4.8
400 mg/1 + Heat 0.0 6.0
Control 3.5 17.0
Heat only 1.8 5.7
LSD 0.7 8.1
Factorial ANOVA  
Fertilizer 0.01² NS
Heat 0.01 0.05
Fertilizer Heat NS³ NS


1 Based upon 0-4 rating scale.
2 Significance level.
3 NS = no significant difference.

Table 3. In vitro effect of amending soil with composted chicken manure' and/or soil heating² on numbers (cfu) of Pythium sp.

Treatment
manure dosage		 cfu Pythium sp./g soil
Control 14.4a³
Heat only 12.0b
2 690 kg/ha 9.6b
5 381 kg/ha 1.1c
2 690 kg/ha + Heat 1.8c
5 381 kg/ha + Heat 0 c


1 Containing 3 280 mg NH4-N/kg.
2 Three day incubation. Diurnal healing regime: 42ºC high; 18°C low.
3 Values within columns followed by different letters are different at P<0.05 according to Duncan's Multiple Range Test.

Table 4. Effect of ammonia-based fertilizers and/or solarization (Sol) on soil N and pH levels¹

  Loam soil Fine sandy loam soil
Kjeldahl-N
(m g/g)		 NH4 -N
(m g/g)		 NO3-N
(m g/g)		 NH4+NO3-N
(m g/g)		 pH Kjeldahl-N
(m g/g)		 NH4-N
(m g/g)		 NO3-NH
(m g/g)		 H4+NO3-N
(m g/g)		 pH
Pre-Treatment 810 8 24 32 7.0 510 8 12 20 7.1
Post-Treatment
Control		  
1 027 6 32 38 7.0 608 5 14 19 7.1
Sol 945 5 50 65 7.1 595 8 41 49 6.7
Aqua ammonia 1 070 5 26 31 7.1 788 5 22 27 6.9
Aqua ammonia
+Sol		  
1 027 30 38 68 7.1 735 11 31 42 6.9
Urea 945 7 28 35 7.0 735 10 53 63 6.7
Urea + Sol 1 027 19 57 76 6.8 773 31 104 135 6.7
Ammonium
sulphate		  
1 138 58 74 132 6.6 788 29 53 82 6.6
Ammonium
sulphate+Sol 		 
1 095 64 39 103 6 8 735 14 39 53 6.7
Ammonium
phosphate		  
985 17 35 52 6.9 713 28 39 67 6.8
Ammonium
phosphate
+Sol		  
1 027 56 42 98 6.8 595 28 34 62 6.9


1 Fertilizer were applied at 305 kg N/ha, and soil was solarized for 3.7 weeks.

Table 5. Populations of Pythium ultimum and Verticillium dahliae in soil treated with ammonia-based fertilizers and/or solarization (Sol)¹

  Loam soil Fine sandy loam soil
  P. ultimum² V dahliae P. ultimum V. dahliae
Aqua ammonia 131.2 5.5 38.3 17.4
Aqua ammonia + Sol 34.8 0.1 14.8 5.2
Urea 101.7 1.6 39.2 23.0
Urea + Sol 18.8 0 5.2 5.7
Ammonium sulphate 117.8 3.0 41.8 0.5
Ammonium sulphate  
+ Sol 46.9 0 7.0 0
Ammonium phosphate 150.0 8.9 48.8 14.0
Ammonium phosphate  
+ Sol 40.2 0 12.2 0.4
Non-treated Control 150.0 9.5 66.1 19.2
Sol 29.5 0.1 7.0 0
LSD 32.5 3.6 28.3 13.1
Factorial analysis for variance  
Fertilizers 0.053 0.01 NS NS
Sol 0.01 0.01 0.01 0.01
Fertilizers³ Sol4 NS 0.01 NS NS


1 Fertilizers were applied at 305 kg N/ha.
2 Populations are colony-forming units (cfu)/g of oven-dried soil at 0.15 cm soil depth
3 P<0.05 or 0.01; NS = no significant differences.
4 Interaction of treatments.

Table 6. Fresh market tomato (Lycopersicon esculentum "Early Pak 7") growth in soil treated with ammonia-based fertilizers and/or solarization (Sol)

  Loam soil Fine sandy loam soil
Soil
Treat-
ment¹		 Number
of fruit²		 Fruit
fresh
wt.		 Vegetative
fresh wt.		 Number
of fruit		 Fruit
fresh
wt.		 Vegetative
fresh wt.
  (g) (g)   (g) (g)
Aqua ammonia 5.9 90.8 604 22.7 398.3 1386
Aqua ammonia
+ Sol		  
14.0 210.4 1102 30.5 493.6 1384
Urea 8.7 151.8 538 26.0 490.6 1130
Urea+ Sol 14.5 206.4 1 080 30.7 605.0 1246
Ammonium
Sulphate		  
12.3 175.1 690 22.6 404.8 1160
Ammonium
Sulphate
+ Sol		  
21.4 382.6 1 582 32.3 552.0 1660
Ammonium
Phosphate		  
18.5 321.5 1 162 27.9 359.7 1754
Ammonium
Phosphate
+ Sol		  
26.1 502.7 1 668 28.3 533.0 1766
Non-treated
Control		  
11.7 132.1 638 22.4 360.3 1180
Sol 15.0 215.7 1 078 33.5 574.4 1448
LSD 8.0 171.9 437 11.9 247.6 670
Factorial analysis of variance  
Fertilizers 0.013 0.01 0.01 NS NS NS
Sol 0.01 0.01 0.01 0.01 0.01 NS
Fertilizers³
Sol4 		 
NS NS NS NS NS NS


1 All fertilizers were applied at 305 kg N/ha.
2 All values are given on a per-plant basis.
3 P = 0.05 or 0.01; NS = no significant differences.
4 Interaction of treatments.

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