A long-term field experiment was carried out (since 2008) for evaluating the effects of different substitution rates of inorganic nitrogen (N) fertilizer by green manure (GM) on yield stability and N balance under double rice cropping system. Treatments included, (1) N0 (no N fertilizer and no green manure); (2) N100 (recommended rate of N fertilizer and no green manure); (3) N100-M (recommended rate of N fertilizer and green manure); (4) N80-M (80% of recommended N fertilizer and green manure); (5) N60-M (60% of recommended N fertilizer and green manure); and (6) M (green manure without N fertilization). Results showed that, among all treatments, annual crop yield under N80-M treatment was highest. Crop yield did not show significant differences between N100-M and N80-M treatments. Substitution of different N fertilizer rates by GM reduced the yield variability index. Compared to the N0 treatment, yield variability index of early rice under N100-M, N80-M, and N60-M treatments was decreased by 11%, 26%, and 36%, respectively. Compared to the N0 treatment, yield variability index of late rice was decreased by 12%, 38%, 49%, 47%, and 24% under the N100, N100-M, N80-M, N60-M, and M treatments, respectively. During period of 2009–2013 and 2014–2018, nitrogen recovery efficiency (NRE) was highest under N80-M treatment and N balance was highest under N100 treatment. NRE of all treatments with GM was increased over the time from 2009–2013 to 2014–2018. All treatments with GM showed increasing trend of SOC over the years. Substitution of N fertilizer by GM also increased C inputs and soil C:N ratio compared to the N100 and N0 treatments. Boosted regression model indicated that C input, N uptake and AN were most influencing factors of crop yield. Thus, we concluded that N fertilization rates should be reduced by 20% under GM rotation to attain high yield stability of double rice cropping system through increasing NRE and C inputs.
Soybean is highly demanded by a continuously growing human population. However, increasing soybean yield is a major challenge. FRUITFULL ( FUL ), a MADS-box transcription factor, plays important roles in multiple developmental processes, especially fruit and pod development, which are crucial for soybean yield formation. However, the functions of its homologs in soybean are not clear. Here, through haplotypes analysis, we found that haplotypes H02 of the soybean homolog GmFULa ( GmFULa-H02 ) is dominant in cultivated soybeans, suggesting that GmFULa-H02 was highly selected during domestication and varietal improvement of soybean. Interestingly, transgenic overexpression of GmFULa enhanced vegetative growth with more biomass accumulated and ultimately increased the yield but without affecting the plant height or changing the flowering time and maturity, indicating that it enhances the efficiency of dry matter accumulation. It also promoted the yield factors like branch number, pod number and 100-seed weight, which ultimately increased the yield. It increased the palisade tissue cell number and the chlorophyll content to promote photosynthesis and increase the soluble sugar content in leaves and fresh seeds. Furthermore, GmFULa were found to be sublocalized in the nucleus and positively regulate sucrose synthases ( SUSs ) and sucrose transporters ( SUTs ) by binding with the conserved CArG boxes in their promoters. Overall, these results showed GmFULa promotes the capacity of assimilation and the transport of the resultant assimilates to increase yield, and provided insights into the link between GmFULa and sucrose synthesis with transport related molecular pathways that control seed yield.
Soil acidification is one of the major soil degradation phenomenon in
tropical and subtropical region, which cause reductions in soil
fertility, particularly potassium (K), and declines in crop yield.
However, it remains unclear whether and how the status of K in soils and
crops changes with the application of lime to alleviate soil
acidification. Six treatments of long-term experiments (started 1990) in
subtropical region were carried out. Regardless of fertilization regime,
lime addition markedly increased grain and straw yields compared to
those yields without lime application. Lime addition also led to
significant decreases in the apparent K balances compared to soils
without lime application. The agronomic K efficiency and partial factor
productivity of K fertilizer both significantly increased after lime
application. Lime addition reduced the soil exchangeable K (EK) content
and stock, while increased soil non-exchangeable K (NEK) content and
stock. Redundancy analysis showed that K input, lime, pH, and
exchangeable calcium all significantly affected the K in soil and crops.
Path analysis showed that lime indirectly influenced soil K (EK and NEK)
by directly affecting soil pH, exchangeable calcium, K uptake and
apparent K balances. These results suggest that lime addition is a
viable strategy for improving crop yields and K fertilizer efficiency in
degraded soils caused by acidification. Lime significant increased K
uptake which lead to decreased soil EK content and stock. Additional,
lime also increased soil NEK content and stock which was regulated by
soil pH, exchangeable calcium, and crop growth.
The sustainability of food production systems requires accurate assessments of the combined impacts of climate change and soil fertility on crop yield. However, a knowledge gap remains regarding the interactions of climate and soil fertility for the determination of crop yield and sustainability. For this study, we investigated how climate and soil fertility affected maize yield and its sustainability over a 30‐year experiment on red soil. Seven fertilization treatments were selected (CK (no fertilizer), N (chemical nitrogen), NP (chemical nitrogen and phosphorus), NK (chemical nitrogen and potassium), NPK, M (pig manure), and NPKM (NPK and M)). The link between grain yield and the sustainability yield index (SYI) increased exponentially (p < 0.001). Manure (M and NPKM) improved the concentrations of soil nutrients considerably compared to chemical fertilizer treatments (N, NP, NK, and NPK). The explanatory rates of selected climatic and soil parameters for grain yield and its SYI varied from 56.6% to 66.9%. Soil available nutrients (AP and AK) and total nutrients (TN and TP) regulated grain yield and the SYI at low and high soil fertility, respectively. Redundancy analysis showed a negative correlation between temperature throughout the maize growing season, grain yield, and the SYI, excluding the NPKM treatment. Correlations between temperature, grain yield, and the SYI were reduced as soil fertility increased. Climate (44.0%) and nutrient inputs (40.2%) under chemical and manure fertilization contributed the most to the observed yield. Path analysis explained 68% and 77% of the variations in grain yield under chemical fertilizers and manure treatments, respectively. Additionally, the results suggested that as air temperatures are predicted to rise early maize should be planted earlier and late maize should be planted later to optimize grain yield. Together, this study emphasized that improving soil quality and adjusting planting schedules in agricultural management practices can attenuate the negative impact of climate warming on grain yield sustainable production in the global subtropical regions.
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