**2.9 Effect of rice husk biochar on SPAD value of maize at reproductive stages under drought stress**


SPAD value of maize plant was reduced significantly at drought conditions, and reduction was higher at 40% field capacity than 60% of field capacity at tasseling stage and cob initiation stage (**Table 6**).

#### **Table 5.**

*Effect of rice husk biochar on SPAD value in maize at vegetative stages under drought conditions.*


#### *Amelioration of Drought Tolerance in Maize Using Rice Husk Biochar DOI: http://dx.doi.org/10.5772/intechopen.88824*

**Table 6.**

**2.8 Effect of rice husk biochar on SPAD value of maize at vegetative stages**

At vegetative stage SPAD value of maize plant was reduced significantly at drought stress conditions. SPAD value varied with different doses of biochar under

when no biochar was applied. Under 60% of field capacity, highest SPAD value (30.5) was found when biochar was applied at 20 t/ha, and it was lowest (23.7) when no biochar was applied. Under 40% of field capacity, highest SPAD value (29.5) was found when biochar was applied at 20 t/ha, and it was lowest (20.4) when no biochar was applied. At the 10th leaf stage of maize after under control condition, highest SPAD value (33.3) was found when biochar was applied at 20 t/ha, and it was lowest (29.3) when no biochar was applied. Under 60% of field capacity, highest SPAD value (30.2) was found when biochar was applied at 20 t/ha, and it was lowest (29.3) when no biochar was applied. Under 40% of field capacity, highest SPAD value (29.8) was found when biochar was applied at 20 t/ha and at 5 t/ha (29.4), and it was lowest (29.0) when no biochar was applied. At the 14th leaf stage of maize after under control condition, highest SPAD value (35.3) was found when biochar was applied at 20 t/ha, and it was lowest (29.5) when no biochar was applied. Under 60% of field capacity, highest SPAD value (32.0) was found when biochar was applied at 20 t/ha, and it was lowest (27.7) when no biochar was applied. Under 40% of field capacity, highest SPAD value (31.8) was found when biochar was applied at 20 t/ha, and it was lowest (27.2) when no biochar was applied. It indicates that the longer the exposure to drought stress, the higher the decreases of the SPAD value. The decrease of SPAD reading under drought conditions is reported by [36]. [37] showed that biochar may alleviate

**2.9 Effect of rice husk biochar on SPAD value of maize at reproductive stages**

SPAD value of maize plant was reduced significantly at drought conditions, and reduction was higher at 40% field capacity than 60% of field capacity at tasseling

**6th leaf stage 10th leaf stage 14th leaf stage**

**40% of FC**

**Control 60% of FC**

d

**40% of FC**

31.8b– d

**Control 60% of FC**

0 25.3c–e 23.7e 20.4f 30.4cd 29.3ef 29.0f 29.5de 27.7e 27.2e 5 27.5bc 25.2de 24.4de 30.7c 29.9de 29.4ef 33.0a–c 29.9b–e 28.9de 10 29.5ab 26.4cd 26.2cd 32.0b 30.0cd 29.7d–f 33.3ab 31.1bd 29.7c–e

20 30.7a 30.5a 29.5ab 33.3a 30.2cd 29.8d–f 35.3a 32.0a–

CV (%) 5.0 1.6 6.6

*Effect of rice husk biochar on SPAD value in maize at vegetative stages under drought conditions.*

At the 6th leaf stage of maize after under control condition, highest SPAD value

, and it was lowest (25.3)

**under drought stress**

*Maize - Production and Use*

drought conditions (**Table 5**).

(30.7) was found when biochar was applied at 20 t ha<sup>1</sup>

water stress in plants and increased SPAD value.

**under drought stress**

**Biochar doses (t/ha)**

**Table 5.**

**66**

stage and cob initiation stage (**Table 6**).

**Control 60% of FC**

*Figure having similar letter did not vary significantly.*

**40% of FC**

*Effect of rice husk biochar on SPAD value in maize at reproductive stages under drought conditions.*

When biochar was applied at different doses, SPAD value was increased. At tasseling stage of maize under control condition (80% of FC), 60% of field capacity, and 40% of field capacity, highest SPAD values were 33.5, 31.2, and 30.7, respectively, when biochar was applied at 20 t/ha, and lowest SPAD values were 30.2, 28.0, and 27.8, respectively, when no biochar was applied. At cob initiation stage of maize under control condition (80% of FC), 60% of field capacity, and 40% of field capacity, highest SPAD values were 31.3, 31.0, and 30.7, respectively, when biochar was applied at 20 t/ha, and lowest SPAD values were 28.2, 27.6, and 27.1, respectively, when no biochar was applied. Similar result was reported by Mannan et al. (2016) in soybean plant under salinity stress due to poultry litter biochar. With increasing drought stress levels, SPAD readings were decreased [38]. [39] reported biochar increased soil moisture level and maize yield.
