Substitution of inorganic fertilizers with organic manure reduces nitrate accumulation and improves quality of purslane

Abstract

<span><span style="font-family: Calibri;"><span style="font-size: medium;">Growers often apply high amounts of chemical fertilizers for vegetable production and this application contributes to concerns about nitrate levels in food. An experiment was conducted to investigate soil N amendment effects for reducing the nitrate accumulation and improving the quality of fresh purslane (<em>Portulaca oleracea</em> L.). Treatments included four levels of animal manure as follows, N-based broiler litter (T</span>_{<span style="font-size: small;">1</span>}<span style="font-size: medium;">), P-based broiler litter (T</span>_{<span style="font-size: small;">2</span>}<span style="font-size: medium;">), N-based cattle manure (T</span>_{<span style="font-size: small;">3</span>}<span style="font-size: medium;">), P-based cattle manure + urea (T</span>_{<span style="font-size: small;">4</span>}<span style="font-size: medium;">), four levels of chemical fertilizer equivalent to organic treatments, and a T</span>_{<span style="font-size: small;">0</span>}<span style="font-size: medium;"> (no fertilizer and manure). Results showed that nitrate levels of broiler litter and cattle manure treatments were significantly lower than those of chemical fertilizer treatments. The highest level of nitrate in the first harvest was recorded in the T</span>_{<span style="font-size: small;">7</span>}<span style="font-size: medium;"> treatment and higher levels were recorded in T</span>_{<span style="font-size: small;">5</span>}<span style="font-size: medium;"> and T</span>_{<span style="font-size: small;">7</span>}<span style="font-size: medium;"> treatments in the second harvest. In the first harvest, T</span>_{<span style="font-size: small;">1</span>}<span style="font-size: medium;"> and T</span>_{<span style="font-size: small;">2</span>}<span style="font-size: medium;"> treatments had higher appearance quality but in the second harvest, appearance quality of T</span>_{<span style="font-size: small;">2</span>}<span style="font-size: medium;"> and T</span>_{<span style="font-size: small;">5</span>}</span><span style="font-family: Calibri; font-size: medium;"> treatments showed a significant increase compared to the other treatments. It is concluded that organic manure application results in higher quality as compared with the inorganic fertilizer and</span></span><span style="font-size: medium;"><span><span style="font-family: Calibri;">reduces nitrate accumulation in fresh purslane. </span></span></span>