**3. Maize response to foliar nutrition**

Amanullah et al. [30] studied the response of maize to urea spray (U0 = control, U1 = 2, U2 = 4, U3 = 6, and U4 = 8% urea) at different growth stages (T1 = V9, T2 = V12, T3 = VT, and T4 = R1 stages) assigned to subplots. It was concluded from the study that urea spray at the rate of 6% at V12 stage improves the grain yield and yield components of maize. Foliar application of nitrogen (2%) from different sources (e.g., urea, ammonium sulfate (AS), and calcium ammonium nitrate (CAN)) and its application time (15, 30, 45, and 60 days after emergence (DAE)) were studied on maize. It was concluded from the results that late foliar-N application (urea, CAN, or AS) about 1 week before tasseling up to silking could increase maize productivity in the study area [31]. Amanullah et al. [12] reported that foliar nutrient management not only applies nutrients to the hungry crops, but it could also be beneficial in terms of providing water to the thirsty crops under moisture stress condition. They conducted field experiment to investigate effects of foliar NPK (2% each) applied alone and in various combinations (N, P, K, N + P, N + K, P + K, and N + P + K) and their application time (one split at 30 and 60 days after emergence (DAE) and two equal splits at 30 + 60 DAE) on the growth and yield of maize (*Zea mays* L., cv. Azam) under moisture stress condition. It was concluded from the results that combined foliar application of the three major nutrients (N + P + K) at the rate of 1% each in two equal splits at 30 and 60 DAE increased maize productivity under moisture stress condition. In our recent study (Amanullah et al. [4]), response of dryland maize was investigated to foliar phosphorus (1, 2, and 3% P) and zinc levels (0.1, 0.2, and 0.3% Zn) and their application time (T1 = at boot stage and T2 = at silking stage). It was concluded from this study that the application of 3% foliar P + 0.3% foliar Zn at boot stage improves growth and increases maize productivity and profitability under moisture stress condition in semiarid climates.

## **4. Maize response to organic matter**

Soil organic matter (SOM) is a key indicator of soil health because of its vital functions that affect soil fertility, productivity, and the environment. Soil organic matter plays a key role in supplying plants with the nutrients they require. Organic matter improves soil physical (texture, structure, bulk density, and water-holding capacity), soil chemical (nutrient availability, cation exchange capacity, reduced aluminum toxicity, and allelopathy), and soil biological (nitrogen mineralization bacteria, dinitrogen fixation, mycorrhizae fungi, and microbial biomass) properties. SOM adsorb heavy metals in the soils, which reduce toxicity of these metals to plants and reduce their escape to ground water. SOM also adsorbs herbicides, which may inhibit contamination of surface and groundwater. Furthermore, SOM also functions as a sink to organic carbon and mitigates carbon dioxide escape to the environment. SOM stabilize soil aggregates, making soil easier to cultivate, increasing soil water-holding and buffering capacities, and releasing plant nutrients upon mineralization [32]. Adequate amount of SOM maintains soil quality (health), preserves sustainability of cropping systems, and reduces environmental pollution [33].
