Fertilization is an effective technique to improve soil fertility and increase crop yield. The long-term effects of different fertilizers on soil considerably vary. Over 38 consecutive years of different fertilization positioning experiments in a double cropping rice field of Qiyang Red Soil Experimental Station, seven different fertilization treatments including CK (no fertilization), NPK (nitrogen, phosphorus, and potassium fertilizer), M (cow manure), NPKM (nitrogen, phosphorus, and potassium with cow manure), NPM (nitrogen and phosphorus with cow manure), NKM (nitrogen and potassium with cow manure), and PKM (phosphorus and potassium with cow manure) were applied to study the effects on rice yield, soil fertility, and nutrient apparent balance in a paddy field. The results showed that the annual average yields of rice in NPKM, NPM, NKM, PKM, M, NPK and CK treatments ranged from 6 214 to 11 562 kg ha^–1. Yields under longterm organic and inorganic treatments (NPKM, NPM, NKM and PKM) were 22.58, 15.35, 10.53 and 4.41%, respectively, greater than under the NPK treatment. Soil organic carbon (SOC), total nitrogen (TN), available nitrogen (AN) and available potassium (AK) concentration with long-term organic and inorganic treatment (NPKM, NPM, NKM and PKM) were significantly higher than in inorganic fertilizer (NPK) treatments. Soil total phosphorus (TP) and available phosphorus (AP) contentration with organic fertilizer combined with inorganic N and P fertilizer treatment (NPKM, NPM and PKM) were significantly higher than with inorganic fertilizer alone (NPK treatments). The average annual rice yield (11 562 kg ha^–1), SOC (20.88 g kg^–1), TN (2.30 g kg^–1), TP (0.95 g kg^–1), TK (22.50 g kg^–1) and AP (38.94 mg kg^–1) concentrations were the highest in the NPKM treatment. The soil AN concentration (152.40 mg kg^–1) and AK contentration (151.00 mg kg^–1) were the highest in the NKM treatment. N and P application led to a surplus of nitrogen and phosphorus in the soil, but NPKM treatment effectively reduced the surplus compared with other treatments. Soils under all treatments were deficient in potassium. Correlation analysis showed that SOC, TN, AN, TP, and AP contentration was significantly correlated with rice yield; the correlation coefficients were 0.428, 0.496, 0.518, 0.501, and 0.438, respectively. This study showed that the combined application of N, P, and K with cow manure had important effects on rice yield and soil fertility, but balanced application of N, P, and K with cow manure was required.

Soil organic carbon (SOC) and nitrogen (N) are two of the most important indicators for agricultural productivity.  The primary objective of this study was to investigate the changes in SOC and N in the deep soil profile (up to 100 cm) and their relationships with crop productivity under the influence of long-term (since 1990) fertilization  in the wheat-maize cropping system.  Treatments included CK (control), NP (inorganic N and phosphorus (P) fertilizers), NPK (inorganic N, P and potassium fertilizers), NPKM (NPK plus manure), and M (manure).  Crop yield and the properties of topsoil were measured yearly from 2001 to 2009.  C and N contents were measured at five different depths in 2001 and 2009.  The results showed that wheat and maize yields decreased between 2001 and 2009 under the inorganic fertilizer (NP and NPK) treatments.  The average yield between 2001 and 2009 under the NP, NPK, NPKM, and M treatments (compared with the CK treatment) increased by 38, 115, 383, and 381%, respectively, for wheat and 348, 891, 2 738, and 1 845%, respectively, for maize.  Different long-term fertilization treatments significantly changed coarse free particulate (cfPOC), fine free particulate (ffPOC), intramicroaggregate particulate (iPOC), and mineral-associated (mSOC) organic carbon fractions.  In the experimental years of 2001 and 2009, soil fractions occurred in the following order for all treatments: mSOC>cfPOC>iPOC>ffPOC.  All fractions were higher under the manure application treatments than under the inorganic fertilization treatments.  Compared to the inorganic fertilization treatments, manure input enhanced the stocks of SOC and total N in the surface layer (0–20 cm) but decreased SOC and N in the deep soil layer (80–100 cm).  This reveals the efficiency of manure in increasing yield productivity and decreasing risk of vertical loss of nutrients, especially N, compared to inorganic fertilization treatments.  The findings provide opportunities for understanding deep soil C and N dynamics, which could help mitigate climate change impact on agricultural production and maintain soil health.

Pod shattering is an important domesticated trait which can cause great economic loss of crop yield in cultivated soybean.  In this study, we utilized two recombinant inbred line populations (RILs, CY, Huachun 2×Wayao; GB, Guizao 1×B13) to identify quantitative trait loci (QTLs) associated with pod shattering in soybean across multiple environments.  A total of 14 QTLs for pod shattering were identified in the two RIL populations, which had LOD scores ranging from 2.64 to 44.33 with phenotypic variance explanation (PVE) ranging from 1.33 to 50.85%.  One QTL qPS16-1, located on chromosome 16, included a well-known functional gene Pod dehiscence 1 (Pdh1) that was reported previously.  Ten new putative QTLs were validated in two RIL populations, and their LOD scores were between 2.55 and 4.24, explaining 1.33 to 2.60% of the phenotypic variation.  Of which four novel QTLs (qPS01-1, qPS03-2, qPS05-1, and qPS07-1) could be detected in two environments where nine genes had specific changes in gene expression.  Although the nine genes may have significant effects on pod shattering of soybean, their detailed functions still need to be further explored in the future.  The results of this study will facilitate a better understanding of the genetic basis of the pod shattering-resistant trait and benefit soybean molecular breeding for improving pod shattering resistance

Soil productivity (SP) without external fertilization influence is an important indicator for the capacity of a soil to support crop yield. However, there have been difficulties in estimating values of SPs for soils after various long-term field treatments because the treatment without external fertilization is used but is depleted in soil nutrients, leading to erroneous estimation. The objectives of this study were to estimate the change of SP across different cropping seasons using pot experiments, and to evaluate the steady SP value (which is defined by the basal contribution of soil itself to crop yield) after various longterm fertilization treatments in soils at different geographical locations. The pot experiments were conducted in Jinxian of Jiangxi Province with paddy soil, Zhengzhou of Henan Province with fluvo-aquic soil, and Gongzhuling of Jilin Province with black soils, China. Soils were collected after long-term field fertilization treatments of no fertilizer (control; CK-F), chemical fertilizer (NPK-F), and combined chemical fertilizer with manure (NPKM-F). The soils received either no fertilizer (F0) or chemical fertilizer (F1) for 3–6 cropping seasons in pots, which include CK-P (control; no fertilizer from long-term field experiments for pot experiments), NPK-P (chemical fertilizer from long-term field experiments for pot experiments), and NPKM-P (combined chemical and organic fertilizers from long-term field experiments for pot experiments). The yield data were used to calculate SP values. The initial SP values were high, but decreased rapidly until a relatively steady SP was achieved at or after about three cropping seasons for paddy and fluvo-aquic soils. The steady SP values in the third cropping season from CK-P, NPK-P, and NPKM-P treatments were 37.7, 44.1, and 50.0% in the paddy soil, 34.2, 38.1, and 50.0% in the fluvo-aquic soil, with the highest value observed in the NPKM-P treatment for all soils. However, further research is required in the black soils to incorporate more than three cropping seasons. The partial least squares path mode (PLS-PM) showed that total N (nitrogen) and C/N ratio (the ratio of soil organic carbon and total N) had positive effects on the steady SP for all three soils. These findings confirm the significance of the incorporation of manure for attaining high soil productivity. Regulation of the soil C/N ratio was the other main factor for steady SP through fertilization management.

Nitrogen (N) loss from fertilization in agricultural fields has an unavoidable negative impact on the environment and a better
understanding of the major pathways can assist in developing the best management practices. The aim of this study was
to evaluate the fate of N fertilizers applied to acidic red soil (Ferralic Cambisol) after 19 years of mineral (synthetic) and
manure fertilizer treatments under a cropping system with wheat-maize rotations. Five field treatments were examined:
control (CK), chemical nitrogen and potash fertilizer (NK), chemical nitrogen and phosphorus fertilizer (NP), chemical nitrogen,
phosphorus and potash fertilizer (NPK) and the NPK with manure (NPKM, 70% N from manure). Based on the soil
total N storage change in 0–100 cm depth, ammonia (NH3) volatilization, nitrous oxide (N₂O) emission, N plant uptake, and
the potential N leaching loss were estimated using a mass balance approach. In contrast to the NPKM, all mineral fertilizer
treatments (NK, NP and NPK) showed increased nitrate (NO₃^–-N) concentration with increasing soil depth, indicating higher
leaching potential. However, total NH3 volatilization loss was much higher in the NPKM (19.7%) than other mineral fertilizer
treatments (≤4.2%). The N₂O emissions were generally low (0.2–0.9%, the highest from the NPKM). Total gaseous loss
accounted for 1.7, 3.3, 5.1, and 21.9% for NK, NP, NPK, and NPKM treatments, respectively. Estimated N leaching loss
from the NPKM was only about 5% of the losses from mineral fertilizer treatments. All data demonstrated that manure
incorporation improved soil productivity, increased yield, and reduced potential leaching, but with significantly higher NH₃
volatilization, which could be reduced by improving the application method. This study confirms that manure incorporation is an essential strategy in N fertilization management in upland red soil cropping system.

Dissimilatory Fe(III) reduction is an important process in the geochemical cycle of iron in anoxic environment.  As the main products of dissimilatory iron reduction, the Fe(II) species accumulation could indicate the reduction ability.  The effects of different green manures on Fe(III) reduction in paddy soil were explored based on a 31-year rice-rice-winter green manure cropping experiment.  Four treatments were involved, i.e., rice-rice-milk vetch (RRV), rice-rice-rape (RRP), rice-rice-ryegrass (RRG) and rice-rice-winter fallow (RRF).  Soils were sampled at flowering stage of milk vetch and rape (S1), before transplantation (S2), at tillering (S3), jointing (S4), and mature (S5) stages of the early rice, and after the harvest of the late rice (S6).  The contents of TFe_HCl (HCl-extractable total Fe), Fe(II)_HCl (HCl-extractable Fe(II) species) and Fe(III)_HCl (HCl-extractable Fe(III) species) were measured.  The correlations among those Fe species with selected soil environmental factors and the dynamic characteristics of Fe(II)_HCl accumulation were investigated.  The results showed that TFe_HCl in RRF was significantly higher than those in the green manure treatments at most of the sampling stages.  Fe(II)_HCl increased rapidly after the incorporation of green manures in all treatments and kept rising with the growth of early rice.  Fe(II)_HCl in RRG was quite different from those in other treatments, i.e., it reached the highest at the S2 stage, then increased slowly and became the lowest one at the S4 and S5 stages.  Fe(III)_HCl showed oppositely, and Fe(II)_HCl/Fe(III)_HCl performed similarly to Fe(II)_HCl.  The maximum accumulation potential of Fe(II)_HCl was significantly higher in RRF, while the highest maximum reaction rate of Fe(II)_HCl accumulation appeared in RRG.  Significant correlations were found between the indexes of Fe(II)_HCl accumulation and soil pH, oxidation-reduction potential (Eh) and total organic acids, respectively.  In together, we found that long-term application of green manures decreased the TFe_HCl in red paddy soils, but promoted the ability of Fe(III) reduction, especially the ryegrass; Fe(II)_HCl increased along with the growth of rice and was affected by soil conditions and environmental factors, especially the water and redox ability.

On the basis of a long-term (30 years) field experiment that involved four rotation systems, rice-rice-winter fallow (RRF), rice-rice-ryegrass (RRG), rice-rice-rape (RRP), and rice-rice-milk vetch (RRV), this study described the effects of green manure on the microbial communities in the red paddy soils using 454 pyrosequencing for the 16S rRNA gene. The Chao1 richness and non-parametric Shannon’s index increased in all soil samples that received green manure treatments. The communities’ structures with the green manure applications were significantly dissimilar from that under the winter fallow. Using Metastats tests, many genera in the RRG, RRP and RRV soils were significantly different from those in the RRF soil, including a number of genera that functioned in the nitrogen and sulfur cycles. Analyses of the genera with these functions revealed the shifts in microbial ecosystem functions after long-term green manuring. Changes in the microbial communities increased the ammonium supply and decreased the soil acidification in green-manure-amended soils. Together, these data suggested powerful effects of green manure on both the microbial communities and the biogeochemical cycle driven by the shifts in bacterial functional groups.

Combined with remote sensing data and meteorological data, cold damage risk was assessed for planting area of double cropping rice (DCR) in Hunan Province, China. A new methodology of cold damage risk assessment was built that apply to grid and have clear hazard-affected body. Each station cold damage annual frequency and average annual intensity of cold damage was calculated by using 1951-2010 station daily mean temperature and simple cold damage identification index. On this basis, average annual cold damage risk index was obtained by their product. The spatial analysis models of cold damage risk index about double-season early rice (DSER) and double-season later rice (DSLR) were established respectively by the relation of average annual cold damage risk index and its geographic factors. Critical threshold of level of average annual cold damage risk index for DSER and DSLR were respectively divided by the correlative equation of cold damage annual frequency and average annual intensity of cold damage. 2001-2010 planting area of DCR, acquired by time series analysis of MOD09A1 8-d composite land surface reflectance product, was as target of assessment. The results show average annual intensity of cold damage is exponential function of cold damage annual frequency, average annual cold damage risk index is directly proportional to cold damage cumulant and cold damage annual frequency, and is inversely proportional to happen times of cold damage and the square of statistical time sequence length. Cold damage risk of DSER is higher than DSLR in Hunan Province. In the 10-yr stacking map, DCR planting in low risk area accounted for 11.92% of total extraction area, in moderate risk area accounted for 69.62%, in high risk area accounted for 18.46%. According to the cold damage risk assessment result, DCR production can be guided to reduce cold damage losses.

Adequate freshwater supply has become an issue of increasing local and international concern. Reducing water use in agriculture, which is the largest water using sector of the economy, is both important and urgent. The aim of this paper was to quantify how recent cropping pattern changes have influenced water resources in the great Beijing metropolitan area, an expanding megacity which also includes rural counties. Crop production affects blue water use through water consumption and water pollution, the latter assessed here using a critical dilution method. From 1990 to 2010, the total blue water used by crop production declined due to a decrease in overall cropped area, initially in response to local government policies favouring urban development. However, the average blue water use per hectare increased from 2 112 m3 ha-1 yr-1 in 1990 to 2 764 m3 ha-1 yr-1 in 2003, largely as the result of a transition from cereal to vegetable crops, and in particular an increase in intensively managed plastic and glass covered vegetable production systems. Current policies aim to conserve agricultural land, in the interests of food security, and to stimulate cereal production systems with higher ecosystem services provision. As such, in 2010 the average blue water use was 2 425 m3 ha-1 yr-1. These results demonstrate that cropping pattern changes in peri-urban regions and rural communities surrounding the Beijing metropolitan area can have a substantial impact on water resources. They also highlight the tradeoffs between food production and urban and industrial water supply and the need for integrated policy development.

A long-term field experiment was established to determine the influence of mineral fertilizer and organic manure on soil fertility. A tract of red soil (Ferralic Cambisol) in Qiyang Red Soil Experimental Station (Qiyang County, Hunan Province, China) was fertilized beginning in 1990 and N2O and CO2 were examined during the maize and wheat growth season of 2007-2008. The study involved five treatments: organic manure (NPKM), fertilizer NPK (NPK), fertilizer NP (NP), fertilizer NK (NK), and control (CK). Manured soils had higher crop biomass, organic C, and pH than soils receiving the various mineralized fertilizers indicating that long-term application of manures could efficiently prevent red soil acidification and increase crop productivity. The application of manures and fertilizers at a rate of 300 kg N ha-1 yr-1 obviously increased N2O and CO2 emissions from 0.58 kg N2O-N ha-1 yr-1 and 10 565 kg C ha-1 yr-1 in the CK treatment soil to 3.01 kg N2O-N ha-1 yr-1 and 28 663 kg C ha-1 yr-1 in the NPKM treatment. There were also obvious different effects on N2O and CO2 emissions between applying fertilizer and manure. More N2O and CO2 released during the 184-d maize growing season than the 125- d wheat growth season in the manure fertilized soils but not in mineral fertilizer treatments. N2O emission was significantly affected by soil moisture only during the wheat growing season, and CO2 emission was affected by soil temperature only in CK and NP treatment during the wheat and maize growing season. In sum, this study indicates the application of organic manure may be a preferred strategy for maintaining red soil productivity, but may result in greater N2O and CO2 emissions than treatments only with mineral fertilizer.