The impact of biochar on soil health and cotton yield in an irrigated and non- irrigated cropland in West Texas

Globally, semiarid regions are facing challenges from climate extremes and deteriorating soil health. Biochar incorporation into soil is a promising solution to address both, because of its ability to aid in carbon sequestration and improve soil health properties. I conducted a full-factorial field experiment in semiarid Lubbock, Texas, centrally located in a cotton growing region that produces 60% of Texas cotton and 25% of the nation’s cotton. I examined whether biochar effects were different in irrigated versus dryland cotton fields. I used two types of biochar, one made from pinewood (PB), and another made from biosolids (BB) to determine which of the two increased soil organic matter, microbial biomass, soil moisture, soil CO flux (respiration), nutrients (N, P and K) cotton yield and plant aboveground biomass the most. Pinewood biochar has been shown to make plants more resilient in drought prone regions while biosolids biochar is rich in soil organic matter. Both biochar types were applied at a rate of 40t/ha. Of all variables measured, I found that biochar increased soil organic matter (SOM) (BB alone), soil Phosphorus (both BB and PB) and soil moisture (PB alone). Compared to the control, SOM was 9.5% higher in plots with BB. Soil P was 38% higher in plots with BB and 14% higher in plots with PB. Soil moisture was 16% higher in plots with PB. Irrigation did not affect any of the variables. Since the effect of biochar on most variables is not always seen in the first year, my findings suggest that we would need a longer experimental time period (>1 year) to understand the various conditions under which biochar might positively or negatively impact soil health variables and crop growth. This knowledge would help growers and scientists make informed decisions about using biochar amendment to combat the negative effects climate change on agricultural sustainability.

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