Abstract:
Drought is an environmental stress that impact on plant growth, crop productivity and nutrients availability. Phosphorus is easily to fixed in the soil and phosphorus availability may be related on soil moisture. This study aims to investigate the effects of drought stress and arbuscular mycorrhizal fungi (AMF) addition on phosphorus fraction and sweet corn growth. The study was divided into 2 experiments, the first experiment was the study of the influence of drought stress and the addition of arbuscular mycorrhizal fungi (AMF) on phosphorus fraction in soil. The experimental study was set in 4×2 factorial in CRD, which compared in 2 SOIl series i.e. Chon Buri soil series (low available phosphorus) and Mae Rim soil series (high available phosphorus). The first factor was soil moisture contents consisted of 0%, 25%, 50% and 75% of soil water holding capacity (WHC). The second factor was AMF addition consisted of inoculation and non- inoculation. The result showed that in the Chon Buri soil series, when moisture decreased result in decreased phosphorus in the easily available phosphorus in the form of P-loosely. Inoculation of AMF reduced content of unavailable phosphorus for plants (P-Al, P-Ca and P-apatite). Experiments in the Mae Rim soil series found that when decreased soil moisture result in decreased available phosphorus in the form of P-water and P-loosely. Inoculation of AMF reduced content of unavailable phosphorus for plants (P-Al, P-Ca and P-apatite). The second experiment was the study of the influence of drought and the addition of arbuscular mycorrhizal fungi on phosphorus fraction and the growth of sweet corn. The experimental study was set in 3×2 factorial in CRD, using Chon Buri soil series. The first factor was soil moisture contents consisted of 25%, 50% and 75% of soil WHC. The second factor was AMF addition consisted of inoculation and non-inoculation. The results of the experiment with growing plants did not find the available phosphorus, but found increased unavailability phosphorus (P-Al and P-Ca) when increased soil moisture. In addition, higher soil moisture and addition of AMF increase content of organic matter, total nitrogen, calcium and magnesium. The inoculation of AMF in the roots also increased in higher soil moisture content. The highest sweet corn growth found under 50% WHC combined with AMF inoculation condition. The both experiments showed that when moisture content increased result in increased available phosphorus form (P-water and P-loosely). In addition, under the sweet corn planting experiments did not find available phosphorus. The inoculation of AMF reduced unavailable phosphorus form (P-Al, P-Ca and P-apatite) and increase soil organic matter, total nitrogen, calcium and magnesium in the soil.