## 2 Materials and Methods
### Experimental Design and Treatments  
Two consecutive crops of maize (Thai Super Sweet F1 Hybrid variety) were planted, each lasting 70 d. The field trials started in April 2014 and ended in August 2014. The total experimental area was 15 m \(\times\) 12 m (180 m\({}^{2}\)). A randomized complete block design was used with seven treatments and three replications resulting in a total of 21 experimental units or plots. The experimental units or plots were one meter apart to prevent cross-contamination of treatments and other research activities. Each experimental unit was 7.5 m\({}^{2}\) in size (3 m \(\times\) 2.5 m). A total of 12 maize plants were grown in each plot with 60 cm equidistance between the plants and between the rows for each of the two consecutive crop cycles. The treatments evaluated in the field study for the two planting cycles were as follows:  
**T0:**: No fertilizer application (Control);
**T1:**: 100% recommended chemical fertilizers (0.13 t ha\({}^{-1}\) urea + 0.10 t ha\({}^{-1}\) triple superphosphate (TSP) + 0.07 t ha\({}^{-1}\) muriate of potash (MOP));
**T2:**: 100% recommended chemical fertilization amended with CZ (0.13 t ha\({}^{-1}\) urea + 0.10 t ha\({}^{-1}\) TSP + 0.07 t ha\({}^{-1}\) MOP + 5 t ha\({}^{-1}\) CZ);
**T3:**: 25% reduction of recommended chemical fertilization and amendment with rice straw compost and CZ (0.09 t ha\({}^{-1}\) kg urea + 0.07 t ha\({}^{-1}\) TSP + 0.05 t ha\({}^{-1}\) MOP + 10 t ha\({}^{-1}\) compost + 5 t ha\({}^{-1}\) CZ);
**T4:**: 50% reduction of recommended chemical fertilization and amendment with rice straw compost and CZ (0.04 t ha\({}^{-1}\) urea + 0.03 t ha\({}^{-1}\) TSP + 0.02 t ha\({}^{-1}\) MOP + 15 t ha\({}^{-1}\) compost + 5 t ha\({}^{-1}\) CZ); \begin{table}
\begin{tabular}{c c c} \hline \hline
**Parameters** & **Mean Value (\(\pm\)Standard Error)** & **Standard Data Range \({}^{\dagger\dagger}\)** \\ \hline CEC (\(\text{cmol}_{(+)}\) kg\({}^{-1}\)) & 9.32 (\(\pm\)0.03) & 5.89 \\ pHwater & 4.25 (\(\pm\)0.05) & 4.7–5 \\ Exchangeable calcium (\(\text{cmol}_{(+)}\) kg\({}^{-1}\)) & 0.82 (\(\pm\)0.008) & 0.05 \\ Exchangeable magnesium (\(\text{cmol}_{(+)}\) kg\({}^{-1}\)) & 0.53 (\(\pm\)0.05) & \textless{}0.01 \\ Exchangeable potassium (\(\text{cmol}_{(+)}\) kg\({}^{-1}\)) & 0.36 (\(\pm\)0.02) & \textless{}0.09 \\ Total nitrogen (\%) & 0.15 (\(\pm\)0.01) & 0.06 \\ Organic matter (\%) & 5.51 (\(\pm\)0.06) & Not determined \\ Total organic carbon (\%) & 3.20 (\(\pm\)0.09) & 1.30 \\ Total phosphorus (mg kg\({}^{-1}\)) & 0.005 (\(\pm\)0.001) & Not determined \\ Available phosphorus (mg kg\({}^{-1}\)) & 2.16 (\(\pm\)0.05) & Not determined \\ Exchangeable ammonium (mg kg\({}^{-1}\)) & 12.35 (\(\pm\)0.05) & Not determined \\ Available nitrate (mg kg\({}^{-1}\)) & 2.12 (\(\pm\)0.01) & Not determined \\ \hline \hline \end{tabular}  
\({}^{\dagger\dagger}\) Cited from [PERSON] [21].  
\end{table} 
Table 3: Some chemical characteristics of the soil used in this study. **T5:**: 25% reduction of recommended chemical fertilization and amendment with paddy husk compost and CZ (0.09 t ha\({}^{-1}\) kg urea + 0.07 t ha\({}^{-1}\) TSP + 0.05 t ha\({}^{-1}\) MOP + 10 t ha\({}^{-1}\) compost + 5 t ha\({}^{-1}\) CZ);
**T6:**: 50% reduction of recommended chemical fertilization and amendment with paddy husk compost and CZ (0.04 t ha\({}^{-1}\) urea + 0.03 t ha\({}^{-1}\) TSP + 0.02 t ha\({}^{-1}\) MOP + 15 t ha\({}^{-1}\) compost + 5 t ha\({}^{-1}\) CZ). The recommended chemical fertilizer together with rice straw compost and paddy husk compost, without CZ, were not tested in this field experiment because these treatments (recommended chemical fertilizers, rice straw compost, and paddy husk compost without CZ) were tested in a greenhouse pot trial. There were no significant effects on soil N, P, K availability as well as the N, P, K uptake, and use efficiencies [10]. The CZ and different rates of rice straw compost and paddy husk compost components of the treatments were applied before sowing the maize seeds only for the first crop.