Combined effects of planting patterns and mowing time on different organs and soil stoichiometry of Cyperus esculentus in desert oasis transition zone.

There are many different planting methods for crops, however it is very important to improve the distribution ratio of elements in different organs of crops. Therefore, to understand the effect of different planting patterns on crop element balance, we selected Cyperus esculentus continuous cropping (CC) and C. esculentus - wheat rotation cropping (RC). The leaves, tubers, roots, and soil samples were taken at the mowing time (August 1st, on the 81st day after seed sowing; August 24th, on the 105th day after seed sowing; September 16th, on the 128th day after seed sowing). Results showed that CC and RC had significant effects on soil SO42- and Cl-. With the mowing time, the relative abundance of TN (total nitrogen) in tubers showed an increasing trend, the relative richness of TN in roots decreased, and the relative content of TN in leaves showed no change in the trend under the two planting modes. CC significantly increased the TN/TP (total phosphorus) of leaves, roots, and tubers. However, RC significantly increased the AN (available nitrogen)/AP (available phosphorus) of soil. The random forest analysis (RF) showed that abiotic factors contributed the most to TN/TK (total potassium) of roots, followed by TN/TK of tubers and TP/TK of roots. We found that abiotic factors had no significant impact on TP/TK of leaves and TN/TP of tubers. As expected, different planting patterns alter the plant's N (nitrogen)/P (phosphorus)/K (potassium), which in turn may modify N and P conservation strategies.

Phosphorous Supplementation Alleviates Drought-Induced Physio-Biochemical Damages in Calligonum mongolicum.

Calligonum mongolicum is a phreatophyte playing an important role in sand dune fixation, but little is known about its responses to drought and P fertilization. In the present study, we performed a pot experiment to investigate the effects of P fertilization under drought or well-watered conditions on multiple morpho-physio-biochemical attributes of C. mongolicum seedlings. Drought stress leads to a higher production of hydrogen peroxide (H2O2) and malondialdehyde (MDA), leading to impaired growth and metabolism. However, C. mongolicum exhibited effective drought tolerance strategies, including a higher accumulation of soluble sugars, starch, soluble protein, proline, and significantly higheractivities of peroxidase (POD) and catalase (CAT) enzymes. P fertilization increased the productivity of drought-stressed seedlings by increasing their growth, assimilative shoots relative water content, photosynthetic pigments, osmolytes accumulation, mineral nutrition, N assimilation, and reduced lipid peroxidation. Our findings suggest the presence of soil high P depletion and C. mongolicum high P requirements during the initial growth stage. Thus, P can be utilized as a fertilizer to enhance the growth and productivity of Calligonum vegetation and to reduce the fragility of the hyper-arid desert of Taklamakan in the context of future climate change.