4.1 Legumes Shoot Biomass and P and K absorption
Legume shoot dry biomass production and P and K absorption (uptake) capacity showed significant difference among all treatments (Table 3). However, the common vetch was produced highest biomass production by 151.0% compared to milk vetch variety. The percentages dry biomass production of other legume treatments were increased in the following direction: smooth vetch hairy vetch and lathryus sativus i.e., 99.2, 100.3, 112.9% respectively, compared to the milk vetch. The smooth vetch had highest P and K uptake abilities by 120.4 and 171.9 % greater than milk vetch treatment. The lowest P (64.1%) and K (104.0%) uptakes were observed in lathryus sativus, when compared to the milk vetch.
Table 3
Shoot dry biomass (g/m2), and P, K absorption (g/m2) in different legumes
Legumes varieties
|
Shoot biomass (g/m2)
|
P absorption (g/m2)
|
K absorption (g/m2)
|
Smooth vetch
|
42.8 ± 1.34 a
|
0.10 ± 0.01 a
|
1.07 ± 0.04 a
|
Hairy vetch
|
43.1 ± 4.80 a
|
0.09 ± 0.01 a
|
0.83 ± 0.08 b
|
Common vetch
|
54.0 ± 4.2 a
|
0.09 ± 0.00 a
|
0.93 ± 0.09 ab
|
Lathryus sativus
|
45.8 ± 2.04 a
|
0.08 ± 0.01 b
|
0.81 ± 0.03 b
|
Milk vetch
|
21.5 ± 2.62 b
|
0.05 ± 0.01 b
|
0.39 ± 0.04 c
|
Legume species i.e., smooth vetch hairy vetch, common vetch, lathryus sativus and milk vetch, are tested. The different letter shows significant variance at (p < 0.05) by Duncan’s tests.
4.2 Non-legumes shoot biomass and P and K absorption
The dry biomass production and P, K absorption ability of non-legumes cultivar also showed significant results among all different treatments (Table 4). The greatest biomass production and P uptakes increased in rape seed by 391.3%, and 463.6% respectively, when compared to the february orchid. The minimum dry biomass ratio and P uptake were found in ryegrass compared to february orchid. While highest K uptakes among non-leguminous species was recored in chinese radish by 556.9% compared to february orchid. The minimum K uptake was seen in ryegrass i.e., 234.8% higher than february orchid.
Table 4
Shoot dry biomass (g/m2), P and K absorption (g/m2) in various non-legumes
Non-legumes Species
|
Dry biomass (g/m2)
|
P absorption (g/m2)
|
K absorption (g/m2)
|
February orchid
|
6.11 ± 1.44 c
|
0.01 ± 0.00 b
|
0.12 ± 0.04 c
|
Chinese radish
|
34.1 ± 4.02 b
|
0.07 ± 0.14 a
|
0.82 ± 0.17 a
|
Forage radish
|
34.0 ± 2.34 b
|
0.06 ± 0.01 a
|
0.73 ± 0.07 a
|
Rape seed
|
46.0 ± 3.32 a
|
0.08 ± 0.01 a
|
0.76 ± 0.08 a
|
Ryegrass
|
27.1 ± 1.06 b
|
0.03 ± 0.00 b
|
0.42 ± 0.04 b
|
Non- legumes species i.e., February orchid, Chinese radish, forage radish, rape seed and rye grass are tested. The different letter shows significant variance at (p < 0.05) by Duncan’s tests.
4.3 Effects of legumes on soil available P and K Contents
Table 5 indicates that significant changes in the soil available P and K content among all leguminous varieties. The maximum soil P content was found in common vetch by 205.7% as compared to the hairy vetch. Moreover, the lowest P content observed in smooth vetch i.e. 50% higher than hairy vetch. Whereas, higher soil available K contents developed by following order: hairy vetch, lathryus sativus, milk vetch and smooth vetch were 17.2%, 9.4%, 7.5% and 2.0% respectively, in different leguminous treatments higher than common vetch.
Table 5
Influence of various leguminous species on soil available P and available K contents (average ± standard error)
legumes varieties
|
Available P (mg/kg1)
|
Available K (mg/kg1)
|
Smooth vetch
|
11.3 ± 0.57 bc
|
110.9 ± 3.5 cd
|
Hairy vetch
|
7.50 ± 0.56 c
|
127.5 ± 2.7 a
|
Common vetch
|
22.9 ± 1.85 a
|
108.7 ± 1.2 d
|
Lathryus sativus
|
14.9 ± 1.60 b
|
118.9 ± 1.6 b
|
Milk vetch
|
15.4 ± 1.59 b
|
116.7 ± 2.2 bc
|
Legumes i.e., smooth vetch hairy vetch, common vetch, lathryus sativus and milk vetch, are tested. The different letter shows significant changes at (p < 0.05) by Duncan’s tests.
4.4 Effects of non-legumes on soil available P and K Contents
Significant modifications were observsed in soil available P and K content among all non-leguminous cultivar (Table. 4). The soil available P content in variuos non-leguminous treatments were higher than forage radish. The available soil P was developed by chinese radish and february orchid i.e.,103.4% and 72.2% repectively, compared to the forage radish. However, among all species maximum soil available K content was increased in the February orchid by 16.9% greater than the rape seed. While, lower soil K content was improve in other non- legume vareities i.e., 10.9%, 4.7%, and 2.7% in ryegrass, chinese radish, and forage radish compared to rape seed variety.
Table 6
Influence of different of non-leguminous varieties on soil available P and available k contents l (average ± standard error)
Non-legumes varieties
|
Available P (mg/kg1)
|
Available K (mg/kg1)
|
February orchid
|
21.4 ± 2.59 a
|
132.0 ± 2.1 a
|
Chinese radish
|
25.2 ± 2.36 a
|
118.2 ± 1.8 c
|
Forage radish
|
12.4 ± 0.39 b
|
116.0 ± 0.6 c
|
Rape seed
|
14.6 ± 0.12 b
|
112.9 ± 2.1 c
|
Ryegrass
|
14.4 ± 0.21 b
|
125.2 ± 2.0 b
|
Non- legumes i.e., February orchid, Chinese radish, forage radish, rape seed and rye grass are tested. The small letter specifies significant variance at (p < 0.05) by Duncan’s tests.
4.5 Influence of legumes varieties on soil Enzymes
Different leguminous crops significantly influenced (p < 0.05) on various extracellular enzymes phosphatase (Phos), N-acetylglucosaminidase (NAG), β-glucosidase (BG), and leucine-aminopeptidase (LAP) activities (Fig. 1). However, the lathryus sativus stimulated greatest phosphates activities by 150.7% compared to the hairy vetch and N-acetylglucosaminidase activities by 95.4% compared to the common vetch. The highest β-glucosidase and leucine-aminopeptidase activities were accumulated in lathyrus sativus i.e., 95.2%, and 107.6% respectively compared to the smooth vetch. While, minor variations were also found in other legumes to different enzyme activities.
4.6 Influence of non-legumes varieties on soil Enzyme
However, various non-leguminous treatments also showed significant modifications (p < 0.05) on different enzymes i.e., phosphatase (Phos), N-acetylglucosaminidase (NAG), β-glucosidase (BG), and leucine-aminopeptidase (LAP) activities (Fig. 2). The greatest phosphatase, (500.5%), β-glucosidase (424.4%), and N-acetylglucosaminidase (256.3%), enzyme activities were developed in Chinese radish compared to the rapeseed. In contrast, the highest leucine-aminopeptidase activity was recorded in ryegrass by 182.7% compared to the forage radish. While the lowest phosphatase, β-glucosidase activities were observed in forage radish only 49.7% and 37.5% higher than rape seed. The lower leucine-aminopeptidase activities were found in February orchid by 35.6% higher than the forage radish.
4.7 Interaction between plants P and K absorption and Soil Properties
The Pearson correlation (r) analysis demonstrated that plant P and K significantly correlates with soil properties (Table 7). The plant P absorption significantly related with soil ammonium (NO3−) and available K, (r = 0.400**, 0.333*) respectively, while plant K uptake also showed a significant positive correlation with soil ammonium (NO3−) and soil available K (r = 0.561**, 0.546**). However, non-significant correlations were found between other soil properties and P and K uptake of plant.
Table 7
Pearson correlations (r) among nutrient (P, K) uptake and soils property
Parameters
|
K uptake
|
SOM
|
TN
|
NH4+
|
NO3-
|
AP
|
AK
|
pH
|
P uptake
|
0.926**
|
0..051
|
0.186
|
0.45
|
0.400**
|
-0.184
|
0.561**
|
-0.121
|
K uptake
|
1
|
0.105
|
0.074
|
0.011
|
0.333*
|
-0.183
|
0.546**
|
-0.156
|
SOM
|
|
1
|
-0.297
|
0.502**
|
0.236
|
0.281
|
0.025
|
-0.112
|
TN
|
|
|
1
|
-0.257
|
0.163
|
-0.229
|
-0.051
|
-0.187
|
NH4+
|
|
|
|
1
|
0.173
|
0.254
|
-0.051
|
-0.037
|
NO3−
|
|
|
|
|
1
|
-0.340*
|
0.117
|
-0.327*
|
AP
|
|
|
|
|
|
1
|
-0.084
|
-0.217
|
AK
|
|
|
|
|
|
|
1
|
-0.135
|
|
|
|
|
|
|
|
|
1
|
Note : Soil organic matter (SOM), total nitrogen (TN), ammonia (NH4+), nitrite (NO3−) available phosphorus (AP) (available potassium), and pH (soil pH)
4.8 Relationship between soil Enzymes Activities and Soil Properties
The redundancy analysis (RDA) presented that the both axes explained 26.6% and 4.8% variation for enzymes activity and soil properties (Fig. 3). Both canonical axes indicated that 53.8% and 51.1% respectively of the total differences between enzymatic activities and soil properties. The left upper corner of the second axis of RDA was correlated to the enzyme activities. The activities of soil enzymes have shown a negtive significant relationships with SOM (F = 4.2, p < 0.026), AP (F = 3.6, p < 0.04), respectively. Non-significant correlations were seen between soil enzymes and other soil properties.
4.9 Relationship among Different Species and Soil Properties
The Principal Component Analysis (PCA) indicated a clear difference among different legumes and non-legume treatments and soil properties (Fig. 3). The two PCA axes contributed 82.2% and 12.1%, respectively of the variation between legumes and non-legumes crops and soil properties. The first axis of PCA was related to the high concentration of SOM, NH4+ and available P with different species followed by legumes: common vetch, lathyrus sativus, and non-legumes included Chinese radish and february orchid. The content of total N and soil available K concentration correlated to various legume species i.e., smooth vetch, milk vetch, and non-legume included ryegrass treatments.